Four undescribed flavonoids and monoacylglucosylglycerols from Ligustrum sinense lour. and their xanthine oxidase inhibitory activity

Two undescribed flavonoid glycosides, (2 R,3R)-dihydrokaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (1) and 5,7,4′-trimethoxyflavone 3-O-β-D-xylopyranosyl-(1→2)-β-D-glucopyranoside (2), two undescribed monoacylglucosylglycerols, (2S)-1-O-(6-deoxy-6-sulfo)-α-D-glucopyranosyl-3-O-linolenoyl glyceride (3) and (2S)-1-O-(6-deoxy-6-sulfo)-α-D-glucopyranosyl-3-O-oleoyl glyceride (4), together with five known compounds, gingerglycolipid B (5), 3-O-neohesperidosyl-7-O-rhamnosylkaempferol (6), 3-O-glucosyl-7-O-rhamnosylkaempferol (7), kaempferitrin (8), and 7-O-glucosylapigenin (9) were isolated from the leaves of Ligustrum sinense. Structural elucidation of 1–9 was achieved using 1H,13C NMR, COSY, HSQC, and HMBC experiments, in conjunction with HRESIMS data. The absolute configuration of 2 was deduced by ECD spectrum. Flavonoids (1,2, 6–9) inhibited xanthine oxidase activity with IC50 values ranging from 11.6 to 58.4 μM. Meanwhile, monoacylglycosylglycerols 3–5 were inactivity (IC50 > 100 μM).