Abstract::
Thymoquinone (TQ), the bioactive constituent of Nigella Sativa seeds is a well-known natural compound for the
management of several types of cancers. The anti-cancer properties of thymoquinone are thought to be operated via intervening
with various oncogenic pathways including cell cycle arrest, prevention of inflammation and oxidative stress, induction
of invasion, metastasis, inhibition of angiogenesis, and apoptosis. As well as up-regulation and down-regulation of specific
tumor suppressor genes and tumor promoting genes, respectively. Proliferation of various tumor cells is inhibited by
TQ via induction of cell cycle arrest, disruption of the microtubule organization, and down regulating cell survival protein
expression. TQ induces G1 phase cell cycle arrest in human breast cancer, colon cancer and osteosarcoma cells through inhibiting
the activation of cyclin E or cyclin D and up-regulating p27and p21 a cyclin dependent kinase (Cdk) inhibitor. TQ
concentration is a significant factor in targeting a particular cell cycle phase. While high concentration of TQ induced
G2 phase arrest in human breast cancer (MCF-7) cells, low concentration causes S phase arrest. This review article provides
mechanistic insights into the anti-cancer properties of thymoquinone.