Phytochemical screening and antimicrobial activity of leaves extract of Annona senegalensis from rainforest of Ahmadu Bello University Zaria, Nigeria

Annona senegalensis belongs to the family Annonaceae which is known to possess wide range of bioactivities. The leaves of A. senegalensis have been traditionally used as stimulant and a pain reliever. This study aims to determine the presence of some of the bioactive molecules in the leaves of this plant, and further investigate the antimicrobial activity of the extract against certain bacteria. The crude methanolic extract of the leaves was tested for phytochemicals, and revealed the presence of carbohydrates, flavonoids, steroids, saponins, tannins, anthraquinone and cardiac glycosides, and triterpenoids. The crude methanolic extract was purified using column chromatography techniques. The Fourier Transform Infrared Spectroscopy (FT-IR) analysis of the isolated compounds revealed the presence of C–H, C=O, O–H and C=C functional groups, which are characteristics of the compounds in the secondary metabolites. The antimicrobial screening of the crude methanol extract was carried out on Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Salmonella typhi and Klebsiella pneumonia, using agar well diffusion method. The antimicrobial screening showed that the extract was active against Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The solvent extract was more effective against Staphylococcus aureus with zones of inhibition of 20mm and 18mm at a concentration of 100mg/ml and 50mg/ml respectively. The minimum inhibitory concentration of the crude extract carried out against the test microorganisms were within the range of 12.5 – 25mg/ml while the minimum bactericidal concentration was within the range of 25 – 50mg/ml. The result from this study justifies the use of the leaves of Annona senegalensis in treatment of microbial diseases.