[Two new phenolic glucosides with antioxidant activity from Lythrum salicaria]

Chromatographic techniques were employed to separate and purify the active components with antioxidant activity from the aboveground part of Lythrum salicaria. The data of 1D/2D NMR, optical rotation, and high-resolution mass spectrometry were used to identify the purified compounds. Six phenolic glucosides were identified, including 6'-(p-methoxyphenyl)gallate-7-O-β-D-glucopyranoside(1), 6'-ethyl-p-hydroxyphenylethanol-β-D-glucopyranoside(2), 3,4,5-trimethoxyphenol-β-D-glucopyranoside(3), 3,4,5-trimethoxyphenyl 1-O-β-apiofuranosyl(1″→6')-β-glucopyranoside(4), benzylalcohol O-α-L-arabinopyranosyl(1→6)-β-D-glucopyranoside(5), and 6'-acetylethanol-β-D-glucopyranoside(6). Compounds 1 and 2 were novel phenolic glucosides, and compounds 3-6 were isolated from Lythrum for the first time. Furthermore, the antioxidant activities of compounds 1-6 were evaluated. Compound 1 showed potent antioxidant activity, with the half maximal inhibitory concentration(IC_(50)) of 0.16 mmol·L~(-1), which was stronger than that of the positive control trolox with the IC_(50) of 0.24 mmol·L~(-1).