Abstract

PHYTOCHEMICAL SCREENING, ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES STUDY ON THE ROOT BARK OF VERNONIA AMYGDALINA DEL

Zelalem Abdisa* and Habtamu Legese

ABSTRACT

Objective: The use of plant continues to play essential roles in traditional medicine for the treatment of various human diseases. The present study was aimed to conduct phytochemical screening and bioactivity studies on the root bark of Vernonia amygdalina. Method: The collected root bark of Vernonia amygdalina was air-dried at room temperature under shade and ground into powder. The powdered plant material was subjected to sequential solvent extraction using cold maceration techniques using solvents of different polarities. Phytochemical screening test was performed following standard protocols in order to detect the presence of plant constituents. The antibacterial properties of plant extracts were tested against two gram positive (Streptococcus pyogenes and Staphylococcus aureus) and three Gram negative bacteria (Bacillus cereus, Escherichia coli, and Salmonella typhimurium) using the disc diffusion technique. The radical-scavenging activity was assessed using the DPPH radical-scavenging assay. Result: The phytochemical screening result showed the existence of phytochemicals like alkaloids, anthraquinones, cardiac glycosides, flavonoids, phenols, saponins, steroids and terpenoids in chloroform extract and tannins were detected in ethyl acetate and methanol extracts. The antibacterial activity tests indicated that all the crude extracts tested were good bactericides with the maximum zone of inhibition (19 mm) by ethyl acetate extract against Escherichia coli as compared to the standard Gentamicin (21 mm). The result of antioxidant test revealed that the crude extract of root bark of Vernonia amygdalina scavenged DPPH by 95.17% while that of the reference ascorbic acid was 97.72% at 500μg/mL.

Keywords: Vernonia amygdalina, Asteraceae, phytochemical, Antioxidant.