Natural molecules to fight Asian hair exposome

In this study, we evaluated the effect of a natural complex extract, AC, which associates the antioxidant activity and photo-protective power of Zingiber officinale roots and Magnolia officinalis bark with the Pracaxi oil (Pentaclethra macroloba), an original oil rich in long chain fatty acid to reinforce lipid layer and to refill cuticle gap. Permeation, protein carbonylation, mechanical resistance and hair strengthening and gloss were evaluated in Asian hair. The active ingredient named AC (trade name Zoryalys®) penetrates to the heart of the hair. Thanks to this, it prevents protein oxidation induced by pollution and UV exposure. As a result, the hair structure integrity is protected, inducing strength and resistance of the hair, and finally gloss.

Hair has always been considered as a symbol of beauty. The appearance of hair is one of the main factors that contributes to our sense of attractiveness and can therefore have a strong influence on one’s self-esteem and self-confidence. However, every day, hair is exposed to exposome, leading to external and internal damage of the hair shaft and therefore impacting its beauty. This term exposome was first introduced by Wild, 1 who described it as totality of exposures to which an individual is subjected from conception to death. A redefined definition was provided by Miller and Jones, 2 who proposed that the exposome should be considered as a cumulative measure of environmental influences and the subsequent associated biological responses of an individual throughout their life. More precisely, three broad exposome domains, often overlapping with each other are proposed to classify environmental exposures within the exposome. These domains are as follows:

More precisely, stress and health, pollution, nutrition, physical and chemical manipulation, climate and radiation, and microbiota are included in Hair Exposome. Among them, exposure to sunlight and urban pollution are considered as the main unavoidable stressors that impact physicochemical properties of hair and lead to cuticle and cortical damages to the hair fibre affecting its strength and its beauty. 3,4 The lipid layer, mainly composed of covalently bound fatty acids whose major component is 18-MEA (18- methyleicosanoic) and covering the outermost surface hair fibre cuticle, is the most vulnerable to external damages. 18- MEA creates a hydrophobic mantle around the hair fibre surface that acts as a boundary lubricant to reduce friction resistance between hair fibres. 5 With the loss of this natural protection, the hair is more hydrophilic and proteins of the underlying cuticle and then of inner cortex, which are the key component of hair, become more exposed to harmful factors and more prone to be degraded. 6,7 The deleterious effect of exposome reaches the inside of the cuticle, inducing photodegradation of the cysteine groups and peroxidation of the cell membrane complex, composed by fatty acids, cholesterol and ceramides. As the cysteine disulphide bonds are broken by UV light, they are oxidised and thus produce cysteic acid. This increase in cysteic acid is considered to be a major cause of hair integrity damage and reduced mechanical strength. Oxidation of the amide carbon of polypeptide chains also occurs, producing carbonyl groups. It is important to note that protein carbonylation is induced either by the direct impact of ROS or by reactions with secondary products of oxidative stress such as reactive aldehydes produced by lipid peroxidation, forming adducts with side chains of cysteine, histidine and lysine residues. 8,9 As hair fibre cannot be repaired, protecting and maintaining the hair fibre architecture are essential to prevent daily damages and to retain both mechanical and cosmetic hair properties. This protection requires an adequate combination of bio-active components. The use of natural antioxidants from plants such as polyphenols have been shown to protect hair from lipid peroxidation and protein degradation induced by UV exposure. 10 More precisely, shogaol and gingerol (6- gingerol, 8-gingerol, and 10-gingerol), which are the major polyphenols of Zingiber officinalis roots, possess high antioxidant activity. 11 Detailed literature survey has pointed out that Zingiber officinalis roots described for treatment of many diseases and herbal medicine play a major role in the preparation of many Ayurvedic medicine, the science of life