Antibacterial activity and preliminary screening of phytochemicals of locally available Green Leafy Vegetables in Batticaloa district, Sri Lanka

Plants and plant products are a better alternative, compared to antibiotics and other synthetic drugs, which show negative side effects, including, sensitization reactions and disruption of the metabolic processes in the body via interaction with the body system. Herbal remedies offer deeper healing benefits, while providing lesser side effects, lower costs, and easy access. This study was aimed to investigate the antibacterial activity and the phytochemical properties of three locally available Green Leafy Vegetables (GLVs), namely, Argyreia pomacea (Convolvulaceae), Coccinia grandis (Cucurbitaceae) and Mollugo pentaphylla (Molluginaceae). All leaf samples were collected from different localities of Batticaloa district, Sri Lanka. The leaf extracts from acetone and ethanol at the concentrations of 25.0, 50.0 and 75.0 mg/100μL were tested for antibacterial activity against Escherichia coli and Staphylococcus aureus, using well diffusion method and the qualitative phytochemical properties were also determined. The inhibitory effect was observed at all concentrations of acetone and ethanol extracts of C. grandis against both bacteria. The highest inhibitory effect on E. coli and S. aureus was shown by ethanol extract of all samples. The ethanolic extract of C. grandis at the concentration of 75.0 mg/100μL showed highest antibacterial activity against S. aureus (22.7±0.5 mm) and E. coli showed higher susceptibility to C. grandis (20±0.6 mm) in ethanol extract at 75.0 mg/100μL. Phytochemical analysis revealed the presence of alkaloids, saponins, flavonoids and tannins in both extracts of C. grandis. Flavonoids were found in the ethanol extracts of A. pomacea and M. pentaphylla.