Azoxymethane induced colon cancer, effect

Weisburger, J.H. et al.. Effect of tea extracts, polyphenols, and epigallocatechin gallate on azoxymethane-induced colon cancer, Prac. Soc. Exp. Biol, Med., 217, 104, 1998. 

Harris, G.K., Gupta, A., Nines, R.G., Kresty, L.A. et al.. Effects of lyophilized black raspberries on azoxymethane-induced colon cancer and 8-hydroxy-2 -deoxyguanosine levels in the Fischer 344 rat, Nutr. Cancer, 40,125-133, 2001. 

Ju J, Liu Y, Hong J, Huang MT, Conney AH, Yang CS. 2003. Effects of green tea and high-fat diet on arachidonic acid metabolism and aberrant crypt foci formation in an azoxymethane-induced colon carcinogenesis mouse model. Nutr Cancer 46 172-178. 

Although there are preliminary data supporting the antitumoral activity of quercetin, the most common flavonoid, in humans in the course of a Phase I clinical trial [189], direct evidence of the anticancer effect of flavonoids is derived almost exclusively from studies performed in animal models as well as studies performed on cultured cell lines, Fig. (2). Most animal studies on gastrointestinal cancer have focused on colon cancer using the azoxymethane (AOM) model in rats or mice [190-197]. There are also available reports on models of cancer of the stomach (induced by benzo[a]pyrene [198] or N-methyl-N-nitro-N-nitro so guanidine [199]), oesophagus (N-methyl-N-amylnitrosamine [200]), and the tongue/oral cavity (methyl-(acetoxymethyl)-nitrosamine [198], 7,12-dimethyl-... 

Fiber was shown to inhibit carcinogenicity of 2-acetylaminofluorene more than thirty years ago (7,17). A recent review (18) has pointed out the lack of consistency in studies of fiber effects on experimental colon carcinogenesis. Investigators use different strains of rat, stock or semipurified diets, and different carcinogens administered orally, subcutaneously or intrarec-tally (Table v). Ward et al. (19) found cellulose to have no effect on the carcinogenicity of azoxymethane (AOM) in male Fisher rats fed a semipurified diet. Freeman et al. (20), on the other hand, found cellulose to protect male Wistar rats from colon cancer induced by subcutaneous injection of 1,2-dimethylhydrazine (DMH). 

Ohkami, H., Tazawa, K., Yamashita, I., Shimizu, T., Murai, K., Kobashi, K. and Fujimaki, M. 1995. Effects of apple pectin on fecal bacterial enzymes in azoxymethane-induced rat colon carcinogenesis, Jpn. J. Cancer Res., 86(6) 523-529. 

Koratkar, R. A.V. Rao. Effect of soya bean saponins on azoxymethane-induced preneoplastic lesions in the colon of mice, Nutr. Cancer 1997,27, 206-209. 

The effect of black tea and tea with milk was evaluated on colon cancer induced by azoxymethane in F344 rat models (Weisburger et al, 1997). Foci of aberrant ciypts in the colon were decreased in both tea-fed and tea-and-milk-fed animals. The study showed... 

Rao, C.V., Desai, D., Simi, B., Kulkami, N., Amin, S., and Reddy, B.S. (1993) Inhibitory Effect of Caffeic Acid Esters on Azoxymethane-Induced Biocbemical Changes and Aberrant Crypt Foci Formation in Rat Colon, Cancer Res. 53, 4182-4188. 

Cancer chemopreventive activity of garcinol have been also demonstrated in animal model dietary administration of garcinol significantly inhibited azoxymethane(AOM)-induced aberrant crypt foci (ACF) formation in male F344 rats without causing any adverse effects [63], ACF are precursor lesions for colon carcinoma. 

Rao CV, Rivenson A, KatiwaUa M, KeUoff GJ, Reddy BS, Chemopreventive effect of oltipraz during different stages of experimental colon carcinogenesis induced by azoxymethane in male F344 rats. Cancer Res 1993 53 2502-2506. 

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