Abstract:
Medicinal plants have been very intensively screened for their bioactivity in order to treat various disease
and disorders in human. In this study some common medicinal plants (Cassia fistula, Heliotropium
indicum, Mimosa pudica, Rhinacanthus nasutus, Pongamia pinnata and Vernonia zeylanica) available in
Jaffna peninsula, Sri Lanka, were tested for their antibacterial activity. Leaf powders of above plants
were sequentially extracted with petroleum ether, ethyl acetate, ethanol and water respectively. The dried
extracts were tested for their antibacterial activity against Staphylococcus aureus (NCTC 6571) and
Escherichia coli (ATCC 25922) by agar well diffusion method. The yield percentage was relatively high
in tested polar solvents than tested non polar or low polar solvents. Among the tested extracts, aqueous
extract of Mimosa pudica and ethyl acetate extract of Cassia fistula revealed significantly higher
inhibition against S. aureus and E. coli respectively. The test extracts of Mimosa pudica showed
interesting results, all of its extracts were able to inhibit both S. aureus and E. coli. Most of the tested
extracts could be used for further screening of specific bioactive compounds which responsible for their
antibacterial activity
