Endophytic fungi from healthy leaf tissues of Houttuynia cordata Thunb., a widely used ethno-medicinal plant of North East India was investigated and an attempt has been made to characterize the antimicrobial metabolites from some potent endophytic strains. Altogether, 56 endophytic fungal isolates were obtained from surface sterilized leaf fragments of H. cordata. The endophytes consisted of fungi belonging to genera Colletotrichum, Curvularia, Bipolaris, Corynespora, Pseudozyma and non-sporulating fungi categorized as mycelia sterilia. Assay for antimicrobial activity revealed, 73.07% of the isolates showed activity against the test pathogens in varying degree whereas 92.32% of the isolates showed anti-candida activity against Candida albicans. Among the isolates, two endophytic fungi identified as Colletotrichum coccodes and Phyllosticta capitalensis showed significant antimicrobial activity against all the test pathogens. The metabolites obtained from Colletotrichum coccodes revealed presence of different functional groups and bioactive compounds like geranylgeraniol, farnesol, hexacosanol, oleic acid and squalene. Metabolites obtained from Phyllosticta capitalensis also showed various functional groups and presence of bioactive compound, 1-Octacosanol among several others. The study indicated ethno-medicinal plants are colonized by rich diversity of endophytic fungi with antimicrobial activity. Further detailed investigation could practically lead to development of pharmaceutical agents in the future.
Key words: Houttuynia cordata, Endophytic fungi, Antimicrobial activity, Metabolite characterization
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