Phytochemical Screening and Antibacterial Activities of the Root Bark Extracts of Hippocratea africana (Willd.) Loes. ex Engl.

The root of Hippocratea africana (Celastraceae) is used in ethnomedicine in South-Western Nigeria to treat infectious and parasitic diseases. This study aimed at identifying the compound(s) that are responsible for the antimicrobial activities of the roots and also to contribute to the chemistry of the plant species. Investigation of the phytochemical constituents and antimicrobial activity of the n-hexane and methanol root bark extracts of Hippocratea africana was carried out. These extracts were subjected to screening of preliminary phytochemical test, which showed the presence of alkaloids, flavonoids, glycosides, phytosterols, phlobatanins and diterpenes. The crude methanol extract exhibited the largest zone of inhibition (16 mm in diameter with 700 mg/mL extract) against Morganella morganii and the largest zone of inhibition of the n-hexane crude extract (8 mm in diameter with 700 mg/mL) against E. coli. The methanol extract was subjected to column chromatography. Four isolates (A, B C & D) were obtained. Isolates C exhibited largest zone of inhibition (21 mm in diameter at 15 mg/mL) against Escherichia coli while isolate D exhibited the lowest zone of inhibition (3.7 mm in diameter at 15 mg/mL) against Klebsiella neumoniae.