ABSTRACT:
The total phenolic content (TPC) and total flavonoid content (TFC) of ethanol extract of three Flemingia species Flemingia chappar(EFC) Flemingia macrophylla (EFM) and Flemingia strobilifera(EFS) were measured using Folin–Ciocalteau and aluminium chloride colorimetric methods, respectively. The in vitro antioxidant activities were also investigated by using in vitro antioxidant models including 2,2´-azinobis–(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), 1,1- diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO), hydroxyl radical (OH), super oxide (SO) and reducing power (Fe3+ to Fe2+ transformation) assay. The TPC were 14.725, 12.725 and 9.072 mg/gallic acid equivalent (GAE)/g extract while TFC were 16.715, 13.853 and 10.657 quercetin equivalents (QRT)/g extract sample for EFS, EFM and EFC respectively. Analysis of the free radical scavenging activities of the extracts revealed a concentration dependant antiradical activity resulting from reduction of ABTS+, DPPH, NO and OH- radicals to non radical form. The scavenging activity of ascorbic acid, a known antioxidant used as positive control, was however higher and scavenging potential was in the order: ascorbic acid> EFS>EFM>EFC. The reducing power of ascorbic acid, EFS, EFM and EFC increased gradually with increasing concentration. The order of the reduction potential was ascorbic acid> EFS>EFM>EFC. These results obtained in the present study indicate that ethanol extract of Flemingia species can be a potential source of natural antioxidant with strong antiradical capacity.