Chromones and tannins from the fruit of Euscaphis japonica var. wupingensis

Euscaphis japonica var. wupingensis is a variety of E. japonica in the family Staphyleaceae. The biological characteristics of E. japonica var. wupingensis have been well described, but few studies have been conducted on its constituents. After repeated separation using column chromatography and preparative high performance liquid chromatography (HPLC), ten compounds were isolated from the methanol extract of fruit of E. japonica var. wupingensis. The structure of the components was characterized on the basis of spectroscopic data, including nuclear magnetic resonance (NMR), and mass spectra (MS). These compounds included five chromone derivatives: isobiflorin (1), biflorin (2), 2-methyl-5,7-dihydroxy-chromone-7-O-ß-D-glucopyranoside (5), 5,7-dihydroxy-2-methyl-4H-chromen-4-one (6), and quercetin-3-O-D-arabinoside (7), and four tannins: eugeniin (3), ellagic acid (8), 3, 3′-di-O-methylellagic acid 4-(5”-acetyl) -α-L-arabinofuranoside (9), 3,3′-di-O-methylellagic acid (10), and methyl 3,4,5-trihydroxybenzoate (4). The antioxidant activity of the isolated compounds were tested. Ellagic acid (8) exhibited potent 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity with an SC50 value of 4.05 M.