In vitro and in silico investigation of the photoprotective and antioxidant potential of Protium spruceanum leaves and its main flavonoids.

Abstract

For the first time, the photoprotective potential (UV absorption and antioxidant properties) of Protium spru- ceanum leaves and its main flavonoids was investigated combining an in vitro and in silico approach. The extract

was standardized in rutin content (0.8% w/w), quantified by a validated HPLC-DAD method. The extract pro- tected fibroblasts and keratinocytes against cell death in the stress oxidative H2O2-induced test, with greater

effect than rutin standard. This cytoprotection is correlated to the free radical scavenging action, determined by DPPH method. The theoretical investigation on the UV absorption showed an excellent correlation of the results (R2 = 0.911) allowing valuable information about the photoprotective properties of rutin, afzelin and quercitrin, as the importance of the A, B and C rings in the UV absorption property and the hydroxyls in B ring (catechol group) leading to a better antioxidant action. Therefore, the extract from P. spruceanum leaves is a promising candidate for sunscreen development.