Anti-bacterial, free radical scavenging activity and cytotoxicity of acetone extracts of Grewia flava

BACKGROUND Bacterial infections of the gastrointestinal tract (GIT) cause vomiting, diarrhoea and even systemic disease. There is a need for the development of natural products into alternative and safer medicines. OBJECTIVES This study evaluated the anti-microbial activity of extracts prepared from berries, leaves, bark and roots of the edible plant Grewia flava. METHODS The anti-bacterial activity was evaluated by the broth microdilution method. Anti-oxidant activity of the most active extracts was performed by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. The cytotoxicity of the extracts was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS The acetone extracts of the leaves and roots showed the best activity with MIC values as low as 0.03 mg/mL against Staphylococcus aureus and Salmonella typhimurium and 0.07 mg/mL against Bacillus cereus, Escherichia coli and Staphylococcus aureus. Quantitative analysis of the scavenging ability showed that acetone extracts exhibited good free radical scavenging activity in a dose-dependent manner. The berries extract had the highest LC50 (lowest toxicity) of 551.68 68 µg/mL. CONCLUSION Acetone extract of leaves and roots of Grewia flava contain anti-microbial and anti-oxidant compounds and could therefore be used as a natural product with little toxicity to host cells.