Polysaccharides in cosmetics

Author: Natalia Korneiko, cosmetologist K éraskin Esthetics (Kiev)

Species diversity

Polysaccharides are high-molecular carbohydrates formed by monosaccharide residues (glucose, fructose, etc.). In living organisms, polysaccharides play the role of an energy reserve (glycogen) and are structural components of cells and tissues (glycosaminoglycans). The diversity in the structure of polysaccharides can be due not only to the nature of the monosaccharides and the method of their connection, but also to the fact that the hydroxyl and carboxyl groups of monosaccharides and their derivatives can be methylated, esterified with organic and inorganic acids (for example, sulfuric acid - agar-agar); hydrogens of carboxyl groups are replaced by metal ions (pectin substances, gums).

There are several classifications of polysaccharides. One of them divides polysaccharides into homopolysaccharides and heteropolysaccharides.

Homopolysaccharides consist of monosaccharide units of the same type (for example, starch, cellulose; from animal polysaccharides - glycogen, chitin).

Heteropolysaccharides consist of residues of various monosaccharides and their derivatives (for example, hemicellulose, inulin, pectin, mucilage and gum).

Another classification divides polysaccharides into:

• anionic: alginic acid, pectin, xanthan gum, hyaluronic acid, chondroitin sulfate, karaya gum, cellulose gum;
• cationic: cationic guar gum, cationic hydroxyethylcellulose;
• nonionic: starch, dextrins, guar gum;
• amphoteric: for example, carboxymethylchitosan.

Hyaluronic acid

Skin glycosaminoglycans are of particular interest for cosmetology and aesthetic medicine. Glycosaminoglycans, primarily hyaluronic acid, are produced by skin dermal cells - fibroblasts. The function of hyaluronic acid in the skin is to maintain the natural level of moisture. This function is ensured due to the high hydrophilicity of the hyaluronic acid molecule (today, even the most “unadvanced” client knows that it is capable of binding and retaining up to a thousand water molecules, thereby preventing its excessive evaporation from the surface of the skin). By binding water, glycosaminoglycans form an intercellular gel-like substance, which is a protective and supporting matrix for the collagen fibers of the dermis and serves as a kind of “support” for the epidermis.

The whole history of hyaluronic acid is the history of improving methods for its isolation and purification. The fact is that the quality of hyaluronic acid as a cosmetic ingredient is determined by its molecular weight. Depending on the source and technology for producing hyaluronic acid, its molecular weight can vary from 70 to 4,000 kDa. The longer the molecular chain and the smaller the variation in molecular weight, the better the polymer network is formed, the greater the viscosity of the solution at low concentrations and the greater the surface of the skin that can be covered with a continuous moisturizing film.

Unlike many biologically active substances, hyaluronic acid exhibits all its valuable properties at very low concentrations (0.01–0.1%), which makes it possible to create effective cosmetics at a price that will suit both manufacturers and consumers. This mainly refers to high molecular weight hyaluronic acid. The use of cosmetics containing hyaluronic acid improves the appearance of the skin, softens, moisturizes and protects the skin.

Carrageenans

Cosmetic compositions for anti-aging and moisturizing programs include carrageenans, a mixture of polysaccharides obtained by extracting red algae and Irish moss. Carrageenans effectively moisturize the skin, forming a moisture-retaining film. Carrageenan is a natural gelling agent obtained by processing red seaweed by extraction followed by purification from organic and other impurities (multiple sedimentation, filtration and washing in water and alcohol).

Alginates

Salts of alginic acid, which are isolated from brown seaweed (kelp, fucus, spirulina), are a source of substances used in various industries, including medicine and cosmetology. Among the substances that have found use in various therapeutic and prophylactic drugs and cosmetics are agar, alginic acid and its salts, and mannitol.

Since the discovery of alginic acid in algae, many of the healing properties of seaweed have been attributed to the presence of this acid. In addition to alginic acid, seaweed is rich in other biologically active substances: microelements and vitamins.

Alginic acid is a polysaccharide, it is built from residues of uronic acids - mannuric and guluronic. Alginic acids are insoluble in water, but are highly hygroscopic, that is, they are able to bind large amounts of water. Alginic acid salts (sodium, potassium, magnesium alginates) dissolve in water to form viscous solutions. This property allows alginates to be used as thickeners, stabilizers, and binders.

In addition, alginates are also suppliers of active biological substances in medical and cosmetic preparations. Alginate masks in their pure form have positive cosmetic effects: they tighten the skin, improve blood circulation, smooth out facial wrinkles, but the introduction of additional biological components into them (essential oils, extracts of medicinal plants, collagen, anti-inflammatory substances, etc.) makes it possible to achieve higher efficiency of their use .

Depending on the active components introduced into the composition, alginate masks can predominantly have nourishing, moisturizing, cleansing, whitening properties, and have anti-aging, anti-cellulite and other effects.

The most important property of alginate masks is their ability to enhance the effect and increase the flow of active substances into the deep layers of the skin of serums applied under the alginate mask. Therefore, the choice of a serum of a certain direction will largely determine the final result of the procedure, for example, a moisturizing or anti-wrinkle serum will accordingly increase the effectiveness of a moisturizing or lifting procedure using an alginate mask. Alginate masks can be the final stage of procedures such as mesotherapy, photorejuvenation, peelings to eliminate skin irritation.

Chitosan

I would like to say a few words about chitosan. Chitosan has new properties that are attractive for cosmetology compared to high molecular weight products. Low molecular weight chitosan has excellent emulsifying ability for the formation of stable emulsions such as “water in oil”, “oil in water”. This property makes chitosan oligomers an ideal binding additive for cosmetic compositions containing oils, complexes of water- and fat-soluble vitamins, and polyunsaturated fatty acids. The chemical characteristics of chitosan solutions (in particular, low pH) help maintain the acid-base balance of the skin, and this also makes it possible to bring the pH of the cosmetic product to the most “comfortable” level for the epidermis. Chitosan is a natural source of glucosamine and N-acetylglucosamine, which serve as the main building blocks of the structural basis of connective tissue - hyaluronic acid, keratan sulfate; chondroitin sulfate; glycosaminoglycans, which we discussed above.

Immunomodulatory effect of polysaccharides

One of the most important properties of polysaccharides is the activation of macrophages - thereby they perform an immunomodulatory function. These processes involve the participation of so-called peptidoglycans - polysaccharides of the bacterial cell wall, for the recognition of which macrophages have special receptors. The receptor recognizes a molecule or its section, and then a series of processes occur that entail an increase in the phagocytic and bactericidal activity of macrophages.

Among the cytokines produced by Langerhans cells are those that stimulate tissue regeneration. Regenerative reactions lead to improved skin structure, stimulation of collagen and glycosaminoglycan synthesis.

In medicine and cosmetology, peptidoglycans are widely used due to the fact that most of them also have pyrogenic, sensitizing and cytotoxic effects. There are cosmetic companies that produce immunomodulatory cosmetics based on peptidoglycans, but in cosmetology they use glucan group polysaccharides to stimulate Langerhans cells. These include β-(1,3)-glucan from baker's yeast, aloe gel (contains α-(1,4)-glucomannan, chitosan. The use of cosmetics with polysaccharides (β-glycans) restores the activity of immunocompetent skin cells. That is macrophages and Langerhans cells are activated, while the synthesis of substances by macrophages - growth factors that promote epidermal regeneration, the synthesis of collagen fibers - increases, and the content of angiogenesis factors also increases. In addition, β-glycans have an antioxidant effect, protecting skin cell membranes and epidermal matrix lipids. free radical oxidation, protecting the skin from the development of signs of premature aging. Stimulation of collagen fiber synthesis by β-glycans helps improve skin elasticity and smooth out wrinkles.

Less common are polysaccharides from seaweed, mussels, and some medicinal mushrooms. The polysaccharide arabinogalactan, which is contained in echinacea and larch extract, has an immunostimulating effect. Glucan from baker's yeast accelerates resistance to fungal infections and protects against UV radiation.

New trends

The launch of new products in the anti-aging market usually comes with a lot of promises to help combat the signs of skin aging. As technology develops, products appear that contain several polysaccharides. For example, this is a combination of hyaluronic acid and biocellulose. Biocellulose is an exclusive material borrowed from surgery, where it is used as a “second skin” to restore the skin. It is created by bacterial fermentation and recreates extremely thin tissue, similar in structure to human skin. Due to its similarity to human skin, biocellulose increases the penetration of active ingredients inside. This technology is just one of many innovations coming to market.

Source: Les Nouvelles Esthetiques Ukraine, No. 5 (69), 2011, pp. 100-102