Evaluation of Antimicrobial Potential of Rhizospheric Soil Fungi Isolated From Tinospora Cordifolia, Mentha Arvensis and Ocimum Tenuiflorum Medicinal Plants

Abstract

Apart from producing phytohormones, plant associated microbes like rhizospheric microbes are also found to be the producers of pharmaceutically active compounds. The rhizosphere is a narrow region around plant roots, a hot spot for diverse and active population of soil microbes where various ecological and biological complex interactions occur. Medicinal plants harbour a distinctive microbiome in their rhizosphere due to their unique and structurally divergent bioactive secondary metabolites that are most likely responsible for the high specificity of the associated microbes. In the present investigation, fungi were isolated from rhizosphere of three medicinal plants Tinospora cordifolia, Mentha arvensis and Ocimum tenuiflorum of Kurukshetra and some nearby districts and screened for antimicrobial activity by agar well diffusion method. Out of 10 fungal isolates, TF1 isolate was found to be potent antimicrobial metabolite as showed highest activity against all bacteria and yeast pathogens. The Minimum inhibitory concentration calculated by agar dilution method showed that Minimum Inhibitory Concentration of yellow oily metabolite extracted by ethyl acetate by solvent extraction method was 0.039mg/ml against Pseudomonas aeruginosa, Escherichia coli, Streptococcus pyogenes and Candida albicans. According to microscopic examination TF1 fungal isolate was found to belong to Aspergillus species. The potent isolate could be exploited for optimization of various parameters like pH, temperature, carbon and nitrogen sources etc. to increase the yield of metabolite.

Isolation of Pectinase Producing Bacteria from the Rhizosphere of <i>Andrographis paniculata</i> Nees and 16S rRNA Gene Sequence Comparison of Some Potential Strains

“…The total heterotrophic bacterial count observed in this study corroborates with previous report that the bacterial population in the rhizosphere ranges from 10 8 to 10 9 per gram of rhizosphere soil [32].…”