In Vitro antioxidant and antibacterial activity of leaf extracts of Measa lanceolata

Abstract

ABSTRACT This study investigated total phenolic contents (TPC), total flavonoid contents (TFC), antioxidant activity, and antibacterial activities of different leaf extracts of Measa lanceolata. The TPC and TFC of the extracts were determined by Folin-Ciocalteu and aluminum chloride methods, respectively. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, reducing power, and phosphomolybedinium assays were used to evaluate antioxidant activity. Antibacterial properties were assessed using the disc-diffusion assay based on minimum inhibitory concentration (MIC). Bacteria tested were three strains of gram-negative (Escherichia coli (ATCC-25922), Proteus vulgaris (ATCC-13315), and Pseudomonas aeruginosa (ATCC-43495)), and two strains of gram-positive (Staphylococcus aureus(ATCC-25923), and Enterococcus faecalis(ATCC-29212)). It was found that methanol extract contained the highest TPC (60.6 ± 4.4 mg of gallic acid equivalent/g of dried extract) and TFC (6.4 ± 6.0 mg of catechin equivalent/g of dried extract). Extract showed the strongest DPPH radical scavenging activity (EC50 = 76.7 ± 7.3 µg/mL), iron reducing power (EC50 = 74.0 ± 1.6 µg/mL), and total antioxidant activity (128 ± 4 mg of ascorbic acid equivalent per dried extract). Inhibition zones were observed in water and methanol extracts against bacterial strains, whereas Staphylococcus aureus (ATCC-25923), Escherichia coli(ATCC-25922), Pseudomonas aeruginosa (ATCC-43495), and Proteus vulgaris(ATCC-13315) were resistant against chloroform and ethyl-acetate extracts.