Since when it has been demonstrated that vitamin C played an important role as an inhibitor of the formation of carcinogenic compounds of alkyl-oxide, studies have been directed toward identifying substances that may inhibit the development of cancerous tumors. These substances interfere with one or more stages of tumor formation (carcinogenesis).
A pioneering work conducted by Wattenberg, 1971, identify enzymes that metabolize hydrocarbons that can cause cancer, such as the benzopyrene, in existing insecticides (product of the inappropriate production of the grilled food).
Enzymes are activated when we eat cruciferous vegetables such as kale, cabbage, turnips, broccoli and cauliflower. The enzymes are also activated by flavones. Some are natural – tangeretina and nobiletina – and other synthetic – beta-naphthoflavone. When placing beta-naphthoflavone in the diet of guinea pigs, there is the almost complete inhibition of pulmonary adenoma formation, which proves that this flavone is a potent activator of enzyme inhibitors of cancer. Subsequently, three substances were identified from the class of indoles which are able to induce the enzyme activity of the chromosomes. These indoles, such as isothiocyanates, also occurs in cruciferous vegetables and inhibit the formation of breast tumors and neoplasia, chemically induced in guinea pig stomach. Other substances with inhibiting tumor: coumarin, alpha-angelicalactona, caffeic acid, ferulic acid and hydroxy-cinnamic acid. These substances are present in many plants.
Studies carried out after 1980s, describe a large number of substances which increase the activity of various enzymes. Besides these substances, it was confirmed that cabbage, cauliflower, coffee grounds and tea leaves, when dried and pulverized, also induce the enzyme activity to inhibit the formation of cancerous tumors.
Have been identified many substances inhibiting cancer. These substances, which belong to twenty different classes of organic compounds, have the potential ability to prevent various cancers.
The substances that have anti-cancer activity can be divided into the following categories:
- Substances which prevent the formation of cancer by other substances, called precursors. Examples: caffeic acid. ferulic acid, propyl gallate, vitamin C and tocopherols.
- Substances that are blocking agents for cancer. Here are the coumarins, the diterpenes, dithiocarbamates, the ditioltionas, flavones, indoles, phenols, phenothiazines and trimetilquinolinas.
- Substances which suppress cancer. Within this category are the carotenoids, aspirin, indomethacin, isothiocyanates, phenols, plant sterols, the protease existing soybean, caffeine, retinoids and derivatives of selenium.
- Substances which inhibit the progression of cancer. These include: diazepam, dexamethasone, indomethacin, phenol, retinoic acid and leupeptin.
Many cancer-inhibiting substances are natural while others are synthetic – prepared in the laboratory. The substances synthesized in laboratory allow better direct the
action of the substance in the organ of the body where the cancer is located. So. the 13-cis-retinoic acid prevents the formation of bladder tumors and 4-hydroxyphenyl-retinamida inhibit breast cancer.
Many efforts have been directed towards understanding the mechanism of action of these inhibiting cancer substances. So far, the obtained results encourage research for the production of new synthetic compounds and testing with natural products such as vitamins, minerals and phytochemicals. Many epidemiological studies have been conducted in recent years and new substances that act as inhibitors of tumor formation were identified. Among the synthetic compounds to enhance some are: aspirin, N-acetyl cysteine, ibuprofen, oltipraz, piroxicam, sulindac, tamoxifen and vorozol. Among the components of natural products are: calcium, beta-carotene, curcumin, folic acid, genistein, tea extracts, polyphenols, vitamin A, vitamin D3 and vitamin E.
- Cancer – Lee W. Wattenberg MD Professor of Pathology
- Cancer Chemoprevention – Lee W. Wattenberg MD Professor of Pathology
- Matrix Metalloproteinase Inhibitors in Cancer Therapy – Clendeninn, Neil J.; Appelt, Krzysztof
- Principles of Anticancer Drug Development – Garrett-Mayer, E.; Hidalgo, M.; Eckhardt, S.G.; Clendeninn
- Foods That Can Help Fight Cancer (cnh2.wordpress.com)
- Eating to Beat Breast Cancer (massageenvy.com)
- Marijuana cuts lung cancer tumor growth in half, Harvard study shows (federaljack.com)