A study on the antibacterial activity of certain plant extracts.

摘要

Petroleum ether extract of the leaves of plants such as Acalypha indica, Achyranthes aspera, Aegle marmelos, Andrographis paniculata and Leucas aspera were screened for antibacterial activity against three selected bacteriae i.e Escherichia coli, Staphylococcus aureus and Proteus spp. The mixed plant extracts were also screened for synergistic effect against the three selected bacteriae. Among the five individual plants tested a higher degree of antibacterial effect was exhibited by the leaves of A. marmelos, L. aspera, and A. paniculata. E. coli was susceptible to the extracts of all the five individual plants. The zone of inhibition was higher when the plates were incubated for 48 h than for 24 h. Among the mixtures of extracts tested, higher synergistic efficacy was observed in the mixtures of A. marmelos+A. paniculata, A. marmelos+L. aspera and A. marmelos+A. indica at 24 h and 48 h against E. coli.