METHODS: Five groups of adult male rats were used in this experiment. Normal/control group; the rats were injected subcutaneously with 15 mg/kg of sterile normal saline once a week for two weeks, and orally administered with 10% Tween 20 (5 mL/kg). Carcinogen and treatment groups; the rats were injected subcutaneously each with 15 mg/kg body weight AOM once a week for 2 weeks and were continued to be fed for two months, respectively with 10% Tween 20, 500 and 250mg/kg body weight plant extracts. Reference group; the rats were injected subcutaneously with 15 mg/kg body weight AOM once a week for 2 weeks, and injected intraperitoneally with fluorouracil 35 mg/kg body weight for five consecutive days.

RESULT: Total ACF detected in methylene blue stained whole mounts of rat colon were 21, 23and 130 in rats fed with 500, 250 mg/kg body weight treatment and carcinogen groups, respectively. Treatment with high and low doses of the plant extract led to83.6% and 82.2% decrease in the total crypts in the groups fed 500 mg/kg and 250 mg/kg Gynura procumbens respectively compared to carcinogen group. Immunohistochemical staining of ACF showed suppressed azoxymethane induced colonic cell proliferation and Bcl-2 expression. Glutathione-S-transfarase and superoxide dismutase activities were higher in treated rats compared to carcinogen groups.