Antimicrobial and phytochemical properties of neem leaf and bark extracts on selected microorganisms

Abstract

This study evaluated the antimicrobial and phytochemical properties of neem leaf and bark extracts on selected microorganisms. Neem plant parts (bark and leaf) were gotten from neem plant tree at School of Business Technology, Federal Polytechnic Nekede, Owerri, Imo State. The plant parts were dried, ground and extracted using ethanol. Qualitative phytochemical screening was adopted in the determination of the phytochemical constituents of the extracts while agar well diffusion technique was adopted in the determination of the antimicrobial activities of the extracts against Staphylococcus, Salmonella, Escherichia, Pseudomonas and Candida species. Tube dilution technique was adopted in the minimum inhibitory concentration of the extracts. The presence of saponins, anthranoids, anthraquinones, alkaloids, phenols, tannins and phlobatannins and cardiac glycosides were detected from the leaf and stem bark extracts. The zones of inhibition recorded ranged with 18mm to 24mm with leaf extract and 16mm to 20mm with stem bark extract. Inhibitory concentrations recorded ranged from 125mg/ml to 250mg/ml with both leaf and stem bark extracts. Bactericidal effect was recorded at 250mg/ml and 500mg/ml. The leaf extract of neem showed better antimicrobial activity compared to the stem bark extract. Similarly, Salmonella and Staphylococcus species were the most susceptible bacteria compared to the other test organisms. The results of this study therefore justify the use of these plant parts in alternative medicine.