Tyrosinase inhibitor and radical scavenger fractions and isolated compounds from aerial parts of Peucedanum knappii Bornm.

In this study, we investigated tyrosinase inhibitory and radical scavenger activities of the hydroalcoholic extract from Peucedanum knappii Bornm aerial parts, together with its fractions. The EtOAc fraction showed the highest antioxidant and anti-tyrosinase activity was selected for the isolation and identification of major active compound(s). Two flavonol glycosides, named rhamnetin-3-O-β-D-glucopyranoside (1) and isorhamnetin-3-O-β-D-glucopyranoside (2) were isolated from the EtOAc fraction. Compound 1 showed the most active radical scavenging and potential anti-tyrosinase activity with SC50 values of 2.9 µg mL(-1) on the DPPH test and IC50 27.95 µg mL(-1) in mushroom tyrosinase method. Therefore, isolated flavonoids from P. knappii can be considered as antioxidant and effective tyrosinase inhibitors.