An Investigation into phytochemical constituents, antioxidant, antibacterial and anti-cataract activity of Alternanthera sessilis, a predominant wild leafy vegetable of South India

Abstract

Abstract Alternanthera sessilis, a widely consumed leafy vegetable in different parts of India, was investigated for its phytochemical composition, antioxidant, antibacterial and anti-cataract activities using standard procedures. Antioxidant assays were done by in vitro methods such as 1,1-diphenyl −2- picrylhydrazyl (DPPH) and reducing power assays. Total phenolic content was determined by Folin-Ciocalteu method. Antibacterial tests were performed by disc/agar well diffusion methods using laboratory and clinical human isolates of chosen micro-organisms. Anti-cataract activities were determined by lipid peroxidation and Na+- K+ ATPase assays. Experimental results indicate that all the organic solvent extracts contained flavonoids, terpenoids, phenols, phytosterols and alkaloids. Highest total phenolic content was found in ethyl acetate extract (67.75 μg GAE/mg) followed by methanolic (44 μg GAE/mg), Chloroform (12.13 μg GAE/mg) and petroleum ether (0.013 μg GAE/mg) extracts. In general, the reducing power ability increased with the increase in concentration of the extract. Highest reducing power ability was shown by the chloroform extract followed by ethyl acetate, petroleum ether and methanolic extracts. High percentages of DPPH radical scavenging activities were obtained with acetone (57.6%) and ethyl acetate (64.73%) extracts while very low/no activity was obtained with petroleum ether (20.04%) and chloroform (0%) extracts. Antibacterial potential of the extracts was evident from the zones of inhibition obtained against different clinical bacterial strains tested and the minimum inhibitory concentration ranged from 18.75 mg/ml to 75 mg/ml. Thus, the leaves of A. sessilis have good antioxidant, antibacterial and anti-cataract activities and their consumption by humans have beneficial effects.