Analytical Characterization of Secondary Metabolites from Indian Xenorhabdus Species the Symbiotic Bacteria of Entomopatathogenic Nematode (Steinernema spp.) as Antifungal Agent

摘要

Steinernema is symbiotically associated with bacteria of the genus Xenorhabdus. It produces a wide range of bioactive metabolites including antimicrobial substances that inhibit the growth of bacteria, fungi and other microbes. Bacterial broth of different strains of Xenorhabus [(X. assam-isolate (SG as1), X. indica and X. Gujarat-isolate (SG gj)] was extracted with ethyl acetate. Potential activity resided in the ethyl acetate extract. X. assam-isolate (Sg as1) exhibited highest antifungal activity (EC50 55.98 mu g ml(-1)) against M. phaseolina. LC-MS analysis of the ethyl acetate extract of most active isolate showed the presence of three major groups of compounds viz. nematophins, xenocoumacins and xenorhabdins.