STUDIES ON IN VITRO SCREENING OF SOME MEDICINAL PLANT EXTRACTS FOR THEIR ANTIMICROBIAL ACTIVITIES.

The present study was conducted to evaluate the in vitro screening of antimicrobial activities of some medicinal plants against the four bacterial (Bacillus subtilis, Staphyylococcus aureus, Escherichia coli and Pseudomonas aeroginosa) and two fungal (Aspergillus nigar and Penicillium chrysogenium) species. The solvent extracts like aqueous, acetone, methanol, hexane and chloroform were tested for antimicrobial activities by disc diffusion method. The results showed that, among the plant tested, four medicinal plants i.e. Adhatoda vasica, Alternanthera sessilis, Plumbago zelanica and Tridex procumbense had strong inhibitory effect and inhibit the growth of microbes. Other plants like Phyllanthus niruri and Withania somnifera could inhibit moderate activity; whereas remaining plants had lowest activity. Further, among the extracts used, the antimicrobial activities were found to be better in polar solvents like aqueous extract and least in non-polar solvent extracts. Except Adhatoda vasica and Tridex procumbense, most of plants revealed antibacterial activity than antifungal.