Comparative study between NAD(P)H:quinone Oxidoreductase 1 (NQO1) and Heme Oxygenase-1 (HO-1) enzymes induced by an equal dose of different classes of dietary chemicals in mice liver

Abstract

Objective: Dietary chemicals, which are generally found in vegetables, fruits and spices, have been reported to protect against cancer based on their ability to activate endogenous defenses by inducing the expression of phase II detoxification and antioxidant enzymes such as NAD(P)H:quinone Oxidoreductase 1 (NQO1) and Heme Oxygenase-1 (HO-1). The objective of this study is to compare the potency of induction of NQO1 and HO-1 genes, and their protein products in mice livers following administration of equal doses (50 mg/kg) of five different dietary chemicals (sulforaphane, quercetin, curcumin, butylated hydroxyanisole, indole-3-carbinol). Methods: Adult male ICR white mice were divided into 8 groups (n=6 per group) i.e. normal control, sulforaphane, quercetin, curcumin, butylated hydroxyanisole, indole-3-carbinol, vehicle 1 control and vehicle 2 control groups. The chemicals were administered intraperitoneally for 14 days at a dose of 50 mg/kg body weight. At day 15, the mice were sacrificed and their livers isolated. Total RNA was extracted, reverse transcribed and subjected to quantitative real-time PCR to detect NQO1 and HO-1 gene expression. Western blots were also performed to determine NQO1 and HO-1 protein expression. Results: The comparison between NQO1 and HO-1 gene expression showed that equal doses (50mg/kg) of dietary chemicals induced HO-1 gene expression more potently than NQO1. Meanwhile, they induced NQO1 and HO-1 protein with the similar potency. Conclusions: Equal doses (50mg/kg) of sulforaphane, indole 3 carbinol, butylated hydroxyanisole and curcumin induced HO-1 gene expression more potently than NQO1 while they induced NQO1 and HO-1 protein expression with the similar potency.