Abstract

IN VITRO: EVALUATION OF ANTIBACTERIAL ACTIVITY OF AZADIRACHTA INDICA A. JUSS. FRUIT EXTRACTS AGAINST GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA

Manoj Kumar*

Abstract

Antibacterial activity of Azadirachta indica A. Juss. fruit extracts in different solvents (methanol, ethanol and aqueous) was carried out against seven different bacterial strains, including four gram-positive (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and Streptococcus sp.) and three gram-negative (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) bacterial strains by using the agar well diffusion assay (AWDA) method. The obtained results indicated that the methanol extract gave the highest yield percentage as compared to aqueous as well as ethanol extracts. The patterns of inhibition varied with the solvent as well as the tested bacterial strains. The results showed that B. subtilis among the gram-positive and E. coli among the gram-negative were highly susceptible as compared to other tested bacterial strains. It has been showed that the methanol extract had widest range of inhibitory activity as compared to the ethanol and aqueous extracts. The minimum inhibitory concentrations (MIC) as well as minimum bactericidal concentration (MBC) of the extracts were determined for the various tested bacterial strains which ranged between 12.5 to 100 mg/ml. The remarkable antibacterial activity of the fruit extracts against tested gram-positive and gram-negative bacteria suggests that the fruit extracts of A. indica plant could be a possible source of novel broad spectrum drug for the treatment of various infectious diseases.

Keywords: Antibacterial activity; Azadirachta indica; Solvent extracts; Zone of Inhibition.