Cell kill pattern and acute toxicity studies of the aqueous fraction of the methanolic extract of parts of Parkia biglobosa

Abstract

The pattern and rate of kill of the aqueous fraction of the methanolic extract of the stem bark of Parkia biglobosa (WS) against three standard organisms of medical and pharmaceutical importance; Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, as well as the acute toxic effects of the same extract along with those of the leaf (WL) and root (WR) were studied. Results obtained showed the fractions as bactericidal to the test organisms and that the S. aureus and P. aeruginosa were completely killed by WS within 120 min at 12.5 mg/ml and within 90 min at higher concentrations. LD₅₀ results fell within the range of 500 – 5000 mg/kg body weight confirming them to be only slightly toxic and hence not potentially dangerous. These results are discussed in the context of the fact that P. biglobosa parts have been reported to be used extensively in the treatment of a wide variety of infections.

Key words: Methanolic, aqueous fraction, Parkia biglobosa, bactericidal, slightly toxic.