Evaluation of the in vitro combined antibacterial effect of the leaf extracts of Bryophyllum pinnatum (Fam: crassulaceae) and Ocimum gratissimum (Fam: labiatae)

The antibacterial activities of the infusion (hot water extract) and methanolic extracts of Bryophyllum pinnatum and Ocimum gratissimum were evaluation against Staphylococcus aureusi ATCC 13709, Escherichia coli ATCC 9637, Bacillus, Pseudomons aeroginosa, Klebsiella pneumonia and Salmonella typhi using the agar diffusion method. The combined antibacterial effects of various decimal combinations of the B. pinnatum methanol extract (BPME) and O. gratissium water extract (OGWE); B. pinnatum methanol extract (BPME) and O. gratissimum water extract (OGWE) were further evaluated against S. aureus, E. coli, S. typi, Klebsiella spp and P. aeruginosa using a modification of checkerboard method. Results show that the BPME has minimum inhibitory concentration (MIC) value of 36.81μg/mL against S. aureus and B. subtilis respectively while the BPWE values of the OGWE were calculated to be 0.275, 0.138, 0.209, 0.158 and 0.044μg/mL against S. aureus, Klebsiella spp, E. coli, P. aeruginosa and B. subtilis respectively while that of the OGWE against B. subtilis, S. aureus and S. typi were calculated to be 0.631, 3.162 and 3.02μg/mL respectively. All the decimal combinations of BPME/OGWE, BPME/OGWE and OGWE yielded synergistic effects test bacteria.Keywords: leaf extracts, Bryophyllum pinnatum, Ocimum gratissimum, combined antibacterial effectPlant Products Research Journal Vol. 9 2005: 23-2