Antioxidant and cytotoxic activity of Rutin isolated from Nigrospora sphaerica, an Euphorbia hirta based endophytic fungus

The objective of this study was to isolate and characterize rutin from the endophytic Nigrospora sphaerica of Euphorbia hirta L. The compound was isolated and purified through thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Further, it was identified as rutin (RN) using fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and high resolution mass spectroscopy (HRMS) analyses. The estimated RN concentration in the culture filtrate of N. sphaerica was 19.54 mg/L. The calculated IC50 values of RN with respect to antioxidant potential estimated using 2, 2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide (H2O2), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and nitric oxide (NO) approaches were 29.1, 36.5, 42.2 and 43.4 µg/mL, respectively. Besides, a combined treatment of RN and cisplatin (CP) inhibited the survival of tumor cells (HuT-78) significantly (P<0.05). Interestingly, the RN enhanced the apoptosis-inducing ability of CP considerably. In conclusion, N. sphaerica may be exploited as an alternative source of rutin for various commercial applications.