Chemical Constituents of the Flowers of and Their Cytotoxic Properties.

The flower of (Puerariae Flos) is a reddish-purple to violet-purple flower that blooms between July and September. In our preliminary study, Puerariae Flos extract exhibited significant activity against a human ovarian cancer cell line. This research aims to identify the active compounds in Pueraria Flos. By repeated chromatography, one new tryptophan derivative (), two new flavanones ( and ), and 19 known compounds, including tryptophan derivatives ( and ), flavonoids (-), isoflavonoids (-), a flavonolignan (), and a phenolic compound (), were isolated from a methanol extract of Puerariae Flos. The structures of new compounds were elucidated as 13--benzoyl-l-tryptophan-1--d-glucopyranoside (), 2-hydroxy-5-methoxy-naringenin (), and 2-hydroxy-5-methoxy-naringenin 7---d-glucopyranoside (). Among the isolates, afromosin (), tectorigenin (), apigenin (), glycitein (), (-)-hydnocarpin (), irilin D (), irisolidone 7--glucoside (), and genistein () showed cytotoxicity against human ovarian cancer cell line A2780. Apigenin () and (-)-hydnocarpin () were the most active (IC values of 9.99 and 7.36 μM, respectively).