Context: Antibiotic resistance has become a global concern. There has been an increasing incidence of multiple resistances in human pathogenic microorganisms in recent years, largely due to indiscriminate use of commercial antimicrobial drugs commonly employed in the treatment of infectious diseases. Tribulus terrestris (Family: Zygophyllaceae) is a well-known medicinal plant and has been used world-wide for the treatment of infectious diseases. Alkaloids are group of naturally occurring chemical compounds, which are known to have antimicrobial properties. Aim: The present study is designed to evaluate the antimicrobial potential of alkaloids of T. terrestris L. Materials and Methods: Alkaloids extracted from different parts (root, stem, leaf and fruits) of T. terrestris were screened by Disc diffusion assay against three bacterial strains: gram positive (Staphylococcus aureus), gram negative (Escherichia coli and Proteus mirabilis) and two fungal strains: Aspergillus flavus and Aspergillus niger. Minimum inhibitory concentration of the extracts was evaluated by micro broth dilution method while minimum bactericidal/fungicidal concentration was determined by sub culturing the relevant samples. Total activity of the extracts against each sensitive test pathogens was also calculated. Statistical Analysis: Mean value and standard error mean were calculated for the results of disc diffusion assay and data were analysed by one-way analysis of variance and P values were considered significant at P < 0.05. Results: The alkaloid extracts of T. terrestris showed significant antibacterial potential as all test extracts were found active against both the gram positive and negative bacteria, but were inactive against the tested fungi. Conclusion: The present study indicates the broad spectrum antibacterial potential of the alkaloids of T. terrestris, hence may be exploited for future antibacterial drugs.

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Context:The persistent increase in the number of antibiotic resistant strains of microorganisms has led to the development of more potent but more expensive antibiotics. Synthetic drugs are mostly associated with side effects and are generally costly, hence are not affordable to economically poor class of the society when long term treatment is required, thus interest has been developed in the use of herbal medicines which have been reported to have either very little or no side effects. Aims: Present work was carried out to assess the antimicrobial activity of A. paniculata against some multidrug resistant pathogenic bacteria. Materials and Methods: Different parts (leaf, stem, root) of A. paniculata were collected and air dried and soxhlet extracted by using standard methods for flavonoid and alkaloid extraction. These extracts were then tested for antimicrobial activity using disc diffusion method. Minimum inhibitory concentration, Minimum bactericidal concentration and Total activity were also calculated. Statistical Analysis: Mean value and Standard Deviation were calculated for the test bacteria and fungi. Data were analysed by one-way analysis of variance and P values were considered significant at P < 0.05. Results: C. albicans was found to be the most susceptible organism followed by P. mirabilis, S. aureus, E. coli, P. aeruginosa and A. flavus. A. niger and T. mentegrophyte were observed to be resistant as none of the tested extracts showed activity against them. Free flavonoid extract of root showed best activity against C. albicans (IZ 14 mm, MIC 0.156), whereas leaf free flavonoid extract showed maximum 21 mm inhibition zone against P. mirabilis.The range of MIC and MBC was found to be 1.25-0.039 and 2.5-0.078 respectively. Conclusion: Results of the present study reveal that extracts of A. paniculata are showing great antimicrobial potential against tested microorganisms, and may be exploited for future antimicrobial drugs