Experimental Oral Cancer: Antioxidant Effect of Lycopene

Oxygen free radicals are an important factor in oral cancer development. Micronutrient components of plant foods have been suggested to have chemopreventive activity through their ability to inactivate oxygen free radicals, preventing DNA mutations and protecting cells membranes against oxidative damage. Objectives: the objective of this study was to evaluate the antioxidant effect of lycopene in oral pre-cancerous lesions of hamsters previously treated with dymethyl-benz-anthracene (DMBA). Methods: DMBA solution (0,5% in mineral oil) was applied to the cheek pouch of 30 hamsters, 3 times/week for 11 weeks. One group of 10 animals was sacrificed just after this period and the other 20 animals were divided into 2 groups of 10. N group received normal diet for the next 11 weeks and L group received lycopene-supplemented (20ppm) diet for the same period. Results: lycopene supplemented groups had significantly lower levels of hepatic lipid peroxidation, measured through concentration of malondihaldehide (p < 0,05). Levels of hepatic reduced glutathione, however, did not yield significant differences. Differences in number and size of tumors, as well as incidence of squamous cell carcinoma were also not significant. Conclusions: these results suggest that lycopene antioxidant capacity may not be sufficiently effective in preventing post-initiation lesions to progress to invasive tumors.