Biological Activity of Endophytic Fungi of Rauwolfia serpentina Benth: An Ethnomedicinal Plant Used in Folk Medicines in Northeast India

Abstract

Rauwolfia serpentina Benth is an ethnomedicinal plant used as anti-hypertensive remedy by the ethnic tribes of northeast India. The plant was screened for the endophytic fungi and their associated biological activities to assess if these fungi have any significant hypocholesterolemic, anti-oxidant and antimicrobial activities. The endophytes were characterized as Colletotrichum gloeosporioides, Penicillium sp. and Aspergillus awamori, from a total 15 isolates, using biochemical and molecular approaches. The colonization rate of endophytes in the leaf and the stem was found to be 12.04 and 4.02 % respectively. C. gloeosporioides was found to be the dominant fungus with an average colonization frequency of 6.8 % followed by Penicillium sp. (3.8 %) and A. awamori (2.1 %). Being the most potential isolate, Penicillium sp. showed the promising hypocholesterolemic activity. The antimicrobial potential against four pathogenic bacteria, viz., Streptococcus pyogenes, Escherichia coli, Enterococcus faecalis, Salmonella enterica ser paratyphi and three fungal pathogens, viz, Candida albicans, Emericella nidulans var nidulans, Fusarium oxysporum showed promising antagonistic ability. A. awamori showed the highest antioxidant potential and also had the maximum phenolic content among the characterized endophytes. This investigation revealed that the endophytic fungal extracts can be a potential source of alternative natural hypocholesterolemic, antimicrobials and antioxidant agents mimicking the activity of the host plant and purification of active metabolites may provide lead molecule of pharmaceutical importance.