Antioxidant and cytotoxic activities of Isaria amoenerosea Henn.: An entomopathogenic fungus from Darjeeling Hills, Eastern Himalaya

Abstract

Isaria amoenerosea Henn., an entomopathogenic fungus parasitizing on the beetle adult was collected from the subtropical forest of Darjeeling, India. Axenic culture of the mycelia for metabolite extraction was carried out through submerged fermentation. The methanolic mycellial extract was evaluated for its antioxidant as well as cytotoxic activities. Through a series of the in-vitro antioxidant assay, it was found that the methanolic extract scavenged DPPH and ABTS radicals up to the extent of 56.17 and 83.35% respectively at the tested concentrations. The 10 mg/mL extract chelated 73.82% of ferrous ions and it also showed an appreciable capacity to reduce ferric ions to ferrous ions. Cell viability was assessed by the MTT assay on the three human carcinoma cells: HeLa (cervical cancer), PC3 (prostate cancer) and HepG2 (hepato carcinoma). Among them, HeLa was recorded to be most susceptible exhibiting 53.48% inhibition at 100 µg/mL. The total phenol and flavonoid content of the extract was 11.58±0.12 and 9±2.1 µg/mg of gallic acid equivalent respectively. The evidence presented herein suggests that the mycelial methanolic extract indicates a correlation between the presence of varied functional groups (FTIR spectrum) and antioxidative as well as cytotoxic activities. No direct test of the hypothesis has been made which demands further investigations.