Abstract: The effect of ginger extract on antioxidant and phase II detoxifying enzymes in mice exposed to benzo(α)pyrene (BαP) was investigated and the underlying regulatory mechanism was elucidated. Kunming mice were administered by gavage with ginger extract at 100 (low-dose group, LG), 200 (medium-dose group, MG) and 400 mg/(kg·d) (high-dose group, HG) for 14 consecutive days before intraperitoneal injection with 50 mg/(kg·d) of BαP. Glutathione peroxidase (GSHPx), catalase (CAT), superoxide dismutase (SOD), quinone reductase (QR), hemooxygenase 1 (HO-1) and glutathione-Stransferase (GST) activity and their protein and mRNA expression were analyzed. The expression levels of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and Kelch like ECH-associated protein 1 (Keap1) were examined as well. Results showed that BαP + MG and BαP + HG significantly (P < 0.05) elevated CAT and GSH-Px activities in the serum and CAT, SOD and GSH-Px activities in the liver and kidney in mice compared to BαP alone. Meanwhile, the administration of BαP + MG and BαP + HG led to a significant increase of QR, HO-1 and GST activity by 21.7%, 23.99% and 32.40% in liver, and by 29.05%, 56.39% and 15.08% in kidney, respectively. In contrast to BαP, BαP + MG treatment led to a 21.9% increase of Nrf2 protein expression and a 34.7% reduction of Keap1 protein expression. Totally, 19 compounds were identified in ginger extract by high performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (HPLC/LTQ- Orbitrap-MS). Our results suggest that ginger extract was able to induce antioxidant and phase II enzymes in mice exposed to BαP by a mechanism related to Nrf2-Keap1 signaling pathway.

Key words: ginger, benzo[α]pyrene, antioxidant enzymes, phase II enzymes, Nrf2-Keap1