FR2838341A1 - Cosmetic or dermatological compositions, e.g. for combating skin aging, erythema or irritation, containing extract of Cystoseira stricta brown algae having e.g. DNA protecting action - Google Patents

Abstract

Cosmetic or dermatological compositions containing an extract (I) of the brown alga Cystoseira stricta Sauvageau (also known as Cystoseira amentacea Bory variety stricta Montagne) are new.

Description

level of the skin, mucous membranes and / or integuments.

- 1

  SEAWEED EXTRACT OF THE KIND CYSTOSEIRA AND

  USE IN CARE PRODUCTS

  The present invention relates to the use of an extract of a seaweed of the genus Cystoseira, in particular Cystoseira stricta Sauvageau (= Cystoseira amentacea Bory variety stricta Montagne), in an effective amount and in a physiologically acceptable medium for topical use, in the products. cosmetics and / or dermatological care, more particularly in applications where protection is sought against radical attacks of various origins and o a soothing and protective role with regard to inflammatory processes,

  irritations, allergic manifestations and erythema.

  It is well known that the effects of free radicals are neLast and numerous because their reactions are almost always part of a chain reaction process: the radical meets a non-radical molecule which allows it to stabilize at the expense of the creation of 'a new radical capable of continuing the reaction. Free radicals in particular cause a whole series of alterations in the cellular constituents, in particular of DNA and its lipids. But their preferred targets are the polyunsaturated fatty acids present in the phospholipids of cell membranes. This radical attack on lipid derivatives is called lipid peroxidation or lipoperoxidation. It is a chain reaction which is going to be at the origin of the degradation of the molecular and architectural structure of cell membranes with in particular inactivation of receptors and modification of the exchanges of the cell with the medium.

  exterior (Belleville, 1988 - Angiology, 41: 79-86).

  Lipid peroxidation can take place according to two different mechanisms (Emerit & Galli, 1987 - Cah. Nutr. Diét., 22: 35-39): a non-

  enzymatic and an enzymatic mechanism.

  - 2 In the non-enzymatic mechanism, all the membranes are susceptible to attack, in particular the mitochondrial membranes with modification of the energy flow and the lysosomal membranes with release of the hydrolases. The specificity of the substrate is very low QU zero. The susceptibility of fatty acids to this mechanism of peroxidation depends on their degree of unsaturation. In the enzymatic mechanism, there is a specificity of the substrate and the radical tearing will be selective and stereospecific. Arachidonic acid, which is a normal constituent of cell membranes, is released under the influence of the phospholipases A2 and C. Then there is a progressive oxidation carried out in two ways: - by cyclo-oxygenase which removes the hydrogen in C13 of arachidonic acid and forms pro staglandins and thromboxanes and - by 5-lipoxvengenase which removes the hydrogen in C7 from the acid

  arachidonic and forms leukotrienes.

  During this euzymatic oxidation, oxygenated free radicals appear, in particular hydroxyl and alkoxy radicals as well as

singlet oxygen.

  The consequences of lipid peroxidation are multiple in the short term as in the long term: - in the short term, it causes ionic disorders with in particular an alteration of the sodium pump and a homeostasis of intracellular calcium, which leads to energy stress with cell edema,

  decrease in ATP levels and cell death.

  - in the long term, the modifications of the membrane lipids are responsible for the accumulation of lipofuscinic pigments observable during aging (Therond, 1989 - J. Med. Esth. and Chir. Derm., 26:

273-280).

  - 3 The free radicals released also amplify inflammatory phenomena with in particular the stimulation of the synthesis of lipid mediators (prostaglandins and leukotrienes), the activation of certain transcription factors, the induction of the synthesis of interleukin IL-1 and heat shock proteins s (hsp). More particularly, the superoxide anion intervenes at the level of inflammation on the one hand by activating a latent chemotactic plasma factor which increases the accumulation of neutrophils and, on the other hand, by allowing the formation of other oxygenated radical species themselves very active. We therefore understand the importance of having products that help control radical reactions and maintain good regulation of lipid peroxidation processes, given their major roles in

  alteration of cell membranes and inflammatory phenomena.

  In this regard, the Applicant has surprisingly and unexpectedly discovered that the extract prepared from the brown alga Cystoseira stricta has, in addition to protective properties of DNA, also protective properties with regard to the harmful damage caused by the two mechanisms of lipoperoxidation, namely alterations of cell membranes and

  development of inflammatory processes.

  Due to its multiple activities, said extract advantageously finds its use alone or in combination with at least one other active principle, in a physiologically acceptable medium, in care products intended in particular to combat skin aging, to reduce or even to free skin irritations, inflammations, erythema, especially erythema induced by ultraviolet radiation, localized erythematous rashes

  or diffuse on the skin and therefore to treat so-called sensitive skin.

  By physiologically acceptable medium is meant a compatible medium

  with the skin, mucous membranes and dander.

  Preferably according to the invention, the extract or the applications comprising it are used topically. According to the invention, the products comprising the extract can be cosmetic or dermatological compositions. More particularly according to

  the invention is cosmetic compositions.

  The genus Cystose ira belongs to the phylum of HeteroLontophyta, to the las of Phacophyta (brown algae) and to the order of Fucales. It groups together around 30 species in the Mediterranean. The species stricta, also called Cystoseira amentacea variety stricta grows there in dense belts on rocky substrates. Its ecological requirements make it an alga very characteristic of our rocky shores by its adaptation to the shock of the waves, its resistance to strong variations of the solar radiation and its resilience to live in the affected stations.

by pollution.

  To the knowledge of the applicant, industrial applications for this species, in particular in the field of care have never been described to date. In an advantageous embodiment, the extract of the alga Cystoseira stricta according to the present invention is an extract which can be obtained from thalli or from some isolated part of thalli in fresh, frozen, dry form,

whole, fragmented or ground.

  Any extraction method known to a person skilled in the art can be

  used to prepare the extract contained in the compositions according to the invention.

  More particularly, the extract is advantageously obtained by maceration of the thalli in a solvent or a mixture of solvents followed by filtration and

  centrifugation to remove particles.

  In a preferred embodiment of the present invention, the extract thus

  obtained is calibrated by successive ultrafiltrations and concentrations.

  As solvents advantageously used, mention will be made of water, chlorinated solvents such as chloroform, ethers such as ethyl ether, acetone, C 2 to C 8 lo esters such as ethyl acetate and butyl acetate, C1 to C6 alcohols such as methanol, ethanol, isopropanol and butanol, C2 to C6 polyols such as propylene glycol and butylene glycol, without this list being

  limiting. These solvents can be used alone or as a mixture.

  The extraction can be repeated several times until the exhaustion of

  thalli according to methods well known to those skilled in the art.

  The proportion by mass between the solvent and the fresh material to be extracted can vary within wide limits. More precisely it can be between 15: 1

and 1: 1 preferably 8: 1.

  It is possible to make improvements, optimizations and modifications to the process for preparing the extracts. So instead of simple maceration, we can use countercurrent techniques, decoction, leaching, reflux extraction, extraction using ultrasound or microwaves associated or not with solvents , extraction using supercritical fluids,

  in particular supercritical CO2 with or without co-solvent.

  Whatever the mode of preparation used according to the invention, subsequent steps aimed at promoting conservation and / or stabilization can be added without modifying the very nature of the extract. Thus, for certain cosmetic applications, it may be advisable to concentrate and purify the liquid extract or even to prepare a dry extract from liquid extract, for example by conventional drying, precipitation, evaporation techniques,

atomization or lyophilization.

  Other characteristics and advantages of the invention will appear on reading the examples which follow, which are given purely by way of illustration and are not limitative of the invention, as regards the other cosmetic and dermatological activities which have been highlighted at the heart of the development of this

o cosmetic active ingredient.

  Example nl: Preparation of an Extract According to the Invention The preparation of the extract of Cystoseira stricta (: C. amentacea variety stricta) according to the invention comprises the succession of the following stages: - 200 g of thalli pre-dried and reduced in powder are dispersed in 1700 ml of water with moderate stirring and at room temperature, - the suspension is filtered and centrifuged to remove the particles, - the supernatant is then subjected to successive ultrafiltrations and finally

  concentrated until the calibration of its activities.

  The extract obtained is clear and dark amber in color.

  Example 2: Demonstration of the orotective effect of DNA vis-à-vis the oxene sinaulet This example demonstrates the protective effect of the extract of Cystoseira stricta

  prepared according to the invention on DNA vis-à-vis singlet oxygen.

  Singlet oxygen is formed by the direct action of light on the oxygen molecule. The photobiological reaction is triggered by radiation

W and those of the visible spectrum.

  Singlet oxygen diffuses very easily. He then becomes very aggressive and causes DNA damage. This damage corresponds to several categories of lesions, for example base alterations, DNA-protein bridging, DNA strand breaks. They intervene as well on the DNA of the cell nucleus as on the DNA of the mitochondria. In case of failure or inadequacy of the DNA repair systems, this damage leads to mutations and the

cell death.

  Experimental conditions: The protocol used is the in vitro 3D test (SFRI) on plasmid DNA. It is a system for detecting damage on DNA captured on

  microplate (Salles et al., 1995 - Anal. Biochem. 232: 37-42).

  Singlet oxygen is generated by illumination of methylene blue. A stock solution of methylene blue at 10 µg / ml was diluted with

  concentration of 4 ng / ml in ultrapure water (MilliQ quality from Millipore).

  This solution is mixed in equal volume with different dilutions of the extract of Cystoseira stricta (0.1% - 1% and 10%). 501 of the mixture are added to the wells of a microplate containing adsorbed plasmid DNA. The whole is then lit for 20 minutes under two 100 Watt lamps, 30 cm apart. The other stages of the test are as follows:

  2s - a stage of repair of lesions by specific repair complexes.

  During the resynthesis phase of the excised DNA strand, a biotin-labeled nucleotide is incorporated into DNA, - a step of recognition of biotin by an avidin molecule coupled to a peroxidase molecule, - a step of revealing the reaction by adding a chemiluminescent substrate

peroxidase.

  Results: For a better visualization of the results, these are expressed as the percentage of inhibition of the formation of oxidative damage on DNA or percentage of protection. The value 0% corresponds to the repair signal of

DNA damaged by the oxidant alone.

  The percentage of inhibition or protection (P) in the presence of reactive oxygen species is calculated as the relative decrease in the lesional effect due to singlet oxygen, namely: 0 [oxidizing RLU] - [RLU (oxidizing + sample)] () x 100 [oxidizing RLU]

  with RLU: Relative Light Units.

  The specific protection is the reilet of the anti-free radical activity due to the tested extract.

  The results obtained show that in the presence of the extract of Cystoseira stricta prepared according to the invention at the concentration of 0.1% - 2.5% and 10% the specific protection of DNA vis-à-vis the singlet oxygen is respectively

from 41% - 77% and 86%.

  This protection is indeed very active since 50% of the protection

  specific are achieved with only a concentration of said extract of 0.2%.

  This property allows applications intended to protect the genetic material and to fight against mutations induced for example by various radicals

  free and chemical agents or by the different ultraviolet rays.

  Example No. 3: Demonstration of the protective e ect of the membrane members against notice of the lipid perordation The lipid peroxidation attacks the lipid derivatives of the membranes and causes alterations which may lead to cell lysis. It includes four

  successive stages: initiation, propagation, reactivation and termination.

  In the initiation step, the hydroxyl radical generated at the cellular level by ionizing radiation, ultraviolet radiation A and B. Oxidases or ferry ions tears off a hydrogen atom from a carbon located between two double bonds d 'a malonic sequence of a polyunsaturated membrane fatty acid [eg linoleic acid C18: 2 (n-6), linolenic acid C18: 3 (n-3), arachidonic acid C20: 4 (n-6)] which after activation and rearrangement forms a

alkyl radical.

  In the propagation step, molecular oxygen binds to the alkyl radical 0 to form a peroxyalkyl. The latter tears off a hydrogen atom from another polyunsaturated fatty acid molecule close to the former. I1 forms a

  hydroperoxide and a second aLEyl radical.

  The reaction intensifies all the more since the fatty acid chains have a large number of double bonds. Several hundred fatty acids can be reached and lead to an accumulation of hydroperoxides which

  represent, in fact, a source of alkyl radicals.

  In the reactivation step in the presence of ferrous ions, the hydroperoxide constitutes a very aggressive alkoxyl radical, ferric ions and hydroxyl ions. It's Fenton's reaction. The superoxide anions revive the Fenton reaction by reducing the ferric ions to ferrous ions: this is the Haber-Weiss cycle. Like hydroxyl ions, alkoxy radicals pull a proton from a polysunsaturated fatty acid to form a fatty alcohol and an alkyl radical

  and, thereby, relaunch a new chain of reactions: this is the reactivation phase.

  In the termination step, the blocking of the auto-oxidation chain can occur spontaneously at the level of the alkyl and peroxyalkyl radicals by interaction with free radicals of the same kind or of others formed on

  peptide or nucleic acid chains. It is Russel's bimolecular ending.

  However, this mechanism is not very active.

  All cytomembranes are susceptible to attack from the initiation phase. Indeed, the peroxidation of unsaturated membrane lipids alters their structure, their permeability and their functionality with disturbance of transmembrane potentials, ion fluxes and membrane transport, inactivation of membrane receptors and deregulation of transduction signals. These

  alterations are irreversible and can lead to cell lysis.

  Since lipid peroxidation is a chain reaction, the intramembrane effects of free radicals continue even when the attack

radical fades.

  In the context of the present invention, it has been demonstrated that the extract of

  Cystoseira stricta have protective effects on cytomembranes.

  These results are proven using in vitro tests on keratinocytes and fibroblasts subjected to three different peroxidative systems: - the hypoxanthine-xanthine oxidase enzyme system which generates superoxide anions and hydrogen peroxide, - the action of t- butyl hydroperoxide in the presence of ferrous ions which generates alkoxy radicals and - 1 irradiation of WA radiation which releases singlet oxygen and

hydroxyl radicals.

  These effects were assessed according to a biochemical approach to the evaluation of an enzymatic activity: cytoplasmic lactate dehydrogenase. The classic dosage of lactate dehydrogenase present in the cell cytoplasm

  allows to quantify the membrane alterations caused by an attack.

  Indeed, the release of the enzyme in the culture medium reflects the alteration of the

plasma membrane.

  Depending on the type of attack, the extract which is the subject of this patent is incorporated at a rate of 2 or 4% either in the complete culture medium or in the PBS according to several methods: before the attack for 48 hours (P1) , during the assault 30 (P2) as well as before and during the assault (P3). The standard chosen is alpha tocopherol incorporated at a dose of 5.10 M after having been previously diluted in - 11 of 5% ethanol (10-2M). Details of experimental protocols are provided

for each example.

  All the results are expressed in% of protective activity relative to the control cells from the following formula: C (%) = [(AB) A] x 100] for which A = [DOCT - DOCA) / DOCT] x 100 B [DO CTB-DOCAB) / DOCTB] x 100 with DO: optical densities CT: unaggressed control cells, cultured without extract CA: assaulted cells, not protected by the CTB extract: unaggressed control cells, cultured in the presence of 'extract

  CAB: attacked cells, protected by the extract.

  They represent the average of three experiments with 3 points for

  each treatment. The means are expressed with a risk of error a = 0.05.

  3 -1 Protection of Cytomembranes Against Superoxide Anions and Hydrogen Peroxide This example demonstrates the protective effects of the extract according to the invention on keratinocytes and fibroblasts in culture subjected to an attack on the hypoxanthine system. xanthine oxidase which generates superoxide anions and

hydrogen peroxide.

  Experimental conditions and results: The protocol used in this example is adapted from Christmas work

  Hudson et al., (1990 - Int. J. Cosmetic Sc., 12: 105-114).

  Suspensions of keratinocytes and fibroblasts are seeded in their respective culture medium in 96-well microplates. After 24 h of incubation, at 37 ° C. in an atmosphere at 5% CO 2, the medium is removed and replaced with new medium. The addition of the extract which is the subject of this patent is carried out -12 at the concentrations of 2% and 4% before the attack (P1) as well as before and during

  aggression (P3) for both cell types.

  The aggression is carried out in PBS for 150 minutes with the hypoxanthine concentrations of 160 g.ml and xanthine oxidase of 20 mU.mli for keratinocytes and 5 mU.mli for fibroblasts. The evaluation of the release of lactate dehydrogenase is carried out on the supernatant after the attack. For a dose of 2% of extract according to the invention and with the experimental conditions defined in this patent, the anti-free radical protective activity (in%) is for - the keratinocytes of 74 + 4 for P1 and 111 + 5 for P3

  - fibroblasts of 50 + 2 for P 1 and 103 + 4 for P3.

  For a dose of 4% of said extract, this anti-free radical protective activity is for - keratinocytes of 85 + 4 for P1 and 128 + 6 for P3 - fibroblasts of 79 i 4 for P1 and 126 + 6 for P3. We note that alpha-tocopherol, which is the reference, leads to a result for - keratinocytes of 94 + 4 for P1 and 150 + 7 for P3

  - fibroblasts of 67 + 3 for P1 and 79 + 4 for P3.

  The analyzes carried out by the inventors clearly demonstrate that the Cystoseira extract according to the invention has a protective effect on the cytomembranes of keratinocytes and fibroblasts against free radicals generated by the aggression of the hypoxanthine-xanthine oxidase system. At the lipoperoxidation level, this effect reflects a blockage of the initiation phase and the

2 5 Haber- We is s.

  3 - 2 Protection of Cytomembranes Against Alkoxy Radicals This example demonstrates the protective effects of the extract according to the invention on keratinocytes and fibroblasts in culture subjected to an aggression of t

  butyl hydroperoxide which in the presence of ferrous iron generates alkoxy radicals.

  - 13 Experimental conditions and results: The aggression is carried out in the complete culture medium for 7 hours for keratinocytes and for 6 hours for fibroblasts at 37 ° C. in an atmosphere with 5% CO 2. The addition of the extract which is the subject of this patent is carried out at concentrations of 2% and 4% during the attack (P2) as well as before and during

  aggression (P3) for both cell types.

  For a dose of 2% of extract according to the invention and with the experimental conditions defined in this patent, the anti-free radical protective activity is (in%) for - the keratinocytes of 47 + 2 for P2 and 116 + 5 for P3

  - fibroblasts of 37 + 2 for P2 and 58 + 3 for P3.

  For a dose of 4% of said extract, this anti-radical protective activity is for - keratinocytes of 53 * 3 for P2 and 12X + 6 for P3

  1S - fibroblasts of 61 + 4 for P2 and 74 + 4 for P3.

  We note that the reference to alpha-tocopherol leads to a result of: - keratinocytes of 40 + 2 for P1 and 107 + 5 for P3

  - fibroblasts of 49 + 3 for P1 and 78 + 4 for P3.

  The analyzes carried out by the inventors clearly demonstrate that the extract of Cystoseira stricta according to the invention has a protective efiSet for the cytomembranes of keratinocytes and fibroblasts against alkoxy radicals generated by the aggression of t-butyl hydroperoxide. At the level of lipoperoxidation, this effect

  therefore reflects a blockage of the reactivation phase.

  2s 3 - 3 Protection of cytomembranes against UVA radiation This example demonstrates the protective eects of the extract according to the invention on fibroblasts in culture subjected to WA radiation. Ultraviolet

  release hydroxyl radicals and singlet oxygen inside the cells.

  Experimental conditions and results: The aggression is carried out in PBS for 6 h. The addition of the extract which is the subject of this patent is carried out at concentrations of 2% and 4% before the attack (P1) and before and during the attack (P3). Lactate release assessment

  dehydrogenase is carried out on the supernatant at the end of the test.

  For a dose of 2% of extract according to the invention and with the experimental conditions defined in this patent, the anti-free radical protective activity

  o is (in%) of 52 + 3 for P1 and 140 + 6 for P3.

  For a dose of 4% of said extract, this anti-radical protective activity

  goes to 68 i 4 for P1 and 148 + 6 for P3.

  The analyzes carried out by the inventors clearly demonstrate that the extract of Cystoseira stricta according to the invention has a protective effect on the cytomembranes of keratinocytes and fibroblasts against ultraviolet A radiation. The results obtained by the inventors and presented in l example 3 prove that the extract of Cystoseira stricta according to the invention protects the

  cytomembranes of harmful dogats caused by lipid peroxidation.

  The inhibition of superoxide anions, alkoxy radicals and singlet oxygen reveals a triple blockage of the auto-oxidation chain of polyunsaturated fatty acids at the initiation phase, the Haber-Weiss cycle and the reactivation phase. The results obtained by the inventors clearly demonstrate that said extract allows the synthesis of the most aggressive radicals, namely the

  hydroxyl radicals and alkoxy radicals.

  The fact of introducing the active principle at various stages of cell culture (before and / or during the assault) also makes it possible to specify the mode of action of

this asset.

  - In the Pl administration, the extract is eliminated from the culture medium before

- 15-.

  aggression. The recorded activity reveals that the Cystoseira extract prepared according to the invention is capable of penetrating both keratinocytes and

  fibroblasts to protect them from intracellular free radicals.

  - In the P2 administration, the extract is present only during the aggression.

  The recorded activity therefore reveals that said extract is capable of intercepting free radicals inside the cells to protect them from free radical attack. - In the P3 administration, the extract is present before and at the time when the enzymatic aggression takes place. The recorded activity confirms although the extract has

o anti-radical activity.

  Example No. 4: Demonstration of the Anti-Inflammatory Protective Effect Inflammation is a reversible process resulting from damage to cellular structures. Oxygenated free radicals amplify this process, in particular by stimulating the synthesis of lipid mediators (pro staglandins and leukotrienes). These reformed substances are released from a constituent

  normal cell membranes: arachidonic acid.

  Arachidonic acid is released from membrane phospholipids under the action of phospholipases A2 (and C). I1 then occurs an oxidation,.,; progressve realsee - by cyclooxygenase which removes C13 hydrogen from arachidonic acid and forms prostaglandins and thromboxanes and - by 5-lipoxygenase which removes C7 hydrogen from arachidonic acid and forms lencotrienes .

  Newly trained mediators: lencotrienes, prostaglandins and thromboxanes

  act on the permeability of the vessels and cause painful effects.

  The two examples inserted below illustrate the inhibitory action presented by the extract according to the invention at two levels of the inflammatory process, namely a

  anti-phospholipase A2 activity and anti-lipoxygenase activity.

  - 16 4 - 1 Inhibition of phospholipase A This example demonstrates the inhibitory activity of the extract of Cystoseira stricta

  prepared according to the invention, with respect to phospholipase A2.

  Experimental conditions and results:

  The protocol used is adapted from the work of Uthe & Magge (1971 - Can.

  J. 13iochem., 49: 776) and those of Dennis (1973 - J. Lipids Res., 14: 152}.

  lo The reaction medium contains the substrate (a phospholipid: L phosphatidylcholine dimyristoyl) and the extract to be tested in increasing concentrations: 2% - 3% - 4% and 5%. In the presence of the enzyme phospholipase A2, the phospholipid transforms into lysolecithin with release of a fatty acid insoluble in the medium. The reaction is monitored by turbimetry using a spectrophotometer at the wavelength of 360 nm. The reported values correspond to the arithmetic mean of three

  tests carried out for each concentration of algal extract.

  With the increasing concentrations of the extract of Cystoseira stricta according to the invention, namely 1% - 2.5% - 5% and 7.5%, an inhibition of

  the enzyme activity of 34% - 70% - 86% and 88% respectively.

  4 - 2 Inhibition of 5-lipowenase This example demonstrates the inhibitory activity of the extract of Cystoseira stricta

  prepared according to the invention with respect to 5-lipoxygenase.

  S-lipoxygenase is the key enzyme for the synthesis of lencotrienes from

arachidonic acid.

  Lencotrienes are involved in the development of skin tumors and in several other diseases (asthma, psoriasis ...}. Leukotriene B4 - 17 induces chemotaxis and aggregation of lencocytes. Leukotrienes C, D and E are involved in anaphylaxis (generalized allergic shock) as inducers of bronchoconstriction and changes in patency

vascular of the lungs.

  Lencotrienes are present in neutrophils. By binding to receptors of many cells, they cause negative biological effects and lead to the phenomena of irritation, pain and redness. lo Experimental conditions and results: The protocol used is that described in the Methods of Enzymatic journals

  Analysis (411, 1965) and Brit. Med. Bull., (30: 219, 1989).

  The reaction medium contains the substrate (an unsaturated fatty acid: linoleic acid) and the extract to be tested in increasing concentrations: 1% - 1.5% - 2% and 2.5%. In the presence of the enzyme, linoleic acid is transformed into 5 hydroperoxy-6,8,11,14-eicosatetraenoic acid (5 HÉETE3 whose formation is followed

at 234 nm.

  The reported values correspond to the arithmetic mean of three

  tests carried out for each concentration of algal extract.

  With the increasing concentrations of the Cystose extract will go strictly according to the invention, namely 1.5% - 2% - 2.5% - 3% and 4%, an inhibition of

  the enzymatic activity of 38% - 6Q% - 90% - 97% and 100% respectively.

  The results of these last two examples demonstrate that the extract which is the subject of this patent has significant inhibitory capacities at the level of two of the enzymes strongly implicated in inflammatory processes, namely the

  phospholipase A2 and 5-lipoxygenase.

  - 18 These properties allow applications where one seeks to limit or block the processes of formation of mediators of inflammation and skin allergy. They are also useful in treatments aimed at reducing or eliminating irritations, stinging, allergic manifestations, erythema and redness. Conclusion The above examples demonstrate that the extract prepared from the macroalga o Cystoseira stricta (= Cystoseira amentacea variety stricta) according to the invention has good repair capacities for DNA lesions but also high capacities for inhibiting neLast consequences of membrane lipoperoxidation and this at the level of the two mechanisms of this peroxidation, namely the non-enzymatic mechanism which attacks all cytomembranes and the enzymatic mechanism which triggers inflammatory processes. Thus, said extract can be advantageously used in various applications involving in particular: - the protection of genetic material from, for example, free radicals and ultraviolet radiation, the inhibition of the degradation and / or destruction of cells , - the fight against the effects of intrinsic and / or extrinsic aging of cells, particularly of skin cells, - inhibition or even suppression of inDarnmatory processes such as allergic manifestations in the skin, - treatment of so-called sensitive skin, - the treatment of cutaneous erythema, particularly erythema induced by ultraviolet radiation or localized or diffuse erythematous eruptions on the skin and caused by various infectious agents or not. - 19 Said compositions using the present invention contain said extract as active principle, alone or in combination with at least one other principle

  active, but in an effective amount for topical application.

  Advantageously, the final composition of said products contains between 0.1% and 40% (w / w), preferably between 1% and 5% by weight of the extract.

prepared according to the invention.

  The extract which is the subject of the present invention can be used in cosmetic or dermatological compositions for the exploitation either of one of the activities or properties demonstrated and taken in isolation, or of at least two of these

  activities are still all of these activities considered together.

  Said extract can be incorporated in all the galenical forms normally used in the cosmetic and dermatological fields for topical application to the skin, in particular aqueous or oily solutions or dispersions of the lotion or serum type, emulsions ions of liquid or semi consistency. -liquid of the milk type obtained by dispersion of a fatty phase in an aqueous phase (O / W) or vice versa (E / W), the suspensions or emulsions of o soft consistency of the aqueous or anhydrous cream or gel type, the dispersions

  Ionic and / or non-ionic vesicles.

  When applied to the integuments, said extract can also be incorporated in various galenical forms, in particular in the form of aqueous, alcoholic or hydroalcoholic solutions or also of creams, gels, emulsions,

  foams and even aerosols with a pressurized propellant.

  These cosmetic and dermatological compositions according to the invention can constitute cleaning, protection, treatment or care creams for the face or the body (for example day or night creams, make-up removing creams, foundation creams, anti-soals cream), foundations, -20 cleansing milks, body care or protective milks or even anti-sun, lotions for skin and integuments, foams for care

  skin, bath or hair compositions, anti-hair loss compositions

  sunscreen or after shave or depilatory without these lists being exhaustive. All these compositions are prepared according to the usual methods

of the skilled person.

  The extract of Cystoseira stricla according to the invention can be combined in said cosmetic and dermatological compositions with any other ingredient lO usually used in formulations in topical application: extraction and / or synthetic lipids, hydrophilic or lipophilic gelling polymers , surfactants, emulsifiers, preservatives, antioxidants, perfumes, vitamins, emollients, sequestrants, depigmentants, sunscreens, slimming agents, ceramides, dyes, bactericides, dandruff, water- or fat-soluble active ingredients, plant extracts,

  marine extracts, tissue extracts without this list being exhaustive.

  Of course, care will be taken to select the possible ingredient (s) to be added to said compositions so as not to alter or substantially alter the properties advantageously attached to these compositions and to add them

  in amounts conventionally used in the cosmetic field.

  It is also possible to incorporate the algal extract according to the invention into any suitable cosmetic carrier such as, for example, film-forming agents,

  liposomes, chylomicrons, cyclodextrins, micelles, macro-, micro-

  and nanoparticles of macro-, micro- and nanocapsules, or to absorb them on

  organic polymers, textile and mineral supports.

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Claims (10)

  1 - Cosmetic and dermatological compositions characterized in that they contain an extract of the bran alga Cystoseira stricta Sauvageau (= Cystoseira amentacea Bory variety stricta Montagne). 2 Cosmetic and dermatological compositions according to claim 1 characterized in that one carries out the extraction from thalli or any part of thalli of said alga in fresh, frozen, dry, whole, fragmented or crushed form. 3 - Cosmetic and dermatological compositions according to any one   claims 1 and 2 characterized in that said extract is obtained by   maceration of the thalli of the said alga, followed by filtration, centrifugation, ultrafiltration and concentration.   4 - Cosmetic and dermatological compositions according to any one   claims 2 and 3 characterized in that the maceration can be replaced   by countercurrent techniques, decoction, extraction under reflux, extraction using ultrasound, microwaves associated or not with solvents, extraction by supercritical fluids, in particular supercritical CO2 with or without co-solvent.   5 - Cosmetic and dermatological compositions according to any one   of claims 2 to 4, characterized in that the extraction solvent is chosen   from the group consisting of water, chlorinated solvents such as chloroform, ethers such as ethyl ether, acetone, C2 to C8 esters such as ethyl acetate and butyl acetate , C1 to C6 alcohols such as methanol, ethanol, isopropanol and butanol, C2 to C6 polyols such as propylene   glycol and butylene glycol and mixtures thereof.   6 - Cosmetic and dermatological compositions according to any one   of claims 1 to 5, characterized in that said extract is used either under   liquid form or in dry form obtained by drying, precipitation,   atomization, evaporation or lyophilization.   - 22 7 - Cosmetic and dermatological compositions according to any one   claims 1 to 6 characterized in that said extract is incorporated or   associated with a suitable cosmetic vector such as for example film-forming agents, liposomes, chylomicrons, micelles, cyclodextrins, macro-, micro- and nanoparticles, macro-, micro and nanocapsules or absorbed   on organic polymers, textile and mineral supports.   8 - Cosmetic and dermatological compositions according to any one   of claims 1 to 7, characterized in that they comprise from 0.1% to   % by weight, in particular from 1% to 5% by weight of extract of said alga.   o 9 - Cosmetic and dermatological compositions according to any one   claims 1 to 8 characterized in that said compositions are presented   in any dosage form suitable for topical application to the skin,   mucous membranes and / or integuments in a physiologically acceptable medium.   - Use of an extract of Cysfoseira stricta Sauvageau (= Cystoseira amenfacea Bory variety stricta Montagne) as active ingredient, said active ingredient being incorporated alone or in combination with at least one other active ingredient, for cosmetic and dermatological compositions in application topical   as defined in one of claims 1 to 9.   11 - Use of an extract of said alga according to claim 10 characterized in that said extract has a protective activity vis-à-vis   free radicals of various origins.   12 - Use of an extract of said alga according to claims 10 and 11   characterized in that said extract exhibits protective activity against DNA molecules.   2s 13 - Use according to one of claims 10 to 12 characterized in that   that said compositions are intended to protect genetic material and to fight against mutations induced in particular by free radicals and the various ultraviolet radiation.   14 - Use according to any one of claims 10 to 13   characterized in that said compositions are intended to inhibit degradation and / or the destruction of cells.   - 23 - Use of an extract of said alga according to any one of   claims 10 to 14 characterized in that said extract is intended to treat the   intrinsic and / or extrinsic aging.   16 - Use of an extract of said alga according to any one of   s claims 10 to 15 characterized in that said extract has an activity   phospholipase A2 and / or 5-lipoxygenase inhibitor.   17 - Use according to any one of claims 10 to 16   characterized in that said compositions are intended for treating so-called skins