Application of oxygen radical absorbance capacity (ORAC) assay in the estimation of antioxidant value of botanicals

Abstract

Mohamed Rafiq, Mohammed Azeemuddin, Suryakant D. Anturlikar, Gollapalle L. Viswanatha, Pralhad S. Patki

Abstract Present study was carried out to standardize the oxygen radical absorption capacity (ORAC) assay for the estimation of antioxidant value of botanicals indigenous to Indian subcontinent by taking Amalaki (Emblica officinalis) and an Ayurvedic proprietary polyherbal formulation (PHF) as a representative standard. The ORAC assay for ethanolic and aqueous (Organic Amla-C ® ) extracts of Amalaki and PHF were carried out using 96-well flat optical bottom clear black plates by the use of sensitive florescent multiple plate reader and fluorescein as a probe, vitamin C was used as a reference standard. The assay was found to be simple, versatile, reproducible, and can be widely used for estimating the total antioxidant activity of the herbs and propriety PHF. The study also highlights Amalaki and Himalaya PHF as rich sources of antioxidants. The antioxidant activities of Amalaki extracts were found to be slightly more than vitamin C and similarly the antioxidant activity of Himalaya PHF was comparable to that of vitamin C (in terms of total ORAC values).