Effect of Leguminosae family plant extracts and polyphenolic fractions on topoisomerase I-induced nicking of DNA

Abstract

Topoisomerase I constitutes one of the enzymes playing crucial role in replication, transcription, recombination, chromosome condensation and maintenance of genome stability. Because it is an essential enzyme for vital functions of DNA during normal cell growth, inhibitors of its activity are considered as promising anticancer agents. Eleven aqueous and two methanolic extracts derived from Leguminosae family plants cultivated in Greece, along with fractions rich in phenolic compounds isolated from the two methanolic extracts of Vicia faba and Lotus edulis were examined for their ability to affect topoisomerase I-induced nicking of DNA, using topoisomerase I relaxation assay. From the tested extracts, only the aqueous extracts of aerial plant parts of Lathyrus laxiflorus subsp. Laxiflorus and Vicia faba and both methanolic extracts of aerial plant parts of Vicia faba and Lotus edulis exhibited the ability to inhibit the nicking activity of topoisomerase I. Among them, the extract derived from Lathyrus laxiflorus subsp. Laxiflorus aerial plant parts was the most potent. As for the flavonoid fractions isolated from the methanolic extracts, the majority of them exhibited significant inhibitory activity which was more potent than that of the initial extracts, implying that the polyphenols compounds present in the fractions may constitute some of the extract components responsible for the observed properties of the extracts. These results also indicate a mechanism by which these plant extracts and their active principles exert chemopreventive properties and can be considered as possible anticancer agents. ©PHARMAKON-Press.