Antimicrobial activities of Turbinaria conoides (J. Agardh) Kutzing and Marsilea quadrifolia Linn

Turbinaria conoides (J. Agardh) Kutzing ,(Phaeophyceae) a marine seaweed, and Marsilea quadrifolia Linn. (Marsileaceae) an aquatic fern, were tested for activity against Tobacco necrotic virus (TNV) and bacteria (antimicrobial). Local lesion method was adopted and half leaf comparisons were made in cotyledonary leaves of Cyamopsis tetragonoloba Taub.(Linn.). Extracts of the experimental plants were prepared with water , methanol and toluene: methanol (2:1 v/v). Various concentrations were tested and the toluene : methanol extract of Turbinaria exhibited good activity at a concentration of 1000 μg/mL when compared to Marsilea. These results clearly depict the potential of the algae against plant virus when compared to the aquatic fern. Contradictory to the antiviral activity the extracts of Marsilea showed good antibacterial activity and produced the zone of inhibition of 32mm. The aqueous leaf extract showed maximum zone of inhibition at 300 μg/ml against Pseudomonas fluorescens. The present study clearly indicates that M. quadrifolia had a profound antimicrobial activity and it may be useful in the treatment of various infectious bacterial diseases. Thus both the plants of aquatic habitat have different activities against microbes.