A rapid determination of the effective antioxidant agents using their Fe(III) complexes

Abstract

A simple, cheap and rapid colorimetric method to determine the total amount of ortho-hydroxyphenolic compounds (TOHPC) as the effective antioxidant agents in food and natural products samples using ferric chloride (FeCl3) reagent was developed. The developed assay shows good linearity, reproducibility, LOD and LOQ. In addition, the performance of the method was validated against the conventional assay by analyzing the total amount of phenolic content (TPC) of twenty tea samples. Similarly, a high correlation was observed between TOHPC and TPC (R2 = 0.9651). In addition, the correlations between TOHPC and TPC and antioxidant activities including DPPH· and ABTS·+ assays were studied. It was found that when the total phenolic content in both assays increased the antioxidant activities also increased. The results demonstrated that the developed assay could be used as an alternative method to determine the total amount of effective antioxidant agents in several food, beverages and natural products samples.

Keywords

• Phenolics
• Ortho-hydroxyphenolics
• Ferric chloride
• Colorimetric method
• Antioxidant activity