Study on Natural Phenols with Catalytic Activity of Cytochrome

Author(s): Sudhir Kumar Mishra, Pramendra Ranjan and Dhiraj Kumar

The effect of protocatechuic acid, tannic acid and trans-resveratrol on the activity of p-nitrophenol hydroxylase (PNPH), an enzymatic marker of CYP2E1, was examined in liver microsomes from acetone induced mice, trans-Resveratrol was found to be the most potent inhibitor (IC50 = 18.5 ± 0.4 μM) of PNPH, whi1e protocatechuic acid had no effect on the enzyme activity. Tannic acid with IC50 = 29.6 ± 3.3 μM showed mixed and trans-reseveratrol competitive inhibition kinetics (Ki = 1, μM and 2.1 μM, respectively). Moreover, trans-resveratrol produced a NADPH-dependent loss of PNPH activity, suggesting mechanism-based CYP2E1 inactivation. These results indicate that trans-resveratro and tannic acid may modulate cytochrome P4502E1 and influence the metabolic activation of xenobiotics mediated by this P450 isoform.

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