Biological and therapeutic activities of thymoquinone: Focus on the Nrf2 signaling pathway

Thymoquinone is a monoterpenoid compound, which is derived from volatile and fixed oil ofNigella sativa(Ranunculaceae). This phytochemical compound has several biological effects, including antioxidant, antibacterial, antineoplastic, nephroprotective, hepatoprotective, gastroprotective, neuroprotective, anti-nociceptive, and anti-inflammatory activities. Thymoquinone shows pharmacological activities, including anti-hepatocellular carcinoma, nephroprotection, neuroprotection, retina protection, gastroprotection, cardioprotection, anti-allergy, reproductive system protection, bladder protection, and respiratory protection. It was found that these beneficial effects are mostly related to modulation of the Nrf2 signaling pathway by blockage of Keap1, stimulating the expression of the Nrf2 gene, and inducing the nuclear translocation of Nrf2. In the present review, the therapeutic effects of thymoquinone are overviewed through the Nrf2 signaling pathway.