Phytochemical Investigation of an Ostrya carpinifolia L. Extract: An Effective Anti-Pollution Cosmetic Active Ingredient.

Ostrya carpinifolia L., a member of the Betulaceae family, is a tree endemic to the Mediterranean basin that is well known for the hardness of its wood. In this study, we assess the anti-pollution activities of a hydroalcoholic extract of O. carpinifolia twigs using several judiciously selected in vitro cosmetic bioassays. The extract's capacity to counteract excessive production of reactive oxygen species following a cutaneous exposure to atmospheric pollution was evaluated using a combination of several antioxidant assays: DPPH, FRAP and β-carotene bleaching assays. These antioxidant assays were complemented by anti-elastase, anti-collagenase, anti-hyaluronidase and anti-lipoxygenase assays to evaluate the capacity of the extract to preserve the integrity of the skin. The hydroalcoholic extract of O. carpinifolia demonstrates intriguing biological antioxidant activities, with approximately 50 % inhibition observed in DPPH and β-carotene assays. Furthermore, its anti-lipoxygenase, anti-hyaluronidase, and anti-collagenase activities are noteworthy, exceeding 50 % inhibition. The two major compounds of O. carpinifolia ethanolic extract were isolated and identified as myricitrin (1) and quercitrin (2). Myricitrin and quercitrin exhibit antioxidant and anti-hyaluronidase properties; we explored the correlation of these properties with the activity of the crude hydroalcoholic extract. Notably, these compounds have not been previously described in the Ostrya genus.