Electrochemical Study of Commercial Black Tea Samples

摘要

Black tea (BT) is a widely consumed natural product whose myriad of therapeutic applications rely onits constituents of remarkable antioxidant power. The electroanalysis is unique to provide a preciseredox characterization of samples presenting a single compound or even a pool of electroactivespecies. Hence, this work aims to study the BT redox profile through electroanalytical methods.Voltammetric techniques such as Ciclic Voltammetry, Square Wave Voltammetry and DifferentialPulse Voltammetry were conducted in BT crude vegetal mater samples and pharmaceutical gradestandardized dried extract. It was found for all BT samples two anodic processes, the first occurring atpeak potentials bellow +0.5V, thus indicating a strong antioxidant activity. The results related to BTpool compounds voltammetric profile suggested that the first anodic process is reversible, whereas thesecond irreversible. In addition, such electron/proton transfer reactions undergo EC mechanisms,which are mostly diffusion controlled electrochemical processes. Since low anodic potential andreversible redox behavior are related to high reducing power and good regenerating ability, it can beinferred, that the recognized antioxidant activity of BT samples is undeniable.