Influence of total phenolic content and total flavonoid content on the DPPH radical scavenging activity of Costus speciosus (Koen Ex. Retz.) Sm.
The focus of the present study was to determine the association of the anti-oxidant activity of Costus speciosus (Koen Ex. Retz.) Sm. with the total phe-nolic content and the total flavonoid content. The antioxidant activity of the extracts was quantified by diphenylpicrylhydrazyl (DPPH) assay. The total phenolic content was determined by the Folin-Ciocalteau method and the total flavonoid content was determined by the aluminium chloride method. Among the four extracts of the plant, the ethanol extract exhibited the high-est antioxidant activity and also the highest total phenolic and flavonoid con-tents. A strong correlation was observed between the antioxidant activity and the total phenolic and flavonoid contents. A statistical model was de-rived to explain this dependence and a non-linear association was observed between the antioxidant activity and the total flavonoid content.