Antitumorigenic

Some other saponins have been reported to have a potentiation activity on the nerve growth factor [12], stimulate the pituitary-adrenocortical system [13], and saponins were recently shown to have favorable antitumorigenic effects [14, 15]. 

Thus, TCDD exhibited antitumorigenic activity by disrupting... 

Different mechanisms have been postulated to contribute to the antitumorigenic activity of flavonoids at the gastrointestinal tract, taking into consideration evidence collected from experiments with both gastrointestinal and nongastrointestinal cell lines. A brief review of these activities with a special emphasis on their relevance in cancer is provided below. 

Thompson, L.U., Seidl, M., Rickard, S., Orcheson, L., and Fong, H. 1996b. Antitumorigenic effect of a mammalian lignan precursor from flaxseed. Nutr. Cancer 26, 159-165. 

Intake of dietary sources of n-3 fatty acids is associated with reduced incidence and severity of inflammatory disorders, cardiovascular diseases, and some cancers in humans (12, 98-103). Populations consuming fish that are rich in n-3 fatty acids are known to have a low incidence of atherosclerotic disorders (104). Dietary fish oil, which is high in EPA and DHA, also was shown to reduce myocardial ischemic damage (105) and ventricular fibrillation (106). The antitumorigenic effect of n-3 fatty acids was demonstrated in breast cancer (107), colon cancer (108-110), and pancreatic neoplasm (111). In addition to their beneficial influence on cardiovascular disorders and cancers, n-3 fatty acids are also known to decrease the severity and minimize symptoms of inflammatory diseases, including rheumatoid arthritis (15) and inflammatory bowel disease (16), and may be of benefit in correcting psychological disorders (17). 

The chaetomellic acids A and B (43 and 44), isolated from Chaetomella acutiseta found in seeds of peas, are potent and highly specific famesyl-mimic inhibitors of ras farnesyl-protein transferase. Farnesylation by this enzyme is the first and obligatory step for the post-translational modification of ras. The modified ras protein appears to be involved in tumorigenesis (approximately 25% of tumours) and there is evidence that inhibitors of the transferase have the potential to be antitumorigenic agents. These metabolites can be considered to be assembled by condensation of a palmitoyl and oleic acid chain C2 with pyruvate or oxaloacetate (Scheme 2) [38, 39]. Two syntheses have been reported for chaetomallic acid A [39, 40], one of which is patterned on the probable biogenesis [39]. 

Although most of the past theories have attempted to define the relationship between structural properties of the PAHs and their specific tumorigenicity as measured individually in skin-painting studies, little has been done to explain the behavior of a PAH when it is present in a complex mixture that includes a host of PAHs some of which are known antitumorigens as well as numerous known non-PAH antitu-morigens (1174). 

In subsequent studies, other nontumorigenic PAHs (phenanthrene, fluoranthene, pyrene) were reported to be effective antitumorigens against B[a]P and DMB[a]A (976, 3686). The nontumorigenic hydrocarbons — benzene, naphthalene, anthracene, phenanthrene, fluoranthene, pyrene — are MSS components, present at per cigarette delivery levels... 

The antitumorigens and antimutagens in Table XXVI-7A are presented in a slightly different way in Table XXVI-7B. Several of the significant PAH, NNA, and (V-heterocyclic amine tumorigens or mutagens are listed in the same sequence... 

Anticarcinogens, Antitumorigens, Inhibitors, and Antimutagens in Tobacco, Tobacco Smoke, and Tobacco... 

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