ANTIMICROBIAL FLAVONOIDS FROM PSIADIA TRINERVIA AND THEIR METHYLATED AND ACETYLATED DERIVATIVES

Article abstract of DOI:10.1016/S0031-9422(00)97976-7

Key Word Index - Psiadia trinervia; Compositae; flavonoids; antifungal; antibacterial; Cladosporium cucumerinum; Bacillus cereus; bioautography.Abstract - From a dichloromethane extract and a hydrolysed methanolic extract from the leaves of Psiadia trinervia, 13 3-methylated flavonol have beeen isolated.Their structures were established by the usual spectoscopic methods (UV, EIMS, 1H and 13CNMR).Ayanin, casticin, chrysosplenol-D and 5,7,4'-trihydroxy-3,8-dimethoxyflavone were responsible for the antifungal activity found in the preliminary screening.Chrysosplenol-D, isokaemferide, 5,7,4'-trihydroxy-3,3'-dimethoxyflavone and 5,7,4'-trihydroxy-3,8-dimethoxyflavone displayed antibacterial activity.Twenty-nine derivatives were prepared by permethylation and selective methylation of the free hydroxyl group at C-5.The antimicrobial activities of the isolates and derivatives were determined by bioautographic assays using C. cucumerinum and B. cereus as test organisms.