| Co-Investigator(Kenkyū-buntansha) |
TAKASAKI Midori Chiba Institute of Science, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 助教授 (10179434)
TOKUDA Harukuni Kyoto Prefectural University of Medicine, Department of Medicine, Research Instructor, 医学部, 助手 (60111960)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Many kinds of antitumor agents and their related compounds have been isolated from natural resources. However, perfectly effective antitumor agents free from side action have not been found out yet. Furthermore, these side actions of antitumor agents are serious problems in the treatment of cancer, and cancer currently remains a tragic disease which has been one of the major causes of death. Therefore, the advancement of chemoprevention is important, as well as the development of cancer treatment. To search for cancer chemopreventive agents from natural resources, many phytochemicals and food additives, especially natural sweeteners, were screened by the in vitro assay indicated by the inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) induction. Of active compounds showed the remarkable inhibitory effects on the EBV-EA induction, stevioside, from the leaves of Stevia rebaudiana, and mogroside V and 11-oxo-mogroside V, from the fruits of Momordica (=Siraitia) grosvenori, exhibited significant inhibitory effects on the two-stage mouse skin carcinogenesis in vivo induced by DMBA and TPA. The inhibitory effects of these sweeteners are stronger than that of glycyrrhizin, which had been well known as an anti-tumor-promoter in chemical carcinogenesis. Further, these sweeteners also strongly inhibited mouse skin carcinogenesis initiated by peroxynitrite, UVB irradiation or advanced glycation end-products (AGE).
These results suggested that natural sweeteners, stevioside and mogrosides, which have been used as an alternative sweeteners to sucrose might be also valuable as chemopreventive agents for chemical carcinogenesis.
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