Inhibition of methylnitrosourea-induced large bowel cancer development in rats by sarcophytol A, a product from a marine soft coral Sarcophyton glaucum.
An antitumorigenic effect of sarcophytol A (SaA), a simple monohydroxycembratetraene isolated from a marine soft coral Sarcophyton glaucum, was investigated in rat colon carcinogenesis. Three groups (26 rats each) of female CD-Fischer rats given an intrarectal dose of 2 mg of N-methyl-N-nitrosourea 3 times weekly for Wk 1 to 3 were fed standard laboratory chow in the control group or the chow containing 0.01% SaA from Wk 1 or from Wk 4 in experimental groups. The body weight gain and the food intake were not different among all 3 groups, and SaA intake was similar in both experimental groups at a dosage of 6.18 and 6.14 mg/kg of body weight/day at Wk 5 and 3.87 and 3.90 mg/kg of body weight/day at Wk 25. At autopsy at Wk 26, the incidence of large bowel tumors was found to be significantly lower and the mean number of tumors per tumor-bearing rat to be insignificantly smaller in experimental groups than in the control group: 50% and 58% versus 85%, 1.8 and 1.8 versus 2.0. The tumors in both experimental groups were generally smaller. All the tumors except two signet ring cell carcinomas were well-differentiated adenocarcinomas. Induction of ornithine decarboxylase activity, a marker of tumor promotion, in the large bowel mucosa of rats which were fed the SaA chow for 1 wk, then received an intrarectal dose of 12, 6, or 1.2 mumol of deoxycholate, a tumor promoter in large bowel carcinogenesis, and were killed 4 h later was significantly lower than in control rats. Thus, it was concluded that SaA inhibited the development of large bowel cancer, probably through an antipromoting mechanism.
Narisawa
T
T
Department of Surgery, Akita University School of Medicine, Japan.
Takahashi
M
M
Niwa
M
M
Fukaura
Y
Y
Fujiki
H
H
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D004224:Diterpenes / Q000494:pharmacology*; D005260:Female; D008770:Methylnitrosourea; D008974:Mollusca; D051381:Rats; D011916:Rats, Inbred F344; D012016:Reference Values
D000970:Antineoplastic Agents; D004224:Diterpenes; C058761:sarcophytol A; D008770:Methylnitrosourea