Study and evaluation antioxidant activity of dietary supplements with green tea extract

Abstract

The aim of the work is to determine and evaluate the antioxidant activity of dietary supplements with green tea extract, as well as to introduce conditional terms of the level of AOA. Materials and methods. The object of the study was dietary supplements of different manufactures: “Green Tea Extract” of Natural Sources, USA (DS1), “Extract of green tea” of Elit-Pharm, Ukraine (DS2) and “Green tea” of Pharmakom, Ukraine (DS3). Potentiometric measurements were conducted by pH meter Hanna 2550 (Germany) with a combined platinum electrode EZDO 5010. Epigallocatechin-3-O-gallate ˃98.0 % (Sigma Aldrich), K3[Fe(CN)6], K4[Fe(CN)6], NaHPO4, KH2PO4 were analytical grade. Results. It was established that a value of the antioxidant activity of DS1 was 36.51 mmol/tab, DS2 – 29.78 mmol/tab, and DS3 – 16.67 mmol/tab. DS1 had the highest value of the antioxidant activity, which correlated with the content of catechins (r2 = 0.9314). According to the proposed conditional terms of antioxidant activity dietary supplements, DS1 and DS2 possessed a low level of antioxidant activity, whereas DS3 corresponded to very low level of antioxidant activity. Conclusions. It was found that the studied dietary supplements with green tea extract have antioxidant activity, which correlates with the content of catechins.