Phenylpropanoids from the leaves of Acanthopanax koreanum and their antioxidant activity

By various chromatographic methods, one new phenylpropanoid, acanthopanic acid (1), and three known compounds, 1,2-O-dicaffeoylcyclopenta-3-ol (2), (4S)-α- terpineol 8-O-β- D-glucopyranoside (3), and rutin (4), were isolated from the methanol extract of the Acanthopanax koreanum leaves. Their structures were elucidated on the basis of spectroscopic analyses, and their antioxidant activities were evaluated by the intracellular reactive oxygen species (ROS) radical scavenging 2',7'-dichlorofluorescein diacetate assay. Among them, compounds 1, 2, and 4 showed significant scavenging capacity with IC₅₀ values of 3.8, 2.6, and 2.9μM, respectively, and compound 3 showed weak scavenging capacity with the inhibition rate of 37% at 40μM.