CHEMOPREVENTIVE EFFECT OF SQUALENE ON COLON-CANCER

Epidemiologic and laboratory studies suggest a cancer protective effec t and/or lack of a tumor promoting effect by dietary olive oil as comp ared with other types of non-marine oils. Squalene, a constituent of o live oh, and a key intermediate in cholesterol synthesis may be regard ed as partially responsible for the beneficial effects of olive oil, w hich include decreased mortality rates among populations with high oli ve oil consumption. Thus, in this study we have assessed the chemoprev entive efficacy of squalene on azoxymethane (AOM)-induced colonic aber rant crypt foci (ACF). In addition, we measured the effect of squalene on serum cholesterol levels in the rats, Male F34 rats (5 weeks old) were fed the control diet (modified AIN-76A) or experimental diets con taining 1% squalene or 320 p.p.m. sulindac, two weeks later, all anima ls except those in vehicle (normal saline)-treated groups were s,c, in jected with AOM (15 mg/kg body wt, once weekly for 2 weeks). At 16 wee ks of age, all rats mere killed, colons were evaluated for ACF and ser um was assayed for the cholesterol levels. As expected, dietary admini stration of sulindac suppressed ACF development and reduced crypt mult iplicity, i.e. number of aberrant crypts/focus. Administration of diet ary squalene inhibited total ACF induction and crypt multiplicity by s imilar to>46% (P < 0.001). Further, squalene at a level of 1% did not show any significant effect on serum cholesterol levels. Our finding t hat squalene significantly suppresses colonic ACF formation and crypt multiplicity strengthens the hypothesis that squalene possesses chemop reventive activity against colon carcinogenesis.