Development and validation of a radical scavenging antioxidant assay using potassium permanganate

Abstract

The main objective of the study was to develop and validate a novel radical scavenging antioxidant assay using KMnO4. In this method tannic acid at concentration 6.25 μg/ml – 200 μg/ml was used as the standard antioxidant. KMnO4 solution (80.00 μg/L) in phosphate buffer (pH= 9) was developed as the prooxidant. Absorbances of KMnO4 both in the presence and absence of the antioxidant were taken spectrophotometrically at a wavelength of 526 nm after 30 minutes incubation period. The results obtained were then compared to results from reference method which employs 40.00 μg/L DPPH in methanol prepared and subjected to similar experimental conditions. The results showed that KMnO4 solution prepared in a phosphate buffer (pH= 9), was most stable and had the highest molar absorptivity. The method developed was precise, accurate and specific. The method developed passed all the validation parameters according to the ICH guidelines. This offers a new antioxidant method that is relatively cheap and safe to use.