Antimicrobial activities of Trichilia heudelotii (Meliaceae) Planch, a Nigerian medicinal plant

Abstract

Trichilia heudelotii (Th) (Meliaceae) is common in the western part of Nigeria and is commonly used in traditional medicine for the treatment of many microbial infections ranging from gastrointestinal infections to gonorrhoea. The preliminary phytochemical screening revealed the presence of tannins, saponins, alkaloids, cardenolides and anthraquinones in the leaf, stem bark and root bark of Th. First, the crude hexane and methanol extracts was prepared, after which the methanol extract was partitioned into petroleum ether, chloroform and aqueous fractions. The antibacterial and antifungal activity of the extracts was determined out using agar well diffusion method and they showed considerable activity against Gram positive and Gram negative organisms as well as fungi and yeast, namely Klebsiella spp, Escherichia coli, Proteus spp, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Neisseria gonorrhoeae, Mycobacterium smegmatis, Candida albicans, Aspergillus niger, Rhizopus stolomtes, Penicillium spp, Microsporum canis, and Trychophyton mentagrophytes. The mean diameter of zones of inhibition exhibited by the extracts was between 10mm and 32mm. The methanol extracts compared favourably with the gentamycin used as standard control. The minimum inhibitory concentration (MIC) was determined by agar dilution method. The range of MIC was between 1.57mg/ml and 200mg/ml. The crude methanol extracts and methanol residue showed the highest activity of all the extracts, the hexane showed the lowest activity while petroleum ether extracts were inactive