< previous page | page_114 | next page >
Page 114
| aggressiveness of the cancer cells. 33 Laminin accumulates between invading cells and host tissue. It aids cancer-cell growth by promoting adhesion. |
| Catechin, a flavonoid found in many plants, including green tea and the Chinese herb fo ti (Polygonum multiflorum), inhibits the invasion of a variety of tumor-cell lines. At least one of the mechanisms by which catechin inhibits tumor-cell growth is its ability to bind tissue-type plasminogen activator (t-PA) to laminin, which leads to partial inactivation of t-PA and cancer-cell growth. Tissue-type plasminogen activator is an enzyme that facilitates tumor invasion. |
| Herbs contain agents that can also inhibit the malfunction of tumor-suppressor genes by stopping or inhibiting them from mutating and causing DNA to become jumbled. Quercetin, a flavone found in many plants and foods, including eucalyptus, ginkgo biloba, and onions, can inhibit the tumor-suppressor protein gene p53, a critical suppressor gene involved in at least half of all cancers, including breast and prostate cancers. This keeps cell growth in check and prevents cancer transformation. |
| Enzyme inhibitors found in plants can block certain enzyme pathways that cancer uses to proliferate. One common cancer enzyme pathway, called lactate dehydrogenase, works by blocking anaerobic glycolysis. During this conversion, pyruvic acid is converted to lactic add without the body being under any physical exertion. This creates a healthy acid blood environment for cancer that is referred to as lactic acidosis. Some plant agents that inhibit lactate dehydrogenase include oxalic acid found in rhubarb, sorrel, and spinach; allicin, found in garlic; and gossypol, from cottonroot. |
| Herbs that contain antitumor alkaloids can directly inhibit cancer growth because of their inhibitory activity against reverse transcriptase of RNA tumor viruses. The mechanism of action occurs within the cell cycle process. There it interacts with adenine-thymine (A:T) template primers, stopping DNA synthesis at the initiation of the polymerization processes.34 Many cancers, particularly leukemias, lymphomas, and brain tumors, are believed to be initiated by tumor viruses such as the Epstein-Barr virus (EBV), and use reverse transcriptase to promote infiltration. The HIV virus also uses reverse transcriptase to promote its growth. |
| A more direct antitumor mechanism of plant compounds has to do with inhibiting tubulin polymerization. This is the way that most chemotherapies work. These antitumor compounds are called antimitotic agents. Taxol, a nat- |
< previous page | page_114 | next page >

If you like this book, buy it!