A new way to compare the antioxidant activity of phenolic substances of different plant extracts

Abstract

With the growing evidence of potential health risks associated with the consumption of synthetic antioxidants, the demand for natural antioxidants has increased rapidly. In the assessment of the antioxidant activities of plant extracts IC 50 values of the extracts or antioxidant activity of a known concentration (g/L) (but not the concentration of active ingredients) of an extract, is determined. However, the results of such experiments do not clearly reflect the quality of antioxidants of the plant extracts due to the fact that the amounts of active antioxidant ingredients are not considered for such evaluations. In the present study the DPPH radical scavenging activities of phenolic extracts from different plant sources were compared. For this comparison, the colorimetrically measured total phenol contents of the phenolic extracts of different samples were adjusted to an equal concentration by suitable dilutions and the DPPH radical scavenging activity of each phenolic extract was measured (Figure 1). Five samples from each plant extract were used for the study and the measurements were done in triplicate.