Chemical composition, antimicrobial and free radical scavenging activities of Grewia pubescens

The phytochemical screening of Grewia pubescens leaf extracts showed the presence of alkaloids, steroids, terpenoids, flavonoids, saponins, anthraquinones, tannins, glycosides and fats and oils. Hexane, ethyl acetate and methanol extracts of the plant were tested on six bacterial strains and four fungal strains and exhibited satisfactory inhibitory activities against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomona aeruginosa, Salmonella typhii, Klebsiellae pneumonae, Candida albicans, Aspergillus niger, penicillium notatum and Rhizopus stolonifer, except ethyl acetate extract which showed no antifungal property on penicillium notatum and Rhizopus stolonifer. Methanol extract of the plant possessed significant antioxidant activity by exhibiting DPPH free radical scavenging property with IC50 of 10.26 μM, using DPPH antioxidant assay. The compounds present in the extracts were characterised using Gas chromatograph-Mass spectroscopy (GC-MS). Six compounds in the Grewia pubescens of while hexadecanoic acid is the most abundant constituting 62% and this plant has potential to act as antimicrobial agent in antimicrobial drugs.