Chemopreventive activity of natural source compounds against advanced glycation endproduct induced carcinogenesis

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Advanced glycation end products(AGE) is generally recognized as several complications including cancer and increased the volumein diabetes mellitus patients. In course our human related carcinogens studies for chemoprevention, we were investigated the HAGE (Human alubumin and glucose mixture) sample for carcinogenic

activity and were found the significant tumor initiating potency on two-stage mouse skin test. SENCAR mice were initiated with three times dose of each 100 μg HAGE and promoted with 1 μg TPA twice a week for 20 weeks. Resently, we also found that natural colorant, betanin and natural occurring substance showed the inhibitory effects against HAGE induced carcinogenesis. For this study, from 1 week before to 1 week after tumor initiating potency treatment by betanin and substance of natural Brazilian traditional medicine, Tabebuia avellanedae , which is native to South America from Brazil to northern Argentina, is well known in traditional folk medicne used for the treatment of various disease colorant, they delayed the formation of papillomas and reduced the number of papillomas per mouse. Topical application of these substances

inhibited the number of induced skin tumors per mouse by 60 and 70 % , respectively, and the percent of mice with skin tumor was inhibited by 40 and 50 %, respectively. To characterize a proper mechanism for inhibition, we employed the use of qualitative and quantitative expression of the MAPK pathway by western blot analysis and found that modulation of carcinogenic pathway by HAGE treatment varies in time-dependent manner. Results given evidence for a possible and necessary, interesting role of these substances as chemopreventive agent.