Chemical constituents of the leaves of Campylospermum elongatum.

The leaves of Campylospermum elongatum have furnished the cyano-glycoside (lithospermoside), nine isomeric biflavonoid derivatives among which five are I-3 -II6 linked (robustaflavone; 4'-O-methyl robustaflavone; 4', 4 "'-di-O-methyl robustaflavone; 7,4', 4 "-tri-O-methyl robustaflavone; 4', 7.-di-O-methyl robustaflavone) and four I-3 -II8 linked (amentoflavone; 7-O-methyl amentoflavone; 7,7 "-di-O-methyl amentoflavone; 7, 4', 7 "-tri-O-methyl amentoflavone) and a flavone glycoside, 4 "-O-methyl-7-O-beta-D-galactosylapigenin. All structures were established from a complete spectroscopic analysis (MS, IR, 1D, and 2D NMR, including HSQC, HMBC, and NOESY) as well as by comparing the obtained spectroscopic data with literature. This is the first report on the characterization of 4'-O-methyl-7-O-beta-D-galactosylapigenin from the genus campylospermum and thus has important chemotaxonomic implications.