Phytochemical characterization, biochemical profiling and evaluation of anticancer potential of methanolic extract of Withania somnifera stem.

Abstract

Phytotherapy employs phytoconstituents/phytomedicines derived from plants for treating and preventing illnesses. Withania somnifera is known in the Indian Ayurveda Pharmacopoeia for its medicinal applications and pharmacological properties. In this study, we examined the biological activity spectrum of Withania somnifera methanolic extract of stem (WSME), which is valued as a "Rasayana" due to its extensive range of medicinal uses. WSME was subjected to TPC and TFC quantification and bioactive components were characterized using LC-MS. Its antioxidant potential was gauged by DPPH and H2O2 radical scavenging assays, while antibacterial efficacy was assessed against S.aureus and E.coli using disc diffusion assay. In vitro anticancer activity was evaluated against human breast cancer MDA-MB-231 cells while toxicity was evaluated against normal Vero cells using MTT assay. WSME, rich in Withaferin A, showed TPC of 4.73±0.15 mg GAE/g and TFC of 94.94±6.15 mg QE/g dry weight of extract. It exhibited significant antioxidant activity (43.28 and 66.8 % inhibition at 1,000 μg/mL using DPPH and H2O2 assays, respectively) and mild antibacterial effects against S.aureus (300-500 mg/mL). WSME induced cell death in MDA-MB-231 cells and significantly inhibited their growth (IC50: 66 μg/mL, P value<0.05) without affecting normal Vero cells in the studied range of 25-400 μg/mL (IC50: 6.09 mg/mL, P value>0.05). The present study lends support to further testing of WSME against other cancer cell lines and animal models of cancer. These preclinical studies would provide further validation to its prospective use as an adjunct in human breast cancer therapy.