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Male Wistar rats were fed the control casein diet, 10% mango fruit bar (MFB) substituted casein diet and 20% MFB substituted casein diet for 12 weeks. Dimethylhydrazine (DMH) was coadministered weekly (s.c) to another 3 groups of rats maintained on the same diets. At the end of the experimental period the rats were sacrificed. The results revealed that the ingestion of the processed mango fruit altered the DMH-induced reduced catalase activity in the liver. However, MFB did not elicit any effect on the induced peroxidative stress by DMH administration. The DMH exposure increased the kidney GGT and femur micronuclei and the fruit bar consumption reduced it. The MFB feeding also increased hepatic vitamin A and glutathione-S-transferase (GST) activitiy. The study suggested that the long term consumption of the processed mango fruit may have significant inhibitory effects on the cytotoxicity of DMH in rats.

The effects of fiber isolated from black gram (Phaseolus mungo) and Coconut (Cocos nucifera) kernel on the metabolic activity of intestinal and fecal beta glucuronidase activity during 1,2-dimethylhydrazine induced colon carcinogenesis were studied. The results indicated that the inclusion of fiber from black gram and coconut kernel generally supported lower specific activities and less fecal output of beta-glucuronidase than did the fiber free diet. This study suggests that the fibers isolated from coconut or black gram may potentially play a role in preventing the formation of colon tumors induced by the carcinogen 1,2-dimethylhydrazine by reducing the activity of the intestinal as well as fecal beta-glucuronidase.

Curry leaves are one of the spices used in Indian dishes for aroma and preservation. There are no reports on the antioxidant properties of curry leaves. In this study, the antioxidant potential of curry leaves in rats treated with a known chemical carcinogen, dimethylhydrazine hydrochloride (DMH) was investigated. Food intake was reduced in the rats fed curry leaf-supplemented diet but the body and the organ weights were not affected. Vitamin A content in the liver was significantly increased whereas glutathione (GSH) content was not altered. A 50% reduction was seen in the micronuclei induced by DMH and a 30% reduction in the activity of gamma-glutamyl transpeptidase when the rats were fed a curry leaf-supplemented diet. These results indicate that curry leaves have high potential as reducer of the toxicity of DMH.

In a 30-week preliminary study and a follow-up 22-week study (2 × 2 factorial), dimethylhydrazine (DMH)injections effectively induced colon tumors in Fischer-344rats. How this incidence of colon tumors might be affected by cellulose (preliminary study) or by calcium and folic acid (follow-up study) was examined. Cellulose in the dietappeared to provide some protection against DMH-induced colon tumors, but the protective effect of calcium was moreevident; normal levels of calcium (500 mg per 100 g diet), but not of folic acid (0.1 mg per 100 g diet), provided protection against colon tumors. The effect due to calciumwas observed whether viewed in terms of total number of tumors (p lt 0.01) or number of tumors per tumor-bearing rat(p < 0.01).