Characterization of Bioactive Metabolites of Endophytic Fusarium solani Isolated from Withania somnifera

Abstract

This study was conducted to characterize and explore the endophytic fungi of Withania somnifera plant for their bioactive potential. A total of 70 segments of W. somnifera were screened and the highest species richness, as well as frequency of colonization was found in root determined as 25%. Endophytic fungi shown significant antibacterial activity against Staphylococcus aureus, E.coli, Proteus sp, Klebsiella pneumoniae and Pseudomonas sp. and were identified as Corynespora cassicola, Fusarium solani and Penicillium chrysogenum. The minimum inhibitory concentration (MIC) by the micro dilution broth was in the range of 21-82 μg/mL. Isolates revealed the presence of different phytochemicals, which includes, terpenoids, tannins, alkaloids and flavonoids. Based on its antibacterial, antioxidant and cytotoxic potential, Fusarium solani was selected, characterized genotypically by 28S rDNA typing and the sequence was deposited in NCBI database under accession number KJ193849. Fusarium solani was found to possess higher relative percentage reducing power of about 90.62% than that of Corynespora cassicola (57.47%) and Penicillium chrysogenum (52.37%) and the absorbance value obtained is comparable with the control. Percentage cell viability on cultured HeLa cell lines was determined as 6.25 μg/mL (64.74%), 12.5 μg/mL (61.08%), 25 μg/mL (58.68%), 50 μg/mL (53.24%), and 100 μg/mL (49.94%).There was significant reduction in the viability of cancer cells at 100 μg/mL. GC-MS analysis of the HPTLC fractions of Fusarium solani showed a wide range of compounds and the compounds taraxasterol, acenaphthylene, 3,4-oxadiazole, benzenamine were pharmaceutically important.