Glycosides from Bougainvillea glabra.

Three glycosides were isolated from Bougainvillea glabra and their structures were determined by extensive use of 1D and 2D NMR spectroscopy ((1)H and (13)C). First compound was identical to momordin IIc (quinoside D) [beta-D-glucopyranosyl 3-O-[beta-D-xylopyranosyl-(1 --> 3)-O-(beta-D-glucopyranosyluronic acid)] oleanolate], second compound was quercetin 3-O-alpha-L-(rhamnopyranosyl)(1 --> 6)-[alpha-L-rhamnopy-ranosyl(1 --> 2)]-beta-D-galactopyranoside and third compound was its derivative quercetin 3-O-alpha-L-(4-caffeoylrhamnopyranosyl)(1 --> 6)-[alpha-L-rhamnopyranosyl (1 --> 2)]-beta-D-galactopyranoside, a new natural product.