Abstract

The fruits of Terminalia chebula, Terminalia bellerica and Emblica officinalis are important herbal raw materials containing polyphenols. They form the major constituents of widely used Ayurvedic formulations like Triphala churna. The extracts of these materials were standardized with respect to their total polyphenol contents as determined by Prussian blue method using gum acacia and phosphoric acid as stabilizers. The antioxidant activities were determined by DPPH (1,1-diphenyl-2-picryl-hydrazyl) method and inhibition of lipid peroxide formation induced by Fe²⁺-ascorbate system. They were found to strongly correlate with total polyphenol contents. The EC50 value (μg/ml) for free radical scavenging activity by DPPH method and IC₅₀ value (μg/ml) for lipid peroxidation inhibitory activity along with the total polyphenol contents can be used as quality control parameters for standardization of herbal raw materials containing polyphenols as major phytoconstituents.