Isolation, structure elucidation, tyrosinase inhibitory, and antioxidant evaluation of the constituents from Angelica dahurica roots

Two undescribed phenolic compounds, angelicols A ( 1 ) and B ( 2 ) and one undescribed coumarin rhamnoside, angelicoside A ( 3 ), together with 17 known compounds ( 4 – 20 ) were isolated from the roots of Angelica dahurica . Their structures were characterized by physical data analyses such as NMR, HRESIMS, and X-ray diffraction. Compounds 2 , 3 , 5 , 6 and L-ascorbic acid (positive control) exhibited obvious DPPH radical scavenging activities with IC 50 values of 0.36 mM, 0.43 mM, 0.39 mM, 0.44 mM, 0.25 mM, respectively. At a concentration of 25 μM, all compounds showed weaker tyrosinase inhibition activities (%inhibition