A study of the electrochemical behavior of hematoxylin as an important bioactive flavonoid

The electrochemical oxidation of hematoxylin, as an important biological molecule, was studied using cyclic voltammetry. In this study, the effect of different parameters such as pH, hematoxylin concentration, and time window of the chosen electrochemical method has been used for understanding the oxidation mechanism of hematoxylin. The results show that the oxidation mechanism of hematoxylin is an ErCiEr mechanism. Also, the experimental data indicate that, in acidic and basic pHs, the rate of the subsequent chemical reaction is less than neutral pH. It is supposed that the subsequent chemical reaction of dimerization is more likely for the oxidation form of hematoxylin and hydroxylation, and intramolecular reactions cannot be considered as coupled chemical reactions. Finally, it is concluded that, in the dimerization process, hematoxylin reacts as a nucleophile with the o-quinone ring formed through the electrooxidation of hematoxylin and produces a dimer compound.

► The oxidation mechanism of hematoxylin is an ErCiEr mechanism.
► In acidic and basic pHs, the rate of coupled chemical reaction is less than neutral pH.
► The coupled chemical reaction of dimerization is more likely for the ErCiEr mechanism.