Nordihydroxyguaiaretic acid

Azoxymethane, nordihydroxyguaiaretic acid and methylene blue were purchased from Sigma-Aldrich Fine Chemicals (St Louis, MO). Acetone and 10% formalin-phosphate buffer were obtained from Fisher Scientific (Springfield, NJ). 

Female CF-1 mice (4-6 weeks old) were purchased from Charles River Laboratories (Wilmington, MA). The animals had free access to food and water throughout the experiment. The mice (initially fed the control AIN 76A diet for 4 days after arrival at the laboratory) were either continued on the same diet (control) or fed a 0.2% orange peel extract in AIN 76A diet or 0.2% nordihydroxguaiaretic acid (NDGA) in AIN 76A diet until the end of the experiment. AIN 76A diet and 0.2% orange peel in AIN 76A diet and 0.2% nordihydroxyguaiaretic acid in AIN 76A diet were purchased from Research Diets, Inc. (New Brunswick, NJ). 

Female CF-1 mice were s.c. injected with AOM (5, 10, 10, and 10 mg/Kg body wei t) starting at 6 weeks of age once every 4 days resulted in formation of an average of 0.52 colon tumors per mouse and 44% of mice had colon tumor at 37 weeks after the first dose of AOM injection. Feeding 0.2% orange peel extract or 0.2% nordihydroxyguaiaretic acid in the diet to mice inhibited the number of AOM-induced colon tumor per mouse by 44% or 48%, respectively. Colon tumor incidence was reduced by 34% or 39%, respectively (Table II). 

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