PHYTOCHEMICAL COMPOSITION, ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES STUDY OF THE STEM BARK EXTRACT OF GREWIA FERRUGINEA

Advisor: Zelalem Abdisa (PhD) Grewia ferruginea is traditionally used for many purposes. The crushed leaves and stem bark is used for cleaning clothes, for cleaning dirty pots and dishes, to remove head lice and its larva from hair and it is also used for treating fungal attack of skins. The purpose of this study was to identify the class of phytochemicals composition of the extract of Grewia ferruginea stem bark and evaluate its antibacterial and antioxidant capacity. The plant materials were collected, washed, dried at room temperature, milled into a fine powder and sequentially extracted with chloroform and methanol. Higher percentage yield was obtained by methanol extract (1.38%) when compared to chloroform extract (0.62%). The Phytochemical screening test suggested that terpenoids, steroids and flavonoids were present in chloroform extracts while Alkaloids, terpenoids, steroids, flavonoids, saponins and tannins were present in methanol crude extracts. The antibacterial activity test was done against four bacterial strains:- Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Escherichia colasea using disk diffusion method. The highest inhibition showed by methanol extract against Escherichia colasea (13 mm) and lowest inhibition showed by chloroform extract against Staphylococcus aureus (10.2 mm) at 20 mg/mL. Radical scavenging activity evaluation was done with using DPPH assay. The results indicated that the chloroform extract inhibited the DPPH radical by 87.69% while methanol extract inhibited by 92.71% at the highest concentration tested (12 mg/mL). Methanol extract (92.71%) showed comparable DPPH radical scavenging power as compared to that of ascorbic acid (93.63%) at maximum concentration tested. Natural products have been a source of drugs for centuries. Methanol stem bark extracts of Grewia ferruginea has showed better antibacterial and antioxidant activities. Generally this study, on the stem bark of Grewia ferruginea would lead to the improvement of the usage of traditional medicinal plants and search for more antibacterial and antioxidant drugs of natural origin. Key words:-Phytochemical analysis; antibacterial; antioxidant; Grewia ferruginea.