Application of electron paramagnetic resonance spectroscopy for investigating antioxidant activity of selected herbs

Abstract

Antioxidant properties of selected herbs were investigated using electron paramagnetic resonance (EPR) spectroscopy. This was possible by measuring changes in the intensity of the EPR spectrum that resulted from the interaction of the stable radical 1,1-diphenyl-2-picrylhydrazyl with antioxidants found in herbal samples. Moreover, the total phenolic content (TPC) was measured using UV-Vis spectroscopy. The values of trolox equivalent antioxidant capacity were in the range of 10.95 to 505.95 μmol Trolox/1 g of dry weight of sample. TPC values were in the range of 3.38 to 63.13 mg of gallic acid/1 g of dry weight. The results showed that all of the investigated herbs exhibit antioxidant properties. A positive and significant correlation between antioxidant activity and total phenolic content was observed. The studied herbs could be a good source of natural antioxidants.