Curcumin: from exotic spice to modern anticancer drug.
Inhibition of defined molecular steps of tumourigenesis by natural non-toxic compounds may be an efficient means to tackle the population cancer burden. Extensive research has addressed the chemotherapeutic potential of curcumin (diferuloylmethane), a relatively nontoxic plant derived polyphenol. Curcumin is used for centuries in cuisine and indigenous medicine against several major human diseases. Cancer is the second leading cause of death worldwide. Disruption of a proper regulation of cell proliferation can ultimately cause cancer. Most human malignancies are driven by chromosomal translocations or other genetic alterations that directly affect the function of critical cell cycle proteins such as cyclins as well as tumor suppressors, e.g., p53. In this regard, curcumin, the yellow pigment of the spice turmeric, has been reported to have immense potentialility for being used in cancer chemotherapy because of its control over the cell growth regulatory mechanisms and for its anti-inflammatory, anti-toxic and anti-oxidative properties. Increasingly reports are showing that curcumin can induce apoptosis in a wide variety of cancer cells. The mechanisms implicated in the inhibition of tumorigenesis by curcumin are diverse and seem to involve a combination of cell signalling pathways at multiple levels. When curcumin is combined with some cytotoxic drugs or certain other diet-derived polyphenols, synergistic effects have been demonstrated. Taken together, this review seeks to summarise the unique properties of curcumin that may be exploited for successful clinical cancer prevention.