Unique natural exopolysaccharides for biomimetic protective effect against urban pollution.

Through natural selection, living organisms have evolved well-adapted survival strategies over time. The shallow salt waters of Moorea lagoon are the site of accumulation of microbial mats called "Kopara," in the native Polynesian language. This unique ecosystem is rich in film-forming exopolysaccharides (EPSs) secreted by microorganisms within the biofilm, as a mean to protect themselves from environmental stress (strong ultraviolet [UV], pH, salinity … ). Using blue biotechnology, a manufacturing process was developed to obtain an EPS with skin benefits. The active ingredient (EPS-229) protects against urban pollution, including free radicals, heavy metals, hydrocarbons, and PM2.5 (particulate matter with a size lower than 2.5 µm). METHODS: The anti-lipid peroxidation action of EPS-229 was studied in an in vitro UVB-irradiated keratinocyte culture model, using lipophilic fluorescent probe. The chelating properties of EPS-229 were evaluated in tubo in the presence of cadmium and lead. The protective effect of EPS-229 on pollution-exposed skin explants was investigated through quantification of released malondialdehyde (MDA) and histological observation of skin morphology using optical microscopy. Clinical evaluation of the protective and cleansing efficacy of a water solution containing EPS-229 (0.02% and 0.01% w/v, respectively) was performed, against placebo, on a panel of 18 volunteers. For these studies, the forearms of volunteers were treated with EPS-229 before (anti-adhesion affect) or after (cleansing effect) application of PM2.5 (iron particles of 1 µm). The presence of skin-adherent particles was observed and quantified by image analysis, using specific digital masks. RESULTS: In vitro, EPS-229 significantly protected keratinocyte cell membranes from lipid peroxidation. A decrease of 28% was achieved when a concentration of 0.001% w/v EPS-229 was applied to the cell culture. In tubo, EPS-229 also presented strong chelating properties. Maximal adsorption was estimated at 154 mg/g (1.37 mmol/g) of EPS-299 for cadmium and at 250 mg/g (1.21 mmol/g) of EPS-229 for lead. In the skin explant model of pollution exposure, EPS-229 (0.03% w/v) reduced MDA production by 44%, preserved cell integrity, improved dermal-epidermal cohesion, and normalized the collagen network. In vivo, treatment of skin with EPS-229 before exposure to PM2.5 created a protective film limiting particle adhesion. When used in a cleansing solution after exposure to PM2.5, EPS-229 formed a mesh that entrapped particles and removed them from the skin surface. CONCLUSION: Inspired by the French Polynesia Kopara unique ecosystem, a bioactive exopolysaccharide (EPS-229) has been developed that offers protection from environmental aggression. As a biomimetic shield at the surface of the skin, EPS-229 provides an immediate multiprotective action that efficiently fights the harmful effects of urban pollution and smog.

New targets in the battle against dandruff.

Dandruff is a scalp disorder characterized by flaking skin and itch of an excessive oily scalp skin. It affects 55% of the global youth and adult population. Seborrheic dermatitis is a similar scalp skin disorder with aggravated itchy rashes and flaking. Different factors are identified in the dandruff development: increased sebum production, uncontrolled fungal growth of Malassezia strains and individual reaction to pro-inflammatory environment, and the susceptibility to trigger an immunological response. Using in vitro and ex vivo models, we show that an Epilobium angustifolium extract dose dependently reduces lipid synthesis in sebocytes to a maximum of -43% (1% extract), and protects the epidermis from Malassezia-induced morphological changes. Epilobium angustifolium extract also acts through innovative mechanisms involving regulations of defensins (human beta-defensins [hBD2] and hBD3) and toll-like receptor 2 involved in the immunological response of the skin. The anti-dandruff and sebum-regulating efficacy of E. angustifolium extract (1.5%) was confirmed in a clinical study that mobilized 24 volunteers with dandruff and greasy scalp for 30 days. At the end of the study, nonadherent and adherent dandruffs were significantly (p < 0.0001) reduced in average by -54% and -48%, respectively. Using Sebumeter® measurements, scalp sebum production was inhibited by -67% (p < 0.0001) in average over baseline. In conclusion, E. angustifolium extract offers a new innovative approach to dandruff reduction through immunomodulation of the skin response to Malassezia invasion.