Aim: The aim of the present study was to determine the antimicrobial activity of different solvent extracts of leaf and stem of Marsilea minuta (L.) against some selected pathogenic microorganisms. Methods: The antibacterial and antifungal studies were carried out by well diffusion method in the Research Laboratory, Department of Biochemistry, Government Arts College (Autonomous), Kumbakonam 612 001, Tamilnadu, India during the months between October and December 2015. Wells of 6mm diameter were punched in the agar medium and filled with different volume of extracts (50mg/ml) like 50, 75 and 100µl contains 2.5, 3.75 and 5mg of extract, respectively. The antimicrobial activity of different solvents like aqueous, methanol, ethanol and diethyl ether extracts of leaf and stem of M. minuta at different concentrations was analysed against selected bacterial pathogens such as Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens and Streptococcus pyogenes and the fungal pathogens such as Aspergillus niger, Aspergillus flavus, Aspergillus terreus, Trichoderma viride and Fusarium solani. Results: The leaf and stem extracts showed antibacterial and antifungal activities by the formation of zone of inhibition ranges from 07±0.8 to 25±0.9 mm. Among the tested concentrations, 5mg of both leaf and stem extracts showed best antibacterial and antifungal activities than other concentrations like 2.5 and 3.75mg. The maximum level of zone of inhibition 25±0.9mm was observed in aqueous stem extract against Klebsiella pneumoniae and the minimum level of zone of inhibition 08±0.4mm was observed in the methanol leaf extract against Streptococcus pyogenes. The antifungal activity of tested solvent extracts of leaf showed positive results against in all fungal strains used in the study. The aqueous leaf extracts showed maximum level of zone of inhibition 25±0.9mm against Trichoderma viride. The methanol stem extracts showed the minimum level of zone of inhibition 07±0.8mm against Aspergillus terreus. Conclusion: The results of this study confirmed that the antimicrobial activity of leaf and stem of M. minuta and it may be source for the discovery of novel antimicrobial compounds.
Key words: Marsilea minuta, antimicrobial activity, well diffusion method, microorganisms, leaf, stem.