Preliminary phytochemical screening and in vitro antibacterial evaluation of the leaf and root extract of Azadirachta indica Plant

Abstract

The plant Neem (Azadirachta indica) is used traditionally for treatment of various illnesses in Ethiopia. However, there was paucity of information with regard to antibacterial activity of part of Neem used. So in our study we evaluate the antibacterial activity of Neem plant. An experimental study design was conducted to evaluate in vitro antibacterial activity of the plants from January to May 2010. The n-hexane, methanol and acetone extracts of the leaves and roots of Neem were screened for their antibacterial activity using the Cup plate agar well diffusion method. They were tested against four bacteria; one Gram-positive bacterium (Staphylococcus aureus) and three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi). The susceptibility of the microorganisms to the extracts of the plant was compared with selected antibiotics. The antibacterial activities of Neem were discussed according to their phytochemical components. Most of the gradient extracts of Neem extracts of leaf and root shows dose dependant antibacterial activity. Among all the extracts tested, the acetone and methanol extract was found to be the most active against all the selected strains. The antibacterial activities of the extracts are probably because of polyphenolic compounds and alkaloids detected. Although, this study provides some evidence concerning the claimed biological activities of these plants, it is not adequate. So, further work should be done to show the potential of these plants for further development of modern therapeutic agents.