ANTIBACTERIAL EFFICACY OF PIGMENTED AND DE-PIGMENTED EXTRACTS OF Tridax procumbens LINN (WHOLE PLANT)

Abstract

This work was carried out to evaluate the an Abacterial efficacy of pigmented and de-pigmented petroleum ether and methanolic extracts of Tridax procumbent (whole plant). Phytocliemical screening of these extracts using standard metnoa. revealed that the pigmented and de-pigmented petroleum etlicr extract showed the strong presence of steroidal nucleus only, while the pigmented and de-pigmented methanol extracts revealed the presence of alkaloids, saponins, tannins, flavonotds steroidal nucleus and cardiac glycosides. The in-vitro antibacterial assay of these extracts revealed that the de-pigmented methanol extract shpwed appreciable activity against all the test organisms at 100mg/ml- a broad spectrum inhibitory effect that was quite similar to that produced by the standard drug, Tetracycline at 0.5mg/ml against Gram positive Staphylococcus aureus and Bacillus subtilis and was slightly better against Gram negative Pseudomonas aeruginosa. The minimum inhibitory (MIC), minimum bactericidal (MBC) concentrations and MBC/M1C ratio of the active extract ranged between 12.5-100mg/ml and 25-100mg/ml and 1.00 2.00 respectively. Purification of the active ex tractby preparative thin layer chromatography gai>e rise to polar fractions that exhibited similar/slightly better inhibitory activities against the test organisms at 50mg/ml tlwn the crude de-pigmented methanolic extract at l00mg/ml. MIC, MBC and MBC/MIC ratios of the active fractions ranged between 12.5-50mg/ml and 25- 50mg/ml and 1.00 4.00 respectively. The above findings suggest that the de-pigmented methanol extract of A. boonei might be a valuable source of antibacterial substance(s) for the treatment of diarrhea, typhoid fever, urinary and gastrointestinal infections.