Effect of advanced oxidation and amino acid addition on antioxidant capability, iron chelating property and anti-cancer activity of tannic acid

Abstract

Although tannic acid (TA) has been shown to exhibit various biological properties, its properties may be hindered by alteration of its chemical structure. To explore the possible alterations in living system-like conditions, we firstly investigated oxidation reaction and amino acid addition of TA in physiological buffered solutions. Evidently, TA was found to be easily oxidized and interacted with amino acids in a phosphate buffered saline solution at 37 °C. The modified TA samples were found to conserve iron-chelating property, but diminish antioxidant capability and anti-cancer activity. As far as biomedical utilizations of TA is concerned, therefore, the structure alterations by above phenomena need to be taken into account. On the other hand, we might also take advantage of advanced oxidation and amino acid addition of TA by pre-treatment of TA according to our described procedures to generate TA derivatives for utilization in specific applications.