title: Cancer prevention by antioxidants.
abstract: Various antioxidants in foods, such as phenolic compounds and carotenoids, were proven to have anticarcinogenic activity. In the case of carotenoids, the mixture of them was found to be very effective. In fact, the development of hepatoma in the high risk group of liver cancer, was significantly suppressed by the treatment with natural carotenoids mixture. The role of nitric oxide (NO) in carcinogenesis has been pointed out, since large quantity of NO has been detected in cancer tissues, and the expression of inducible NO synthase (iNOS) was found to correlate with tumor growth and metastasis. Recently, we found that NO possessed tumor initiating activity in mouse skin carcinogenesis. It has been suggested that some parts of pathological effects induced by NO may depend on peroxynitrite, an active metabolite of NO. Thus, we accessed the tumor initiating activity of peroxynitrite, and found that treatment with peroxynitrite (initiator) plus TPA (promoter) resulted in the formation of skin tumors. Under this experimental condition, it has been proven that natural antioxidants, such as curcumin and nobiletin, showed anti-tumor initiating effect. In the case of nobiletin, suppressive effect on iNOS induction has also been demonstrated. It is of interest that suppression of iNOS induction was also observed in phytoene synthase transgenic mouse. After administration of glycerol (a lung tumor promoter), lower induction of iNOS gene was observed in lung of the phytoene producing mice, comparing with that of control mice. Combinational use of various kinds of antioxidants distributed in foods, e.g., mixture of carotenoids and flavonoids, seems to be effective methods for cancer prevention.
authors.affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan. hnishino@basic.kpu-m.ac.jp
authors.forename: Hoyoku
authors.initials: H
authors.lastname: Nishino
authors.forename: Harukuni
authors.initials: H
authors.lastname: Tokuda
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Satomi
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Masuda
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Osaka
authors.forename: Shingo
authors.initials: S
authors.lastname: Yogosawa
authors.forename: Saeri
authors.initials: S
authors.lastname: Wada
authors.forename: Xiao Yang
authors.initials: XY
authors.lastname: Mou
authors.forename: Junko
authors.initials: J
authors.lastname: Takayasu
authors.forename: Michiaki
authors.initials: M
authors.lastname: Murakoshi
authors.forename: Kenji
authors.initials: K
authors.lastname: Jinnno
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yano
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D001628:Beverages; D002338:Carotenoids / Q000494:pharmacology; D003474:Curcumin / Q000627:therapeutic use; D000077276:Lycopene; D018551:Solanum lycopersicum; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008815:Mice, Inbred Strains; D030421:Peroxynitrous Acid; D012878:Skin Neoplasms / Q000139:chemically induced / Q000517:prevention & control; D013755:Tetradecanoylphorbol Acetate
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D030421:Peroxynitrous Acid; D002338:Carotenoids; D003474:Curcumin; D013755:Tetradecanoylphorbol Acetate; D000077276:Lycopene