Abstract

The petroleum ether and methanol extracts of the ripe and unripe fruits, the partitioned-soluble portions of the ripe fruits and the water-insoluble sub-portions of both the ripe and unripe fruits of Nauclea latifolia revealed the presence of alkaloids, flavonoids, steroidal nucleus, saponins, coumarins and tannins. Antibacterial activity of the extracts (100 mg/ml), portions (50 mg/ml) and sub-portions (50 mg/ml) in comparison with standard drugs (1 mg/ml) against two Gram-positive (Bacillus subtilis and Staphylococcus aureus) and four Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella typhi) using the agar-well diffusion method revealed higher zones of inhibition, higher calculated percent activities (A%), higher calculated bacterial susceptibility (BSI), lower minimum inhibition concentrations (MICs) and minimum bactericidal concentrations (MBCs) for the extract/sub-portions of the unripe fruits than the extracts/portions/sub-portions of the ripe fruits, an indication that the unripe fruits exhibited better antibacterial efficacy against the tested strains. The diethyl ether (MuiD) and ethyl acetate (MuiE) sub-portions of the unripe fruits displayed broad spectrum activity than chloramphenicol and tetracycline supporting their use in the treatment of dysentery and diarrhea.

Key words: Nauclea latifolia, ripe/unripe fruits, extracts/portions/sub-portions, standards, phytoconstituents, antibacterial.