Antioxidant, antibacterial and cytotoxicity studies from flavonoid rich fraction of Enicostemma axillare (LAM.) raynal leaves

Abstract

The aim of this research was to explore the in vitro antioxidant, antibacterial and anticancer activities of flavonoid rich fraction from the leaves of Enicostemma axillare. The total phenolic and flavonoid contents were assessed by Folin-Ciocalteu and Aluminium chloride method respectively. Antioxidant activities of this plant was confirmed on the source of ABTS (2,2'-azino-bis-3-ethyl benzthiazoline-6sulphonic acid), Radical scavenging assay, Inhibition of lipid peroxidation, Super oxide radical scavenging activity, Nitric oxide radical scavenging activity and Metal chelating activity. Correspondingly, antibacterial activities were accomplished by disc diffusion method and MIC (Minimum Inhibitory Concentration) against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pnemoniae, Escherichia coli and Enterococcus faecalis and anticancer activity was performed against human breast cancer cell MCF-7. The total phenolic and flavonoid content in flavonoid rich fraction of E. axillare was 136.8±13.00 mg GAE/g and 75.2±1.23 μg RE/g respectively. The flavonoid rich fraction of the leaves of E. axillare exhibited significant antioxidant activity. Similarly, the study on antibacterial activity of flavonoid rich fraction of E. axillare exposed inhibitory activity. However flavonoid rich fraction of E. axillare showed high inhibitory zone against E. coli, S. aureus, K. pneumoniae (18, 15 and 14 mm). The flavonoid rich fraction of E. axillare also unveiled strong cytotoxic effect with IC 50 values of 15.39 μg/ml against MCF-7. This research work has made it clear that E. axillare possess excellent antioxidant, antibacterial and cytotoxic activity and the extracts can be more extensively used in developing countries for the prevention and treatment of ageing and infective associated diseases and may be considered as good source for drug discovery.