Cancer phytochemicals

Ohnishi H, Asamoto M, Tujimura K, Hokaiwado N, Takahashi S, Ogawa K, et al. Inhibition of cell proliferation by nobiletin, a dietary phytochemical, associated with apoptosis and characteristic gene expression, but lack of effect on early rat hepatocarcinogenesis in vivo. Cancer Sci 2004 95 936-42. 

There is now a growing body of evidence to suggest that phytochemicals may have a protective role against a variety of chronic diseases such as cancer and cardiovascular disease. Part 1 reviews this body of evidence, its strengths and its weaknesses. Chapter 2 discusses the ways in which phenolic... 

The discovery that, in industrialised societies, diets deficient in fruits and vegetables can effectively double the risk of developing many different types of cancer has focused renewed attention on the beneficial properties of these foods (Block e/a/., 1992 Patterson ef a/., 1990 Southon and Faulks, 2002). As we have seen, plant foods are rich in micronutrients, but they also contain an immense variety of biologically active secondary metabolites providing colour, flavour and natural toxicity to pests and sometimes humans (Johnson et ah, 1994). The chemistry and classification of such substances is still a matter for much research and debate, but this has not prevented attempts to isolate and exploit substances that have variously been termed protective factors , phytoprotectants , phytochemicals and nutraceuticals . Phytochemical compounds include ... 

TALALAY p and FAHEY j w (2001) Phytochemicals from cruciferous plants protect against cancer by modulating carcinogen metabolism , JNutr, 131 3027S-33S. 

Phytochemicals have little nutritional value and do not get absorbed in the body, but they seem to turn on certain switches in the biochemical mechanisms, which signal the beneficial pathways to maintain health, and to turn off the switches which proceed to adverse biochemical pathways. Rice bran products have demonstrated significant benefits as nutritional therapies in diabetes, hyperlipidemia, cancer, fatty liver, hypercalcuria and heart disease. There is experimental and clinical evidence for the beneficial health effects of the following bioactives of rice bran ... 

The above scientific information on rice bran phytochemicals indicates that a multitude of mechanisms are operating at the cellular level to bring about specific health effects. Several health benefits of rice bran appear to be the result of the synergistic function of the many phytochemicals, antioxidants, vitamins and minerals which operates through a specific immune response. Their role in the biochemical mechanisms at the cellular level which result in major health effects is shown in Fig. 17.1. A short overview summarizing the effect of the various phytochemicals on major health issues such as cancer, immune function, cardiovascular disease, diabetes, altered liver function and gastrointestinal and colon disease will be given below. 

Tocotrienols are another group of phytochemicals of rice bran which have a chemopreventive effect and have been demonstrated to inhibit breast cancer (Nesaremam et al., 1998). The polysaccharides of rice bran contain a-glucan, the anti-tumor effect of which has been demonstrated by its inhibition of gastrointestinal carcinogenesis (Akeshita et al., 1992). Rice bran agglutinin has been shown to induce apoptosis of cancer cells by the mechanism of cell cycle dysregulation (Miyoshi et al., 2001). 

Carter, O., Bailey, G.S., and Dashwood, R.H., The dietary phytochemical chlorophyllin alters E-cadherin and P-catenin expression in human colon cancer cells International Research Conference on Food, Nutrition and Cancer, J. Nutr., 134,3441S, 2004. 

Campbell, J.K. et al.. Tomato phytochemicals and prostate cancer risk, J. Nutr., 134, 3486S, 2004. 

Extensive research in the last few years has revealed that the regular consumption of certain fruits containing carotenoids, an important group of phytochemicals derived from such fruits and vegetables, is involved in cancer prevention. Both prospective and retrospective epidemiological studies have consistently and clearly shown that an increased intake of fruits and vegetables rich in carotenoids is associated with a decreased risk of cancer (Mayne, 1996 Peto... 

Phytochemicals have been the subject of many studies evaluating their effects in relation to common chronic human illnesses such as cancer and cardiovascular diseases. These studies encounter difficulties in using this information to influence the dietary patterns of consumers because in the past they have used models or experiments with animals. However, in the last decade, researchers have moved away from animal studies in favour of human cell models or human intervention studies. Scientists still need to determine the likely incidence of illness from exposure to known amounts of a given natural compound in the diet and specifically in relation to the complex matrices of whole foods. Therefore, it is inevitable that some animal studies have to be continued for toxicological studies. 

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