7-O-Galloyltricetifavan: a promising natural radical scavenger.

7-O-Galloyltricetifavan ( 7OGT ), a natural flavonoid, is isolated from the leaves of Pithecellobium clypearia . The compound exhibits a variety of biological activities. This study details the evaluation of the HOO • antiradical activity of 7OGT by quantum chemistry calculations. The HOO • trapping activity of 7OGT in the gas phase (reference state) was discovered to follow the formal hydrogen transfer mechanism with a rate constant of k = 4.58 × 10 8 M -1 s -1 . In physiological environments, 7OGT is predicted to be an excellent HOO • radical scavenger with k overall = 2.65 × 10 8 and 1.40 × 10 4 M -1 s -1 in water and pentyl ethanoate solvents, respectively. The HOO • antiradical activity of 7OGT in water at physiological pH is approximately 2000 times that of Trolox and substantially higher than that of other well-known natural antioxidants such as trans-resveratrol or ascorbic acid. Thus, 7OGT is an excellent natural antioxidant in polar environments.