Interaction between antioxidants and hydroquinone/bisphenol

We have investigated the stability of semiquinone radical (Se)produced from the mixture of hydroquinone (Hg) and bisphenol A (BPA) in the presence of various antioxidants, some of which induce apoptosis in tumor cell lines. B PA produced no detectable amount of ESR signal. The acceleration of HQ oxid ation by BPA results in the production of Se. The BPA-enhanced SQ . product ion may occur through either SQ . regeneration by electron transfer from BP A working as an antioxidant or the O-2(-) scavenging activity of BPA. SQ . intensity of HQ/BPA was reduced by lower concentrations of sodium ascorbate , epigallocatechin, gallate and quercetin, but significantly enhanced by ga llic acid The initial Se was replaced by the radicals of antioxidants excep t lignin and salicylic acid at higher concentrations. due to their radical- radical coupling or dismutation process. Among these compounds, gallic acid enhanced the radical intensity of SQ . to the greatest extent. The results suggest that antioxidants from foods suppress the activity of xenobiotics such as He, however, they produce their own radical at higher concentration s, suggesting heir bimodal actions. The present study demonstrates the usef ulness of ESR spectroscopy for the interaction between HQ/BPA and antioxida nts.