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Indole-3-carbinol (I3C)

Indole-3-carbinol (I3C), also known as 1H-indole-3-methanol, is a naturally occurring component of Brassica vegetables, such as cabbage, broccoli, and Brussels sprouts. Diindolylmethane (DIM), as well as its precursor, Indole-3-carbinol (I3C), and cogener, 2-(Indol-3-ylmethyl)-3,3'-diindolylmethane (LTR-1) are natural phytochemicals and part of the family of dietary indoles discovered in cruciferous vegetables. DIM and I3C are found in cruciferous vegetables including broccoli, cauliflower, cabbage and Brussels sprouts. DIM, together with the linear trimer, LTR-1, are formed from the precursor indole, I3C, after the enzymatic release of I3C from parent glucosinolates found in all cruciferous vegetables. I3C is now in use as a dietary supplement and has been reported to beneficially shift estrogen metabolism to favor 20 H estrone. I3C is highly acid sensitive and it can be converted by gastric acid to form several metabolites in stomach. It is known that I3C and its metabolites also possess anticancer activities that are independent of their antiestrogenic properties. For example, these compounds have been found to suppress the migration and invasion of breast cancer cells by mechanisms that include up-regulation of the BRCA1 gene, E-cadherin (a regulator of cell) and PTEN (a tumor suppressor gene). I3C and its metabolites have also been found to inhibit cell cycle progression at G1 by inhibiting cyclin-dependent kinase in both estrogen receptor-positive and estrogen receptor-negative breast cancer cells. They have also been shown to induce apoptosis in breast cancer cells by means independent of the p53 gene, and down-regulation of the apoptosis inhibitory protein Bcl-2. In addition, I3C and its metabolites appear to be protective against colon cancer by stimulating apoptosis in precancerous cells and by preventing potentially cancer-causing intracellular DNA damage. I3C has also been demonstrated as useful in suppressing growth and inducing apoptosis in prostate cancer cells by mechanisms independent of its antiestrogenic properties. I3C has additionally been found to exhibit efficacy against cancers of the liver and lung.

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