Rubia cordifolia L. is an important plant used in Ayurvedic and Siddha medicinal systems of India for treatment of blood disorders. Of all the plant parts, roots of R. cordifolia are the most suitable source of effective secondary metabolites. The present work investigated phytochemical content and antioxidant potential of R. cordifolia root powder extracted in different solvents. Total polyphenols and flavonoids content were estimated. High antioxidant activity was corroborated with DPPH, hydrogen peroxide, nitric oxide, reducing power and total antioxidant assays. Obtained results showed that ethanol extracts were most potent over methanol, aqueous and PBS extracts for DPPH, hydrogen peroxide and reducing power assays. In contrast, methanol and aqueous extracts had higher potency in nitric oxide and total antioxidant assays. Encouraging results were obtained for antioxidant activity even upon PVPP treatment that removed the polyphenols from the extracts. The results suggest a potential of ethanol/methanol extracts for anticancer cellular activities as many reports earlier have shown that antioxidant activities are closely correlated with anticancer activities.

Rubia cordifolia L. (Rubiaceae) is an important plant in Indian and Chinese medical systems. Extracts prepared from the root, stem and leaf have been used traditionally for the management of various diseases. Some of the known effects are anti-inflammation, neuroprotection, anti-proliferation, immunomodulation and anti-tumor. A comparative account of the extracts derived from different organs that lead to the identification of the most suitable solvent is lacking. We explored the presence of phytochemicals, antioxidant activity and anti-proliferative properties of a variety of solvent-based extracts of root, and methanol extracts of stem and leaf of R. cordifolia L. The antioxidant potential was determined by DPPH, hydrogen peroxide, nitric oxide and total antioxidant assays. The anti-proliferative nature was evaluated by MTT assay on HeLa, ME-180 and HepG2 cells. The composition of the extracts was determined by UPLC-UV-MS. We found that the root extracts had the presence of higher amounts of antioxidants over the stem and leaf extracts. The root extracts prepared in methanol exhibited the highest cytotoxicity in HepG2 cells. The main compounds identified through UPLC-UV-MS of the methanol extract give credibility to the previous results. Our comprehensive study corroborates the preference given to the root over the stem and leaf for extract preparation. In conclusion, we identified the methanol extract of the root to be the most suited to have bioactivity with anti-cancer potential.