TitlePost-initiation effects of chlorophyllin and indole-3-carbinol in rats given 1,2-dimethylhydrazine or 2-amino-3-methyl- imidazo.
Publication TypeJournal Article
Year of Publication2001
AuthorsXu M, Orner GA, Bailey GS, Stoner GD, Horio DT, Dashwood RH
Date Published2001 Feb
Keywords1,2-Dimethylhydrazine, Adenosarcoma, Animals, Anticarcinogenic Agents, Antimutagenic Agents, Carcinogens, Chlorophyllides, Colonic Neoplasms, Disease Models, Animal, Indoles, Liver Neoplasms, Male, Quinolines, Rats, Rats, Inbred F344

Chlorophyllin (CHL) is a water-soluble derivative of chlorophyll, the ubiquitous pigment in green and leafy vegetables, whereas indole-3-carbinol (I3C) is present in cruciferous vegetables such as cabbage, broccoli and cauliflower. In rats initiated with 1,2-dimethylhydrazine (DMH), CHL and I3C reportedly promoted or enhanced the incidence of colon tumors when they were administered after, or during and after the carcinogen exposure, respectively. The same compounds given post-initiation inhibited the formation of colonic aberrant crypts induced by heterocyclic amines, such as 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), but tumor suppression was not examined in the latter studies. In the present investigation, male F344 rats were treated with IQ or DMH during the first 5 weeks of a 1 year study; IQ was given in the diet (0.03%), whereas DMH was administered once a week by s.c. injection (20 mg/kg body wt). Beginning 1 week after the last dose of IQ or DMH until sacrifice, rats received 0.001, 0.01 or 0.1% (w/v) CHL in the drinking water or 0.001, 0.01 or 0.1% I3C in the diet. Compared with controls given carcinogen alone, 0.1% I3C treatment suppressed the multiplicity of IQ-induced colon tumors, and CHL inhibited in a dose-related manner the incidence of IQ-induced liver tumors. However, 0.001% CHL increased significantly the multiplicity of DMH-induced colon tumors while having no effect on the colon tumors induced by IQ. These results indicate that both the choice of carcinogen as well as the dose of the tumor modulator can be important determinants of the events that occur during post-initiation exposure to CHL or I3C. Based on the present findings and data in the literature, it is possible for CHL and I3C to act as tumor promoters or anticarcinogens, depending upon the test species, initiating agent and exposure protocol.

Alternate JournalCarcinogenesis
PubMed ID11181453
Grant ListCA34732 / CA / NCI NIH HHS / United States
CA65525 / CA / NCI NIH HHS / United States
CA90176 / CA / NCI NIH HHS / United States
ES00210 / ES / NIEHS NIH HHS / United States
ES03850 / ES / NIEHS NIH HHS / United States
T32 ES07060 / ES / NIEHS NIH HHS / United States