Antibacterial Activity of Some Weeds: Case Study

Methanol and water (aqueous) extracts (whole plant) of ten common weedy plants possessing medicinal properties were screened for antibacterial activity against five bacteria viz., E.coli, Klebsiella pneumoniae, Proteus vulgaris (Gram-Negative), Bacillus subtillis and Staphylococcus aureus (Gram-Positive) using agar diffusion method. Methanolic extracts of Zornea diphylla, Andrographis paniculata, Ocimum sanctum, Euphorbia hirta, Ipomea obscura, Tridax procumbens, Tephrosia hirta and Croton bonplandianus showed higher antibacterial activity against to five test bacteria. Aqueous extracts of Euphorbia hirta, Tridax procumbens and Croton bonplandianus exhibited higher antibacterial activity.In the present investigation it was found that methanolic plant extracts of ten taxa exhibited higher levels of antibacterial activity (Inhibition zone) against five selected bacteria compared to those of aqueous extracts of the same taxa. Further, the antibacterial activity of the methanolic extracts tested against the five bacteria in most of the taxa showed higher levels of antibacterial activity compared to those tested against the different concentrations of Tetracycline.