Objective: NAD(P)H: quinone oxidoreductase 1 (NQO1) is important in xenobiotic and carcinogenic detoxifications. NQO1-mediated detoxification of quinones is thought to be an important strategy for cancer chemoprevention. The objective of this study was to determine the expressional levels of liver NQO1 that could be observed by administration of an equal dose (50 mg/kg) of five different dietary chemicals (sulforaphane, quercetin, curcumin, butylated hydroxyanisole, indole-3-carbinol) to mice.
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, mice were sacrificed and their livers harvested. Total RNA was extracted, reverse transcribed and subjected to quantitative real-time PCR to detect NQO1 gene expression. Agarose gel electrophoresis was performed to verify the specificity of amplification. Western blots were performed to detect NQO1 protein expression.
Results: There was 3.1-, 1.5-, 2.2-, 2.5- and 2.5-fold increase in mice liver NQO1 gene expression after treatment with 50 mg/kg sulforaphane, curcumin, quercetin, indole 3 carbinol and butylated hydroxyanisole respectively (P<0.05). The results also showed that NQO1 protein expression in the livers of mice treated with 50 mg/kg sulforaphane, curcumin, quercetin, indole-3-carbinol and butylated hydroxyanisole was increased by 2.3-, 1.7-, 1.8-, 1.9- and 1.9-fold respectively (P<0.05).
Conclusions: At the dose of 50 mg/kg, sulforaphane exhibited the highest level of liver NQO1 expression, followed by indole