In vitro antibacterial activity of Synclisa scabrida whole root extracts

Ethanolic, cold water and hot water extracts of the root of Synclisia scabrida were tested, by the agar-well diffusion and macro-broth methods, for activity against clinical and typed strains of Escherichia coli, Salmonella sp., Staphylococcus aureus, Pseudomonas aeruginosa, Proteus sp. and Bacillus subtilis. The ethanolic extract was bactericidal at the minimum inhibitory concentration (MIC) against 8 of the 10 test organisms (MIC, 3.125 to 12.50 mg/ml and MBC, 3.125 to 25.00 mg/ml). The cold water extract was bactericidal against E. coli (clin) and B. subtilis ATCC 6051 strains and bacteriostatic against 5 others while the hot water extract was bacteriostatic against 2 of the organisms at MIC. Three column chromatographic fractions of the crude ethanolic extract, F sub(ss-1), F sub(ss-2), and F sub(ss-3), were active against 5 to 8 of the 10 test bacterial strains. F sub(ss-3) was bacteriostatic against the Proteus sp. (clin), which was not susceptible to the crude ethanolic extract. Conversely, the crude ethanolic extract was bactericidal against P. aeruginosa ATCC 10145 to which none of the fractions showed activity. Thus, the results justify the folklore application of extracts of S. scabrida in treatment of bacterial gastroenteritis among other diseases.