Characterisation and bioactivity of oosporein produced by endophytic fungus Cochliobolus kusanoi isolated from Nerium oleander L.

Abstract

Bioactive compounds comprising secondary metabolites produced by endophytic fungi have wide applications in pharmacology and agriculture. Isolation, characterisation and evaluation of biological activities of secondary metabolites were carried out from Cochliobolus kusanoi an endophytic fungus of Nerium oleander L. The fungus was identified based on 18S rDNA sequence analysis. There are no reports available on the compounds of C.kusanoi hence, antimicrobial metabolite produced by this fungus was extracted and purified by fractionation using hexane, diethyl ether, dichloromethane, ethyl acetate and methanol. Out of all the solvent fractions, the methanol fraction exhibited better antimicrobial activity which was further purified and characterised as oosporein. Oosporein from C.kusanoi exhibited broad spectrum in vitro antimicrobial, antioxidant and cytotoxic activities. The characterisation and antioxidant activity of oosporein from C. kusanoi are reported for the first time.

Keywords::

• Nerium oleander L
• Cochliobolus kusanoi
• oosporein
• antimicrobial activity
• antioxidant activity
• anticancer activity

Acknowledgements

The authors are grateful to Prof. T.N. Guru Row, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore for providing single-crystal XRD facility. We also sincerely thank the Society for Innovation and Development and NMR Research Centre, Indian Institute of Science, Bangalore for providing the facility for spectral analysis.