Phytochemical characteristics and in vitro antibacterial activity of caesalpinia pulcherrima stem bark extracts against some clinical isolates

Abstract

The aqueous and ethanol stem bark-extracts of Caesalpinia pulcherrima (Pride of Barbados) were screened for phyto-constituents and in vitro antimicrobial activity on clinical isolates of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, Salmonella typhi and Klebsiella pneumoniae using paper disc diffusion method. The phytochemical analysis revealed the presence of saponins, flavonoids, alkaloids and tannins in the extracts. The in vitro antimicrobial assay result showed that both ethanol and aqueous extracts displayed concentration dependent activity against all the test isolates. The ethanol extract demonstrated higher and better activity comparable to those of conventional antibiotics (Chloramphenicol and Ampicillin) used, especially at the highest concentrations of test extract( 200 mg/ml). The most and least sensitivity organisms were Pseudomonas aeruginosa (20.0+0.10 mm zone of inhibition) and Proteus mirabilis (5.2+0.01 mm zone of inhibition). The minimum inhibitory concentration and minimum bactericidal concentration values ranged from 6.25 - 50 and 12.5-100 mg/ml respectively. The results obtained in this study showed that this plant could be used in treating diseases caused by the test organisms.

Keywords: Caesalpinia pulcherrima, Pride of Barbados, antimicrobial activity, disc diffusion

International Journal of Natural and Applied Sciences, 6(3): 329-336, 2010