INHIBITION OF METHYLNITROSOUREA-INDUCED LARGE BOWEL-CANCER DEVELOPMENT IN RATS BY SARCOPHYTOL-A, A PRODUCT FROM A MARINE SOFT CORAL SARCOPHYTON-GLAUCUM

  • 15 June 1989
    • journal article
    • research article
    • Vol. 49  (12) , 3287-3289
Abstract
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 exprimental 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 the 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 .mu.mol 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.