Antioxidant Activity and Mechanism of Tetrahydroamentoflavone <i>in vitro</i>

Abstract

(2 S,2″ S)-Tetrahydroamentoflavone (THA) is a typical biflavonoid. In this study, we systematically evaluated its antioxidant activity by various antioxidant assays in vitro. The IC 50 values of THA were 4.8±0.3, 743.2±49.5, 35.5±1.9, 165.7±22.8, 4.4±0.2, and 77.1±2.2 μg/mL, respectively, for superoxide (•O 2 - ) radical-scavenging, Fe 2+ -chelating, Cu 2+ -chelating, DPPH• (1,1-diphenyl-2-picrylhydrazyl radical) scavenging, ABTS• + (3-ethylbenzthiazoline-6-sulfonic acid radical) scavenging, and Cu 2+ -reducing power. The average ratio value of IC 50, Trolox :IC 50, THA was calculated as 2.54, suggesting that THA possesses 2.54 times the total antioxidant level than the standard antioxidant Trolox. THA exerts its antioxidant activity in vitro through metal-chelating, and radical-scavenging, which is via donating a hydrogen atom (H•) and an electron (e). Its antioxidant activity can be responsible for its pharmacological effect and make it an attractive natural antioxidant.