The chemopreventive effects of curcuminoids are well-documented¹. One 12 week study examined the chemopreventive effects of carotenoids such as fucoxanthin, lycopene and lutein as well as curcumin and THC on the development of putative preneoplastic aberrant crypt foci in colons of mice initiated with the tumor promoter 1,2-dimethylhydrazine dichloride (DMH). Of the compounds tested, dietary fucoxanthin (0.01% in drinking water), lutein (0.05% in the diet) and THC (0.5% in the diet) significantly reduced the number of aberrant crypt foci, when administered from weeks 5 to 12 of the study¹². Significant inhibition of ACF (aberrant crypt foci) development in the colons of mice treated with fucoxanthin, lutein or THC when given in the post-initiation phase (tumors were initiated using DMH) (Figure 10(a),(b))* was observed. Influence of proliferation of colonic crypt epithelial cells was also assessed in terms of 5-bromo-2'-deoxyuridine (BrdU) incorporation. BrdU labeling indices (LI) in mice treated with lutein and 0.5% THC were significantly decreased in both the upper and lower half compartments of colonic crypts as compared to the controls (Figure 11)*.

The dose dependent decreases of BrdU LI observed for lycopene and THC indicate that larger doses might be more effective for inhibition of ACF development. This study demonstrated that THC is more active than the parent compound, curcumin, in terms of inhibition of ACF development and cell proliferation. This observation combined with the fact that THC which has both phenolic and beta-diketone moieties in the same molecule, is a stronger antioxidant^4,5, suggests that THC might be particularly suitable for application as a chemopreventive agent against in vivo carcinogenesis.

* Figures 10(a), 10(b), and 11 are displayed under the section, Effects Against Colon Cancer