Phytochemical Analysis and Antioxidant Activity of Endophytic Fungi Isolated from Dillenia indica Linn.

Endophytic fungi live symbiotically inside plants and are hidden source of natural bioactive molecules. The present study was carried out to investigate the phytochemical analysis and antioxidant activity of endophytic fungi isolated from the ethnomedicinal plant Dillenia indica L. The ethyl acetate crude extracts of the endophytic fungal strains were preliminarily evaluated for their phytochemical analysis, and the results showed the presence of alkaloids, flavonoids, phenolics, terpene, and saponins. The crude extracts of more than 60% of the isolates showed 50-90% antioxidant activity by DPPH and H2O2 assay. The inhibition percentage of ethyl acetate extracts ranges from 34.05 to 91.5%, whereas IC50 values vary from 72.2 to 691.14%. Among all the strains, Fomitopsis meliae crude extract showed a maximum inhibition percentage, i.e., 91.5%, with an IC50 value of 88.27 µg/mL. Chaetomium globosum showed significant activity having an inhibition percentage of 89.88% and an IC50 value of 74.44 µg/mL. The total phenolic and flavonoid content in the crude extract of Chaetomium globosum was 37.4 mg gallic acid equivalent (GAE)/g DW and 31.0 mg quercetin equivalent (GAE)/g DW. GC-MS analysis of crude extract of C. globosum revealed different compounds, such as squalene; butanoic acid, 2-methyl-; hexadecanoic acid; 2-propanone, 1-phenyl-; 5-oxo-pyrrolidine-2-carboxylic acid methyl ester; 9,12-octadecadienoic acid (z)- etc. Many of these belong to phenolics, which are natural antioxidant compounds. The findings suggested that endophytic fungi associated with Dillenia indica L. can be a potential source of novel antioxidant compounds.