Cytotoxic Flavonol Glycosides from Triplaris cumingiana

Three new compounds, 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-oxo-4H-chromen-3-yl-4,6-bis-O-β-d-(3,4,5-trihydroxybenzoyl)glucopyranoside (1), 5,7-dihydroxy-2-(4-hydroxyphenyl)-4-oxo-4H-chromen-3-yl-5-O-α-l-(3,4,5-trihydroxybenzoyl)arabinofuranoside (2), and 2-hydroxy-4-O-α-l-(3,5,7-trihydroxy-4-oxo-4H-chromen-2-yl)phenylarabinofuranoside (3), were isolated from the young leaves of Triplaris cumingiana, together with two known compounds, quercetin 3-O-α-l-(5' '-O-galloyl)arabinofuranoside (4) and quercetin 3-O-β-d-(6' '-O-galloyl)glucopyranoside (5). The structures of 1−3 were established by spectroscopic methods. Compounds 1−5 were evaluated for their cytotoxic activities against the MCF-7, H-460, and SF-268 human cancer cell lines.