Antimicrobial liquid compositions and their use as activators of cosmetic preservatives

Abstract

This application relates to the use of antimicrobial compositions, primarily comprising naturally derived ingredients, as preservative activators in cosmetics. Due to the selection of the components in such antimicrobial compositions, the compositions exhibit very broad compatibility with most cosmetic formulations, and in particular, can be added to these formulations without compromising their stability or requiring modification, while maintaining the transparency of the cosmetic.

Description

Technical Field

[0001] This invention relates to the field of cosmetic preservatives, and more specifically to the field of cosmetic preservative activators. Background Technology

[0002] In recent years, cosmetics have faced an increasingly difficult situation in an aspect as important as the effectiveness of the cosmetics themselves: preservatives in the microbiological sense. Cosmetics are aqueous media that promote the growth of bacteria, fungi, and yeasts. To ensure consumer safety, molecules or compounds with antibacterial and antifungal activities should be added to cosmetics. Regulations strictly define the properties of these molecules or compounds and the dosages they can be added to cosmetics; for example, Annex 5 of French Cosmetics Regulation No. 1223 / 2009, entitled "List of Preservatives Permitted for Use in Cosmetics," contains sixty authorized preservatives.

[0003] In reality, cosmetic manufacturers actually use far fewer authorized preservatives, close to fifteen. Widely recognized preservatives can even be counted on one hand. Manufacturers limit themselves to these preservatives either in anticipation of regulatory changes or to meet consumer demand for the cleanest or most natural cosmetics.

[0004] To successfully meet these consumer expectations, cosmetic manufacturers have gone even further, attempting to reduce the amount of preservatives to a minimum, even below their known minimum required dosage, and combine them with other molecules or compounds known as "preservative activators" to achieve a preservative effect. These "preservative activators" are not the preservatives listed above, but primarily possess antimicrobial activity, supplementing or enhancing the antimicrobial activity of preservatives.

[0005] Essential oils are widely known for their antibacterial and antifungal properties. Numerous patents attempt to combine them with other ingredients.

[0006] Lonza's patent WO2014 / 014416 discloses an antimicrobial composition consisting of a preservative active ingredient and a synergist of said active ingredient. The preservative active ingredient can be selected from a variety of compounds, from cinnamaldehyde to sorbic acid or benzoic acid, as well as white beech oil or lemongrass oil. The synergist can be selected from isoascorbic acid or gluconic acid, or salts thereof. For gluconic acid, its cyclic form, called gluconic acid lactone, is preferred. Lemongrass oil is cited in the application, and the antimicrobial activity data provided indicate that this essential oil does not have sufficient activity to act as a preservative or preservative activator. The application mentions various additives, including solubilizers, but does not describe their properties or usefulness in the composition or cosmetic formulation.

[0007] CleanWell's patent US6346281 proposes combining lemongrass essential oil with metal ions (such as copper sulfate), a "biosurfactant," and a solvent. The "biosurfactant" can be "BOD" or Tween-80, the latter being polyethoxylated sorbitol. The solvent can be an organic solvent such as ethanol. According to another Cleanwell patent WO2010 / 059399, a combination of thyme oil with copper ions (Cu2+) and alkyl polyglucosides yields a foaming composition that can be used to treat and prevent antibiotic-resistant bacterial infections, particularly methicillin-resistant Staphylococcus aureus strains.

[0008] Reckitt Benckiser's patent US5403587 combines thyme or lemongrass essential oil with ethoxylated fatty acids, carboxylic acid "nonyl alcohol ether-10" or sodium coconut fatty acid salts, and surfactants and organic solvents. The surfactants and organic solvents are crucial for providing compositions in a dispersible or soluble liquid form. Surfactants can be selected from anionic or amphoteric surfactants. These combinations exhibit antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.

[0009] Procter & Gamble's patent WO2008 / 126057 discloses antimicrobial compositions for oral care. These comprise mixtures of essential oils containing acyclic and cyclic compounds. Gluconic acid is suggested for its ability to chelate calcium ions on bacterial walls, which helps improve the composition's bactericidal activity. As additives, the compositions may include all surfactants, but anionic, cationic, or amphoteric surfactants are preferred. Nonionic surfactants are also mentioned, and the patent insists on using nonionic surfactants prepared by epoxide condensation, i.e., polyethoxylated nonionic surfactants.

[0010] Indusco's patent US9687002 proposes adding a microemulsion of lemongrass essential oil to water containing citric acid, lactic acid, or acetic acid as a pH buffer. The microemulsion is obtained using at least two surfactants with an HLB value between 9 and 18, and these surfactants can be nonionic. Microemulsions allow for the acquisition of stable compositions, that is, maintaining macroscopic homogeneity and transparency.

[0011] L'Oréal's patent FR3061010 discloses essential oil nanoemulsions obtained by emulsifying these essential oils in a mixture of water and a water-soluble organic solvent with a surfactant selected from anionic, nonionic, amphoteric, zwitterionic, or cationic surfactants. These nanoemulsions are prepared for topical application to treat bacterial or fungal infections. Citronella essential oil is mentioned, although it lacks antimicrobial activity. Among nonionic surfactants, alkyl polyglucosides are preferred, and particularly octanoyl / octyl glucosides, such as Oramix from Seppic. TM CG110. In the sole embodiment of this patent, Oramix TM CG110 is formulated with ten essential oils, ethanol, and water. Oramix is ​​one of them. TM The amount of CG110 used is 0.05% of the total weight of the formulation. Generally, L'Oréal's patent FR3061 010 recommends that the amount of nonionic surfactant used is less than 1% of the total weight of the nanoemulsion. It is the combination of nonionic surfactant and ethanol that allows for the preparation of nanoemulsions. This nanoemulsion state has advantages in terms of texture, softness to the touch, and transparency.

[0012] According to Nestec's food sector patent WO2012 / 072488, formulating essential oils into emulsions allows for increased effectiveness or a reduction in the amount of essential oil required. This patent uses gum arabic as an emulsifier to form an essential oil emulsion in water.

[0013] However, using essential oils as preservative activators is not simple and requires solving several technical challenges.

[0014] In fact, essential oils are water-insoluble natural extracts, renowned since ancient times for their antibacterial properties, but also for their potential sensitizing effects. This necessitates finding a balance between increasing the dosage to enhance antibacterial activity and decreasing it to avoid allergic reactions when used in cosmetics. Furthermore, the general goal is for preservative activity with the broadest possible antimicrobial spectrum to inhibit the growth or kill all microorganisms—bacteria, fungi, yeasts, and viruses. The pursuit of a balance between dosage and broad-spectrum activity often results in the use of very low doses of essential oil blends, or combinations of several essential oils with other antimicrobial active ingredients or compounds that have synergistic or enhancing effects with essential oils. This complicates the antimicrobial composition and increases the risk of harmful interactions.

[0015] Furthermore, modern cosmetics present additional challenges to the use of essential oils, namely the need to ensure their activity in cosmetic formulations containing an aqueous phase and multiple ingredients that may negatively interact with the essential oils. To exert their antibacterial activity in the aqueous phase, essential oils should be finely dispersed or dissolved in this phase. This dispersion or dissolution is typically accomplished at least by adding a solubilizing surfactant to the cosmetic formulation, and more advantageously by adding an additional water-soluble organic solvent. All classes of solubilizing surfactants have been considered in the prior art.

[0016] However, if the combination of solubilizing surfactants and essential oils exhibits antimicrobial efficacy, adding such a combination to cosmetic formulations may disrupt the stability of the formulation and, in particular, lead to phase shifts or the formation of solid particles.

[0017] Furthermore, the composition of cosmetic ingredients differs significantly from that of in vitro test culture media. In cosmetics, interactions may occur between the components of the antimicrobial composition and the cosmetic ingredients, leading to alterations or inhibition of antimicrobial activity. Therefore, it may be necessary to increase the dosage of the antimicrobial composition to restore the original antimicrobial activity.

[0018] Technical issues

[0019] Therefore, it is necessary to find a preservative activator that is composed of natural products or products of natural origin, is biodegradable, free of ethoxylated or organosilicon compounds, transparent, and can be added to cosmetics without altering the product's physicochemical properties—that is, without changing or damaging the stability of the cosmetic, or causing phase shifts or solid particle formation—and is suitable for most galen formulations. It is also necessary to develop a formulation that retains the antimicrobial properties of the activator.

[0020] Brief description of the attached figures

[0021] Other features, details, and advantages of the present invention will now be described in detail, with reference to the accompanying drawings, which are:

[0022] Figure 1

[0023] [ Figure 1 This demonstrates the effect of the antimicrobial liquid composition on Escherichia coli. Results of antimicrobial activity test for 8739.

[0024] Figure 2

[0025] [ Figure 2 This demonstrates the effect of an antimicrobial liquid composition against Candida albicans. Results of antimicrobial activity test for 10231.

[0026] Figure 3

[0027] [ Figure 3 The image shows an antimicrobial liquid composition effective against Aspergillus brasiliensis. Results of antimicrobial activity test for 16404.

[0028] Figure 4

[0029] [ Figure 4 This demonstrates the effect of an antimicrobial liquid composition against Staphylococcus aureus (Aspergillus brasiliensis). Results of antimicrobial activity test for 6538.

[0030] Figure 5

[0031] [ Figure 5 This demonstrates the effect of an antimicrobial liquid composition against Pseudomonas aeruginosa. Results of antimicrobial activity test for 9027. Summary of the Invention

[0032] The applicant states that the antimicrobial composition according to the invention allows for the activation of preservatives and enhances their antimicrobial protective effect. Indeed, when the antimicrobial composition is added in combination with preservatives to a cosmetic composition, the logarithmic reduction in the number of colony-forming units of *Pseudomonas aeruginosa*, *Escherichia coli*, *Aspergillus brasiliensis*, *Candida albicans*, and *Staphylococcus aureus* is observed compared to conventional cosmetic compositions containing only preservatives.

[0033] Therefore, the present invention relates to the use of antimicrobial liquid compositions for activating cosmetic preservatives, said antimicrobial liquid compositions comprising:

[0034] - At least one essential oil selected from the essential oils of plants in the genus Cymbopogon, such as clove, bourbon geranium, bay leaf, lemon balm, lemon balm flower, chili pepper, crown pepper, oregano, tea tree, thyme, and schénanthe.

[0035] - At least one nonionic surfactant selected from alkyl (poly)glycosides, alkyl glycosides, vegetable oil esters, nonethoxylated fatty esters of polyols, C8-C10 alkyl glycoside hybrids, and dehydrated sorbitol fatty esters, or mixtures thereof.

[0036] - At least one free form of carboxylic acid.

[0037] The present invention also relates to an antimicrobial composition comprising:

[0038] -The essential oil of one of the plants in the genus Citronella.

[0039] -Octanyl / Octanylglucoside

[0040] γ-gluconic acid,

[0041] -Sodium gluconate,

[0042] -water.

[0043] These compositions advantageously allow for the stabilization of cosmetics in which they are added without altering or compromising the stability of the cosmetics, nor causing phase shifts or the formation of solid particles. Furthermore, the antimicrobial compositions according to the invention retain their antimicrobial activity when formulated into cosmetics.

[0044] Therefore, the present invention also relates to cosmetics comprising an antimicrobial composition according to the invention and at least one preservative. Detailed Implementation

[0045] For clarity, in this application:

[0046] The expression "composed of XXX" has the same meaning as the expression "contains", that is, it defines an open composition.

[0047] - In addition to water, other components of the target antimicrobial composition of this application are sometimes sold in the form of aqueous solutions, consisting of water and one of the components. To release this water content, it may vary depending on the components and their suppliers. The mass percentage of the components other than water in the antimicrobial composition, expressed as a dry weight percentage, is the mass percentage of the dry matter of the components, in other words, the mass percentage of the dry components excluding water.

[0048] - The target antimicrobial liquid composition of this application is an aqueous composition. The amount of the antimicrobial liquid composition is expressed as a percentage of gross weight of the entire antimicrobial liquid composition (i.e., all components including water), in gross weight percentage.

[0049] This invention relates to the use of an antimicrobial liquid composition for activating cosmetic preservatives, said antimicrobial liquid composition comprising:

[0050] - At least one essential oil selected from the essential oils of plants of the genus Cymbopogon, such as clove, bourbon geranium, laurel, lemon balm, lemon balm flower, chili pepper, crown pepper, oregano, tea tree, thyme, schénanthe, or a mixture of these essential oils.

[0051] - At least one nonionic surfactant selected from alkyl (poly)glycosides, alkyl glycosides, vegetable oil esters, nonethoxylated fatty esters of polyols, C8-C10 alkyl glycoside hybrids, and dehydrated sorbitol fatty esters, or mixtures thereof.

[0052] - At least one free form of carboxylic acid.

[0053] According to another embodiment of the present invention, the present invention relates to the use of an antimicrobial liquid composition for activating a cosmetic preservative, said antimicrobial liquid composition comprising:

[0054] - At least one essential oil selected from the essential oils of plants of the genus Cymbopogon, such as clove, bourbon geranium, laurel, lemon balm, lemon balm flower, chili pepper, crown pepper, oregano, tea tree, thyme, schénanthe, or a mixture of these essential oils.

[0055] - At least one nonionic surfactant selected from alkyl (poly)glycosides

[0056] - At least one free form of carboxylic acid.

[0057] Antimicrobial activity

[0058] In the context of this invention, an antimicrobial composition is a composition having antimicrobial activity, that is, the composition is capable of slowing the growth of at least some bacteria, fungi, or yeasts, better inhibiting the growth of at least some of them and reducing their number by preventing development and proliferation, and even better, making them undetectable and completely eliminating them by killing them. Therefore, this definition encompasses slowing growth, inhibiting growth (known terms as bacteriostatic and antifungal), and lethal activity, referred to as bactericidal or fungicidal activity.

[0059] Cosmetic preservative activator

[0060] According to the invention, the antimicrobial composition is proven to be ineffective in preserving cosmetics as long as it accounts for less than 5% of the gross weight of the cosmetic, or even 2.5% of the gross weight (i.e., it cannot significantly slow down or inhibit the growth of bacteria or fungi and does not have bactericidal or fungicidal activity).

[0061] Advantageously, in combination with commonly used preservatives, the antimicrobial composition according to the invention combines its antimicrobial activity with the activity of the preservatives and enhances the activity of the preservatives. Therefore, lower doses of preservatives, combined with appropriate doses of the antimicrobial composition, can be used to successfully reduce the microbial load in cosmetics, i.e., reduce the number of colony-forming units, and even preferably stabilize the microbiological data of cosmetics according to ISO 11930:2019. Thus, the antimicrobial composition allows for an effective reduction in the amount of preservative required for cosmetic preservation, and the duration is comparable to that of conventional preservatives used at recommended doses, typically equal to the highest permissible concentration in ready-to-use cosmetics. Preservatives in cosmetics, alone or in combination, are present in the cosmetic composition and constitute approximately 1% by weight of the total weight of the composition. As shown in the examples, the antimicrobial composition according to the invention allows for a reduction in the content of preservatives (e.g., 0.4% for potassium sorbate and sodium benzoate) and the use of only one preservative.

[0062] Therefore, a preservative activator is a compound whose inherent antimicrobial activity in cosmetics is insufficient, but which enhances the antimicrobial activity of preservatives in cosmetics. "Insufficient antimicrobial activity" means that the compound cannot significantly slow the growth of bacteria, fungi, or yeasts, let alone inhibit or kill them. Therefore, a preservative activator itself cannot microbially stabilize the culture medium and thus cannot be classified as a preservative in a regulatory sense.

[0063] Therefore, combining preservatives with preservative activators allows for at least an enhancement of the antimicrobial activity of the preservative, and preferably for microbial stabilization of cosmetics. Typically, the goal is to achieve a stabilizing or enhanced effect at a lower dose of the preservative than when using preservatives alone.

[0064] Antimicrobial activity can be evaluated by any method known to those skilled in the art.

[0065] The reduction in the number of colony-forming units (µfc / mL) on days 7, 14, and 28 after microbial inoculation of cosmetics can be classified. The reduction in the number of colony-forming units is expressed as a logarithm to base 10. For example, a reduction of one logarithm corresponds to a reduction of 10^1, or 10 µfc / mL, or a reduction of two logarithms corresponds to a reduction of 10^2, or 100 µfc / mL.

[0066] Preferably, the antimicrobial activity was evaluated according to the international standard 11930:2019 entitled "ISO 11930 Cosmetics — Microbiology — Evaluation of antimicrobial protection of cosmetics". This standard specifies the methods for interpreting test data on the effectiveness of antimicrobial protection and / or microbial risk assessment in the overall evaluation process of antimicrobial protection of cosmetics. This standard can particularly classify the level of microbial protection of cosmetics, targeting major pathogens: bacteria, namely Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, and fungi, namely Candida albicans and Aspergillus brasiliensis.

[0067] According to one embodiment, when the composition is combined with a preservative, it is considered a preservative activator compared to the number of colony-forming units when the preservative is used alone. This activator can increase the reduction in the number of microbial colony-forming units present in the culture medium by at least one log, preferably at least two logs, and more preferably at least three logs.

[0068] According to one embodiment, compared to the number of colony-forming units when the preservative is used alone, the composition, when combined with the preservative, will be regarded as a preservative activator, which can increase the reduction in the number of microbial colony-forming units present in the culture medium by at least 1 log, preferably at least 2 log, and preferably at least 3 log during a period of at least 7 days, preferably at least 14 days, and preferably at least 28 days.

[0069] The target antimicrobial liquid composition of this application can be characterized as a liquid composition having preservative activating activity because it meets the previous definition of a preservative activator. Preferably, the antimicrobial liquid composition is therefore a liquid composition having preservative activating activity.

[0070] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of a preservative and, in combination with said preservative, reduces at least one log, preferably at least two logs, and preferably at least three logs, the colony-forming units of *Pseudomonas aeruginosa*, *Escherichia coli*, *Aspergillus brasiliensis*, *Candida albicans*, and *Staphylococcus aureus*.

[0071] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of a preservative, and, in combination with the preservative, reduces at least one log, preferably at least two log, and preferably at least three log colony-forming units of *Pseudomonas aeruginosa*, *Escherichia coli*, *Aspergillus brasiliensis*, *Candida albicans*, and *Staphylococcus aureus* over a period of at least 7 days, preferably at least 14 days, preferably at least 28 days.

[0072] essential oils

[0073] According to one embodiment, the antimicrobial composition comprises essential oils selected from citronella plant essential oils, clove, bourbon geranium, laurel, lemon balm, lemon balm, chili pepper, crown pepper, oregano, tea tree, thyme, schénanthe essential oils, or mixtures of these essential oils.

[0074] According to one embodiment, the essential oil is selected from the essential oil of plants in the genus *Cymbopogon*.

[0075] *Cymbopogon* is a genus of plants belonging to the Poaceae family, Panicoideae subfamily, comprising about fifty species native to tropical and subtropical regions of Africa, Asia, and Australia. They are herbaceous plants, typically perennial, rarely annual, growing in clusters or on roots, with stems (stems) ranging in length from 15 to 300 cm.

[0076] The citronella essential oil is selected from citronella essential oils rich in citral, neraldehyde, geranialdehyde, and geraniol. Preferably, the citronella essential oil is selected from citronella essential oils containing 30% by weight neraldehyde, 40% by weight geranialdehyde, and 5% by weight geraniol. These weight percentages are typically determined by chromatography.

[0077] Among the essential oils of plants in the genus *Cymbopogon*, the following can be listed:

[0078] Lemongrass (Cymbopogon citratus (DC.) Stapf), also known as West Indian lemongrass (French: lemongrass de l'ouest de l'Inde), Indian lemongrass, or Indian verbena,

[0079] - Lemongrass (Cymbopogon flexuosus Stapf.), also known as East Indian lemongrass (French: lemongrass de l'est de l'Inde),

[0080] -Cymbopogon nardus, also known as Ceylon lemongrass or Sri Lankan lemongrass,

[0081] -Cymbopogon nardus (L.) Watson, Cymbopogon nardus (L.) Rendel),

[0082] - Lemongrass (Cymbopogon schoenanthus (L.)), also known as camel grass or geranium grass,

[0083] - Cymbopogon winterianus Jowitt, also known as Java lemongrass,

[0084] - Lemongrass (Cymbopogon martinii var. sofia), also known as ginger grass,

[0085] - Martin lemongrass (Cymbopogon marrtinii var. motia., Cymbogopon maartiniiroxb.), also known as rose grass.

[0086] According to one embodiment, the citronella essential oil is selected from the essential oils of *Cymbopogon flexuosus* Stapf. and *Cymbopogon citratus* (DC.) Stapf. Most preferably, the essential oil is *Cymbopogon citratus* (Dc.) Stapf. essential oil. Typically, it is *Cymbopogon flexuosus* Stapf. and *Cymbopogon citratus* (DC.) Stapf. essential oil. It contains 30% by weight neraldehyde, 40% by weight geranialdehyde, and 5% by weight geraniol.

[0087] Examples of citronella (Cymbopogon) essential oils that can be used in the target antimicrobial compositions of this application include Elixens's trade name "Cymbopogon flexuosus". "Or the essential oil from Sri-Lanka par H. Reynaud & Fils, marketed under the name "HE Lemongrass citratus".

[0088] Oregano essential oil includes inflorescence oregano, Greek oregano, calf oregano, green oregano, and Spanish oregano.

[0089] Among thyme essential oils, wild thyme, borneol thyme, carvacrol thyme, linalool thyme, thujol thyme, and thymol thyme can be listed.

[0090] Essential oils can also be advantageously selected from those rich in citral, neraldehyde, geraniol, and geraniol.

[0091] It could be, for example, lemon balm essential oil containing about 40% geraniol and about 30% nerol in the total weight of the essential oil, or lemon balm (Melissa officinalis) essential oil.

[0092] It can also be an essential oil rich in geraniol and geranialdehyde, such as, in particular, Cymbopogonmartini essential oil, which contains geraniol, which accounts for about 80% to 85% of the total weight of the essential oil.

[0093] According to one embodiment, the essential oil contains at least one active molecule selected from the active molecules constituting Cymbopogon flexuosus and Cymbopogon citratus: citral trans isomer, named geranialdehyde or citral A, IUPAC name (E)-3,7-dimethyloctyl-2,6-dienal; citral cis isomer, named nerol or citral B, IUPAC name (Z)-3,7-dimethyloctyl-2,6-dienal; geraniol, IUPAC name (2E)-3,7-dimethyloctyl-2,6-dien-1-ol.

[0094] Therefore, according to one embodiment, the essential oil is selected from the citronella plants listed above, specifically lemon balm essential oil.

[0095] According to another embodiment, the essential oils that can be used in the target antimicrobial composition of this application may be selected from Indian thyme (also known as Indian thyme), star anise (also known as anise), basil, Chinese or Ceylon cinnamon, cardamom, Provence cypress, lemon eucalyptus, blue eucalyptus, radiata eucalyptus, black spruce, tarragon, fennel, holly, Virginia juniper, geranium, scented geranium, Bourbon geranium, ginger, clove, inula, bay leaf, redolent lavender, narrow-leaved lavender, and broad-leaved lavender containing eucalyptol. Essential oils of herbs, true lavender, hybrid lavender, super hybrid lavender, garden oregano, sweet oregano, narrow-leaved mulberry, wild mint, peppermint, lemon balm, red myrtle, orange blossom, mulberry, small-grained lime, Scots pine, ravintsare (also known as ravintsare or Madagascar camphor tree), eucalyptus rosemary, camphor rosemary, rosemary, saro, garden pinnatifida, mountain pinnatifida, schénanthe, European thyme, exotic verbena, Indian verbena, or blends of these essential oils.

[0096] Essential oils can also be rich in phenols, especially carvacrol (found in caraway oil), thymol (found in thymol thyme oil), and eugenol (found in clove oil). These phenols give essential oils containing them antifungal and bactericidal activities. More specifically, examples include oils rich in phenols, such as the essential oils of thyme (Thymus mastichina, Thymus vulgaris, Thymus zygis, Thymus thymi), Pimenta (Pimenta racemosa, Pimenta acris), Trachyspermum ammi, Eugenia caryophyllus, Satureja montana, oregano (Origanum heracleoticum, Origanum majorana, Origanum vulgare, Origanum compactum), Corydothymus capitatus, and Cinnamomum verum.

[0097] According to one embodiment, the essential oil will contain at least one active molecule selected from monoterpenoid alcohols, which are alcohols having 10 carbon atoms, preferably geraniol, linalool, thujol, myristol, terpineol, menthol, and piperine. Essential oils containing these active molecules are those of Cymbopogon martinii, Lavandula spica, Mentha piperita, Origanum majorana, and Melaleuca altemifolia.

[0098] According to one embodiment, other essential oils may be added to the target composition of this application in low amounts of at least one of phenol, monoterpene alcohols, epoxy terpenes, aromatic aldehydes, terpene aldehydes, phenylpropene, monoterpenes, and sesquiterpenes, for example, to enhance fragrance, alter odor, or affect antimicrobial activity. These oils may be selected from cedarwood oil, sweet orange oil, lemon oil, green or red citrus oil, or wintergreen oil.

[0099] The total amount of essential oil in the antimicrobial liquid composition accounts for 0.1% to 10% of the total dry weight of the antimicrobial liquid composition, preferably 0.5% to 7%, more preferably 1% to 5%, and very preferably 1.5% to 3%.

[0100] The ratio of the total dry mass of the nonionic surfactant to the total dry mass of the essential oil can also be greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, and very preferably greater than or equal to 5. The amount of essential oil present in the antimicrobial composition is advantageously lower than the amount of nonionic surfactant. Choosing this low content allows the essential oil to dissolve best in the water of the antimicrobial liquid composition, and also helps maintain its solubility in the water of the cosmetic when the antimicrobial liquid composition is diluted, particularly when diluted in the water of the cosmetic.

[0101] This ratio advantageously allows for the acquisition of stable antimicrobial liquid compositions without phase shift or precipitation over time, while remaining transparent or milky white even in concentrated form or after high dilution in water.

[0102] Nonionic surfactants

[0103] According to one embodiment, the nonionic surfactant is selected from:

[0104] - Alcohols, alpha-diols, and alkyl (C1-C20) phenols, these compounds being polyethoxylated and / or polypropoxylated and / or polyglycerol-alkylated, the number of ethylene oxide and / or propylene oxide groups being 1 to 100, and the number of glycerol groups being 2 to 30; or these compounds comprising at least one aliphatic chain containing 8 to 40 carbon atoms, particularly 16 to 30 carbon atoms; particularly saturated or unsaturated, straight-chain or branched oxyethylene alcohols comprising at least one C8-C40 alkyl chain, comprising 1 to 100 moles of ethylene oxide, preferably 2 to 50, more preferably 2 to 40 moles of ethylene oxide and comprising one or two aliphatic chains;

[0105] - A condensation product of ethylene oxide and propylene oxide on a fatty alcohol;

[0106] - Polyethoxylated fatty amides, preferably having 2 to 30 ethylene oxide units, and polyglycerolized fatty amides, on average containing 1 to 5 glycerol groups, particularly 1.5 to 4 glycerol groups;

[0107] -Ethoxylated sorbitol fatty acid esters, preferably having 2 to 40 ethylene oxide units;

[0108] -Sucrose fatty acid esters;

[0109] - Polyoxyethyleneized fatty acid esters, preferably polyoxyethyleneized fatty acid esters having 2 to 150 moles of ethylene oxide, including oxyethyleneized vegetable oils;

[0110] -N-(C6-C24 alkyl)glucosamine derivatives,

[0111] -Amine oxides, such as (C10-C14 alkyl)amine oxides or N-(C10-C14 acyl)-aminopropylmorpholine oxides;

[0112] - Non-ethoxylated fatty acid esters of polyols, particularly non-ethoxylated fatty acid esters selected from glycerol, ethylene glycol, sorbitol, dehydrated sorbitol, and tetrahydrohexitol, especially non-ethoxylated fatty acid esters of isosorbide, mannitol, xylitol, erythritol, maltitol, sucrose, glucose, polydextrose, hydrogenated glucose syrup, dextrin, and hydrolyzed starch.

[0113] - Polyglycerol esters and C4-C20, preferably C8-C18, more preferably C18 saturated or unsaturated fatty acid esters, such as polyglycerol-2 dihydroxystearate and polyglycerol-3 diisostearate.

[0114] - Vegetable oil esters, especially coconut oil esters, such as cocoyl oleate,

[0115] And their mixtures.

[0116] According to another embodiment, the nonionic surfactant is selected from alkyl (poly)glycosides, which are represented by the following general formula:

[0117] R10-(R2O) t -(G) v

[0118] in:

[0119] -R1 represents: an alkyl or alkenyl radical, straight-chain or branched, having 6 to 24 carbon atoms, or 6 to 18 carbon atoms, or 6 to 12 carbon atoms; or an alkylphenyl radical, the straight-chain or branched alkyl radical having 6 to 24 carbon atoms, or 6 to 18 carbon atoms, or 6 to 12 carbon atoms.

[0120] -R2 represents an alkylene radical with 2 to 4 carbon atoms.

[0121] -G represents a sugar unit with 5 to 6 carbon atoms.

[0122] -t specifies a value from 0 to 10, preferably 0 to 4.

[0123] -v refers to a value from 1 to 15, preferably 1 to 4.

[0124] Preferably, the alkyl (poly)glycoside surfactant is a compound of the above formula, wherein:

[0125] -R1 represents a saturated or unsaturated straight-chain or branched alkyl radical with 6 to 18 carbon atoms, or 6 to 12 carbon atoms.

[0126] -R2 represents an alkylene radical with 2 to 4 carbon atoms.

[0127] -t refers to a value between 0 and 3, with 0 being the preferred value.

[0128] -G refers to glucose, fructose, or galactose, with glucose being preferred;

[0129] - The degree of polymerization, i.e., the value of v, can be 1 to 15, preferably 1 to 4; the average degree of polymerization is more specifically between 1 and 2.

[0130] The glucosidic bonds between sugar units are typically of type 1-6 or type 1-4, preferably type 1-4. Preferably, the alkyl (poly)glycoside surfactant is an alkyl (poly)glycoside surfactant, that is, an alkyl (poly)glycoside surfactant, wherein G is glucose. Particularly preferred are 1,4-alkyl C6 / C16-(poly)glucosides, 1,4-alkyl C6 / C12-(poly)glucosides, especially decyl glucosides, dodecyl glucosides, heptaglycosides, octanoyl glucosides, octyl glucosides, and octanoyl / octyl glucosides.

[0131] According to one embodiment, the surfactant is selected from octyl / octyl glucoside.

[0132] Among commercially available products, COGNIS can be listed as having the name... (600CS / U, 1200 and 2000) or Products (818, 1200, and 2000); SEPPIC company sells products called ORAMIX CG 110 and... Products of NS100; products sold by BASF under the name LUTENSOL GD 70, or products sold by CHEMIY under the name AG10 LK.

[0133] The nonionic surfactant may also be selected from alkyl (poly)glycosides, preferably alkyl (poly)glucosides, with an HLB greater than or equal to 10, or greater than or equal to 12, or greater than or equal to 14.

[0134] Alkyl (poly)glycosides, preferably alkyl (poly)glucosides, can be further combined with fatty alcohols.

[0135] Nonionic surfactants can also be selected from hybrids of C8-C10 alkyl glycosides and sorbitol fatty esters, preferably from hybrids of C8-C10 alkyl glycosides and C4-C20 sorbitol fatty esters, and more preferably from hybrids of C10 alkyl glycosides and C18 sorbitol fatty esters. An example of such heteropolymers is Poly from Colonial Chemical Inc. Mulse D9.

[0136] The total amount of nonionic surfactant in the antimicrobial liquid composition accounts for more than or equal to 1% of the total weight of the antimicrobial liquid composition, preferably more than or equal to 5%, more preferably more than or equal to 7.5%, and most preferably more than or equal to 10%.

[0137] Advantageously, the total amount of nonionic surfactant in the antimicrobial liquid composition accounts for 1% to 50% of the total weight of the antimicrobial liquid composition, preferably 1% to 40%, preferably 5% to 40%, preferably 5% to 30%, more preferably 7.5% to 30% by dry weight, more preferably 7.5% to 20% by dry weight, and most preferably 10% to 20% by dry weight.

[0138] The ratio of the total dry mass of nonionic surfactants to the total dry mass of essential oils can also be greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, and very preferably greater than or equal to 5. The amount of nonionic surfactants present in the antimicrobial composition is advantageously higher than the amount of essential oils. Choosing this high content allows the essential oils to dissolve best in the water of the antimicrobial liquid composition, and also helps maintain solubility in the water of the cosmetic when the antimicrobial liquid composition is diluted, particularly in the water of the cosmetic.

[0139] Advantageously, according to an embodiment where the nonionic surfactant is octanoyl / octyl glucoside, the ratio of the mass of octanoyl / octyl glucoside to the mass of the essential oil is greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, and particularly preferably greater than or equal to 5, allowing for a completely transparent antimicrobial liquid composition that is stable over time in both concentrated and water-diluted states. Cosmetic formulators generally prefer to use transparent ingredients to formulate their products.

[0140] Advantageously, the nonionic surfactant according to the invention is selected such that the antimicrobial liquid composition is compatible with both ionic and amphoteric surfactants. Therefore, the antimicrobial composition can be added to cosmetics containing another surfactant while maintaining good physical stability of the cosmetic and preserving the effects of the ionic or amphoteric surfactants, i.e., without masking or neutralizing their effects.

[0141] Therefore, the antimicrobial compositions according to the invention can be added to shampoos or shower gels containing, typically in high amounts, anionic surfactants while retaining the detergency of the anionic surfactants and maintaining a single-phase liquid or gel state. Antimicrobial liquid compositions can also be added to hair dyes or conditioners, typically containing cationic surfactants or cationic polymers while retaining their hair-dyeing and conditioning properties.

[0142] Free carboxylic acids

[0143] The free carboxylic acid that can be used in the target antimicrobial composition of this application is selected from linear or branched monocarboxylic acids and polycarboxylic acids, preferably from carboxylic acids, dicarboxylic acids and tricarboxylic acids, and particularly preferably from monocarboxylic acids and dicarboxylic acids.

[0144] "Free" refers to the carboxylic acid functional group, either in its protonated form COOH or in its ionized form COO- combined with the counterion H+ or H3O+, and the proportion of these components depends on the pH of the acid solution and the strength of the acid as characterized by pKa.

[0145] According to one embodiment, the carboxylic acid is selected from monocarboxylic acids whose carbon chain consists of 2 to 12 carbon atoms or 3 to 8 carbon atoms. Examples include gluconic acid (pKa = 3.86), lactic acid, glycolic acid, glucuronic acid, maltobionic acid, lactobionic acid, malic acid, tartaric acid, mandelic acid, fatty acids (or aliphatic chain carboxylic acids) having a carbon chain of 4 to 12 atoms, preferably natural fatty acids, such as, in particular, propionic acid, butyric acid, hexanoic acid, caprylic acid, decanoic acid, and lauric acid. According to a variation of this embodiment, the carboxylic acid is selected from gluconic acid, glucuronic acid, maltose-inspired acid, and preferably, gluconic acid. According to a variation of this embodiment, the monocarboxylic acid is the cyclic form of gluconic acid, called gluconeolide.

[0146] According to another embodiment, the carboxylic acid is selected from polycarboxylic acids, and is preferably selected from dicarboxylic acids and tricarboxylic acids, and is very preferably selected from aspartic acid, adipic acid, malonic acid, pimelic acid, succinic acid, gluconic acid and glutaric acid, and even more preferably succinic acid.

[0147] The carboxylic acid or polycarboxylic acid that can be used in the target antimicrobial composition of this application is further characterized by a pKa value of 3 to 6, preferably 4 to 6.

[0148] The total amount of free carboxylic acid present in the antimicrobial liquid composition accounts for 10% to 70% of the total dry weight of the antimicrobial liquid composition, preferably 20% to 60%, more preferably 25% to 50%, and very preferably 27.5% to 40%.

[0149] Carboxylate

[0150] The carboxylates that can be used in the target antimicrobial compositions of this application are selected from linear or branched monocarboxylates or polycarboxylates. In acidic salts, the carboxylate functional group is either its protonated form COOH or its ionized form COO- combined with the antimetal ion M+, and the ratio depends on the pH of the acidic aqueous solution, the acidity constant pKa of the corresponding free acid, and the dissociation constant pKd of the salt.

[0151] The carboxylate is selected from the carboxylate of sodium, magnesium, zinc, calcium, potassium, iron, and lithium, and the carboxylic acid is selected from the carboxylic acid of the "free carboxylic acid" portion of this application.

[0152] According to one embodiment, the carboxylate is a salt of a free carboxylic acid that can be used in the target composition of this application. According to a variation of this embodiment, the carboxylic acid consists of at most 35% by dry weight of the carboxylate and at least 65% by dry weight of the free carboxylic acid. This variation is gluconic acid consisting of 35% by dry weight of sodium gluconate and 65% by dry weight of free gluconic acid. Advantageously, such a mixture of acid and its salt has a pH value that is more tolerable to the skin and is less irritating than a single acid.

[0153] According to one embodiment, the carboxylate is selected from the gluconic acid or succinate of sodium, magnesium, zinc, calcium, potassium, iron or lithium, and preferably, the carboxylate is selected from sodium gluconate and sodium succinate, and most preferably, the carboxylate is sodium gluconate.

[0154] The total amount of carboxylates present in the antimicrobial liquid composition can be 1% to 50% of the total dry weight of the antimicrobial liquid composition, preferably 5% to 30%, more preferably 10% to 20%, and very preferably 15% to 17.5%.

[0155] water

[0156] The water present in the antimicrobial liquid composition can be decarbonated water or deionized water.

[0157] The amount of water present in the antimicrobial liquid composition may be 20% to 75% by weight of the total weight of the antimicrobial liquid composition, preferably 30% to 65% by weight, and more preferably 35% to 55% by weight.

[0158] pH of the antimicrobial liquid composition :

[0159] The pH value of the target antimicrobial liquid composition of this application can be 2 to 9, preferably 3 to 8, more preferably 4 to 7, even more preferably 4.5 to 6.5, even more preferably 5.5 to 6.2.

[0160] preservative

[0161] For information on commonly used preservatives and their dosages for specific applications, please refer to Annex 5 of Cosmetics Ordinance No. 1223 / 2009, entitled “List of Preservatives Permitted for Use in Cosmetics”.

[0162] Therefore, preservatives can be selected from propionic acid, calcium propionate, formaldehyde, paraformaldehyde, o-phenylphenol or its salts, zinc pyrithione, sulfites, sodium bisulfite or metabisulfite, ammonium, potassium, chlorobutanol, methylparaben, ethylparaben, propylparaben, butylparaben, formic acid and its salts such as sodium formate, benzoic acid and its salts such as sodium benzoate, sorbic acid and its salts such as calcium sorbate, sodium sorbate, potassium sorbate, salicylic acid and its salts, dehydroacetic acid and its salts such as sodium dehydroacetate, undecenoic acid and its salts. Examples include calcium undecenoate, potassium undecenoate, sodium undecenoate, phenoxyethanol, 1,2-dihydroxymethyl-5,6-dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate, chlorhexidine gluconate, chlorhexidine hydrochloride, behenyltrimethylammonium chloride, cetrimonium chloride, cetrimonium bromide, lauryltrimethylammonium chloride, lauryltrimethylammonium bromide, stearyltrimethylammonium chloride, stearyltrimethylammonium bromide, hexadiazine, hexamidine dihydroxyethyl sulfonate, chlorphenesin, benzalkonium chloride, benzalkonium bromide, benzalkonium saccharin ammonium, and lauroyl arginine ethyl ester.

[0163] According to one embodiment, the antimicrobial composition is a preservative activator for the following preservatives: benzoic acid, sodium benzoate, salicylic acid and its salts, sorbic acid, calcium sorbate, sodium sorbate, potassium sorbate, dehydroacetic acid, sodium dehydroacetate, undecenoic acid, calcium undecenoate, potassium undecenoate, sodium undecenoate, phenoxyethanol, 1,2-dimethyl-5,6-dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate, chlorhexidine gluconate, chlorhexidine hydrochloride, behenyltrimethylammonium chloride, cetrimonium chloride, cetrimonium bromide, lauryltrimethylammonium chloride, lauryltrimethylammonium bromide, stearyltrimethylammonium chloride, stearyltrimethylammonium bromide, hexamethylenetetramine, hexamethylenedihydroxyethyl sulfonate, chlorophenoxyether, benzalkonium chloride, benzalkonium bromide, benzalkonium saccharin ammonium, and ethyl lauroyl arginine.

[0164] According to one embodiment, the preservative is selected from formic acid and its salts, dehydroacetic acid and its salts, benzoic acid and its salts, sorbic acid and its salts, phenoxyethanol, benzyl alcohol and its salts. More preferably, the preservative activated by the antimicrobial liquefaction composition is selected from benzoic acid, sorbic acid, phenoxyethanol, benzyl alcohol, sodium benzoate, and potassium sorbate. Even more preferably, the preservative is selected from phenoxyethanol, benzyl alcohol, sodium benzoate, and potassium sorbate.

[0165] According to one embodiment, the preservative activated by the antimicrobial liquid composition is selected from sorbic acid and its calcium, sodium, potassium, magnesium, or zinc salts, or mixtures thereof. Even more preferably, the preservative is selected from sorbic acid, calcium sorbate, sodium sorbate, or potassium sorbate. Particularly preferred is potassium sorbate.

[0166] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of the preservative activity of phenoxyethanol against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Aspergillus brasiliensis.

[0167] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of phenoxyethanol, and, in combination with said phenoxyethanol, reduces the colony-forming units of at least two logs of Pseudomonas aeruginosa, Staphylococcus aureus, Aspergillus brasiliensis, and Escherichia coli.

[0168] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of phenoxyethanol, and therefore allows for a greater reduction in the number of colony-forming units compared to phenoxyethanol alone.

[0169] - Pseudomonas aeruginosa: at least 2 logs at 7 days, at least 3 logs at 14 days.

[0170] - Staphylococcus aureus: at least 3 logs at 7 days, at least 2 logs at 14 days.

[0171] - Escherichia coli: at least 2 logs at 7 and 14 days, and at least 1 log at 28 days; - Aspergillus brasiliensis: at least 1 log at 14 and 28 days.

[0172] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of benzyl alcohol's preservative activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli.

[0173] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of benzyl alcohol, and therefore allows for a greater reduction in the number of colony-forming units compared to benzyl alcohol alone.

[0174] - Pseudomonas aeruginosa: at least 3 logs at 7 days, at least 4 logs at 14 days.

[0175] - Staphylococcus aureus: at least 3 logs at 7 days, at least 2 logs at 14 days; - Escherichia coli: at least 1 log at 7 days, at least 3 logs at 14 days, at least 4 logs at 28 days.

[0176] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of sodium benzoate's preservative activity against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Aspergillus brasiliensis, and Candida albicans.

[0177] According to one embodiment, the antimicrobial composition according to the invention allows activation of sodium benzoate, and therefore allows a greater reduction in the number of colony-forming units compared to sodium benzoate alone.

[0178] - Pseudomonas aeruginosa: at least 1 log at 7 days, at least 3 logs at 14 days.

[0179] - Staphylococcus aureus: at least 3 logs at 7 days, at least 1 log at 14 days.

[0180] - Escherichia coli: at least 3 logs at 14 days

[0181] - Candida albicans: at least 1 log at 7 days, at least 2 logs at 24 days, and at least 3 logs at 28 days.

[0182] - Aspergillus brasiliensis: at least 1 log at 28 days.

[0183] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of potassium sorbate's preservative activity against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus brasiliensis.

[0184] According to one embodiment, the antimicrobial composition according to the invention allows for the activation of potassium benzoate, and therefore allows for a greater reduction in the number of colony-forming units compared to potassium benzoate alone.

[0185] - Pseudomonas aeruginosa: at least 3 logs at 7 days, and at least 5 logs at 14 and 28 days.

[0186] - Staphylococcus aureus: at least 2 logs at 7 days

[0187] - Escherichia coli: at least 3 logs at 7 days, at least 1 log at 14 days.

[0188] - Candida albicans: at least 1 log at 7 days, at least 3 logs at 14 and 28 days.

[0189] - Aspergillus brasiliensis: at least 2 logs at 14 and 28 days.

[0190] The activation of cosmetic preservatives using antimicrobial liquid compositions can be accomplished as follows:

[0191] - The amount of the antimicrobial liquid composition in the total weight of the cosmetic composition may be at least 0.1% of the gross weight, preferably at least 0.5% of the gross weight, more preferably at least 0.75% of the gross weight, preferably at least 1% of the gross weight, and more preferably at least 1.5% of the gross weight.

[0192] - The amount of preservative in the total weight of the cosmetic composition may be up to 2.5% of the gross weight, preferably up to 1.5% of the gross weight, more preferably up to 1% of the gross weight, preferably up to 0.7% of the gross weight, and more preferably up to 0.6% of the gross weight.

[0193] The activation of cosmetic preservatives using antimicrobial liquid compositions can be accomplished as follows:

[0194] The amount of the antimicrobial liquid composition in the total weight of the cosmetic composition is 0.1% to 5% of the gross weight, preferably 0.5% to 3% of the gross weight, more preferably 0.75% to 2% of the gross weight, and very preferably 1% to 1.5% of the gross weight of the at least one antimicrobial liquid composition.

[0195] - The amount of commonly used preservatives in the total weight of the cosmetic composition is 0.1% to 2.5% of gross weight, preferably 0.2% to 1.5% of gross weight, more preferably 0.3% to 1% of gross weight, and very preferably 0.4% to 0.7% of gross weight.

[0196] Depending on the nature of the preservative used, antimicrobial compositions allow for a reduction of at least 35%, and even at least 50%, of commonly used preservatives in cosmetic formulations, and preferably at least 60%. Therefore, only very small amounts can be used, representing no more than 0.5% or even 0.4% of the gross weight of the cosmetic product. Microbiological stability may be equal to or even better than that of commonly used preservatives used alone at recommended doses.

[0197] Antimicrobial Composition

[0198] According to one embodiment, the target antimicrobial composition of this application comprises or constitutes the following:

[0199] - Essential oils composed of citral and geraniol, preferably lemongrass oil composed of citral and geraniol.

[0200] - Alkyl glucosides with aliphatic chains containing 6 to 12 carbon atoms, preferably octanoyl / octyl glucosides.

[0201] -Carboxylic acid, preferably gluconic acid or succinic acid, with gluconic acid being particularly preferred.

[0202] -Carboxylate, preferably sodium gluconate or sodium succinate, with sodium gluconate being particularly preferred.

[0203] -water.

[0204] According to one embodiment, the antimicrobial composition comprises or consists of the following:

[0205] - an essential oil, preferably lemongrass oil, comprising at least 50% by weight of citral and 0.1% to 10% by dry weight, preferably 0.5% to 7% by dry weight, more preferably 1% to 5% by dry weight, and very preferably 1.5% to 3% by dry weight.

[0206] - An alkyl glucoside comprising 1% to 40% by dry weight, having a fatty chain containing 6 to 12 carbon atoms, preferably an octanoyl / octyl glucoside, preferably comprising 5% to 30% by dry weight, more preferably comprising 7.5% to 20% by dry weight.

[0207] - 10% to 70% by dry weight of gluconic acid, succinic acid, sodium gluconate, or sodium succinate, preferably 20% to 60% by dry weight, more preferably 25% to 50% by dry weight, and very preferably 27.5% to 40% by dry weight.

[0208] -water,

[0209] The percentage by mass is expressed as a percentage of the total weight of the antimicrobial composition.

[0210] Compared to examples using benzaldehyde, examples using terpenoid aldehydes and without benzaldehyde have the advantage of generally being less irritating to the skin and less likely to cause sensitization.

[0211] According to one embodiment, the present invention relates to an antimicrobial liquid composition comprising, and preferably constituting, the following:

[0212] - Essential oils selected from clove, lemongrass, bourbon geranium, geranium grass, ginger grass, bay leaf, lemongrass, west Indian lemongrass, east Indian lemongrass, lemon balm, lemon balm, chili, crown pepper, oregano, tea tree, thyme, and schénanthe.

[0213] - A nonionic surfactant selected from alkyl (poly)glycosides, preferably alkyl (poly)glucosides.

[0214] - Free carboxylic acids, selected from gluconic acid and succinic acid.

[0215] -water.

[0216] According to one embodiment, the antimicrobial liquid composition comprises or preferably consists of the following:

[0217] - Essential oils, selected from lemongrass, west Indian lemongrass, and east Indian lemongrass essential oils, with lemongrass oils being the preferred choice.

[0218] - A nonionic surfactant selected from alkyl (poly)glycosides, preferably alkyl (poly)glucosides.

[0219] - Free carboxylic acids, selected from gluconic acid and succinic acid.

[0220] -water.

[0221] According to one embodiment, the antimicrobial liquid composition comprises or preferably consists of: - an essential oil from one of the plants in the genus Citronella,

[0222] -Octanyl / Octanylglucoside

[0223] γ-gluconic acid,

[0224] -water.

[0225] According to one embodiment, the antimicrobial liquid composition comprises:

[0226] - The essential oil of one of the plants in the genus *Citronella*, comprising 0.1% to 10% by weight of dry weight, preferably 0.5% to 7% by dry weight, more preferably 1% to 5% by dry weight, and very preferably 1.5% to 3% by dry weight.

[0227] -Octayl / octyl glucoside, comprising 1% to 40% by weight of dry weight, preferably 5% to 30% by weight, more preferably 7.5% to 20% by weight.

[0228] - Free gluconic acid, comprising 10% to 70% by mass of dry weight, preferably 20% to 60% by dry weight, more preferably 25% to 50% by dry weight, and very preferably 27.5% to 40% by dry weight.

[0229] - Water, comprising 20% ​​to 75% by weight, preferably 30% to 65% by weight, more preferably 35% to 55% by weight, the weight percentage being expressed as a percentage of the total weight of the antimicrobial liquid composition.

[0230] According to one embodiment, the antimicrobial liquid composition is configured as follows:

[0231] - The essential oil of one of the plants in the genus *Citronella*, comprising 0.1% to 10% by weight of dry weight, preferably 0.5% to 7% by dry weight, more preferably 1% to 5% by dry weight, and very preferably 1.5% to 3% by dry weight.

[0232] -Octayl / octyl glucoside, comprising 1% to 40% by weight of dry weight, preferably 5% to 30% by weight, more preferably 7.5% to 20% by weight.

[0233] - Free gluconic acid, comprising 10% to 70% by mass of dry weight, preferably 20% to 60% by dry weight, more preferably 25% to 50% by dry weight, and very preferably 27.5% to 40% by dry weight.

[0234] - Water, comprising 20% ​​to 75% by weight, preferably 30% to 65% by weight, more preferably 35% to 55% by weight.

[0235] The percentage by mass is expressed as the proportion of the total weight of the antimicrobial liquid composition.

[0236] The sum of the mass percentages of all components is 100%.

[0237] According to one embodiment, the target antimicrobial composition of this application comprises and preferably consists of the following:

[0238] - Essential oils selected from clove, lemongrass, bourbon geranium, geranium grass, ginger grass, bay leaf, lemongrass, west Indian lemongrass, east Indian lemongrass, lemon balm, lemon balm, chili, crown pepper, oregano, tea tree, thyme, and schénanthe.

[0239] - A nonionic surfactant selected from alkyl (poly)glycosides, preferably alkyl (poly)glucosides.

[0240] - Free carboxylic acids, selected from gluconic acid and succinic acid.

[0241] - and / or a salt of the carboxylic acid, selected from calcium, sodium, potassium, calcium, magnesium, and zinc salts.

[0242] -water.

[0243] According to one embodiment, the target antimicrobial liquid composition comprises or preferably consists of the following:

[0244] - Essential oils, selected from lemongrass, west Indian lemongrass, and east Indian lemongrass essential oils, with lemongrass oils being the preferred choice.

[0245] - A nonionic surfactant selected from alkyl (poly)glycosides, preferably alkyl (poly)glucosides.

[0246] - Free carboxylic acids, selected from gluconic acid and succinic acid.

[0247] - and / or a salt of the carboxylic acid, selected from calcium, sodium, potassium, calcium, magnesium, and zinc salts.

[0248] According to one embodiment, the target antimicrobial liquid composition comprises or preferably consists of the following:

[0249] -The essential oil of one of the plants in the genus Citronella.

[0250] -Octanyl / Octanylglucoside

[0251] γ-gluconic acid,

[0252] -Sodium gluconate,

[0253] -water.

[0254] According to one embodiment, the antimicrobial liquid composition comprises:

[0255] - The essential oil of one of the plants in the genus *Citronella*, comprising 0.1% to 10% by weight of dry weight, preferably 0.5% to 7% by dry weight, more preferably 1% to 5% by dry weight, and very preferably 1.5% to 3% by dry weight.

[0256] -Octayl / octyl glucoside, comprising 1% to 40% by weight of dry weight, preferably 5% to 30% by weight, more preferably 7.5% to 20% by weight.

[0257] - Free gluconic acid, comprising 10% to 70% by mass of dry weight, preferably 20% to 60% by dry weight, more preferably 25% to 50% by dry weight, and very preferably 27.5% to 40% by dry weight.

[0258] -Sodium gluconate, comprising 1% to 50% by weight of dry weight, preferably 5% to 30% by weight, more preferably 10% to 20% by weight, and very preferably 15% to 17.5% by weight.

[0259] - Water, comprising 20% ​​to 75% by weight, preferably 30% to 65% by weight, more preferably 35% to 55% by weight.

[0260] The percentage by mass is expressed as the proportion of the total weight of the antimicrobial liquid composition.

[0261] According to one embodiment, the antimicrobial liquid composition is configured as follows:

[0262] - The essential oil of one of the plants in the genus *Citronella*, comprising 0.1% to 10% by weight of dry weight, preferably 0.5% to 7% by dry weight, more preferably 1% to 5% by dry weight, and very preferably 1.5% to 3% by dry weight.

[0263] -Octayl / octyl glucoside, comprising 1% to 40% by weight of dry weight, preferably 5% to 30% by weight, more preferably 7.5% to 20% by weight.

[0264] - Free gluconic acid, comprising 10% to 70% by mass of dry weight, preferably 20% to 60% by dry weight, more preferably 25% to 50% by dry weight, and very preferably 27.5% to 40% by dry weight.

[0265] -Sodium gluconate, comprising 1% to 50% by weight of dry weight, preferably 5% to 30% by weight, more preferably 10% to 20% by weight, and very preferably 15% to 17.5% by weight.

[0266] - Water, comprising 20% ​​to 75% by weight, preferably 30% to 65% by weight, more preferably 35% to 55% by weight.

[0267] The percentage by mass is expressed as the proportion of the total weight of the antimicrobial liquid composition.

[0268] The sum of the mass percentages of all components is 100%.

[0269] The selection of components in the target antimicrobial liquid composition of this application also has the advantage of giving it a natural source content index, denoted by CNO, which means that 100% of the alkyl (poly)glucosides are obtained solely from plant resources.

[0270] Structure of antimicrobial compositions

[0271] The target antimicrobial composition of this application is in liquid form, which is a dispersion of an oil phase in an aqueous phase. This dispersion can be an oil-in-water emulsion, an oil-in-water microemulsion, an oil-in-water nanoemulsion, or a micelle solution, depending on the nature and amount of the composition components and its manufacturing process. According to one embodiment, the antimicrobial composition is an oil-in-water emulsion, and the droplet size of the oil phase is 0.3 micrometers to 10 micrometers. According to another embodiment, the antimicrobial composition is an oil-in-water microemulsion or an oil-in-water micelle composition, and the droplet size is 0.001 micrometers to 0.3 micrometers. The small droplets or microdroplets or micelles of this antimicrobial liquid composition give it a milky white or transparent appearance. Furthermore, they contribute to improving the stability of the oil-in-water mixture and enhance its antimicrobial activity and effectiveness as a preservative activator.

[0272] According to one embodiment, the oily dispersion phase comprises essential oils; the aqueous phase comprises carboxylic acids and / or carboxylates; and a surfactant is located at the interface between the two phases. The oil phase may contain "non-essential" oils, such as triglycerides, to adjust the concentration of essential oils in the oil phase and reduce the potential sensitizing properties of the essential oils. The oil phase may also contain oils, such as vegetable oil methyl esters or short-chain fatty acid triglycerides. Both the oil and aqueous phases may also contain additives without antimicrobial activity, such as rheology modifiers, soluble colorants, pigments, fragrances, humectants, and fillers.

[0273] According to another embodiment, the oily dispersion phase consists of essential oils; the aqueous phase consists of water, free carboxylic acids and / or carboxylates; and a nonionic surfactant is distributed between the two phases. In this embodiment, the aqueous phase contains water as the sole solvent and therefore contains no other solvents, especially no organic solvents.

[0274] Advantageously, the transparency of the antimicrobial liquid composition and its compatibility with ionic surfactants allow such antimicrobial liquid compositions to be added to inherently transparent cosmetics, such as micellar aqueous or gel formulations, while maintaining transparency.

[0275] In fact, this antimicrobial liquid composition is in the form of a macroscopically homogeneous liquid, which allows for its easy use in cosmetic manufacturing processes. Compared to powder handling, liquid handling requires less personal or collective protective equipment. Transferring between containers and precise dosing are also simpler and more reliable than with powder.

[0276] Therefore, this antimicrobial liquid composition can be easily added to cosmetics to activate existing preservatives without compromising the stability of the cosmetic. The composition according to the invention provides good stability and compatibility with cosmetics, allowing for transparency without crystallization or precipitation issues.

[0277] cosmetic

[0278] This application also relates to a cosmetic comprising an antimicrobial liquid composition according to the invention as a preservative activator, and at least one commonly used cosmetic preservative as described above.

[0279] According to one embodiment, the cosmetic product comprises:

[0280] The at least one preservative constitutes at most 2.5% of the total weight of the cosmetic composition, preferably at most 1.5%, more preferably at most 1%, more preferably at most 0.7%, and more preferably at most 0.6%.

[0281] - The at least one antimicrobial liquid composition accounts for at least 0.1% of the total weight of the cosmetic composition, preferably at least 0.5%, more preferably at least 0.75%, more preferably at least 1%, and more preferably at least 1.5%.

[0282] Preferably, the cosmetic comprises:

[0283] - The at least one preservative constitutes at most 0.5% of the gross weight of the cosmetic composition, preferably at most 0.4%.

[0284] - At least one of the said antimicrobial liquid compositions accounts for at least 2.0% of the gross weight of the total cosmetic composition, preferably at least 3%.

[0285] Particularly preferably, the cosmetic comprises:

[0286] - The at least one preservative accounts for 0.1% to 2.5% of the total weight of the cosmetic product, preferably 0.2% to 1.5%, more preferably 0.3% to 1%, and very preferably 0.4% to 0.7%.

[0287] - The at least one antimicrobial liquid composition comprises 0.1% to 5% of the gross weight of the cosmetic, preferably 0.5% to 3%, more preferably 0.75% to 2%, and very preferably 1% to 1.5% of the gross weight.

[0288] According to one embodiment, the cosmetic comprises a single and unique antimicrobial liquid composition according to the present application, and a single and unique preservative.

[0289] The cosmetic product can be in any known form or physical state, namely, an oil-in-water emulsion, a water-in-oil emulsion, a suspension, a foam, a true solution, a micellar solution, a hydroalcoholic solution, an ointment, a gel, a powder, a tablet, or a wipe. Preferably, the product form is selected from oil-in-water emulsions, water-in-oil emulsions, suspensions, foams, true solutions, micellar solutions, hydroalcoholic solutions, ointments, and gels. Particularly preferably, the product form is selected from oil-in-water emulsions, water-in-oil emulsions, suspensions, foams, true solutions, micellar solutions, ointments, and gels.

[0290] Due to the neutral nature of the compositions according to the invention and their high compatibility with most oils and fats, alcohols, surfactants, emulsifiers, solubilizers, conditioning agents, film-forming agents, thickeners, gelling agents, neutralizers or active substances, the cosmetic can be formulated with a wide range of commonly used ingredients without particular difficulty.

[0291] Method for preparing the antimicrobial liquid composition according to the present invention

[0292] The following method describes the preparation of an antimicrobial composition consisting of essential oil, gluconic acid, sodium gluconate, and a solubilizing surfactant. When the solubilizing surfactant is in powder form, it is dissolved in a minimal amount of water. In an open beaker, the desired amount of essential oil is slowly added to the desired amount of the solubilizing surfactant solution, and gently stirred at room temperature (22°C) (e.g., a Rayneri motor equipped with a propeller blade at a speed of 500-1000 rpm) until a homogeneous solution is obtained. This aqueous solution of essential oil and solubilizer is added to an aqueous gluconic acid solution, which consists of the desired amounts of free gluconic acid and sodium gluconate, and gently stirred at room temperature (22°C) (e.g., a Rayneri motor equipped with a propeller blade at a speed of 500-1000 rpm) until a homogeneous solution is obtained.

[0293] The antimicrobial composition used as a preservative activator can be added to the cosmetic at the end of the preparation process; that is, after the preparation of the cosmetic involves steps of heating at a high temperature of 60-80°C for several minutes or more. When the preparation of the cosmetic is completely completed at room temperature, the antimicrobial composition can be added in the first few steps of the preparation process, but it is preferred to add it at the end of the cosmetic preparation process.

[0294] Other possible applications :

[0295] The antimicrobial compositions according to the invention can also be used for non-cosmetic applications, and are particularly suitable for the microbial stabilization of pharmaceutical compositions, food compositions or industrial compositions, such as liquid detergency compositions, liquid detergent compositions, and starch gums.

[0296] Another object of this application is the use of the antimicrobial compositions of this application to kill or inhibit the growth of microorganisms or pathogens on inanimate or artificial substrates. For example, such applications involve the disinfection of surfaces (floors, walls, doors, doorknobs), and the disinfection / preservation of industrial liquid products, such as aqueous solutions of starch, protein, or fiber.

[0297] Example

[0298] Example 1: Selecting a solubilizing surfactant to achieve transparency standards

[0299] This example illustrates the selection of a solubilizing surfactant and the ratio of the surfactant's gross weight to the essential oil's gross weight to obtain an aqueous solution of lemongrass (Cymbopogon flexuosus) essential oil that remains transparent from its concentrated state to its water-diluted state. If both transparency criteria are met, the solubilizing surfactant is acceptable. Only the main tested surfactants for which results were obtained are listed here. The ratio of the surfactant's gross weight to the essential oil's gross weight is expressed below as "TA / HE gross weight ratio".

[0300] For each solubilizing surfactant to be tested (Table 1), liquid compositions were prepared using the following mass of components:

[0301] -1.2g gluconic acid (dried form),

[0302] -3g deionized water

[0303] -2.4g lemongrass essential oil "Cymbopogon fleXuosus" “From supplier Elixens”

[0304] -Commercially available solubilizing surfactants (all nonionic surfactants) listed in Table 1 with a gross weight of 14.4g, 19.2g, or 24g, to achieve a TA / HE gross weight ratio of 6, 8, or 10, respectively.

[0305] The preparation method of the liquid composition is as follows.

[0306] -The first premix was prepared by dissolving gluconic acid in water and gently stirring at 20-22°C.

[0307] - A second premix was prepared by adding the required mass of a solubilizing surfactant to the essential oil, and the mixture was stirred to fully disperse the essential oil and obtain a homogeneous liquid.

[0308] -Then the second premix is ​​added to the first premix and gently stirred without shear for about 20 minutes to allow time for the premix of surfactant and essential oil to disperse, thereby stabilizing the liquid composition.

[0309] Immediately after preparation, the state of the prepared liquid composition is observed visually to evaluate its transparency and homogeneity, particularly across the entire height of the sample, and to facilitate the detection of any possible phases or solid particles (formed through transient precipitation or slower crystallization). This state is referred to as the "concentrated liquid composition." These observations are continued for half-volume liquid compositions stored at 20–22°C for one month.

[0310] For the other half, a performance test was performed on the water dilution. 1.5 g of the liquid composition was diluted with 98.5 g of water. The state of the liquid composition after water addition was visually observed to evaluate its transparency and homogeneity, particularly across the entire height of the sample, and to facilitate the detection of any possible phases or solid particles. This is the "water-diluted" state. These observations continued during storage at 20–22°C for one month.

[0311] The transparency and homogeneity were qualitatively assessed and evaluated for both the "concentrated composition" and "after water dilution" states as follows:

[0312] - "Failure": The presence of solid particles, especially at the bottom of the sample; or the presence of at least two phases, usually one of which is the supernatant; the presence of a paste, especially at the bottom of the sample; slight to heavy turbidity, visible to the naked eye; heterogeneous transparency, with a clear difference between the upper and lower parts; creamy appearance, especially ivory in color.

[0313] - "Success": The opalescence is almost imperceptible; the transparency is uniform and almost perfect to the naked eye; the turbidity is not visible to the naked eye.

[0314] The results of transparency and homogeneity for the “concentrated liquid composition” are shown in Table 2, and the results of transparency and homogeneity for the “after water dilution” are shown in Table 3.

[0315] [Table 1]

[0316]

[0317] [Table 2]

[0318]

[0319]

[0320] [Table 3]

[0321]

[0322] Surfactants A, E, and F can provide transparent concentrated liquid compositions.

[0323] Surfactants B, C, and G cannot provide transparent concentrated liquid compositions, but transparency can be achieved upon dilution in water. Surfactant F can achieve transparency upon dilution in water.

[0324] Therefore, surfactants A, B, C, E, F, and G are suitable for the target antimicrobial compositions of this application.

[0325] Of all the tests conducted, only the solubilizing surfactant F, namely octanoyl / octyl glucoside, simultaneously met the standards for both transparency and homogeneity of the concentrated liquid composition, and the same standards after dilution with water, and this was achieved with a TA / HE gross weight ratio of 8 to 10. In the case of the solubilizing nonionic surfactant octanoyl / octyl glucoside, a TA / HE gross weight ratio of 8 to 10 corresponds to a surfactant dry weight to essential oil dry weight ratio of 4 to 5 (this is because the surfactant contains 50% water and 50% octanoyl / octyl glucoside).

[0326] Example 2: Preparation of antimicrobial composition

[0327] The ingredients used are shown in Table 4 below. The composition of the target antimicrobial liquid composition of this application is shown in Table 5.

[0328] [Table 4]

[0329]

[0330] [Table 5]

[0331]

[0332] Antimicrobial compositions 40 and 43 were prepared according to the following scheme:

[0333] In an open beaker, slowly add the required amount of essential oil to the required amount of solubilizing surfactant solution, and gently stir at room temperature (22°C) (e.g., using a Rayneri motor with propeller blades at a speed of 500-1000 rpm) until a homogeneous solution is obtained. Add this aqueous solution of essential oil and solubilizer to an aqueous solution of gluconic acid and sodium gluconate.

[0334] Example 3: Proof of Microbial Stability

[0335] The antibacterial and antifungal activity of the composition prepared in Example 2 was demonstrated by in vitro growth tests on the following microorganisms on standard culture media: *Escherichia coli* ATCC 8739 and *Pseudomonas aeruginosa*. 9027, Staphylococcus aureus 6538. Candida albicans 10231 and Aspergillus brasiliensis 16404. These tests included comparing the composition components used alone and in combination of the two ingredients to determine the synergistic effect of their antimicrobial activity against these microorganisms.

[0336] For each microorganism, prepare as many test tubes as possible as the analyte, i.e., the antimicrobial composition, a single component, or a combination of two components, and a control, using a culture medium suitable for the microorganism: *Aspergillus brasiliensis* using "potato glucose soup," *Candida albicans* using "yeast mold," *Escherichia coli* using "soy tryptone soup," *Staphylococcus aureus* using "culture medium," and *Pseudomonas aeruginosa* using "culture medium." Then, add a specific dose of the analyte to each test tube according to Table 6 below, in weight / volume percentage. For example, 1.5% (weight / volume) means adding 1.5 g of the analyte per 100 mL of culture medium. Then, carefully homogenize by aspiration-extrusion.

[0337] [Table 6]

[0338]

[0339] Each test tube was inoculated with a known amount of microorganisms: Aspergillus brasiliensis at 10^3 colony-forming units per milliliter of agar (in ufc / mL); Escherichia coli and Candida albicans at 10^4 ufc / mL; Staphylococcus aureus and Pseudomonas aeruginosa at 10^5 ufc / mL. At the end of inoculation, the inoculated medium was carefully homogenized again by aspiration and extrusion.

[0340] Samples inoculated with *Aspergillus brasiliensis* were incubated at 30°C (+ / - 2.5°C) for 48 hours. Samples inoculated with other strains were incubated at 37°C (+ / - 2.5°C) for 48 hours.

[0341] Sampling and counting of each microorganism were performed at 30 minutes, 24 hours, and 48 hours. Inoculated samples were serially diluted with diluents (1 g / L casein peptone, 8.5 g / L sodium chloride, pH 7) and deposited onto potato and glucose agar (Aspergillus brasiliensis), tryptone-casein-soybean agar (Escherichia coli), and glucose sapono agar (Candida albicans), respectively. The agars were then incubated for 24 to 72 hours before counting the existing colonies.

[0342] Microbial population measurements were performed at each sampling point, expressed in ufc / mL. The limit of detection was 100 ufc / mL.

[0343] The test results for Escherichia coli are shown in Table 7, Candida albicans in Table 8, Aspergillus brasiliensis in Table 9, Staphylococcus aureus in Table 10, and Pseudomonas aeruginosa in Table 11.

[0344] [Table 7]: Escherichia coli

[0345]

[0346] [Table 8]: White Candida albicans

[0347]

[0348] [Table 9]: Aspergillus brasiliensis

[0349]

[0350]

[0351] [Table 10]: Staphylococcus aureus

[0352]

[0353] [Table 11]: Pseudomonas aeruginosa

[0354]

[0355]

[0356] All these results indicate that compositions 40 and 43 possess antibacterial and antifungal properties on agar medium under in vitro culture conditions, as they allow for microbial stabilization of media inoculated with reference bacteria and fungi for up to 48 hours.

[0357] Preferably, the antimicrobial composition retains its antifungal and antimicrobial properties after being added to a cosmetic composition.

[0358] Example 4: Activation of preservatives in oil-in-water emulsions at pH 6

[0359] In this embodiment, the ability of composition 43 prepared in Example 3 to activate the antibacterial and antifungal activity of the preservatives in the oil-in-water emulsion at pH 6 was demonstrated. The preservatives were phenoxyethanol, benzyl alcohol, sodium benzoate, and potassium sorbate, as listed in Annex 5 of Regulation 1223 / 2009.

[0360] The cosmetic used for this certification is an oil-in-water emulsion cream, referred to as "cotton paste". The cream was prepared by adding sufficient amounts (denoted as "Qs") of composition 43 and preservatives according to the ingredients listed in Table 12, as shown in Table 10. Antimicrobial protective efficacy tests were performed on each cream in Table 13 against five microorganisms listed in ISO 11930:2019: Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus brasiliensis.

[0361] [Table 12]

[0362]

[0363]

[0364] To prepare the cream in Table 9, all components of phase A were mixed separately and heated to 75°C. Maintaining 75°C, phase B was added to phase A and gently stirred (500-750 rpm; marine propeller blades) until homogenized. Then, phases A and B were added to phase C while emulsifying and stirring (3000 rpm; deflocculation) for 10 minutes, maintaining 75°C. The mixture was cooled to 45°C, and phase D was added with medium-speed stirring (1500 rpm; marine propeller blades). The mixture was cooled to 25°C with gentle stirring (500-750 rpm; marine propeller blades), and finally, the pH was adjusted to 6 using phase E.

[0365] [Table 13]

[0366]

[0367]

[0368] Each antimicrobial protective efficacy test was conducted according to the instructions of ISO 11930:2019. The results are shown in Tables 14 to 19. These results are expressed as a logarithmic decrease in the number of colony-forming units per milliliter. Positive values ​​correspond to a decrease in the number of colony-forming units. Negative values ​​correspond to an increase in the number of colony-forming units.

[0369] [Table 14]

[0370]

[0371] The antimicrobial protection assay for Cream No. 1, a cream containing no preservatives or preservative activators, showed that Cream No. 1 was not protected against Pseudomonas aeruginosa, Escherichia coli, and Candida albicans, but provided protection against Staphylococcus aureus and Aspergillus brasiliensis (referred to as self-protection) for more than 14 days. This assay constitutes our negative control.

[0372] Antimicrobial protection of Cream No. 2, which contains 1% by weight of Thor's... PM4 preservative is protected against all five types of microorganisms. This measurement constitutes our positive control.

[0373] [Table 15]

[0374]

[0375] Antimicrobial protection measurements of creams #3 and #4, containing 1% preservative and 1.5% composition 43 respectively, and without preservative, indicated that these creams were not protected against *Pseudomonas aeruginosa* and *Candida albicans*. Self-protection against *Staphylococcus aureus* and *Aspergillus brasiliensis* was maintained. Protection against *Escherichia coli* was observed starting at day 28. Composition 43 did not protect the creams against microbial growth. However, it should be noted that composition 43 did not reduce the creams' self-protection against *Staphylococcus aureus* and *Aspergillus brasiliensis*.

[0376] [Table 16]

[0377]

[0378] Regarding Cream No. 5, the microbial protection conferred by 0.4% by weight of phenoxyethanol allows for protection of the cream, but the protection is insufficient, especially for Candida albicans, whose colony counts are able to increase and appear stable, and Aspergillus brasiliensis, whose colony counts show almost no reduction and are lower than the positive control.

[0379] Regarding Cream No. 6, which contains 0.4% by weight phenoxyethanol and 1% by weight of Composition 43, its microbial protective effect against Pseudomonas aeruginosa, Escherichia coli, and Aspergillus brasiliensis was found to be significantly better than that of Cream No. 5 and comparable to the positive control. In fact, after 7 or 14 days (for Aspergillus brasiliensis), a substantial log reduction was measured, exceeding the reduction measured for Cream No. 5 by at least two logs. For Escherichia coli and Aspergillus brasiliensis, this reduction continued or remained at 14 and 28 days, respectively, but for Pseudomonas aeruginosa, the bacterial population may have increased by approximately one log between 14 and 28 days. The body's self-protection against Staphylococcus aureus was maintained. However, Cream No. 6 was not protected against the continued growth of Candida albicans.

[0380] Advantageously, composition 43 thus allows the activation of phenoxyethanol's preservative activity against Pseudomonas aeruginosa, Escherichia coli, Aspergillus brasiliensis, and Staphylococcus aureus.

[0381] [Table 17]

[0382]

[0383]

[0384] Regarding Cream No. 7, the microbial protection provided by 0.4% benzyl alcohol by weight is ineffective against the cream itself. In particular, benzyl alcohol severely disrupts (more than 2 logs at 14 days) the self-protective barrier of the ointment against Staphylococcus aureus.

[0385] Regarding Cream No. 8, which contains 0.4% by weight benzyl alcohol and 1% by weight of Composition 43, its microbial protection against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus was found to be significantly better than Cream No. 7 and comparable to the positive control. Indeed, from 7 or 14 days onwards, a significant or substantial reduction in logarithmic counts was measured, and the reduction against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus was at least two logarithms higher than that measured against Cream No. 7. This reduction continued or persisted for 14 and 28 days. However, Cream No. 8 was not protected against the continued growth of Candida albicans.

[0386] Advantageously, composition 43 thus allows for the activation of benzyl alcohol's preservative activity against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus.

[0387] [Table 18]

[0388]

[0389]

[0390] Regarding Cream No. 9, the presence of 0.4% sodium benzoate provides microbial protection, allowing for slight protection of the cream, but not against Candida albicans. Sodium benzoate slightly reduces the cream's self-protection against Staphylococcus aureus.

[0391] Regarding Cream No. 10, which contains 0.4% sodium benzoate and 1% composition 43 by weight, its microbial protection against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Aspergillus brasiliensis, and Candida albicans was found to be significantly better than Cream No. 9 and comparable to the positive control. In fact, from 7 or 14 days (A. brasiliensis), a significant or substantial decrease in logarithmic activity was measured, exceeding the decrease measured with Cream No. 7 by at least 1 or 2 logarithms. This decrease continued or persisted for 14 and 28 days. Self-protection against Staphylococcus aureus was maintained. Notably, Cream No. 10 provided sufficient protection against Candida albicans.

[0392] Therefore, composition 43 allows for the activation of the preservative activity of sodium benzoate against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Aspergillus brasiliensis, and Candida albicans. According to ISO 11930:2019 Standard B, the combination of 1% by weight of composition 43 and 0.4% by weight of sodium benzoate allows for the stabilization of the cream.

[0393] [Table 19]

[0394]

[0395] For Cream No. 11, the presence of 0.4% potassium sorbate by weight provides microbial protection, allowing for protection of the cream in the same manner as the positive control, except against Pseudomonas aeruginosa (after 7 days), Escherichia coli (after 7 days), and Candida albicans (after 28 days).

[0396] Regarding Cream No. 12, which contains 0.4% by weight potassium sorbate and 1% by weight composition 43, it was found to provide significantly better microbial protection against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus brasiliensis than Cream No. 11, and compared with the positive control Cream No. 2 (containing 1% potassium sorbate). Just as good as PM4. In fact, after 7 or 14 days (Aspergillus brasiliensis), a significant log reduction was measured, at least two logs higher than the reduction measured for cream #11. This reduction continued or remained for 14 and 28 days.

[0397] Advantageously, composition 43 thus allows for full activation of the preservative activity of potassium sorbate against Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Staphylococcus aureus, and Aspergillus brasiliensis. According to ISO 11930:2019 Standard A, the combination of 1% by weight of composition 43 and 0.4% by weight of potassium sorbate allows for the stabilization of the cream.

[0398] Example 5: Cosmetics containing "preservative activator" and preservative composition

[0399] Product 1: Shampoo

[0400] [Table 22]

[0401]

[0402] Prepare shampoo according to the ingredient composition in Table 22:

[0403] - Add xanthan gum to water with medium-speed stirring until a homogeneous gel is obtained after approximately 20 minutes of stirring. Continue adding the components of phase B with medium-speed stirring at a temperature of 20-22°C. Then add phase C while gently stirring. Adjust the pH to 4.8 with citric acid while still gently stirring. - Obtain a flowing, clear, and foaming gel. The Brookfield viscosity is 3200 mPa·s + / - 500 at 20 rpm, 20°C, and 1 minute (using an RV M04 mobile equipment). Therefore, composition 43 is highly compatible with the shampoo ingredients. Other shampoos are prepared by modifying the properties of the phase C components according to Table 23.

[0404] [Table 23]

[0405] Shampoo Potassium sorbate (by weight in shampoo) Composition 43 (by weight in shampoo) Reference 0 0 1 0.4 0 2 0 1.0 3 0.4 1.0

[0406] Antimicrobial protective efficacy tests were conducted on each shampoo listed in Table 23 for five microorganisms listed in ISO 11930:2019: Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus brasiliensis. The results are shown in Table 24 below.

[0407] [Table 24]

[0408]

[0409]

[0410] According to the results in Table 24, the control shampoo formula was found to have a self-protective effect against Staphylococcus aureus and Escherichia coli. In Shampoo No. 1, potassium sorbate, a listed preservative, provides protection against Pseudomonas aeruginosa, Candida albicans, and Aspergillus brasiliensis. However, this formula's self-protective effect against Escherichia coli was lost, rendering it unprotected against this bacterium. In Shampoo No. 2, 0.4% potassium sorbate was replaced by 1% of Composition 43. Pseudomonas aeruginosa, Candida albicans, and Aspergillus brasiliensis could grow in this shampoo, but Escherichia coli could not, with a reduction of 4.80 log after seven days. Therefore, in this shampoo formulation, Composition 43 can achieve targeted antibacterial activity against Escherichia coli strains, with an effective period of 7 to 28 days.

[0411] In Shampoo No. 3, which contains 0.4% potassium sorbate and 1% Composition 43, antimicrobial activity against Pseudomonas aeruginosa, Candida albicans, and Aspergillus brasiliensis, as well as antibacterial activity against Escherichia coli, was found, with an effective period of 14 to 28 days. Therefore, Composition 43 allows the shampoo to resist the growth of Escherichia coli, and this does not reduce or interfere with the antibacterial activity of the potassium sorbate preservative; on the contrary, it activates the antibacterial activity of potassium sorbate against Escherichia coli within 14 days, and the reduction is 4 log higher than that of potassium sorbate alone.

Claims

1. Use of an antimicrobial liquid composition for activating a cosmetic preservative, said antimicrobial liquid composition comprising: - At least one essential oil selected from lemongrass ( Cymbopogon flexuosus Essential oils; - At least one octanoyl / octyl glucoside, - At least one gluconic acid, and - At least one sodium gluconate, The preservative is selected from benzyl alcohol, potassium sorbate, phenoxyethanol, and benzoic acid, or mixtures thereof.

2. The use according to claim 1, characterized in that, The ratio of the total dry mass of the octanoyl / octyl glucoside to the total dry mass of the essential oil is greater than or equal to 2.

3. The use according to claim 1, characterized in that, The gluconic acid consists of up to 35% sodium gluconate by dry weight and at least 65% free gluconic acid by dry weight.

4. The use according to claim 1, characterized in that, The antimicrobial liquid composition comprises: - Lemongrass ( Cymbopogon flexuosus Essential oils, with a dry weight percentage of 0.1% to 10%, - Octyl acyl / octyl glucoside, in a mass percentage of 1% to 40% by dry weight. - Glucoic acid, in which the mass percentage is 10% to 70% by dry weight. - Sodium gluconate, with a mass percentage of 1% to 50% by dry weight. The percentage by mass is expressed as the proportion of the total weight of the antimicrobial liquid composition.

5. The use according to claim 4, characterized in that, The antimicrobial liquid composition further comprises water in a mass percentage of 20% to 75% by weight. The percentage by mass is expressed as the proportion of the total weight of the antimicrobial liquid composition.

6. An antimicrobial liquid composition comprising: - Lemongrass ( Cymbopogon flexuosus Essential oils - Octyl / octyl glucoside, - Gluconic acid, - Sodium gluconate, - water.

7. The composition according to claim 6, characterized in that, - the lemongrass ( Cymbopogon flexuosus The essential oil constitutes 0.1% to 10% of the dry weight. - The octanoyl / octyl glucoside accounts for 1% to 40% of the dry weight. - The gluconic acid constitutes 10% to 70% of the dry weight. - The sodium gluconate constitutes 1% to 50% of the dry weight. - Water constitutes 20% to 75% of its mass. The percentage by mass is expressed as the proportion of the total weight of the antimicrobial liquid composition.

8. A cosmetic product, characterized in that... It contains: - At least one preservative, up to 2.5% by gross weight, selected from sodium benzoate, potassium sorbate, phenoxyethanol, and benzyl alcohol, or mixtures thereof. - The antimicrobial liquid composition according to claim 6 or 7 is at least 1% of the gross weight in the total weight of the cosmetic composition.

9. The cosmetic product according to claim 8, characterized in that, It can be an oil-in-water emulsion, an oil-in-water emulsion, a suspension, a foam, a true aqueous solution, a micelle solution, a hydroalcoholic solution, an ointment, a gel, a powder, a tablet, or a wiping agent.

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