Luxenchalcone, a new bichalcone and other constituents from Luxemburgia octandra

Chromatographic fractionation of leaves and branches extracts from Luxemburgia octandra (Ochnaceae) afforded isoliquiritigenin, 3'-hydroxyisoliquiritigenin, beta-sitosterol, stigmasterol, lupeol, betulinic acid, the biflavonoid, 4',5,7-trihydroxyflavone-(3'-->O-->4'")- 5", 7"-dihydroxyflavanone and a new bichalcone 4,2',4'-trihydroxychalcone-(3 --> O --> 4")- 2'", 4'"- dihydroxychalcone (luxenchalcone). The structures were established from analysis of IR, MS and NMR spectral data, including 2D-NMR experiments of the natural substances and of the luxenchalcone methyl derivative.