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

Abdulmumeen A. Hamid, Stephen O. Oguntoye, Sherifat O. Alli, Grace A. Akomolafe, Adejumoke Aderinto, Adeola Otitigbe, Adebola M. Ogundare, Quareeb Musa Esinniobiwa and Rasidat O. Aminu

Abstract

The phytochemical screening of n-hexane, ethyl acetate and methanol extracts of Grewia pubescens leaves showed the presence of alkaloids, steroids, terpenoids, flavonoids, saponins, anthraquinones, tannins, glycosides and fats and oils. The
three extracts were tested on six bacterial 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 chromatography-Mass spectroscopy (GC-MS). Seven, three and six compounds were revealed in n-hexane, ethyl acetate and methanol extracts of Grewia pubescens leaves respectively, while hexadecanoic acid is the most abundant constituent in all three extracts with corresponding percentage of abundance of 47.92, 53.20 and 61.59.