Anticancer activities of Nigella sativa (black cumin)

Abstract

Nigella sativa has been used as traditional medicine for centuries. The crude oil and thymoquinone (TQ) extracted from its seeds and oil are effective against many diseases like cancer, cardiovascular complications, diabetes, asthma, kidney disease etc. It is effective against cancer in blood system, lung, kidney, liver, prostate, breast, cervix, skin with much safety. The molecular mechanisms behind its anticancer role is still not clearly understood, however, some studies showed that TQ has antioxidant role and improves body's defense system, induces apoptosis and controls Akt pathway. Although the anti-cancer activity of N. sativa components was recognized thousands of years ago but proper scientific research with this important traditional medicine is a history of last 2∼3 decades. There are not so many research works done with this important traditional medicine and very few reports exist in the scientific database. In this article, we have summarized the actions of TQ and crude oil of N. sativa against different cancers with their molecular mechanisms.

Keywords: Anti-cancer mechanism; Antioxidant; Nigella sativa; Thymoquinone; Traditional medicine.

Figure 1

Chemical structure of anti-tumor agents isolated from N. sativa

Figure 2

Possible mechanisms of thymoquinone (TQ) action. (1) TQ induces apoptotic cell death in cancerous tissues by up-regulating expression of apoptotic genes (caspases and bax) and down-regulating expression of anti-apoptotic genes (e.g., bcl 2); (2) TQ suppresses Akt activation by dephosphorylation and thus blocks cancer cell survival; (3) TQ deactivates NF-kappa B pathway by inducing cytokine production, and thus control oncogenic expression; (4) TQ increases the activities of antioxidant enzymes and protects cell against cancer; (5) TQ protects normal cells' injury caused by ionizing radiation in the treatment of cancer; (6) TQ prevents CYP450 enzymes from damage. ‘+’ indicates increasing effect and ‘−’ indicates decreasing effect.