Pharmacognostic evaluation of the potential phytocosmetic applications of some Pistacia L. species

Extracts of differing polarity (n-hexane, ethyl acetate, methanol, and water) were obtained by sequential maceration from the leaves of four Pistacia L. species grown in Türkiye (P. atlantica, P. lentiscus, P. terebinthus, and P. vera). In preliminary studies, antioxidant activity was investigated with DPPH and ABTS+ radical scavenging activity and copper (II) reducing power. To evaluate their potential cosmetic use, inhibitory effects on tyrosinase, elastase and collagenase were evaluated. LC–MS/MS analyses were performed on the bioactive methanol extracts. The methanol extract of P. terebinthus displayed the strongest tyrosinase and elastase inhibition relative to the other species; therefore, subsequent isolation work focused on this extract. Fractionation on a polyamide-packed column yielded eight fractions and their chemical contents were determined with LC-MS/MS. Totally 63 compounds were identified by using standard compound or tentatively in the leaves of Pistacia species. In vitro tyrosinase and elastase inhibition was repeated and it was observed that the effect decreased when compared to mother extract. Therefore, synergy studies were performed between effective fractions and Combination Indexes were calculated by Chou-Talalay method. Strong synergistic effects were observed between fraction F, G and H on tyrosinase and the compounds responsible for the effect were investigated by High Performance Thin Layer Chromatography-Effect Directed Analysis (HPTLC-EDA) technique. Inhibitory bands were isolated from the plate and identified by LC-MS/MS. The compounds directly responsible for tyrosinase inhibition were found to be methyl gallate, 3,5-di-O galloylquinic acid, 3,4-di-O-galloylquinic acid and myricetin-3-O-(3"-O-galloyl) rhamnoside.