Microwave-assisted extraction of plants

Abstract

The present invention is in the field of cosmetics and provides methods for the extraction of plants of the family Cucurbitaceae using microwave-assisted extraction, cosmetic compositions and preparations comprising an extract of the invention as well as the use of these compositions and / or preparations for cosmetic non-therapeutical applications. Furthermore, cosmetic compositions and preparations with an improved odor are provided comprising a plant extract as well as the use of these compositions and / or preparations for cosmetic non-therapeutical applications.

Description

[0001] Microwave-assisted extraction of plants

[0002] The present invention is in the field of cosmetics and provides methods for the extraction of plants of the family Cucurbitaceae using microwave-assisted extraction, cosmetic compositions and preparations comprising an extract of the invention as well as the use of these compositions and / or preparations for cosmetic non-therapeutical applications. Furthermore, cosmetic compositions and preparations with an improved odor are provided comprising a plant extract as well as the use of these compositions and / or preparations for cosmetic non- therapeutical applications.

[0003] The cosmetic potential of plant extracts, e.g. of cucumber extract has been known for a long time. Cucumber (Cucumis sativus L.), belongs to the Cucurbitaceae family. It is a worldwide commercially cultivated creeping vine plant with cylindrical to spherical fruits, which are used as seasonal culinary vegetables. The fruits are typically processed for fresh products such as salad, pickles, or vegetable juice due to their high water content and good contents of vitamins and minerals.

[0004] The use for cosmetic purposes has also been described as cucumber is known to provide a healing, soothing, and cooling effect to irritated skin. Cucumber fruit extracts and juice are often used in cosmetic formulas with skin moisturizing benefits. Fresh fruit juice is used for nourishing the skin. Fruits and seeds are widely used for various skin problems including swelling under the eyes and sunburn. It is believed that they promote refreshing, cooling, healing, soothing, emollient and anti-itching effect to irritated skin. Several pharmacological activities including the antioxidant, anti-wrinkle, antimicrobial, antidiabetic, and hypolipidemic potentials have been reported for cucumber.

[0005] Another example for plant extracts are Aloe Vera extracts. Aloe Vera is widely used in cosmetics for its hydrating, soothing, and healing properties. Its gel, rich in vitamins and antioxidants, is a common ingredient in moisturizers, face masks, and serums, where it helps to hydrate skin, soothe irritation, and reduce inflammation, especially after sun exposure. Aloe Vera also promotes collagen production, making it valuable in anti-aging products. Additionally, it is used in hair care to nourish the scalp and promote growth, as well as in acne treatments for its antimicrobial properties. Its versatility and gentleness make it ideal for various skincare and haircare products.

[0006] Anti-hyaluronidase and anti-elastase activities have been shown for lyophilized juice of cucumber fruit. Fruits were also shown to possess sun protective efficiency. Inhibited melanin production in B16 cells was described for methanol extracts of cucumber leaves and stems and anti-tyrosinase inhibition for an ethyl acetate extract of fruits (Mukherjee et al. ’’Phytochemical and therapeutic potential of cucumber1’, Fitoterapia 84 (2013) 227-236).

[0007] The cucumber fruit is composed mostly of water; more than 96% of the unpeeled fruit is water. Other compounds detected in cucumber are vitamins, minerals, amino acids, phytosterols, phenolic acids, fatty acids, terpenoids, essential oil, carbohydrates such as pectins, starch and sugars, curcurbitacins and flavonoids (Cosmetic Ingredient Review Cucumis Sativus (Cucumber) - Derived Ingredients as Used in Cosmetics, March 2012).

[0008] Dried plant materials are typically used for the production of extracts. Drying offers time independence from the seasonal harvest period and protection against possible spoilage. Dry plant material can be stored and transported more easily and cost-effectively. However, both during the drying of the plant material and during the production of the extract, partial changes in the spectrum of compounds of the plant take place.

[0009] Extraction of dried plant material always requires the use of at least one extracting solvent which can be water, an organic solvent such as e.g. ethanol, methanol, acetone, ethyl acetate or a mixture of organic solvents or water and organic solvent(s) to make the contained plant constituents soluble, i.e. extractable, and thereby available. The extraction of fresh plant material also involves the provision of an additional solvent.

[0010] More commonly, cucumbers are used for physical or mechanical extraction by e.g. pressing, squeezing or juicing. For fresh plant extraction, the starting plant material must be cultivated or collected close to the production area. The plants are harvested and must be extracted in a timely manner (usually within one day) to prevent spoilage and microbial contamination. The advantage of such mechanical extraction is the avoidance of extracting solvent. Instead, the soluble ingredients are obtained in the native water contained in the plant itself. The obtained extract must then also be stabilized in a timely manner as it is also highly susceptible to spoilage.

[0011] Microbial quality assurance has always been an important subject in the production, trade, and consumption of cosmetic ingredients. Typical ways to stabilize such kind of extracts are sterilization and sterile packaging working well as long as unopened, or low temperature storage, e.g. in deep frozen, working well as long as not thawed and thereby brought back to growing conditions of microorganisms. Other commonly used possibilities are concentration to reduce the water availability for the microorganisms or addition of a preservative or a preservative system.

[0012] To increase the yield of mechanical fresh plant extractions, enzymes or enzyme cocktails, i.e. mixtures of more than one enzyme, can be applied on the fresh plant material before or during extraction. However, along with this always goes the likelihood of impact on at least some of the naturally contained plant ingredients and their structural integrity as enzymatic conversion cannot be completely excluded. Extent and scope of the enzymatic transformation of course depends on the type of enzyme(s) used.

[0013] Sustainability and naturality are important consumer requests for finished cosmetic products and therefore also for the cosmetic ingredients contained in them. There is a constant demand for such kind of new ingredients and natural cosmetic actives with proven process and biological activity benefits.

[0014] Microwave-assisted extraction is a well-known technology. The patent application WO 2018 / 115296 A1 describes the extraction of a vegetable biomass to extract the contained polyphenols with an extraction solvent. Microwave-assisted extraction of cucumbers has also been described under the use of excessive heat to boil the cucumber during extraction (Gao et al., “Exploration of Cucumber Waste as a Potential Biorefinery Feedstock" Processes 2022, 10, 2694.) or under the use of a solvent (e.g. Kunene et al. “Evaluation of microwave-assisted extraction performance with and without solid-phase extraction cleanup", Sep Sci plus. 2023; 6:2200059 or Debnath et al., “Quality evaluation and quantification of cucurbitacin E in different cultivars of Cucumis sativus L. fruit by a validated high-performance thin-layer chromatography method’, Journal of planar chromatography, 2021 , 34, 139 - 146).

[0015] Additionally, microwave treatment has recently also come up as alternative or additional decontamination technology e.g. for medicinal and aromatic plants (Rahmati et al., Food Sci Nutr. 2022; 10(3), 784-799). In microwave heating, the mechanism of inactivation of microorganisms is based on the electroporation of cell membranes, which, based on the intensity of the electric field used, leads to the formation of reversible or irreversible pores.

[0016] The primary object of the present invention was to provide a method for a gentle extraction of cucumber fruits without altering the active component profile of the extract in comparison to fresh cucumbers. Furthermore, another objective of the present invention was to provide compositions, which show good cosmetic performance, acceptable odor as well as a long shelf life. The primary object has been solved by providing a method for producing an extract from a plant of the family Cucurbitaceae, preferably for producing a cucumber extract, comprising or consisting of the steps: i. providing plant material of a plant of the family Cucurbitaceae, preferably providing cucumber plant material; ii. extracting the provided plant material under the presence of electromagnetic waves having frequencies ranging from 915 MHz to 28 GHz; iii. obtaining a plant extract, wherein the extraction in step ii. is performed at a temperature of or less than 70°C, preferably of or less than 55 °C and especially preferred at a temperature of or less than 40°C, and wherein the extraction in step ii. is performed in the absence of a solvent.

[0017] The taxonomic family Cucurbitaceae encloses several vine plants. The most important plants for human consumption or usage are plants of the genus Cucurbita (e.g. squash, pumpkin, or zucchini), Citrullus fe.g. watermelon) and Cucumis (cucumber or melon). It is preferred in terms of the present invention that plant material of a plant of the genus Cucumis is provided in step i.

[0018] Electromagnetic waves are also called microwaves and are a type of nonionizing radiation of electromagnetic waves with wavelengths and frequencies in the range of 1 mm - 1 m and 300 MHz - 30 GHz, respectively. The interaction of microwaves with a material depends on the wave characteristics (frequency and wavelength) and the nature of the material.

[0019] It was found in terms of the present invention that microwave-assisted extraction offers several advantages for the extraction of plants. On one hand no additional extracting solvent has to be used. The naturally present water in fresh plants is sufficient as solvent. On the other hand, microwaves induce the vibration of water molecules within the cell, increasing the temperature of intracellular liquids. So an inside out instead of outside in way of energy transfer is achieved, making it thereby different to classical solvent extraction under heating. This intracellular temperature increase is followed by water evaporation that exerts pressure on the cell walls leading to disruption of the cell membranes and thus release of the intracellular contents.

[0020] It was furthermore found that a temperature of or less than 70°C, preferably of or less than 55 °C and especially preferred at a temperature of or less than 40°C was suitable for achieving a sufficient extraction and that the degradation of active compounds in the plants to be extracted can be minimized. Thus, the obtained product comprises a high amount of functional components, which have a cosmetic benefit. Additionally, microwave-assisted extraction also shows an effect on the preservation of the obtained extract as the microbial load can be significantly decreased.

[0021] Preferably, the microwave extraction is performed under temperature control, preferably under cooling to avoid high temperatures during extraction and thereby possible temperature induced transformations or degradations of contained ingredients. This can be achieved by performing the extraction in a double jacket extraction vessel using a liquid having a temperature of between 0 and 20°C, preferably between 3 and 15°C, even more preferably between 5 and 10°C passing through the outer section of double jacket extraction vessel. This allows to control the temperature in the tank to the preferred extraction temperature.

[0022] The expression “absence of a solvent” describes that no additional solvent is added in the extraction method. Only the naturally present intracellular water takes over the task of a solvent during extraction.

[0023] It is preferred in terms of the present invention that the provided plant material in step i. is fresh or frozen plant material.

[0024] The term “fresh plant material” relates to unprocessed plant material, which is subjected after harvesting, preferably after a maximum of 14 days after harvesting, moreover preferably after a maximum of seven days after harvesting, to the method according to the invention. Preferably, the plant material is chopped into pieces to increase the surface area of the plant material before subjecting the plant material to the extraction method according to the invention.

[0025] The term “frozen plant material” relates to plant material, which is frozen after harvest, preferably after a maximum of 14 days after harvesting, moreover preferably after a maximum of seven days after harvesting. A frozen plant material is a plant material, which is solid and the present intracellular water is in crystallized from. Optionally, the frozen plant material is partially or completely thawed before subjecting it to the extraction method according to the invention and accordingly the intracellular water is partially or completely in liquid form.

[0026] It is also preferred in terms of the present invention that the extraction in step ii. is performed under vacuum, preferably at a pressure of 50 to 950 mbar, preferably at a pressure of 50 to 600 mbar, especially preferably of 150 to 500 mbar.

[0027] The term “vacuum” refers to a condition, wherein the gaseous pressure is less than atmospheric pressure (ca. 1000 mbar).

[0028] It is furthermore preferred in terms of the present invention that the extraction in step ii. is performed at a power of the electromagnetic waves of between 0.1 to 1 kW , preferably of between 0.4 to 0.8 kW, dependent on 1 kg of plant material.

[0029] It is preferred in terms of the present invention that the extraction in step ii. includes stirring of the plant material. The skilled person is aware of suitable means for carrying out a stirring operation according to the volumes of mixture to be treated. In particular, there are known means of rotating the mixture to be treated, generally by means of rotating blades inside the mixture, or by means of rotating the reactor containing the mixture to be treated. The skilled person may consider other stirring means, such as setting the mixture in motion by bubbling air or inert gas. Preferably, the stirring is carried out by rotating the mixture at a rotational speed which may range from 1 to 50 revolutions per minute, more preferentially by means of rotating blades inside the mixture. Furthermore it is preferred in terms of the present invention that the extraction in step ii. is performed for a time of at least 20 minutes, preferably of at least 30 minutes, moreover preferably of at least 80 minutes, especially preferably of at least 125 minutes.

[0030] It was observed that an extraction time significantly less than 20 minutes may be associated with over-power conditions that can alter the biomass while too long a time may lead to degradation of the extracted products, and therefore in both cases a risk of loss of sensitive ingredients.

[0031] It is also preferred in terms of the present invention that the method comprises an additional step iv.a of drying the plant extract obtained in step iii and / or iv.b of adding at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid or the corresponding salts, and / or adding at least one 1 ,2-alkanediol, selected from the group consisting of

[0032] 1.2-pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol or mixtures thereof, preferably wherein the at least one 1 ,2- alkanediol is 1 ,2-pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol or 1 ,2-octanediol or mixtures thereof.

[0033] In terms of the present invention, it is especially preferred that the at least one 1 ,2- alkanediol is selected from the group consisting of 1 ,2-heptanediol, 1 ,2-octanediol,

[0034] 1.2-nonanediol and 1 ,2-decanediol.

[0035] The additional step iv. a of drying the plant extract obtained in step iii. of the method according to the invention is performed to withdraw water from the extract and thus preserve the extract. Suitable drying operations are known to the person skilled in the art and include spray-drying, band drying, vacuum drying or freeze-drying.

[0036] In spray drying, the material to be dried is introduced into a hot gas stream by means of a vaporizer, which dries it into a fine powder in a very short time (a few seconds to fractions of a second). Spray drying can optionally take place with the addition of carriers such as maltodextrin, cyclodextrin, etc.. The advantage here is that it is an established procedure that can be carried out cost-effectively. Only a very brief exposure, e.g. for a few seconds, preferably less than 3 seconds or less than 1 second, at higher temperatures, e.g. 200-400°C, preferably 250-270°C, is required. A solid that can be well stored without the addition of antimicrobial acids is obtained.

[0037] Freeze drying, also called lyophilization or sublimation drying, is an extremely gentle process, albeit cost-intensive and relatively complex. Freeze drying is based on the physical process of sublimation: The ice crystals thereby sublime directly into the gaseous state without the occurrence of a liquid phase in between. In the present case, freeze drying produces a well storable solid even without the addition of preservatives. Procedures for freeze drying can be taken from, for example, GB 1 447 988 and DE 198 17 177.

[0038] The additional step iv.b includes adding at least one antimicrobial acid to the extract obtained in step iii. of the method according to the invention or adding at least one antimicrobial acid to the dried extract obtained in step iv.a.

[0039] The antimicrobial acids are preferably selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p- anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid and phytic acid also be present in their salt form as sodium benzoate, potassium or sodium sorbate, sodium dehydroacetate, sodium levulinate, sodium anisate and sodium glucoronate, or mixtures thereof.

[0040] Preferably, the antimicrobial acids are selected from the group consisting of sodium benzoate, potassium sorbate, sodium levulinate or mixtures thereof.

[0041] However, for almost all of the above named antimicrobial acids, the solubility of the acid form is very limited in water. This is why these acids are preferably used as their corresponding sodium or potassium salt form, which dissociates to the acidic form in contact with water. For example, the following at least one antimicrobial acid used in terms of the present invention have their strongest antimicrobial behavior at the following pH values:

[0042] Benzoic acid I sodium benzoate from pH 2.5 to 4.0,

[0043] Sorbic acid I potassium sorbate from pH 3.0 to 6.5,

[0044] P-anisic acid I sodium anisate from pH 4.5 to 6.0,

[0045] Levulinic acid I sodium levulinate from pH 4.0 to 6.0.

[0046] It is preferred in terms of the present invention that the drying is performed via spray-drying using a carrier preferably selected from the group consisting of maltodextrin, dextrin and cyclodextrin and mixtures thereof, preferably in an amount of from at least 30 wt.-%, preferably at least 50 wt.-%, especially preferably at least 70 wt.-% dependent on the total weight of the obtained spray-dried composition.

[0047] Another aspect of the present invention relates to a cosmetic composition comprising or consisting of: a plant extract obtained from a plant of the family Cucurbitaceae, Asphodelaceae, Rosaceae or Anardicaceae, preferably wherein the plant extract obtained from a plant of the family Cucurbitaceae is obtained by a method according to any one of claims 1 to 7; at least one antimicrobial acid and / or; at least one 1 ,2 - alkanediol.

[0048] A “cosmetic composition” according to the present invention is to be understood as a “semi-finished” product, which may be incorporated in finished compositions intended for cosmetic use. Cosmetic compositions may be, in particular, skin cosmetic, hair cosmetic, dermatological and hygienic compositions. Preferably, the composition according to the invention is used for skin. Furthermore a “cosmetic composition” can also be a finished product, wherein the composition is not incorporated into another product.

[0049] An “antimicrobial acid” is to be understood as a compound having an acidic pH value of less than pH 7. Furthermore, the “antimicrobial acid” can be understood as being an organic acid, i.e. an organic compound with a dissociable proton. Antimicrobial acids are able to inhibit the growth of microorganisms.

[0050] It was surprisingly found in terms of the present invention that the cosmetic compositions according to the invention have an improved odor in comparison to cosmetic compositions comprising a plant extract, but not the other compounds of the inventive composition.

[0051] The taxonomic family Asphodelaceae encloses perennial herbaceous plants, often with succulent leaves arranged in rosettes. Members of this family typically have thick, fleshy leaves adapted to store water, which makes them well-suited to dry environments. This family includes well-known genera like Aloe, Hemerocallis (daylilies), and Kniphofia (red hot pokers). Many plants in this family are also valued for their medicinal and cosmetic use. Preferably, in terms of the present invention, the plant material of the taxonomic family Asphodelaceae is selected from Aloe Vera, Aloe Barbadensis, Bulbine frutescens or Kniphofia uvaria, wherein Aloe Vera I Aloe barbadensis is especially preferred.

[0052] The Rosaceae family is characterized by its diverse group of plants, including herbs, shrubs, and trees, with members like roses, apples, and strawberries. These plants typically have alternate leaves, often with stipules, and produce showy flowers with five petals and numerous stamens.

[0053] In cosmetics, members of the Rosaceae family, particularly roses, are prized for their fragrant essential oils and extracts. Rose oil, rose water and rose hip extract are commonly used in skincare products for their hydrating, soothing, and antiinflammatory properties, helping to calm irritated skin and reduce redness. Additionally, the antioxidant-rich extracts from fruits like strawberries and apples are used in skincare to help protect the skin from environmental damage and promote a youthful complexion. Preferably, in terms of the present invention, the plant material of the taxonomic family Rosaceae is selected from Rosa damascene, Rosa centifoliam, Rosa canina, Rosa multiflora, Rosa rugose, Prunus persica, Prunus domestica, Pyrus communis or Pyrus malus I Malus domestica, wherein Pyrus malus I Malus domestica is preferred.

[0054] The Anacardiaceae family offers several advantages, including the production of valuable edible fruits and nuts like cashews, mangoes, and pistachios, which are rich in nutrients and widely used in cuisine. In cosmetics, extracts from certain members, such as mango butter, are prized for their moisturizing and nourishing properties, benefiting skin and hair care products. Preferably, in terms of the present invention, the plant material of the taxonomic family Anacardiaceae is selected from Mangifera indica, Pistacia lenticus or Anacardium occidentale wherein Mangifera indica is preferred.

[0055] It is preferred in terms of the present invention that the at least one antimicrobial acid is selected from benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof.

[0056] Preferably, the composition comprises the at least one antimicrobial acid in an amount in a range of between 5 to 0.01 wt.-%, preferably of between 2 to 0.01 wt- %, moreover preferably of between 1 to 0.05 wt.-%, especially preferably of between 0.8 to 0.1 wt.-%, depending on the total weight of the composition.

[0057] It is preferred in terms of the present invention that the at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2-pentanediol, 1,2-hexanediol, 1,2- heptanediol, 1,2-octanediol, 1 ,2-nonanediol and 1,2-decanediol or mixtures thereof, preferably wherein the at least one 1 ,2-alkanediol is 1,2-pentanediol, 1,2- hexanediol, 1,2-heptanediol or 1,2-octanediol or mixtures thereof. In terms of the present invention, it is especially preferred that the at least one 1 ,2- alkanediol is selected from the group consisting of 1 ,2-heptanediol, 1 ,2-octanediol,

[0058] 1.2-nonanediol and 1 ,2-decanediol. Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2-hexanediol and 1 ,2-octanediol.

[0059] It is preferred in terms of the present invention the composition comprises the at least one 1 ,2-alkanediol in an amount in a range of between 30 to 0.01 wt.-%, preferably of between 20 to 0.05 wt.-%, moreover preferably of between 10 to 0.1 wt.-%, especially preferably of between 5.0 to 0.2 wt.-%, depending on the total weight of the composition.

[0060] The cosmetic composition according to the invention optionally comprises additionally at least one additional antimicrobial acid or preservative.

[0061] Antimicrobial acids as used in terms of the present invention have preservative properties. Preservatives can be also named antimicrobials and usually have for example several, preferably all, of the following properties. They are toxicologically harmless, well tolerated by the skin, stable and can be produced easily and inexpensively (i.e. from easily accessible educts). Suitable antimicrobial acids or preservatives can be found for example in WO 2006 / 045743.

[0062] Examples of suitable additional antimicrobial acids or antimicrobials include 2- hydroxybiphenyl ether and its salts, 2-zinc sulfidopyridine N-oxide, inorganic sulfites and bisulfites, sodium iodate, chlorobutanol, 4-ethylmercury(ll)-5-amino-

[0063] 1 .3-bis(2-hydroxybenzoic acid), the esters and salts thereof, dehydroxyacetic acid, formic acid, 1 ,6-bis(4-amidino-2-bromophenoxy)-n-hexane and its salts, the sodium salt of ethylmercury(ll)-thiosalicylic acid, phenylmercury and its salts, 10- undecylenic acid and its salts, 5-amino-1 ,3-bis(2-ethylhexyl)-5- methylhexahydropyrimidine, 5-bromo-5-nitro-1 ,3-dioxane, 2-bromo-2-nitro-1 ,3- propanediol, 2,4-dichlorobenzyl alcohol, N-(4-chlorophenyl)-N'-(3,4- dichlorophenyl)urea, 4-chloro-m-cresol, 2,4,4'-trichloro-2'-hydroxydiphenyl ether, 4-chloro-3,5-dimethylphenol, 1 ,1'-methylene-bis(3-(1 -hydroxymethyl-2, 4- dioximidazolidin-5-yl)urea), poly(hexamethylenebiguanide)hydrochloride, 2- phenoxyethanol, hexamethylenetetramine, 1 (3-chloroallyl)-3,5,7-triaza-1- azoniaadamantane chloride, 1 (4-chlorophenoxy) 1 (1 H-imidazole-1 -y l)-3 , 3- dimethyl-2-butanone, 1 ,3-bis(hydroxymethyl)-5,5-dimethyl-2,4-imidazolidinedione, benzyl alcohol, piroctone olamine, 1 ,2-dibromo-2,4-dicyanobutane, 2,2'- methylene-bis(6-bromo-4-chlorophenol), bromochlorophene, mixture of 5-chloro- 2-methyl-3(2H)isothiazolinone and 2-methyl-3(2H)isothiazolinone with magnesium chloride and magnesium nitrate, 2-benzyl-4-chlorophenol, 2-chloroacetamide, chlorhexidine, chlorhexidine acetate, chlorhexidine gluconate, chlorhexidine hydrochloride, 1-phenoxypropan-2-ol, N-alkyl(C12-

[0064] C22)trimethylammoniumbromide and chloride, 4,4-dimethyl-1 ,3-oxazolidine, N- hydroxymethyl-N-(1 ,3-di(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl)-N'- hydroxymethyl urea, 1 ,6-bis(4-amidinophenoxy)-n-hexane and its salts, glutaraldehyde, 5-ethyl-1-aza-3,7-dioxabicyclo(3.3.0)octane, 3-(4-chlorophenoxy)- 1 ,2-propanediol, hyamine, alkyl-(C8-C18)-dimethylbenzylammonium chloride, alkyl-(C8-C18)-dimethylbenzylammonium bromide, alkyl-(C8-C18)- dimethylbenzylammonium saccharinate, benzylhemiformal, o-cymen-5-ol, sodium hydroxymethylaminoacetate or sodium hydroxymethylaminoacetate, and mixtures thereof.

[0065] Other suitable preservatives or antimicrobials include parabens. Parabens are esters of para-hydroxybenzoic acid, such as methyl paraben, ethyl paraben, n- propyl paraben, n-butyl paraben, isobutyl paraben and mixtures. Parabens may be used alone or in combination as antimicrobials, particularly in cosmetic and pharmaceutical compositions. A preferred combination of parabens with regard to the above mentioned compositions comprises 18 wt.-% methyl parabens and 0.02 wt.-% propyl parabens. Parabens have both an antimicrobial and a fungicidal effect.

[0066] In addition, antimicrobials or antimicrobial excipients commonly used in cosmetics are suitable according to the invention, such as dibromodicyanobutane (2-bromo- 2-bromomethylglutarodinitrile), 3-iodo-2-propinyl butylcarbamate, 2-bromo-2-nitro- propane- 1 ,3-diol, imidazolidinylurea, 5-chloro-2-methyl-4-isothiazolin-3-one, 2- chloroacetamide, benzalkoniumchloride, benzyl alcohol and formaldehyde releasers. In addition, phenylhydroxyalkyl ethers, in particular the compound known as phenoxyethanol, are suitable as antimicrobials because of their bactericidal and fungicidal effects on a number of micro-organisms.

[0067] Preferably, the composition comprises the at least one additional antimicrobial acid or antimicrobial (if present) in an amount in a range of between 5 to 0.01 wt.-%, preferably of between 2 to 0.01 wt.-%, moreover preferably of between 1 to 0.05 wt.-%, especially preferably of between 0.8 to 0.1 wt.-%, depending on the total weight of the composition.

[0068] In terms of the present invention, it is preferred that the plant extract is selected from cucumber, Aloe Vera, apple fruit or mango extract.

[0069] Preferably, the cucumber extract is obtained by a method as described herein.

[0070] The Aloe Vera extract according to the present invention is preferably obtained by mechanical extraction.

[0071] The apple extract according to the present invention is preferably obtained by mechanical, microwave-assisted or solvent extraction. The used solvent is preferably selected from the group consisting of water, alcohol or a mixture thereof.

[0072] Furthermore, the plant extracts may be obtained by a method known in the art, e.g. mechanical, microwave-assisted or solvent extraction.

[0073] Preferably, the cosmetic composition according to the present invention relates to a cosmetic composition comprising or consisting of: an Aloe Vera extract, preferably obtained by mechanical extraction; at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol, preferably 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2- nonanediol and 1 ,2-decanediol. Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2-hexanediol and 1 ,2-octanediol.

[0074] Also preferably, the cosmetic composition according to the present invention relates to a cosmetic composition comprising or consisting of: a cucumber extract, preferably obtained by mechanical extraction or obtained by the method as described herein; at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2- nonanediol and 1 ,2-decanediol, preferably 1 ,2-heptanediol, 1 ,2- octanediol, 1 ,2-nonanediol and 1 ,2-decanediol . Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2- hexanediol and 1 ,2-octanediol.

[0075] Preferably, the composition according to the present invention relates to a cosmetic composition comprising or consisting of: an apple fruit extract, preferably obtained by mechanical extraction or obtained by the method as described herein; at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol preferably 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2- nonanediol and 1 ,2-decanediol. Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2-hexanediol and 1 ,2-octanediol.

[0076] Another aspect of the present invention relates to a cosmetic preparation, comprising the cosmetic composition according to the invention, preferably wherein the preparation is selected from the group consisting of emulsions, milks, lotions, creams, balms, ointments, gels, tonics, serums, cleansers, granules, powders, stick preparations, such as lipsticks, foams, aerosols, or sprays.

[0077] The cosmetic preparation as described herein is a final preparation or a final product. It comprises the composition according to the present invention or consist thereof.

[0078] Preferably, the cosmetic preparation is used for application on the skin and is a topical preparation. “Topical preparation” means a preparation which is suitable for applying the active substances to the skin in a finely distributed form, such as e.g. in a form that is absorbable through the skin. Suitable are e.g. aqueous and aqueous-alcoholic solutions, sprays, foams, foam aerosols, ointments, aqueous gels, emulsions of the O / W or W / O type, microemulsions or cosmetic stick preparations.

[0079] It is preferred in terms of the present invention that the cosmetic composition is contained in an amount in a range of between 100 to 0.001 wt.-%, preferably 80 to 0.001 wt.-%, more preferably 70 to 0.001 wt.-%, especially preferably 40 to 0.001 wt.-%, preferably of between 20 to 0.01 wt.-%, moreover preferably of between 10 to 0.05 wt.-%, especially preferably of between 5.0 to 0.1 wt.-%, dependent on the total weight of the cosmetic preparation.

[0080] Preferably, a cosmetic composition or preparation comprises or consists of the following compounds:

[0081] 1 to 99 wt.-% of a plant extract as defined herein,

[0082] 0.1 to 15 wt.-% of at least one 1 ,2- alkanediol as defined herein,

[0083] 0.1 to 3 wt.-% of at least one antimicrobial acid as defined herein, each based on the total content of the cosmetic composition or preparation.

[0084] Especially preferably, a cosmetic composition or preparation comprises or consists of the following compounds:

[0085] 1 to 97 wt.-% of a plant extract as defined herein,

[0086] 0.2 to 10 wt.-% of at least one 1 ,2- alkanediol as defined herein,

[0087] 0.1 to 2 wt.-% of at least one antimicrobial acid as defined herein, each based on the total content of the cosmetic composition or preparation.

[0088] Moreover preferably, a cosmetic composition or preparation comprises or consists of the following compounds:

[0089] 1 to 95 wt.-% of a plant extract as defined herein,

[0090] 0.5 to 7.5 wt.-% of at least one 1 ,2- alkanediol as defined herein,

[0091] 0.1 to 2 wt.-% of at least one antimicrobial acid as defined herein, each based on the total content of the cosmetic composition or preparation.

[0092] Another aspect of the present invention relates to the use of at least one 1 ,2 - alkanediol for improving the odor of a plant extract, preferably obtained from a plant of the family Cucurbitaceae, Asphodelaceae, Rosaceae or Anacardiaceae and / or a and / or of a preparation according to the invention, preferably wherein improving includes or consists of reducing at least one undesired olfactory impression and / or increasing at least one desired olfactory impression. Cosmetic compositions and / or preparations ideally have no or only low odor by themselves as this allows full flexibility to generate a specific odor by addition of dedicated fragrant mixtures which fits to the planned branding and product concept. Additionally, cosmetic compositions and / or preparations have to be stable over time against microbial contamination.

[0093] Plant extracts and / or compositions comprising a plant extract and at least one antimicrobial acid or preservative, which was added to provide longterm prevention of microbial growth and spoilage, often have a characteristic odor of themselves. Improvement of the odor, preferably wherein improving includes or consists of reducing at least one undesired olfactory impression and / or increasing at least one desired olfactory impression is therefore a big demand.

[0094] Preferably, the at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2-pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol, preferably 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol.

[0095] Especially preferably a combination of two 1 ,2-alkanediols is used, especially preferable a combination of 1 ,2-hexanediol and 1 ,2-octanediol.

[0096] Furthermore, the inventive effect is also present with regard to commercially available plant extracts. Thus, the plant extract may be obtained by mechanical extraction, solvent extraction or by a method according to the invention.

[0097] Especially preferably, the invention relates to the use of at least one 1 ,2- alkanediols or a combination of at least two alkanediols for improving the odor of a cucumber, an apple fruit or an Aloe Vera extract.

[0098] Yet another aspect of the present invention relates to a cosmetic, non therapeutical use of a composition according to the invention, preferably obtained or obtainable by a method according to the invention, or of a preparation according to the invention for strengthening the skin barrier and / or for balancing skin desquamation and / or for stimulation of Bleomycin hydrolase expression. Preferably, the invention relates to a cosmetic, non-therapeutical use of a composition comprising or consisting of: an apple fruit extract, preferably obtained by mechanical extraction or obtained by the method as described herein; at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol, preferably of 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2- nonanediol and 1 ,2-decanediol. Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2-hexanediol and 1 ,2-octanediol for strengthening the skin barrier and / or for balancing skin desquamation and / or for stimulation of Bleomycin hydrolase expression.

[0099] Preferably, the invention relates to a cosmetic, non-therapeutical use of a composition comprising or consisting of: an Aloe Vera extract, preferably obtained by mechanical extraction or obtained by the method as described herein; at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol, preferably of 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2- nonanediol and 1 ,2-decanediol. Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2-hexanediol and 1 ,2-octanediol. for strengthening the skin barrier and / or for balancing skin desquamation and / or for stimulation of Bleomycin hydrolase expression.

[0100] Preferably, the invention relates to a cosmetic, non-therapeutical use of a composition comprising or consisting of: a cucumber extract, preferably obtained by the method as described herein; at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts or mixtures thereof at least one 1 ,2-alkanediol is selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol, preferably of 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2- nonanediol and 1 ,2-decanediol.. Also preferably, at least two 1 ,2-alkanediols are present, preferably a mixture of 1 ,2-hexanediol and 1 ,2-octanediol. for strengthening the skin barrier and / or for balancing skin desquamation and / or for stimulation of Bleomycin hydrolase expression.

[0101] The term “strengthening the skin barrier” and “balancing skin desquamation” are to be understood as the general description of the processes taking place in human skin and contribute to the skin health. The body surface of terrestrial animals and humans is exposed to air and to mechanical stress, both incompatible with the persistence of living cells at the direct interface between an organism and its environment. The stratifying epidermis of the skin physically separates the organism from its environment and serves as its first line of structural and functional defense against chemical substances, physical insults and microorganisms.

[0102] Mammalian epidermis is a stratified epithelium comprising a series of layers of progressively more differentiated cells, called keratinocytes. At the dermal interface, resting on a basement membrane, the basal keratinocyte layer contains cycling cells, responsible for the renewal of the tissue. Basal cells undergo a phase of commitment and then start the process of differentiation, exiting the cell cycle and beginning to migrate upward toward the body surface. As the cells progress through differentiation, they move through the spinous layer and the granular layer, all the while accumulating specific lipids and proteins and building functional ultrastructures. The keratinocytes ultimately lose their nucleus and become flattened “bricks” of insoluble protein called corneocytes, surrounded by lipid “mortar” to hold them together in the outermost impermeable cornified layer or stratum corneum. They form an extremely resistant protein shell, the cornified cell envelope, just beneath their plasma membrane, made of crosslinked involucrin, loricrin, small proline-rich proteins and other proteins.

[0103] Transglutaminases (TGM), enzymes that catalyze the formation of isopeptide protein-protein cross-links, are key enzymes involved in the construction of this structure. Three TGMs are known to be active in surface epithelia and are thought to participate to varying degrees in cross-link formation. These include TGM1 , TGM3, and TGM5. TGM1 , also known as keratinocyte TGM, is an intracellular key enzyme for the formation of the cornified envelope (CE), which acts as a mechanical barrier of the skin. It is found in the upper differentiated layers of the epidermis and in hair follicles and shows a complex pattern of activities given that it exists in multiple cytosolic and membrane-anchored forms in terminally differentiating keratinocytes. It catalyzes the covalent crosslinking of numerous structural CE proteins, including involucrin, loricrin, filaggrin, and small proline-rich proteins. In contrast to other transglutaminases, TGM1 is anchored to the inner plasma membrane of keratinocytes. This membrane localization is thought to be essential for the assembly of CE components. Another important function is the stabilization of the lipid lamella structures of the corneocyte lipid envelope via attachment of long-chain w-hydroxyceramides to involucrin. (Aufenvenne et al., Am J Hum Genet. 2013; 93(4), 620-630). TGM3, also known as epidermal TGM, is expressed in the upper epidermal layers and is localized in the cytoplasm. Like TGM1 , it is involved in the CE assembly in surface epithelia. TGM5 is expressed in the in the spinous and granular layers of human epidermis and is involved in epidermal differentiation.

[0104] It was found in terms of the present invention that the expression of all transglutaminase species can be enhanced with the obtained cucumber extract of the method according to the invention and / or the cosmetic composition according to the invention and therefore strengthen the skin barrier. The skin barrier function is well known to a skilled person and may be determined by various methods, such as by transepithelial electrical resistance (TEER).

[0105] Impairment of differentiation and formation of the cornified envelope results in a reduced stratum corneum (SC) barrier function and decreased structural and functional defense of the skin. Stimulation of TGMs which are involved in the formation of the CE are relevant for cutaneous barrier function improvement resulting in improved skin conditions.

[0106] Stress is also known to alter the skin barrier. Exposome factors that lead to stressed skin can be defined as any disturbance to homeostasis from environmental (meteorological factors such as extreme heat, cold, humidity, solar radiation, pollution or tobacco smoke) and / or internal exposure (unhealthy diet, hormonal variations, lack of sleep, psychosocial stress). Together, these challenges to the skin homeostasis constitute the skin exposome, a term which refers to the totality of exposures to such non-genetic factors encountered by an individual over their lifetime. Humans and terrestrial animals with perturbed barrier function have an increased susceptibility towards e.g. skin infections will benefit from topical application and thereby increased defense functions and promoted skin homoeostasis.

[0107] Skin according to the invention means keratinized stratified epithelium such as e.g. face and body skin but also scalp skin. Keratinized stratified squamous epithelium is important in tissues exposed to regular physical abrasion. Epidermal homeostasis is maintained through the balance between keratinocyte proliferation, differentiation and desquamation. An important physiological process is skin desquamation, which occurs at the stratum corneum on the epidermis.

[0108] During skin desquamation, the cornified keratinocytes (corneocytes) are gradually sloughed, and this helps to maintain epidermal homeostasis and thickness, in a controlled process. Desquamation at the top surface of the epidermis is essential for skin homeostasis and renewing of the stratum corneum protective barrier.

[0109] Proteases such as kallikrein-related peptidases (KLK), are directly involved in skin desquamation as the Kallikrein-related peptidases 5 (KLK5), 6 (KLK), 7 (KLK7), 8 (KLK8), and 14 (KLK14). Kallikreins (KLK) family is composed of 15 secreted serine proteases. They are essential epidermal messengers for regulation of the skin microenvironment. In human skin, kallikreins are produced and secreted by keratinocytes in stratum granulosum and SC interstices. The activation of zymogen occurs in a proteolytic cascade, beginning with KLK5, which is capable of selfactivation. Activated KLK5 can cleave amino-terminal peptides from other kallikreins, including KLK7 and KLK14, both found in SC and involved in skin desquamation.

[0110] The role of KLKs in skin desquamation is regarding the cleavage proteins responsible for cell adhesion. Three proteins are the targets of KLKs, desmoglein I (DSG1), desmocollin I (DSC1), and corneodesmosin (CDSN), that together form the corneodesmosome, a modified desmosome formed in SC during the terminal differentiation of keratinocytes, and responsible for cell-cell junction. KLK5 can cleave all three proteins from the corneodesmosome, and KLK7 can cleave DSC1 and CDSN. These two peptidases are the main responsible for skin desquamation in SC, but KLK6 and KLK14 also showed the capability to cleave DSG1 and may also play a role in desquamation.

[0111] It was found in terms of the present invention that the expression of KLK is enhanced using the obtained extract of the method according to the invention and / or the cosmetic composition according to the invention. This has the effect that skin desquamation is balanced. It was furthermore found that the obtained extract of the method according to the invention and / or the cosmetic composition according to the invention was able to stimulate the hyaluronic acid level in dermal fibroblasts, which plays a major role in water storage in the skin and thus providing firm skin.

[0112] The term “stimulation of Bleomycin hydrolase expression” describes the increase of BLMH expression, which is a protease widely expressed in several mammalian tissues. In skin, BLMH, is involved in the degradation of filaggrin monomers into free amino acids which form an important part of the natural moisturizing factors (NMF). The NMF is essential for appropriate stratum corneum hydration, barrier homeostasis, desquamation, and plasticity.

[0113] In context of the present invention, it is generally possible and regularly advantageous to combine the plant extract, preferably the cucumber, Aloe Vera or apple fruit extract or the composition according to the invention or to be used according to the invention with (other) (active) substances, e.g. selected from the group consisting of abrasives, anti-acne agents and sebum reduction agents, antiaging agents, antibacterial agents, anti-cellulite agents, anti-inflammatory agents, irritation-preventing agents, anti-irritants (anti-inflammatory, irritation-inhibiting and irritation-preventing agents), antioxidants, astringents, antiseptic agents, antistatic agents, binders, buffers, carriers, chelating agents, cell stimulants, cleansing agents, surface-active substances, deodorants and antiperspirants, emulsifiers, enzymes, essential oils, fibers, film formers, fixers, foaming agents, foam stabilizers, antifoaming agents, foam boosters, fungicides, gelling agents and gelforming, moisture regulators (moisturizing, wetting and / or moistening substances), osmolytes, compatible solutes, bleaching agents, optical brightening agents, impregnating agents, moisturizing creams, ointments, turbidity agents, opacifiers, brighteners, polymers, powders, proteins and protein hydrolysates, refattening agents, abrasive agents, skin soothing agents, skin cleansing agents, skin caring agents, skin repair agents, preferably containing cholesterol and / or fatty acids and / or ceramides and / or pseudoceramides, skin whitening agents, skin protecting agents, skin softening agents, skin cooling agents, UV absorbing agents and UV filters, benzylidene-beta-dicarbonyl compounds, alpha-benzoyl cinnamic acid nitriles, detergents, skin tanning agents, thickening agents, vitamins, oils, waxes and fats, phospholipids, fatty acids (saturated fatty acids, mono- or polyunsaturated fatty acids, a-hydroxy acids, polyhydroxy fatty acids), fragrances, preferably those listed in S. Arctander, Perfume and Flavor Chemicals, selfpublished, Montclair, N.J., 1969 and Surburg, Panten, Common Fragrance and Flavor Materials, 5th Edition, Wiley-VCH, Weinheim 2006, surfactants, yeast extracts, extracts of algae or microalgae, electrolytes, liquefiers and organic solvents.

[0114] The invention is additionally characterized in the following by illustrative, nonlimiting examples.

[0115] Example 1 : Microwave extraction of frozen cucumber fruits

[0116] Frozen cucumber (Cucumis sativus) fruits cultivated in France were extracted using two different protocols:

[0117] Protocol 1 :

[0118] 10.6 kg of the frozen raw material was coarsely cut and placed into a 32 L extraction vessel, which was cooled in order to maintain the temperature during the extraction below 40°C. The extraction was performed without additional solvent using only the native water contained in the cucumber fruits.

[0119] The cucumber fruits were subjected to microwaves of 1500 W with a ratio of power to raw material of 141 W / kg for 1 hour. The fruits were manually mixed every 15 minutes and an extract aliquot sample was taken at 15, 30, 45 and 60 minutes. The liquid extract samples were filtered through a 20 - 25 pm filter and the filtered liquid extracts were freeze-dried for determination of the dry extract yield and analytical measurements of the obtained dry extract.

[0120] Protocol 2:

[0121] The protocol parameters of protocol 1 were applied using 9.4 kg raw material and additionally the tank was subjected to a partial vacuum of 400 mbar to avoid possible oxidation of the raw material. The ratio of power to raw material was 160 W / kg.

[0122] The results are shown in table 1.

[0123] Table 1 : Results of an extraction of frozen cucumber fruits using either protocol 1 (P1) or protocol 2 (P2)

[0124] Using the applied extraction parameters, the raw material is softly heated all along the process. Application of partial vacuum in addition to microwaves is able to prevent possible oxidation of the raw material and also has the potential to improve the extraction yield.

[0125] Example 2: Microwave extraction of frozen and fresh cucumber fruits

[0126] Extraction parameters as described in Example 1 protocol 2 were used to extract fresh and frozen cucumber (Cucumis sativus) fruit as raw material. 30 kg of fresh and 20 kg of frozen cucumber fruits were used for each extraction. The extraction was performed for a duration of 60 minutes and under cooling in a double jacket extraction vessel so that the extraction temperature did not exceed 40°C. After the extraction, the material in the extraction vessel was pressed to recover the liquid extract more completely. The obtained liquid extracts were then filtered through a 25 pm filter, weight to determine the liquid extract yield and freeze-dried for determination of dry extract yield and analytical measurements.

[0127] The results of this experiment are shown below in table 2. Table 2: Extraction yields of fresh or frozen cucumbers as starting material

[0128] The results show that the extraction yield is significantly improved by using frozen cucumber fruits as raw material instead of fresh cucumbers. The yield of liquid extract was almost doubled from 35.2 wt.-% to 70.0 wt.-%. The dry extract yield was increased by 14 % from 2.9 wt.-% to 3.3 wt.-% when using frozen cucumber instead of fresh cucumbers.

[0129] An analytical comparison of the two obtained extracts after freeze-drying, is shown in table 3. Table 3: Ingredients contained in freeze-dried cucumber fruit extracts

[0130] * determined by HPLC analysis after derivatization

[0131] ** determined by substraction of the sum of free amino acids before hydrolysis from the sum of total amino acids after hydrolysis

[0132] *** determined by incineration * determined by Ion chromatography

[0133] ** determined by HPLC

[0134] ###determined by GC after methanolysis and derivatization

[0135] Compared to the dry extract obtained by microwave extraction alone, the dry extract obtained by combined extraction of microwave and partial vacuum is especially rich in citrulline, glycine, proteins, potassium, magnesium, calcium, fructose and polysaccharides.

[0136] Example 3: Manufacturing of spray-dried cucumber extract concentrate

[0137] Different extracts were prepared and subjected to subsequent spray-drying. a) Liquid cucumber extract obtained from frozen cucumber fruits as described in example 1 after 45 minutes of combined microwave and vacuum extraction (protocol 2) was mixed with maltodextrin as carrier and the obtained solution was freeze-dried. b) Liquid cucumber extract obtained from frozen or fresh cucumber fruits as described in example 2 were mixed with maltodextrin as carrier and the obtained solution was spray-dried.

[0138] Table 4: Ingredients of the spray-dried cucumber extract compositions (DE = dextrose equivalent).

[0139] To evaluate the behavior of the obtained different dry extracts with carrier versus the freeze-dried extract without carrier, 4 g per extract were weighted into a glass vial and the open vials were placed into a humidity chamber consisting of a desiccator with saturated sodium chloride solution giving a humidity of 70-75% in the gas phase.

[0140] Combination 3-1, dried extract without carrier was subjected to the humidity chamber. A complete liquefaction was observable after 8 hours in the humidity chamber. Combination 3-2 was showing a clumping behavior and blocking together after 24 hours in the humidity chamber. Combinations 3-3 to 3-7 were all still free flowing powders after 24 hours in the humidity chamber. The results show that spray-dried cucumber extract concentrates containing maltodextrin with low DE values, i.e. DE <15, more preferably <DE10 have better handling properties than carrier-free or concentrates containing maltodextrin with high DE, e.g. DE 17-20. Example 4: Preserved liquid cucumber extract obtained by microwave extraction

[0141] Liquid cucumber fruit extracts obtained from cucumber fruits as described in example 2 or by mechanical extraction (pressing, juicing or squeezing) are not stable against microbial growth and spoilage. Therefore, different commonly used antimicrobial acids alone or in combination were used to prepare liquid extract combinations with good storage properties.

[0142] The different compositions are listed in table 5.

[0143] Table 5: Ingredients and extraction method for different compositions. The wt.-% of additives are based on the total weight of the combination with the respective liquid cucumber fruit extract. The wt.-% of the respective liquid cucumber fruit extract is as follows: 100 wt.-% - sum of wt.-% of additives. The pH was adjusted to pH 4.0 - 4.5 with lactic acid.

[0144] Example 5: Odor improvement of preserved cucumber liquid extract obtained by microwave extraction

[0145] The preserved liquid cucumber extracts 4-1 , 4-2 and 4-3 were prepared as described in example 4.

[0146] Eleven volunteers were asked to rank them according to intensity of odor from 1 to 3 with 3 being the most intensive odor and 1 being the lowest intensive odor. The individual scores for each combination were added to each other to give a sum score. The higher the sum score the more intensive the odor. The results are listed below in table 6.

[0147] Table 6: Results of the volunteer ranking of different preserved cucumber compositions

[0148] The composition 4-1 led to the most intensive odor with a sum score of 26. Adding 5 wt.-% 1 ,2-pentanediol to it (= combination 4-2) resulted in a clear reduction of sum score to 20, i.e. lower odor intensity compared to 4-1. Adding 10 wt.-% 1 ,2- pentanediol (= combination 4-3) reduced the sum score even more to only 15, i.e. lower odor intensity compared to 4-1 and 4-2. To evaluate the odor intensity of a combination containing benzoic acid I sodium benzoate and sorbic acid I potassium sorbate versus one containing only benzoic acid I sodium benzoate alone and to investigate if 1 ,2-pentanediol can also improve the odor of it, the study was repeated with combinations 4-1 , 4-2, 4-4 and 4-5.

[0149] Ten volunteers were asked to rank these four combinations according to intensity of odor from 1 to 4 with 4 being the most intensive odor and 1 being the lowest intensive odor.

[0150] The individual scores for each combination were added to each other to give a sum score. The higher the sum score the more intensive the odor.

[0151] Table 7: Results of the volunteer ranking of different preserved cucumber compositions

[0152] The combination of the liquid extract with the antimicrobial acids benzoic acid I sodium benzoate and sorbic acid I potassium sorbate led to an even more intensive odor than use of benzoic acid I sodium benzoate alone with a sum score of 35 for combination 4-4 compared to 23 for combination 4-1 .

[0153] Addition of 5 wt.-% 1 ,2-pentanediol to the combination with benzoic acid I sodium benzoate and sorbic acid I potassium sorbate (= combination 4-5) gave again a clear reduction of sum score from 35 to 29, i.e. lower odor intensity compared to 4-4. To evaluate the odor intensity of a combination containing sorbic acid I potassium sorbate and if 1 ,2-pentanediol or 1 ,2-heptanediol can also improve the odor of it, the study was repeated with combinations 4-10, 4-11 and 4-12.

[0154] Ten volunteers were asked to rank these three combinations according to intensity of odor from 1 to 3 with 3 being the most intensive odor and 1 being the lowest intensive odor.

[0155] The individual scores for each combination were added to each other to give a sum score. The higher the sum score the more intensive the odor.

[0156] Table 8: Results of the volunteer ranking of different preserved cucumber compositions

[0157] The combination of the liquid extract with the antimicrobial acids sorbic acid I potassium sorbate led to a sum score of 24 for combination 4-10.

[0158] Addition of 2 wt.-% 1 ,2-pentanediol to the combination (= combination 4-11) gave again a reduction of sum score from 24 to 21 , i.e. lower odor intensity compared to 4-10. Addition of 2 wt.-% 1 ,2-heptanediol (= combination 4-12) gave an even stronger reduction of sum score from 24 to 16, i.e. lower odor intensity compared to 4-10 and 4-11.

[0159] Taken together, the results clearly show that 1 ,2-alkanediols reduce the intensity of the odor of such preserved liquid cucumber extracts. Cosmetic ingredients ideally have no or only low odor by themselves to allow high flexibility concerning the fragrance of the finished cosmetic products containing them, therefore reduction of intensity of odor is an advantage.

[0160] Example 6: Odor improvement of preserved cucumber liquid extract obtained by mechanical extraction

[0161] Commercially available liquid cucumber fruit extract obtained from cucumber fruits by mechanical extraction (Gesa Gemusesaft GmbH) was preserved with 0.2% sorbic acid I potassium sorbate and combinations with different 1 ,2-alkanediols were prepared.

[0162] The different compositions are listed in table 9.

[0163] Table 9: Ingredients of the different compositions. The wt.-% of additives are based on the total weight of the combination with the respective liquid cucumber fruit extract. The wt.-% of the respective liquid cucumber fruit extract is as follows: 100 wt.-% - sum of wt.-% of additives. The pH was adjusted to pH 4.0 - 4.5 with lactic acid.

[0164] To evaluate if different 1 ,2-alkanediols can improve the odor intensity of combinations containing commercially available cucumber extract obtained from mechanical extraction preserved by use of sorbic acid I potassium sorbate, the study was repeated with combinations 6-1 to 6-4. Eleven volunteers were asked to rank these four combinations according to the intensity of odor from 1 to 4 with 4 being the most intensive odor and 1 being the lowest intensive odor.

[0165] The individual scores for each combination were added to each other to give a sum score. The higher the sum score the more intensive the odor. The results are displayed in table 10.

[0166] Table 10: Results of the volunteer ranking of different preserved cucumber compositions with cucumber extract obtained by mechanical extraction

[0167] The combination of the liquid extract from mechanical extraction with the antimicrobial acids sorbic acid I potassium sorbate led to a sum score of 38 for combination 6-1.

[0168] The addition of 0.5 wt.-% 1 ,2-hexanediol to the combination (combination 6-2) gave a clear reduction of sum score from 38 to 31 , i.e. lower odor intensity compared to 6-1. Addition of 0.5 wt.-% 1 ,2-heptanediol (combination 6-3) gave an even stronger reduction of sum score from 38 to 27, i.e. lower odor intensity compared to 6-1 and 6-2. Addition of 0.5 wt.-% 1 ,2-octanediol (combination 6-4) gave the strongest reduction of sum score from 38 to 14, i.e. lower odor intensity compared to 6-1 , 6-2 and even 6-3.

[0169] Taken together, the results clearly show that 1 ,2-alkanediols also reduce the intensity of the odor of preserved liquid cucumber extracts from mechanical extraction and the effect was observed at the relative low concentration of 0.5% for all the tested 1 ,2-alkanediols.

[0170] Example 7: In vitro stimulation of hyaluronic acid level in dermal fibroblasts

[0171] Liquid cucumber extracts obtained as described in example 1 , protocol 1 and protocol 2 after 30 and 60 min of extraction time were freeze-dried to obtain the respective dry extracts.

[0172] NHDF are seeded into a 96 well plate at a concentration of 2.0 x 104 cells I well. Cells are incubated at 37 °C and 5% CO2 in fibroblast medium containing 5% fetal bovine serum (FBS) until they are 70 - 80% confluent. Then the medium is withdrawn and the test compounds dissolved the fibroblast medium containing 5%

[0173] FBS are added. After incubation for 44-48 h in the presence of the test compounds, the culture medium is collected and hyaluronan is determined by a Hyaluronic Acid Sandwich ELISA kit (Echelon) which is performed according to the supplier instructions. Forskolin was used as positive control. The results are displayed in table 11.

[0174] Table 11 : Results of the determination of the stimulation of hyaluronic acid production in dermal fibroblasts. Different extraction times and the protocols P1 and P2 of example 1 were used.

[0175] All four microwave extracts showed potent hyaluronic acid stimulatory activity.

[0176] The two extracts obtained after 30 min of extraction time showed lower efficacy compared to those obtained after 60 min of extraction time.

[0177] Additionally, the results clearly show the improved efficacy of the extracts obtained by combined microwave and vacuum extraction compared to the extract obtained by microwave extraction alone.

[0178] Example 8: Modulation of gene expression in epidermal keratinocytes in vitro

[0179] Liquid cucumber extracts obtained as described in example 1 , protocol 1 and protocol 2 after 45 min of extraction time were freeze-dried to obtain the respective dry extracts.

[0180] Neonatal human epidermal keratinocytes (nHEK) were cultivated in an EpiLife® medium (Gibco) with 5 % CO2 at 37 °C in accordance with the supplier’s instructions. The cells were treated for 24 hours, with the freeze-dried extracts dissolved in medium and medium alone as the vehicle control. Genomic target expression levels in treated cells were measured using a quantitative Real-Time PCR comparison to vehicle control treatment.

[0181] RNA was isolated using Qiagen’s RNeasy® Mini Kit. The total RNA concentrations were measured using Eppendorf’s pCuvetteG 1.0 and BioPhotometer, by measuring the absorption at 260 nm. Purity control values such as E260 / 280 and E260 / 230 were calculated simultaneously. Reverse transcription was performed using the high-capacity RNA-to-cDNA kit of Applied Biosystems, in accordance with the supplier’s instructions. Samples were treated in Biometra’s PCR Thermocycler. For fast real-time qPCR, the cDNA was diluted with RNase-free water, and the TaqManTM Fast Universal PCR Master Mix of Applied Biosystems was used. Quantitative real time PCR was performed using the StepOnePlus fast real-time PCR instrument by Applied Biosystems. Analysis was conducted using the StepOne software and 2-AAct method leading to the RQ value (normalised to endogenous control HTRP1 expression). For upregulations, RQ values > 2.5 are considered to be relevant. The results are displayed in table 12.

[0182] Table 12: Results of gene expression analysis. Extracts with different extraction protocols and times are examined.

[0183] The results show that cucumber extract obtained according to P2 relevantly up- regulates the gene expression of HAS2 and AQP3 (RQ values of 3.2 and 3.3), whereas cucumber extract obtained according to P1 only shows a tendency to upregulate the gene expression of HAS2 (Rq value of 2.0), but has no effect on AQP3.

[0184] Example 9: Determination of ex vivo skin - stimulation of transglutaminase 1 (TGM1), Bleomycin hydrolase (BLMH) and Kallikrein 5 (KLK5)

[0185] Organ culture of human skin from three donors was performed starting from a skin sample, exciding pieces of approximately 8x3 mm (0 x thickness) and culturing them up to the planned endpoint (TGM1 and BLMH: day 2, KLK 5: day 6).

[0186] Skin samples (6 per treatment) were cultured in an air-liquid interface in a perforated ring of stainless steel in contact with culture medium (modified Williams’ E medium). Freeze-dried cucumber microwave extract obtained as described in example 2 from frozen cucumbers was dissolved at 1 % in DMSO (wt / vol). This stock solution was diluted to the respective test concentrations with water.

[0187] Both the extract sample and the control (water + 4% DMSO) were applied topically and renewed daily. For application, the skin biopsies were gently cleaned with a cotton pad and then 4 pl of each test sample or control were applied on top of each piece and covered with a 6 0 mm delivery membrane.

[0188] Twelve skin sections deriving from six skin samples for each tested condition were immunostained with the selected antibodies (TGM1 : Sigma-Aldrich #HPA040171 , KLK5: Abeam cat. #ab176299, BLMH: Thermofisher cat# PA5-83468). The amount of the antigen present in the epidermis of each slide has been evaluated by estimating the intensity and the distribution of the pink / red within the epidermis and stratum corneum using Image J (NIH-USA). The obtained data have been normalized upon the dimension of the analyzed surface expressed in pixels. Table 13 summarizes the mean percentage score.

[0189] Table 13: Modulation of mean TGM1 , KLK 5 and BLMH staining scores in % (n=3)

[0190] The results surprisingly show that microwave extracts of cucumber fruits clearly stimulate TGM1 , KLK 5 and BLMH on the protein level at very low test concentrations. Compared to the used vehicle, i.e. water + 4% DMSO, finished cosmetic formulations impact the liberation of the extract and its ingredients from the respective matrix depending on formulation type, composition and contained other cosmetic ingredients. Therefore, the effective concentration of the cucumber extract based on its dry matter is typically 2 to 10Ofold higher when applied topically in form of a finished cosmetic formulation on ex vivo human skin.

[0191] Example 10: Odor improvement of Aloe Vera juice

[0192] Commercially available liquid Aloe Vera Gel Concentrate 10 / 1 containing 0.1 % sodium sulfite or dried Aloe Vera juice both obtained from Aloe Vera leaves by mechanical extraction (INCI name: Aloe Barbadensis Leaf Juice) were mixed with antimicrobial acids as given in table 14:

[0193] Table 14: Composition with Aloe Vera extract

[0194] The mixtures were combined with different 1 ,2-alkanediols as listed in table 15 and 17.

[0195] Table 15: Combinations with mixture A and 1 ,2-alkanediols. The wt.-% of additives are based on the total weight of the combination with the respective mixture.

[0196] *SymDiol® 68 green is the trade name of a 1 :1 (wt:wt) blend of 1 ,2-hexanediol and

[0197] 1 ,2-octanediol. To evaluate if different 1 ,2-alkanediols can improve the odor intensity of combinations containing commercially available Aloe Vera Gel Concentrate, ten volunteers were asked to rank these four combinations according to the intensity of odor from 1 to 4 with 4 being the most intensive odor and 1 being the lowest intensive odor.

[0198] The individual scores for each combination were added to each other to give a sum score. The higher the sum score the more intensive the odor. The results are displayed in table 16.

[0199] Table 16: Results of the volunteer ranking of different mixture A comprising compositions

[0200] The combination containing aloe gel concentrate, citric acid, potassium sorbate and sodium benzoate led to a sum score of 33 for combination 11-1.

[0201] The addition of 5.0 wt.-% 1 ,2-pentanediol to the combination (combination 11-2) gave a clear reduction of sum score from 33 to 27, i.e. lower odor intensity compared to 11-1. Addition of 0.5 wt.-% 1 ,2-octanediol (combination 11-4) gave an even lower reduction of sum score from 33 to 21 , i.e. lower odor intensity compared to 11-1 and 11-2. Addition of 1.0 wt.-% of a 1 : 1 blend of 1 ,2-hexanediol and 1 ,2-octanediol (combination 11-3) gave an even stronger reduction of sum score from 33 to 19, i.e. lower odor intensity compared to 11-1 , 11-2 and even 11- 4.

[0202] Table 17: Combinations with mixture B and 1 ,2-alkanediols. The wt.-% of additives are based on the total weight of the combination with the respective mixture. for each combination were performed as described above. The higher the sum score the more intensive the odor. The results are displayed in table 18.

[0203] Table 18: Results of the volunteer ranking of different mixture B comprising compositions

[0204] The addition of 0.5 wt.-% 1 ,2-octanediol (combination 11-7) and addition of 0.5 wt- % 1 ,2-heptanediol (combination 11-6) led to a reduction of sum score from 23 to 21 and 22, i.e. lower odor intensity compared to 11-5.

[0205] Taken together, the results clearly show that 1 ,2-alkanediols also reduce the intensity of the odor of Aloe Vera leaf juice and the effect was observed for all the tested 1 ,2-alkanediols.

[0206] Example 11 : Odor improvement of apple fruit extract

[0207] Liquid apple fruit extract (INCI name: Pyrus Malus Fruit Extract) in water obtained by microwave extraction with 50% aqueous ethanol and subsequent distillative ethanol removal under vacuum comprising 30% glycerin, 0.2% potassium sorbate, 0.5% sodium benzoate and 0.5% lactic acid (= apple fruit extract composition) was combined with different 1 ,2-alkanediols. The different compositions are listed in table 19.

[0208] Table 19: Ingredients of the different compositions. The wt.-% of additives are based on the total weight of the combination. To evaluate if different 1 ,2-alkanediols can improve the odor intensity of apple fruit extract composition, 11 volunteers were asked to rank these four combinations according to the intensity of odor from 1 to 4 with 4 being the most intensive odor and 1 being the lowest intensive odor.

[0209] The individual scores for each combination were added to each other to give a sum score. The higher the sum score the more intensive the odor. The results are displayed in table 20.

[0210] Table 20: Results of the volunteer ranking of different apple fruit extract compositions The combination containing apple fruit extract, lactic acid, potassium sorbate and sodium benzoate led to a sum score of 33 for combination 12-1 . The addition of 0.5 wt.-% 1,2-hexanediol or 0.5 wt.-% 1,2-heptanediol to the apple fruit extract (combination 12-2 and 12-3) gave a clear reduction of sum score from 33 to 27, i.e. lower odor intensity compared to 12-1. Addition of 0.5 wt.-% 1 ,2- octanediol (combination 12-4) gave an even lower reduction of sum score from 33 to 23, i.e. lower odor intensity compared to 12-1, 12-2 and 12-3.

[0211] To evaluate another composition, liquid apple fruit extract obtained from apple fruits by mechanical extraction (pressing, juicing or squeezing) was mixed with 0.2% potassium sorbate, 0.5% lactic acid and 0.5% levulinic acid (= apple fruit mechanical extract composition). 1 ,2-Pentanediol was added to this mixture to evaluate if odor intensity was improved as well (table 21).

[0212] Table 21 :

[0213] Eleven volunteers were asked to rank these four combinations and the individual scores for each combination were calculated as described above. The results are displayed in table 22.

[0214] Table 22: Results of the volunteer ranking of different apple fruit extract compositions with and without 1,2-pentanediol

[0215] Example 12: Formulation examples

[0216] In the formulation examples 1 to 11 , the following two perfume oils PFO1 and PFO2 were each used as fragrance (DPG = dipropylene glycol). Table 23: Perfume oil PFO1 with rose smell (amounts in parts by weight)

[0217]

[0218] Table 24: Perfume oil PFO2 with white blossom and musk smell (amounts in parts by weight)

[0219] Table 25: Cosmetic formulations (amounts in parts by weight) The following cosmetic preparations are prepared:

[0220] 1 = Skin protection balm for sensitive skin

[0221] 2 = Tinted skin barrier balancing face balm, SPF 15

[0222] 3 = After-sun moisturizing spray O / W

[0223] 4 = Night cream W / O 5 = Skin cleansing gel

[0224] 6 = After-shave hydrogel

[0225] 7 = Anti-dandruff hair shampoo

[0226] 8 = Anti-perspirant pump spray

[0227] 9 = Day care fluid O / W 10 = Skin barrier improving cream O / W

[0228] 11 = Sun care lotion SPF 24 (UVA / UVB balance)

[0229]

[0230]

[0231]

[0232]

[0233] Water ad 100

Claims

Claims1. Method for producing an extract from a plant of the family Cucurbitaceae, preferably for producing a cucumber extract, comprising or consisting of the steps: i. providing plant material of a plant of the family Cucurbitaceae, preferably providing cucumber plant material; ii. extracting the provided plant material under the presence of electromagnetic waves having frequencies ranging from 915 MHz to 28 GHz; iii. obtaining a plant extract, wherein the extraction in step ii. is performed at a temperature of or less than 70°C, preferably of or less than 55 °C and especially preferred at a temperature of or less than 40°C, and / or wherein the extraction in step ii. is performed in the absence of a solvent, preferably wherein the extraction in step ii. is performed under vacuum, especially preferably at a pressure of 50 to 950 mbar.

2. Method according to claim 1 , wherein the provided plant material in step i. is fresh or frozen plant material.

3. Method according to any one of the preceding claims, wherein the extraction in step ii. is performed at a power of the electromagnetic waves of between 0.1 to 1 kW , preferably of between 0.4 to 0.8 kW, dependent on 1 kg of plant material.

4. Method according to any one of the preceding claims, wherein the extraction in step ii. includes stirring of the plant material.

5. Method according to any one of the previous claims, wherein the extraction in step ii. is performed for a time of at least 20 minutes, preferably of at least 30 minutes, moreover preferably of at least 80 minutes, especially preferably of at least 125 minutes.

6. Method according to any one of the previous claims, wherein the method comprises an additional step iv.a of drying the plant extract obtained in step iii and / or iv.b adding at least one antimicrobial acid selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid; dehydroacetiC acid, citric acid, lactic acid, phytic acid, their corresponding salts, and / or at least one 1 ,2-alkanediol selected from the group consisting of 1 ,2- pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2-decanediol or mixtures thereof, preferably wherein the at least one 1 ,2-alkanediol is 1 ,2-pentanediol, or mixtures thereof.

7. Method according to claim 6, wherein the drying is performed via spraydrying using a carrier preferably selected from the group consisting of maltodextrin, dextrin and cyclodextrin and mixtures thereof, preferably in an amount of from at least 30 wt.-%, preferably at least 50 wt.-%, especially preferably at least 70 wt.-% dependent on the total weight of the obtained spray-dried composition.

8. Cosmetic composition comprising or consisting of: a plant extract obtained from a plant of the family Cucurbitaceae, Asphodelaceae, Rosaceae or Anardicaceae , preferably wherein the plant extract obtained from a plant of the family Cucurbitaceae is obtained by a method according to any one of claimsat least one antimicrobial acid and / or at least one 1 ,2 - alkanediol.

9. Cosmetic composition according to claim 8, wherein the at least one antimicrobial acid selected from the group consisting of benzoic acid, 4- hydroxybenzoic acid, sorbic acid, salicylic acid, levulinic acid, p-anisic acid, glucuronic acid, gluconic acid, caprylhydroxamic acid, dehydroacetic acid, citric acid, lactic acid, phytic acid, their corresponding salts.

10. Cosmetic composition according to claim 8 or 9, wherein the at least one 1 ,2 - alkanediol is selected from the group consisting of 1 ,2-pentanediol, 1 ,2- hexanediol, 1 ,2-heptanediol, 1 ,2-octanediol, 1 ,2-nonanediol and 1 ,2- decanediol or mixtures thereof, preferably wherein the at least one 1 ,2- alkanediol is 1 ,2-pentanediol, 1 ,2-hexanediol, 1 ,2-heptanediol or 1 ,2- octanediol.

11. Cosmetic composition according to any one of claims 8 to 10, wherein the plant extract is selected from cucumber, Aloe Vera, apple or mango extract, preferably wherein the cucumber plant extract is obtained by a method according to any one of claims 1 to 7.

12. Cosmetic preparation, comprising the cosmetic composition according to any one of claims 8 to 11 , preferably wherein the preparation is selected from the group consisting of emulsions, milks, lotions, creams, balms, ointments, gels, tonics, serums, cleansers, granules, powders, stick preparations, such as lipsticks, foams, aerosols, or sprays.

13. Cosmetic preparation according to claim 12 comprising the cosmetic composition in an amount in a range of between 100 to 0.001 wt.-%, preferably 80 to 0.001 wt.-%, more preferably 70 to 0.001 wt.-%, especially preferably 40 to 0.001 wt.-%, preferably of between 20 to 0.01 wt.-%, moreover preferably of between 10 to 0.05 wt.-%, especially preferably ofbetween 5.0 to 0.1 wt.-%, dependent on the total weight of the cosmetic preparation.

14. Use of at least one 1 ,2 - alkanediol for improving the odor of a plant extract obtained from a plant of the family from a plant of the family Cucurbitaceae, Asphodelaceae, Rosaceae or Anacardiaceae and / or a composition according to any one of claims 8 to 11 and / or of a preparation according to claim 12 or 13, preferably wherein improving includes or consists of reducing at least one undesired olfactory impression and / or increasing at least one desired olfactory impression.

15. Cosmetic, non therapeutical use of a composition according to any one of claims 8 to 11 , preferably obtained or obtainable by a method according to any one of claims 1 to 7, or of a preparation according to claim 12 or 13 for strengthening the skin barrier and / or for balancing skin desquamation and / or for stimulation of Bleomycin hydrolase expression.

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