Abstract

Azadirachta indica commonly known as neem is a plant of the family Meliaceae used as traditional medicine for the treatment of many infections. The research was carried out to determine the antimicrobial effects of aqueous and ethanolic extracts of the neem plant root. Clinical samples of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were used as test organisms. Crude extracts were prepared by dissolving 50 g of the dried powder of the plant root in a sterile beaker of 250 ml of the solvent and kept for 72 h at room temperature with periodic shaking and daily filtration using Watt-man No.1 filter paper and evaporation under reduced pressure to dryness using rotary evaporator. Agar well diffusion method was done for the antimicrobial sensitivity test of the extracts against the pathogens under study. Extract concentrations of 200, 150, 100 and 50 mg/ml, respectively were added into 4 wells in the inoculated petri dishes, allowed to stand for 1 h in the refrigerator and then incubated at 37oC for 24 h. Ethanol extracts showed relatively stronger antimicrobial activity against aqueous extracts across the studied organisms. E. coli was found to have greater sensitivity to aqueous preparation at 200 mg/ml with mean diameter of zone of inhibition of 14.0±0.6 while P. aeruginosa was found to have greater sensitivity ethanolic extract at 200 mg/ml with mean diameter of 21.0±0.8. A. indica root extracts is a resource of herbal medicine and can be used against Gram negative bacteria such as E. coli and Gram positive organisms such as S. aureus.