Diarylheptanoid sulfates and related compounds from Myrica rubra bark.

Three new diarylheptanoids, myricanol 11-sulfate (1), juglanin B 11-sulfate (2), and myricanone 5-O-(6'-O-galloyl)glucoside (3), were isolated from the bark of Myrica rubra. Compounds 1 and 2 were characterized as diarylheptanoid sulfates on the basis of spectroscopic analyses. The antioxidative activities of the fractionated extracts and isolated compounds were estimated by the oxygen radical absorbance capacity (ORAC) and superoxide dismutase (SOD)-like activity assays. The major isolate, myricitrin (4), displayed a high ORAC value and moderate SOD-like activity (13,198 μmol TE (Trolox equivalent)/g and IC₅₀ 127.5 μg/mL, respectively), which might explain the potent antioxidative activity of this material.