Skin UV-protective effect of Microsorum grossum extract on human dermal fibroblast

Microsorum großum (Polypodiaceae family), locally called ”metuapua'a”, are two of the most frequently fern species used in Polynesian traditional medicine. Fronds or rizhomes of this species are common ingredient of popular medicine recipes to cure various ailments. M. großum frond and rizhome extracts contains phytoecdysteroids as main bioactive components such as ecdysone analogues, known to have many interesting biological activities and so considered as adaptogenic compounds. Skin UV-protective effect and mode of action of M. großum extract was investigated using three ways: a transcriptomic study with c-DNA array for gene expression modulation, a stress induced premature senescence (SIPS) test on human dermal fibroblasts and cellular response experiment by activation of protein p53. The total extract of M. großum up-regulates both heme oxygenase 1 and ferritin in human fibroblasts of the m-RNAs, enzymes which protect cells from oxidative stress (through the liberation of biliverdin, itself quickly converted into the antioxidant bilirubin) and which exerts several activities like the photoimmunoprotection of skin by UVA through the liberation of CO. The present work also report that premature senescence of human skin induced by repeated UV irradiations can be prevented by an ecdysteroid fraction of M. großum. The activation of the protein p53 by ecdysone content of M. großum is also indicative of a protective effect provided by cellular response including damage DNA repair processes. It seems therefore that extracts of M. großum could protect skin against oxidative stresses and they could be used to formulate innovative cosmetic products.