Antioxidant, Anticancer and Antibacterial Activity of Withania somnifera Aqueous Root Extract

Aims: To evaluate total antioxidant capacity, anticancer activity and antibacterial effects Withania somnifera aqueous-root extracts.

Study Design: In vitro study.

Place of Study: School of Biomedical Sciences, Ulster University, UK.

Methodology: Total antioxidant capacity (TAC) of whole powder and freeze dried W. somnifera aqueous-root extracts was determined using FRAP, DPPH, Folin and ABTS assays. Anticancer activity was accessed using MDA-MB-231 breast cells and Sulforhodamine B staining for cell viability. Antibacterial activity was by disk diffusion assay with penicillin, amoxicillin and streptomycin as positive controls.

Results: The TAC for W. somnifera extract was 86, 47, 195,or 443 gallic acid equivalents per 100g dry basis (mgGAE/ 100 g) using FRAP, DPPH, Folin or ABTS assays, respectively. Corresponding TAC values for freeze dried W. somnifera aqueous-root extract were, 418, 553, 1898 or, 1770 (mgGAE/100 g). W. somnifera aqueous-root extract inhibited MDA-MB-231 cell proliferation in a dose-dependent manner with IC50 = 0.19 mg/ml (21 µM GAE). Nil antibacterial effects were detected for freeze dried W. somnifera extract (0-1 mg/ml) across six species of bacteria tested.

Conclusion: Withania somnifera root water extract showed significant antioxidant and anticancer activity for MDA-MB-231 breast cancer cells but no antibacterial activity under the conditions of this study.