Flavonoids from Annona dioica leaves and their effects in Ehrlich carcinoma cells, DNA-topoisomerase I and II

Abstract

Chemical investigation of methanol extract leaves from Annona dioica (Annonaceae) resulted in the identification of flavonoids kaempferol (1), 3-O-[3″,6″-di-O-p-hydroxycinnamoyl]-β-galactopyranosyl- kaempferol (2), 6″-O-p-hydroxycinnamoyl-β-galactopyranosyl-kaempferol (3) and 3-O-β-galactopyranosyl-kaempferol (4). The structures were unequivocally characterized by 1H and 13C NMR spectroscopic analyses using 1D and 2D experiments. The cytotoxic effects of the flavonoids and flavonoid fraction (FF) were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against Ehrlich carcinoma cells. The results indicated that 1, 2, 3 and FF exhibit significant antiproliferative action when compared to quercetin. The inhibitory action on DNA-topoisomerase I and II of all the flavonoids was evaluated by relaxation assays on pBR322 plasmid DNA. The results indicated the inhibitory and non-selective effects of the flavonoids on DNA-topoisomerase I and II. ©2007 Sociedade Brasileira de Química.