A human trial conducted by University of California researchers Firestone and colleagues showed that I3C inhibits elastase. Elastase is an enzyme that breaks down protein. High levels of elastase in neutrophils (a type of white blood cell or leucocyte) suggests poor patient survival rates. Elastase shortens cyclin E, a chemical involved in controlling the cell cycle. The shortened version of cyclin, accelerates the cell cycle making cancer cells grow and multiply faster. Firestone et al showed that I3C prevents elastase from shortening the cell cycle thereby arresting the development of breast cancer.
Co-author of the study Bjeldanes stated that I3C is available as a supplement and is a preferred treatment for recurrent respiratory papillomatosis - a non-malignant tumor of the larynx. Improved version of I3C could help breast, prostate, and lung cancer.
"I think one of the real uses of this compound and its derivatives is combining it with other kinds of therapies such as tamoxifen for breast cancer and anti-androgens for prostate cancer. Humans have co-evolved with cruciferous vegetables like broccoli and brussels sprouts, so this natural source has a lot fewer side effects" said Firestone. The study was published in the December 2008 issue of the Proceedings of the National Academy of Sciences.
Indole -3- Carbinol's Chemoprotective Function
Indole-3-Carbinol is a by-product of glucosinolates, water soluble compounds that contains Sulfur and Nitrogen synthesized from glucose and amino acid. They are contained in vegetables belonging of the Cruciferae family (have flowers that looks like a cross) including broccoli, brussels sprouts, and cauliflower,etc. I3C is catalyzed by myrosinase, an enzyme, when the vegetables are "crushed"/ or cooked.
I3C confers protection against hormone dependent tumors by:
- Intervening in the metabolism of estradiol- a sex hormone.
- Enhancing the elimination of estrogen by increasing its oxidation and metabolism, reducing the growth of estrogen receptor positive tumor cells up to 90%. Even in estrogen receptor negative breast cancer, administration of I3C inhibited cancer cell growth while Tamoxifen has no effect on this type of tumor. This is attributed to I3C's strong antioxidant property. Broccoli contains 32 known antioxidants, 12 anti-carcinogenic agents, and 23 anti-tumor compounds.
- Intensifying the action of Tamoxifen
- Inducing apoptosis ( cancer cell suicide), and
- Protecting healthy DNA from destruction. I3C may also be beneficial against lung cancer in female smokers.
Prevalence of Cancer
The World Health Organization forecasts that worldwide cancer rates will increase by 50% to 15 million by 2020. It is estimated that more than 1 million women around the world are diagnosed with breast cancer yearly, and that more than 22,000 cases of breast cancer is diagnosed in Canada each year, while prostate cancer is the most common type of cancer in Canadian men affecting some 24,000 and killing 4,300 males in 2008.
Worldwide, the most common form of cancer is lung cancer with over 1.2 million new cases diagnosed annually according to the European School of Oncology. Lung cancer has the lowest survival rate with only 25% of patients surviving more than one year after diagnosis.
Conclusion
Broccoli is a flavorful, widely available, affordable and a nutrient and phytochemical-dense vegetable that can be easily incorporated in a healthy diet.
References
- Firestone GL et al. "The dietary phytochemical Indole-3-Carbinol is a natural elastase enzymatic inhibitor that disrupts cyclin E protein processing " Proceedings of the National Academy of Sciences, Decmber 2008; 105:19750-19755
- Chiao JW et al. " Ingestion of an isothiocyanate metabolite from cruciferous vegetables inhibit growth of human prostate cancer cell xenografts by apoptosis and cycle cell arrest" Carcinogenesis, 2008;25(8):1403-1408
- Cassie F et al. "Dose-dependent inhibition of tobacco smoke carcinogenesis induced lung tumorigenesis in A/J Mice by Indole-3-Carbinol" Cancer Prevention Research, December 2008;1(7)568-576
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