Isolation and identification of antioxidants from Sophora japonica.

A new flavonol triglycoside, kaempferol 3-O-alpha-L-rhamnopyranosyl-(1 --> 6)-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranoside (1), as well as two known kaempferol 3-O-[alpha-L-rhamnopyranosyl-(1 --> 6)]-[beta-D-glucopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (2) and kaempferol 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranoside-7-O-alpha-L-rhamnopyranoside (3), were isolated from the n-BuOH extract of the pericarps of Sophora japonica by bioassay-guided fractionation. The structure of compound 1 was established by UV, IR, MS, and one- and two-dimensional NMR spectroscopy, including DEPT, NOESY, DQF-COSY, TOCSY, HMQC, and HMBC experiments. Compounds 1-3 showed antioxidative activity in DPPH and cytochrome-c assay using HL-60 cell system.