Extract of Porphyridium purpureum obtained by natural eutectic solvent and its uses

Abstract

The present invention relates to a cosmetic active ingredient and its cosmetic uses. This active ingredient comprises an extract of Porphyridium Purpureum, said extract being obtained by extraction using a natural eutectic solvent (NaDES), and it advantageously exhibits antioxidant, soothing, complexion-perfecting, and moisturizing effects.

Description

Title of the invention: Extract of Porphyridium purpureum obtained by natural eutectic solvent and its uses technical field

[0001] The invention relates to a cosmetic active ingredient comprising an extract of Porphyridium Purpureum, said extract being obtained by extraction using a natural deep eutectic solvent (NaDES), as well as its cosmetic uses. This active ingredient thus has a high concentration of phycobiliproteins and polyphenols, which gives it antioxidant and soothing properties that are particularly interesting for cosmetic applications. State of the art

[0002] In the current context, where the demand for natural and environmentally friendly cosmetic products is constantly increasing, it is essential to develop new extraction methods which not only preserve the quality and effectiveness of the active ingredients, but which are also in accordance with the principles of sustainability and respect for the environment, including during the preparation stages of these active ingredients.

[0003] Often, the extraction of bioactive compounds, known as natural compounds, still uses solvents derived from the petroleum industry which are toxic to humans, harmful to the environment and whose manufacture requires many resources, including energy.

[0004] Several alternatives are already known, notably eco-extraction from plant-based ingredients, which is based on the principles of reduced energy consumption, the use of alternative solvents, and renewable plant resources. Although current reference solutions are eco-friendly and offer numerous ecological advantages (e.g., CO2 and other supercritical fluids, ionic liquids, green organic solvents, enzymes, microwaves, and ultrasound), many factors still limit their use.

[0005] There is therefore a need for the preparation of a cosmetic active ingredient that meets the concerns and expectations of consumers, namely a natural, safe, high-quality and environmentally friendly active ingredient.

[0006] To meet this need, the inventor was particularly interested in "Natural Deep Euctectic Solvents" or NaDES (in French, natural deep eutectic solvents), known for exhibiting good biodegradability, low toxicity, reduced costs, high solubilization potential and negligible volatility.

[0007] Thus, the inventor has developed a specific NaDES-type solvent particularly suited to valorize microalgae biomass, improve the extraction of molecules of interest, with reduced energy demand and without requiring a solvent / extracted molecule separation step. Summary of the invention

[0008] Thus, the invention relates to a cosmetic active ingredient comprising an extract of Porphyridium Purpureum obtained by extraction using a natural eutectic solvent (NaDES) of the hydroglycerin type, said extract comprising at least water-soluble pigments and polyphenols.

[0009] By focusing particularly on Porphyridium Purpureum microalgae and a natural hydroglycerin-type eutectic solvent (NaDES), the inventor has optimized the extraction of molecules of interest, namely water-soluble pigments and polyphenols, while offering an ecological alternative to synthetic solvents traditionally used in the cosmetic industry.

[0010] Thus, the cosmetic active ingredient according to the present invention is advantageously obtained by the use of a solvent consisting of a mixture of glycerol, betaine and water, in which the molar ratio (glycerol / betaine) is very advantageously 1:1. This solvent, composed of biodegradable substances such as glycerol, betaine, and of course water, guarantees the naturalness of the final cosmetic active ingredient, making it possible to meet consumer expectations.

[0011] Preferably, the amount of water present in said solvent is between 20 and 30% by weight of the total weight of the solvent, more preferably 26% (plus or minus 1%) by weight of the total weight of the solvent. Thus, the specific molar ratio of the glycerol / betaine mixture combined with the presence of water, again in specific proportions, allows for a high extraction yield, the production of an extract with a viscosity compatible with sterilization of said extract, while exhibiting good stability of the extract over time, compatible with use in cosmetic formulations.

[0012] According to another preferred object of the invention, the cosmetic active principle according to the invention comprises water-soluble pigments, these comprising at least one pigment selected from the group consisting of phycobilliproteins, C-phycocyanin, allophycocyanin, phycoerythrin and their mixture.

[0013] Furthermore, extraction advantageously carried out at low temperature, in particular below 5°C, not only increases the efficiency of the extraction by preserving the integrity of the phycobiliproteins, but also reduces energy consumption.

[0014] Thus, very preferably, the extract comprises at least 80mg / L of phycobilliproteins and at least 22mg / g of total polyphenols.

[0015] According to another preferred object, the extract comprises a greater quantity of phycoerythrin than of phycocyanins. More preferably, the extract comprises at least 5 mg of phycoerythrin per gram of dry microalgae biomass.

[0016] In a particularly preferred manner, the extract is obtained by the process comprising the following steps: a. Culture of Porphyridium Purpureum in a suitable culture medium, b. Extraction using a natural eutectic solvent (NaDES) of type hydroglycerinated, in which the P. Purpureum biomass / solvent ratio is between 1 / 10 and 1 / 100, c. Separation of biomass and supernatant by settling, and recovery of the supernatant, d. Adjustment to a pH between 3 and 5, preferably 4, e. Filtration of the supernatant, preferably by membrane with a porosity between 0.22 and 0.45 pm, f. Addition of vegetable glycerin at a rate of at least 75% by weight of the total weight of the final extract, preferably 85%.

[0017] Advantageously, the process includes a step of removing the culture medium prior to the extraction step by any known means, in particular by centrifugation or filtration.

[0018] Preferably, the P. purpureum biomass / solvent ratio is between 1 / 10 and 1 / 50, more preferably 1 / 20, improving extraction and yield. Most preferably, the solvent consists of a mixture of glycerol, betaine, and water, in which the molar ratio (glycerol / betaine) is 1:1 and the amount of water present in said solvent is 26% (plus or minus 1%) by weight of the total weight of the solvent.

[0019] According to another object, the extraction is preferably carried out cold, in particular at a temperature below 5°C, preserving the molecules of interest in particular phycobiliproteins.

[0020] According to another preferred object, the process does not include a step of separation / elimination of the eutectic solvent included in the supernatant obtained in step c) or d), or e). The supernatant thus also includes glycerol, betaine and water, as well as the final extract.

[0021] According to another object, the invention also relates to the process of extraction and preparation of the active ingredient as described above.

[0022] Furthermore, the invention also relates to a cosmetic composition comprising at least 1% of a cosmetic active ingredient according to any of the preceding objects, by weight of the total weight of the composition.

[0023] Finally, the invention relates more preferably to the use of this cosmetic active ingredient according to the invention or of a composition comprising it, intended for cosmetic treatment, by topical application on the skin, preferably on healthy skin for multiple cosmetic benefits, such as a soothing and / or skin-protecting effect against external aggressions, and / or complexion perfecting, and / or moisturizing.

[0024] The active ingredient according to the invention is also intended to be used as an antioxidant, and / or antimicrobial and / or soothing agent.

[0025] Furthermore, by specifically selecting biomass and a NaDES-type solvent, the invention enables the preparation of a new cosmetic active ingredient derived from natural raw materials, enriched with water-soluble pigments and polyphenols, with a reduced ecological footprint. This active ingredient is not only effective thanks to its recognized cosmetic properties due to the presence of water-soluble pigments, particularly phycobiliproteins, and polyphenols, but is also produced in a way that supports the environmental and social commitments of cosmetic companies. This holistic approach enhances the appeal of the final products to environmentally conscious consumers, while paving the way for greener and more responsible industrial practices.

[0026] Other features and advantages will become apparent from the detailed description of the invention, the examples and figures that will follow. Detailed description of the invention

[0027] Definition

[0028] For the purposes of this invention, "active ingredient" means an extract comprising at least one molecule, preferably a set of molecules having a cosmetic effect, particularly when applied topically, in particular the cosmetic effect being an antioxidant effect.

[0029] For the purposes of this invention, "Porphyridium Purpureum extract" means at least one molecule or a mixture of at least two molecules obtained from a raw material, namely the microalga of the species Porphyridium Purpureum, regardless of the extraction process of said molecule(s). Preferably, it is an extract obtained by extraction using a hydroglycerin-type NaDES solvent.

[0030] Active ingredient according to the invention

[0031] The present invention therefore relates to a cosmetic active ingredient comprising at least one extract from Porphyridium Purpureum, said extract is obtained by extraction using a natural eutectic solvent (NaDES) of the hydroglycerin type, said extract comprising at least water-soluble pigments and polyphenols.

[0032] The microalga Porphyridium purpureum is a unicellular red microalga belonging to the Rhodophyta division. It is widespread in marine and freshwater environments throughout the world. Characterized by its bright red color due to the presence of specific photosynthetic pigments, Porphyridium purpureum is attracting increasing interest in the fields of biotechnology and cosmetics.

[0033] This microalga is distinguished by its ability to produce a variety of bioactive compounds such as phycobiliproteins, sulfated polysaccharides, and polyunsaturated fatty acids. Phycobiliproteins, in particular, are water-soluble protein pigments that give Porphyridium purpureum its characteristic color. The inventor has thus remarkably exploited this biomass to obtain an extract enriched in water-soluble pigments of interest, notably phycobiliproteins.

[0034] The active principle according to the invention thus comprises an extract of Porphyridium Purpureum obtained by extraction using a natural eutectic solvent (NaDES) of the hydroglycerin type, said extract comprising at least water-soluble pigments and polyphenols.

[0035] Preferably, the water-soluble pigments comprise at least one pigment selected from the group consisting of phycobilliproteins, C-phycocyanins, allophycocyanins, phycoerythrins, and mixtures thereof. More preferably, the water-soluble pigments comprise at least phycobilliproteins, which notably confers antioxidant and soothing properties to the active ingredient.

[0036] According to one object, the active ingredient of the invention is obtained using a hydroglycerin-type NaDES solvent, preferably consisting of a mixture of glycerol, betaine, and water, in which the molar ratio (glycerol / betaine) is 1:1. This significantly improves the extraction yield of the molecules of interest, particularly phycobilliproteins, while also making sterilization of the extract compatible, given its viscosity. Finally, extraction using the NaDES solvent according to the invention provides good long-term stability, which is particularly important for a cosmetic active ingredient.

[0037] According to another preferred object, the amount of water present in the NaDES solvent is between 20 and 30% by weight of the total solvent weight, more preferably 26% by weight of the total solvent weight. This improves the viscosity / fluidity of the solvent, which subsequently allows the membrane filtration step to be carried out without altering the extraction yields. Furthermore, the glycerol-based NaDES solvent requires water to allow the formation of the solvent itself and thus of hydrogen bonds.

[0038] Thus, the extract obtained is particularly enriched in phycobilliproteins and total polyphenols, preferably comprising at least 80 mg / L of phycobilliproteins and at least 22 mg / g of total polyphenols. By using a specific NaDES solvent particularly suited to the extraction of these molecules of interest from Porphyridium Purpureum, the extraction yield of these molecules is improved, the resulting viscosity allows for sterilization, and the long-term stability is enhanced, making it suitable for cosmetic use. Finally, the extraction is natural, environmentally friendly, resource-conserving, and meets consumer expectations.

[0039] In this respect, the extract is obtained, in a particularly preferred manner, by the process comprising the following steps: a. Culture of Porphyridium Purpureum in a suitable culture medium, preferably followed by disposal of the culture medium, b. Extraction by adding a natural eutectic solvent (NaDES) of the hydroglycerin type to the biomass of Porphyridium Purpureum in a biomass / solvent ratio between 1 / 10 and 1 / 100, preferably cold extraction in a ratio of 1 / 20, c. Separation of biomass and supernatant by settling, and recovery of the supernatant, d. Adjusting the pH of the supernatant to a pH between 3 and 5, preferably 4, e. Filtration, to remove contaminants and improve the stability of the extract, f. Addition of vegetable glycerin at a rate of at least 75% by weight of the total weight of the extract obtained in the previous step, preferably 85%.

[0040] The extract obtained at the end of step e) then constitutes a first form of the active ingredient according to the present invention.

[0041] The cosmetic active ingredient according to the invention may also advantageously include at least one excipient selected from a preservative, an antioxidant, a stabilizer, an atomizing support, and / or a combination thereof.

[0042] The extract according to the invention present in the cosmetic active ingredient can then be in liquid or solid form.

[0043] When in liquid form, the active ingredient according to the invention consists exclusively of the extract of Porphyridium Purpureum, possibly accompanied by a stabilizer and / or preservation system.

[0044] When in solid form, the active ingredient according to the invention is preferably made up of the extract of Porphyridium Purpureum as previously described and a carrier, for example maltodextrin, or the extract can be encapsulated.

[0045] Composition according to the invention

[0046] The active principle according to the invention is intended to be integrated into a composition, in particular a composition comprising at least 1% by weight of said active principle and a physiologically acceptable medium, preferably a cosmetically acceptable medium.

[0047] These compositions may be in the form of oil-in-water emulsions, water-in-oil emulsions, multiple emulsions (Water / Oil / Water or Oil / Water / Oil), which may be microemulsions or nanoemulsions, or in the form of solutions, suspensions, hydrodispersions, or aqueous gels. They may be more or less fluid and have the appearance of creams, emulsions, gels, masks, or any other appearance known to those skilled in the art.

[0048] Preferably, it may consist of compositions comprising between 1 and 80% of the active ingredient according to the invention, in particular in liquid form, more preferably between 1 and 50%.

[0049] These compositions comprise, in addition to the active ingredient, a physiologically acceptable medium such as a cosmetically acceptable medium, that is to say, one which does not cause any discomfort to the user such as redness, tightness or tingling.

[0050] The compositions according to the invention may also contain at least one additional ingredient to aid in the formulation of the final product. Examples of such ingredients are cited, in particular, in the CTFA Dictionary (International Cosmetic Ingredient Dictionary and Handbook published by the Personal Care Product Council).

[0051] Of course, a person skilled in the art will take care to choose any additional compounds, active or inactive, and their quantity, in such a way that the advantageous properties of the mixture are not, or substantially not, altered by the envisaged addition.

[0052] Method for preparing the extract according to the invention

[0053] The extract constituting or contained in the active ingredient according to the invention is obtained by using a hydroglycerin-type NaDES solvent, in particular by the process comprising the following steps, namely: a. Culture of Porphyridium Purpureum in a suitable culture medium, preferably followed by disposal of the culture medium, b. Extraction by adding a natural eutectic solvent (NaDES) of the hydroglycerin type to Porphyridium Purpureum biomass at a biomass / solvent ratio between 1 / 10 and 1 / 100, preferably between 1 / 10 and 1 / 50, c. Separation of biomass and supernatant by settling, and recovery of the supernatant, d. Adjustment to a pH between 3 and 5, preferably 4, e. Filtration, to remove contaminants, f. Addition of vegetable glycerin at a rate of at least 75% by weight of the total weight of the extract obtained in the previous step, preferably 85%.

[0054] The culture of Porphyridium purpureum can be carried out under controlled conditions, allowing for sustainable and reproducible production of this biomass. For example, a suitable culture medium is Guillard's f / 2 medium. This medium can be adjusted according to the cultivation objectives. Furthermore, culture conditions, such as temperature (generally between 20-25°C), light intensity, and the light cycle, must also be optimized in conjunction with the culture medium to obtain the best results.

[0055] In addition, this microalga has the advantage of growing relatively quickly and not requiring arable land for its cultivation, thus offering an interesting alternative to traditional sources of bioactive compounds.

[0056] Once the biomass has been obtained, it can be freeze-dried, or frozen with an additional freezing step, well known to those skilled in the art.

[0057] Thus, the extraction step can be implemented from wet / fresh biomass, freeze-dried biomass, or from frozen biomass which will first undergo a thawing step.

[0058] Therefore, the extraction is carried out using a hydroglycerin-type NaDES solvent with Porphyridium Purpureum biomass. The solvent is most preferably composed of glycerol, betaine, and water, in which the molar ratio is 1:1 (glycerol / betaine) and between 20 and 30% water, by weight of the total weight of the solvent. Most preferably, the extraction is carried out for 24 hours with stirring.

[0059] The biomass-to-solvent ratio is, again, specifically determined to improve the extraction yield, namely, it is between 1 / 10 and 1 / 100, preferably between 1 / 10 and 1 / 50, particularly 1 / 20. Finally, the extraction is very preferably carried out at low temperatures, specifically below 5°C, 4°C, 3°C, or even 2°C, thus preserving the molecules of interest and therefore maximizing the extraction yield. In particular, cold extraction prevents the denaturation of phycobilliproteins and thus improves their quality, stability, and activity; it limits the use of specialized equipment (e.g., ultrasonic bath, microwave, freeze dryer) and labor time while obtaining high yields; and it simplifies the process and allows for its easier scaling up to industrial production.

[0060] A step of separating the biomass and the supermatant is then implemented by any suitable means known to those skilled in the art, in particular by decantation.

[0061] The supernatant is retained and its pH is adjusted to a pH between 3 and 5, preferably 4. The resulting supernatant is then optionally filtered using a suitable membrane to remove any contaminants, particularly bacteria. Most preferably, the membrane has a porosity between 0.22 and 0.45 µm.

[0062] Finally, a step of adding vegetable glycerin at a level of at least 75% by weight of the total weight of the extract from step e) enhances the preservation of the extract according to the invention, without the addition of a preservative. By increasing the percentage of glycerin in the extract, the Aw (water activity) index decreases, which enhances the preservation of the extract according to the present invention. Preferably, the glycerin is added at a level of at least 85% by weight of the total weight of the extract from step e).

[0063] Preferably, said process does not include an additional separation step between the supernatant obtained and the eutectic solvent, so that the final extract includes the eutectic solvent.

[0064] Solvent

[0065] According to another aspect, the invention also relates to a specific eutectic solvent of the hydroglycerin type consisting essentially of glycerol, betaine, and water, in which the molar ratio is preferably 1:1 (glycerol / betaine), very preferably water represents between 20 and 30%, by weight of the total weight of the solvent.

[0066] Use

[0067] According to another aspect, the invention relates to the use of the active ingredient obtained according to any of the embodiments described above or of a composition including it intended for a cosmetic treatment by topical application on the skin.

[0068] Preferably, the active ingredient is intended for use as a cosmetic product to improve skin hydration and / or to revive the radiance of the complexion and / or as a colorant. In particular, to improve skin hydration and its luminosity (or radiance of the complexion), but also to contribute to strengthening and protecting the skin barrier, as well as to reduce redness.

[0069] Finally, according to another aspect, the active ingredient according to the invention or composition including it is intended to be used as an antioxidant, and / or antimicrobial, and / or soothing and / or skin protector against external aggressions.

[0070] The invention is now illustrated by non-limiting examples of compositions according to the invention and by results. Examples

[0071] Example 1 - Extract according to the invention

[0072] The active ingredient of Example 1 is obtained from Porphyridium Purpureum according to the following process.

[0073] The eutectic extraction solvent is synthesized from ingredients of natural origin accepted in cosmetics, namely glycerol, betaine and water. It is prepared according to the following process.

[0074] The glassware is sterilized in an oven or autoclave or disinfected with 70% alcohol. The reagents are weighed and then added to a sealed container. The mixture (glycerol / betaine in a molar ratio of 1:1 and 26% water by weight of the solvent) is stirred using a magnetic stir bar (300 rpm) and heated to 60°C (under a fume hood). When the mixture reaches its eutectic point (visible upon the formation of a homogeneous, transparent liquid), it is removed from the heat source. The stability of the solvent is assessed after 24 hours by the transparency and viscosity of the mixture. The solvent is then stored at room temperature in the dark.

[0075] The biomass of Porphyridium Purpureum is then cultivated in a suitable culture medium, then the culture medium is removed, by filtration and / or centrifugation depending on the volume.

[0076] The previously prepared eutectic extraction solvent is added to the fresh or lyophilized microalgae biomass in a previously disinfected container at a solid / liquid ratio of 1 / 20 for Porphyridium Purpureum. The hydroglycerin solvent is added to the Porphyridium Purpureum strain. The mixture is stirred for 24 hours at 4°C. At the end of the extraction period, the biomass is separated by decantation, the pH is adjusted to 4.0, and the supernatant is filtered using a 0.22-micron membrane. The total percentage of vegetable glycerin is increased to 85% (w / w) for the Porphyridium Purpureum extract.

[0077] The extracts then constitute a first form of active ingredient according to the invention and are kept in a closed container at room temperature in the dark before possibly being incorporated into cosmetic compositions.

[0078] The active ingredient according to Example 1 consists of an extract of Porphyridium Purpureum possessing in particular the following characteristics: - At least 80 mg / L of phycobilliproteins (including a quantity of phycoerytrin greater than the quantity of phycocyanins), - At least 5 mg of phycoerythrin per g of dried microalgae biomass - At least 22 mg / g of total polyphenols, - Phycoerythrin purity index >1.5 based on a ratio of 565 / 280, - Absence of heavy metals, allergens (+ 60 allergens), and polysaccharides. - Liquid appearance, dark pink to pinkish-purple in color, with a characteristic odor. pH: 4.85 ± 0.30.

[0079] Example 2 - Comparative test with other NaDES solvents

[0080] The inventor has also reproduced this extraction process with several other NaDES-type solvents.

[0081] The results are presented in Table 1 below.

[0082] [Tables 1] Solvents Substance 1 (electron donor) Substance 2 (electron acceptor) Molar ratio Distilled water addition (%) Notes A Citric acid Betaine 1:1 20-40% Limited yield and very high viscosity A' Citric acid Betaine 2:1 Good extraction yield of phycobilliprotein and polysaccharides but viscosity is too high, which makes the stenosis steps complex and therefore results in low stability B Propanediol Betaine 1:1 Limited yield C Urea Betaine 1:2 Limited yield F Glycerol Glucose 1:1 Limited yield G Glycerol Glucose 2:1 Limited yield

[0083] Thus, only the solvent according to the invention makes it possible to obtain an extract with a high yield and compatible with cosmetic uses (stability, viscosity etc.)

[0084] Example 3: Composition according to the invention

[0085] An example of a formulation comprising the active ingredient according to the invention in the form of a face gel is shown in Table 2 below.

[0086] [Tables2] Ingredients % Distilled water 88 Active ingredient according to the invention 10 Xanthan gum 1 Geogard Ultra® (preservative) 1

[0087] The composition of example 3 can in particular be obtained by the following process: Weigh the ingredients separately has. b. Mix the hydroglycerin extract according to the invention with the xanthan gum c. Gently add the distilled water while stirring. d. Add the preservative e. Measure the pH of the mixture and adjust the pH to 4.5-5.5 if necessary.

[0088] The composition then takes the form of a gel.

[0089] Example 4: Composition according to the invention

[0090] An example of a formulation comprising the active ingredient according to the invention in the form of an oil-in-water emulsion is shown in Table 3 below.

[0091] [Tables3] Ingredients % A Distilled water 71 B Argan oil 15 B Shea butter 5 B Olivem emulsifier 1000 5 C Active ingredient according to the invention 3 D Preservative (Eco Preservative) 1

[0092] The composition of Example 4 can in particular be obtained by the following process: a. Measure the ingredients of phase A and phase B in separate containers b. Place phases A and B in a water bath until their temperature reaches 70°C c. Gently add phase B to phase A while mixing. d. Continue mixing until the emulsion temperature drop below 40°C e. Add phase C to the emulsion by mixing f. Add phase D to the emulsion by mixing g. Measure the pH and adjust the pH to 4.5-5.5 if necessary.

[0093] The composition is then in the form of an emulsion.

Claims

Demands

1. Cosmetic active ingredient comprising an extract of Porphyridium Purpureum obtained by extraction using a natural eutectic solvent (NaDES) of the hydroglycerin type, said extract comprising at least water-soluble pigments and polyphenols.

2. Cosmetic active ingredient according to the preceding claim, wherein the solvent consists of a mixture of glycerol, betaine and water, wherein the molar ratio (glycerol / betaine) is 1:

1.

3. Cosmetic active ingredient according to the preceding claim, wherein the amount of water present in said solvent is between 20 and 30% by weight of the total weight of the solvent.

4. Cosmetic active ingredient according to any one of the preceding claims wherein the water-soluble pigments comprise at least one pigment selected from the group consisting of phycobilliproteins, C-phycocyanins, allophycocyanins, phycoerythrins and mixtures thereof.

5. Cosmetic active ingredient according to the preceding claim, wherein the extract comprises at least 80mg / L of phycobilliproteins and at least 22mg / g of total polyphenols.

6. Cosmetic active ingredient according to any one of the preceding claims, wherein the extract is obtained by the process comprising the following steps: a. Cultivation of Porphyridium Purpureum in a suitable culture medium, b. Extraction by adding a natural eutectic solvent (NaDES) of the hydroglycerin type to the Porphyridium Purpureum biomass at a biomass / solvent ratio of between 1 / 10 and 1 / 100, c. Separation of the biomass and the supernatant by decantation, and recovery of the supernatant, d. Adjustment to a pH of between 3 and 5, e. Filtration of the supernatant, f. Addition of vegetable glycerin at a level of at least 75% by weight of the total weight of the extract.

7. Cosmetic composition comprising at least 1% of an active ingredient according to one of the preceding claims, by weight of the total weight of the composition, and at least one cosmetically acceptable excipient.

8. Hydroglycerinated type eutectic solvent consisting of glycerol, betaine, and water, in which the molar ratio is 1:1 (glycerol / betaine).

9. A process for preparing an active ingredient according to any one of claims 1 to 6 comprising the following steps: a. Culturing Porphyridium Purpureum in a suitable culture medium, b. Extraction by adding a natural hydroglycerin-type NaDES eutectic solvent to the Porphyridium Purpureum biomass at a biomass / solvent ratio of 1 / 20, preferably cold extraction, c. Separation of the biomass and the supernatant by decantation, d. Adjustment to a pH between 3 and 5, preferably 4, e. Filtration of the supernatant, f. Addition of vegetable glycerin at least 75% by weight of the total weight of the supernatant.

10. A process according to the preceding claim, wherein the process does not include a step of separating the extract obtained in step c), or d), or e) and the eutectic solvent.

11. Active ingredient according to any one of claims 1 to 6 or composition according to claim 7 for its use as an antioxidant, and / or antimicrobial, and / or soothing and / or skin protectant against external aggressions.

12. Use of a cosmetic active ingredient according to any one of claims 1 to 6 or of a composition according to claim 7 intended for cosmetic treatment by topical application to the skin.

13. Cosmetic use according to claim 12, to improve skin hydration and / or to revive the radiance of the complexion and / or as a colorant.