Flavanoids from Caesalpinia pulcherrima

Two new flavanoids, 5,7-dimethoxy-3',4-methylenedioxyflavanone and isobonducellin along with 2'-hydroxy-2,3,4',6'-tetra-methoxychalcone, 5,7-dimethoxyflavone and bonducellin were isolated from the aerial parts of Caesalpinia pulcherrima. The structures of the compounds were settled mainly by interpretation of their I D and 2D NMR spectra. Isobonducellin was found to be a homoisoflavanoid containing a cis (Z)-double bond. Antimicrobial activity of the new compounds was evaluated. (C) 2003 Elsevier Ltd. All rights reserved.