PHYTOCHEMICAL CONSTITUENTS, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF Eugenia uniflora Linn. LEAF

Abstract

In this study, the leaf of Eugenia uniflora, an ornamental plant, was evaluated for its phytochemical constituents, antioxidant property and antimicrobial activity. The methanol extract of the leaf was partitioned into hexane, ethyl acetate and aqueous fractions. The antioxidant activities of the crude extract and fractions were performed using 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, and IC50 values were calculated. The antimicrobial activity was tested against five bacteria strains (Pseudomonas aeruginosa, Escherichia coli, Micrococcus varians, Klebsiella pneumonia, Staphylococcus aureus) and two fungal strains (Saccharomyces cerevisiae, Aspergillus niger) using agar well diffusion method. Phytochemical screening indicated the presence of phenols, flavonoids, alkaloids, tannins, cardiac glycosides, saponin glycosides, saponins and anthraquinones in the leaf. The ethyl acetate fraction showed highest antioxidant activity (IC50 value of 0.919 mg/ml) compared with reference standard ascorbic acid (IC50 value of 0.859 mg/ml). The plant fractions demonstrated good antibacterial activities. The ethyl acetate fraction showed MIC values of 1.25 mg/mL, against P. aeruginosa and E. coli; 2.50 mg/mL against A. niger and 5.00 mg/mL against M. varians, K. pneumonia and S. cerevisiae while the aqueous fraction had MIC values of 0.625 mg/mL against S. cerevisiae; 1.25 mg/mL against P. aeruginosa, M. varians, K. pneumonia and A. niger and 2.5 mg/mL against Escherichia coli. The hexane fraction had MIC value of 1.25 mg/mL against Staphylococcus aureus. The results indicate that Eugenia uniflora leaf is rich in natural antioxidants and bioactive compounds which may provide health benefits and serve in the management of bacterial and fungal infections.