Evaluation of Antibacterial and Dpph Radical Scavenging Activities of the Leaf Extracts and Leaf Essential Oil of Syzygium Cumini Linn. from South India

In the present study, the antibacterial and DPPH radical scavenging activities of the leaf extracts and leaf essential oil of Syzygium cumini Linn were investigated. The antibacterial potential of the leaf essential oil, petroleum ether, chloroform, ethyl acetate and methanol extracts of the leaves of Syzygium cumini Linn were studied against human pathogenic bacteria viz. Bacillus cereus, Enterobacter faecalis, Salmonella paratyphi, Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae, Pseudomonas aeruginosa and Serratia marcescens by ‘agar well diffusion’ method and DPPH activity by spectrophotometer assay using ascorbic acid as standard. Leaf essential oil as well as leaf ethyl acetate, chloroform and methanol extracts of Syzygium cumini Linn exhibited pronounced activity against Gram-positive and Gram-negative bacteria and their activity is quite comparable with the standard antibiotics such as tobramycin, gentamicin sulphate, ofloxacin and ciprofloxacin screened under similar conditions. Among the leaf essential oil and leaf extracts of S. cumini studied, methanol extract and leaf essential oil showed potent scavenging activity on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. The remarkable antibacterial and antioxidant activity exhibited by the plant extracts and essential oil can be attributed to the synergic effect of the active compounds present in it. The results obtained showed that the leaf methanol extract and leaf essential oil of S. cumini can be considered as good sources of natural antioxidants and antimicrobial compounds and can be incorporated into the drug formulations.