An interesting finding that has been observed repeatedly is that individuals who consume relatively large amounts of vegetables, fruits, grains, and herbs are at a decreased risk of cancer of many organs . An investigation by Block et al. of 24 epidemiological studies showed that the consumption of a relatively large amount of vegetables and fruits was associated with a decreased incidence of lung cancer. Recent data from 11 cohort and case-control studies showed an inverse relationship between fruit and vegetable consumption and lung cancer . Multiple mechanisms are undoubtedly involved in the protective effect of diets rich in fruits and vegetables . However, it is difficult to identify the relative contribution of various components of a plant-based food to overall cancer risk reduction. The issue is further complicated by the recent demonstration of synergism among pro-tectors . Attention has been focused on intercellular signaling as a common molecular target for various chemopreventive phytochemicals .






Natural products encompass three main categories of compounds, phenylpro-panoids, isoprenoids, and alkaloids, which are widely distributed in plant foods and medicinal herbs. This large array of molecules is crucial to human nutrition and health. Plant-derived foodstuffs and beverages also constitute the so-called func-tional foods and beverages, which include mainly fruits, vegetables, herbs, and spices . Several plant constituents, including polyphenols, appear to be potent antimutagens and antioxidants . Flavonoids and procyanidins are two major classes of polyphenolic phytochemicals demonstrating a wide range of biochemical and pharmacological effects. The flavonoids, such as apigenin and quercetin, have been shown to inhibit melanoma growth and metastatic potential. When tested for the ability to inhibit lung colonization, these polyphenols decrease the number of B16-BL6 colonies in lung in a dose-dependent manner . Dragsted et al. found that polyphenols in fruits, vegetables, herbs, and spices inhibit tumor forma-tion in experimental animals exposed to carcinogens. The role of dietary plant poly-phenol has been emphasized in relation to health maintenance. The various polyphenols have been shown to possess antiatherogenic and anticarcinogenic properties, inhibiting the oxidative destruction of various oxylabel biological struc-tures, inhibiting the processes of bioactivation of carcinogens, blocking LDL oxida-tion, and stimulating the activity of antioxidant and detoxification enzymes .


 Vegetables and Cancer Prevention



The consumption of cruciferous vegetables such as cabbage, broccoli, Brussels sprouts, and cauliflower has been shown to have cancer-chemoprevention effects in human and experimental animals . A striking and characteristic chemical property of cruciferous plants is their high content of glucosinolates, which often approaches 1% or more of their dry weight. Glucosinolates and their isothiocyanate






hydrolysis products are well-known protectors against carcinogenesis . Indole-3-carbinol, found in these cruciferous vegetables, has been shown to have a cancer-chemopreventive effect on liver, skin, colon, and mammary tissue when given before or concurrently with exposure to a carcinogen . The topical application of indole-3-carbinol resulted in a significant protection in 7,12-Dimethylbenz(a) anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted mouse skin carcinogenesis . Lycopene, a natural antioxidant found predominantly in tomato, is also reported as a cancer-prevention agent. Serum and dietary lycopene levels have been found to be inversely related to the incidence of cancer. Although the antioxidant properties of lycopene are thought to be primarily responsible for its apparent beneficial affects, other mechanisms may also be involved . Alternative approaches focusing on the development of tomato-based food products for human clinical trials targeting cancer prevention and as an adjunct to therapy have been planned . The consumption of Phaseolus vulgaris bean species, such as pinto, black, navy, or kidney, may be beneficial in the prevention and treatment of many chronic diseases including cancer.


Soy foods are the major source of isoflavones, which are believed to play impor-tant roles in the genesis of breast cancer and its progression. A prospective study conducted in China indicated that soy food intake is associated with longer survival and low recurrence among breast cancer patients . Meta-analyses of epidemio-logical studies of soy consumption and breast cancer risk have demonstrated modest protective effects. Moreover, concern has been expressed that the estrogenic activity of isoflavones may have adverse effects on breast cancer recurrence. Recent studies on the mechanisms of action of soy in breast cancer provide insights into the epigen-etic effects and the interaction of isoflavones with IGF-1 and with a number of polymorphisms of genes associated with breast cancer risk such as MDM2 and CYP1B1. In particular, women who are at increased risk of breast cancer due to gene polymorphisms may benefit from high soy isoflavone intake. Consumption of soy food has also been found to be associated with lower lung cancer risk .


From time immemorial, mushrooms have been valued by human beings as a culinary wonder and folk medicine in the East . Mushrooms are considered a natural medicine that is widely used and recommended by Asian physicians and naturopaths for its supporting effects on the immune system. Laboratory research and a handful of preclinical trials have suggested that the nonedible Reishi mush-room (Ganoderma lucidum) carries promising anticancer and immunomodulatory properties .Many other commonly consumed edible mushrooms, such as but-ton mushrooms (Agaricus bisporus), oyster mushrooms (Pleurotus ostreatus), shii-take mushrooms (Lentinus edodes), and maitake mushrooms (Grifola frondosa) might also play a role in cancer prevention 



Fruits and Cancer Prevention




Emblica officinalis Gaertn. or Phyllanthus emblica Linn, commonly known as Indian gooseberry or amla, is arguably the most important medicinal plant inAyurveda. Variou parts of the plant are used to treat a range of diseases, but the most important is the fruit. Experimental studies have shown that amla and some of its phytochemicals, such as gallic acid, ellagic acid, pyrogallol, some norsesquiter-penoids, corilagin, geraniin, elaeocarpusin, and prodelphinidins B1 and B2, also possess antineoplastic effects . Amla is an important component of an Ayurvedic preparation called Triphala, which is made by combining three fruits - Emblica officinalis Gaertn, Terminalia chebula Retz., and Terminalia belerica Retz. It is widely used as a colon cleanser, digestive, diuretic, and laxative. Experimental stud-ies have shown that Triphala possesses antineoplastic, radioprotective, and chemo-protective properties .Triphala has tumor-specific cytotoxicity and does not harm normal cells .A recent study showed that Triphala could induce angiogen-esis by suppressing vascular endothelial growth factor receptor-2 phosphorylation and, hence, have tumor-specific activity .


Citrus fruits are essential foods in cancer prevention: for their capacity to act directly on cancerous cells as well as their potential for enhancing the anticancer effects of other phytochemical compounds present in diet . A growing body of evidence from human clinical trials has demonstrated that the consumption of grapes, wine, and grape juice exerts many health-promoting and possibly anticancer effects . The resveratrol present in red wine possesses powerful anticancer properties, which may be responsible for the beneficial effects of wine on the prevention of certain cancers. Grape juice and cranberry juice contain resveratrol, but at levels ten times less than red wine. Grape seed polyphenols or procyanides are shown to have anticarcinogenic or antitumor promoting agents. Several lines of evidence suggest that apples and apple products possess a wide range of biological activities that may contribute to beneficial effects on one's health against cardiovascular disease, asthma, and pulmonary dysfunction, diabetes, obesity, and cancer . Apple products have been shown to prevent skin, mammary, and colon carcinogenesis in animal models. Epidemiological observations indicate that regular consumption of one or more apples a day may reduce the risk of lung and colon cancer .


The anticancer activity of many other fruits, such as black plum (Eugenia jam-bolana L.) jackfruit (Artocarpus heterophyllus) mango (Mangifera indica L.) , plum (Prunus domestica) pineapple (Ananas comosus) prickly custard apple (Annona muricata) , papaya (Carica papaya) , pome-granate (Punica granatum) strawberry watermelon (Citrullus lanatus T.) guava (Psidium guajava L.) and banana was also verified in in vitro experimental studies.