SUMMARY
Antimicrobial properties of medicinal plants are being increasingly reported from different parts of the world. Because of the side effects and the resistance that pathogenic microorganisms that build against antibiotics, many scientists have recently paid attention to extracts and biologically active compounds isolated from medicinal plants. The intention of this study was to evaluate the antibacterial activity of pet-ether, chloroform and ethanol extracts of Gnidia glauca against five Gram-positive bacteria and five Gram-negative bacteria by agar well diffusion method. The zone of inhibition of extracts was compared with standard antibiotics. The results of the study indicated that, the pet-ether and chloroform extracts of the plant were highly effective towards most of the bacterial strains. The ethanol extract showed appreciable activity against B.subtilis and showed a moderate growth inhibitory activity towards all other tested organisms. The organisms which were highly susceptible to extracts were selected for the determination of Minimum Inhibitory Concentration (MIC) by Broth dilution method. When compared to chloroform and ethanol extracts, pet-ether extract has showed a lowest MIC of 1.562 mg/ml against B.subtilis , V.cholerae and 3.125 mg/ml against S.pyogenes . The antitubercular activity of all the extracts of Gnidia glauca have been evaluated against Mycobacterium tuberculosis H 73 Rv strain using Microplate Alamar Blue Assay (MABA). The activity was documented within MIC range of 0.2 to 100g/ml. The results of MABA showed that pet-ether extract exhibited excellent antitubercular activity. The chloroform extract is moderately active, whereas ethanol extract is less active against Mycobacterium tuberculosis . The present investigation suggests that Gnidia glauca posses remarkable antibacterial and antitubercular activity.