A Component of the Nigella sativa Plant as a Radioprotector and Antitumor Drug

Natural species are widely used as pharmaceutical agents for treatment of many human diseases. One of these is the seeds of Nigella sativa and its constituent thymoquinone (TQ). As a biologically active compound, TQ manifests a variety of therapeutic properties, including antioxidant, anti-inflammatory, antitumor and some others. Since TQ is an absorber of free and superoxide radicals, it is a promising natural radioprotector against immunosuppressive and oxidative effects of ionizing radiation. The review presents the data on TQ radioprotective properties and some of the mechanisms of its activity. In addition, TQ exhibits antitumor activity by inhibiting cell proliferation, migration, and invasion. It is known that TQ can induce apoptosis by regulating the expression of pro-apoptotic and anti-apoptotic genes in many types of cancer, but the mechanism of TQ action in oncological diseases has not been fully studied yet. We described in this review the mechanisms of action of TQ as a promising radioprotector and as a future candidate for antitumor therapy.