JOURNAL OF COSMETIC SCIENCE 130 metal removal from the surface of the skin, thus offering a protection from common urban pollutants such as Cd and Pb. Heavy metal exposure has been linked to increase oxidative stress and lipid peroxidation in skin (8). In Figure 3, when exposed to a mixture of urban pollutants, skin explants produced a high quantity of MDA (expressed in picomole/ml) refl ecting the occurrence of oxidation and lipid peroxidation. In the presence of α-tocopherol (positive antioxidant control), MDA production was reduced by 76%, validating the assay. In the presence of EPS-229 (0.03% w/v), MDA production was lowered by 44%. Thus, EPS-229 demonstrated a strong antioxidant activity and protected from lipid peroxidation, under urban pollutant challenge. Preserving skin lipids from oxidation is known to be important for proper maintenance of the barrier function at the stratum corneum (9). In Figure 4, using histochemical techniques, apparition of pycnotic nuclei (deep magenta color) was observed in the epidermis of skin explants following exposure to a mixture of heavy metals and hydrocarbons. As a marker of severe cellular damage, pyknosis has been associated with environmental insults such as urban pollution or heavy metal exposure (10,11). Pol- lutant exposure also resulted in clear dermal–epidermal separation at the dermal–epidermal junction and reduced collagen network (blue color) in the dermis. Pretreatment of skin explants with EPS-229 (0.03% w/v) for 4 days prior to pollutant challenge prevented the formation of pyknotic nuclei and improved dermal–epidermal cohesion, as well as colla- gen fi ber density. Such results attest of the potential of EPS-229 to protect and restore normal skin structure and physiology under urban challenging conditions. Figure 2. EPS-229 chelates heavy metal particles. Figure 3. EPS-229 protects skin explants from pollutant-induced lipid peroxidation.

EXOPOLYSACCHARIDES FOR BIOMIMETIC PROTECTIVE EFFECT 131 In Figure 5, application of EPS-229 (0.02% w/v) on the skin of human volunteers, before exposure to fi ne particles (PM2.5) mimicking air pollution, reduced the number of adher- ent particles by 45% compared to placebo treatment. By forming an invisible fi lm at the surface of the skin, EPS-229 creates a physical shield able to protect from pollution- induced damage. In Figure 6, cleansing the skin of human volunteers with a solution containing EPS-229 (0.01% w/v) following exposure to PM2.5 could washed away 27% more particles than placebo treatment. Thus, when incorporated in a cleansing solution, EPS-229 forms a mesh able to entrap PM2.5 particles and remove them from the skin surface to reduce pollution-induced damage. By limiting PM2.5 adsorption to the skin, EPS-229 may help prevent melasma development and barrier disruption, since both have been associated with PM exposure (12,13). Figure 5. EPS-229 prevents the adhesion of PM2.5 particles to the skin surface. Figure 4. EPS-229 protects skin explants from pollutant-induced structural changes.