Test of catechol, tannic acid, Bidens pilosa, croton oil, and phorbol for cocarcinogenesis of esophageal tumors induced in rats by methyl-n-amylnitrosamine

S. S. Mirvish, S. Salmasi, T. A. Lawson, P. Pour, D. Sutherland

Research output: Contribution to journalArticle

48 Scopus citations


Catechol (CAS: 120-80-9), given in drinking water to rats, was the most effective of 5 phenols in enhancing [3H]thymidine incorporation ([3H]dThd-I) into esophageal DNA. To test for esophageal cocarcinogenesis, groups of 30 male MRC-Wistar rats received 3 weekly ip injections of 25 mg methyl-n-amylnitrosamine [(MNAN) CAS: 13256-07-0]/kg. From the time of the first MNAN injection, each group also received catechol, tannic acid (CAS: 1401-55-4), dried leaves of Bidens pilosa L., or croton oil (CAS: 8001-28-3) (respectively, 2, 10, 50, and 2 g/kg semipurified diet), or were given 20 ip injections of 6 mg phorbol (CAS: 17673-25-5)/rat. The rats were killed after 20-45, 46-52, or 53-72 weeks (subgroups A, B, and C). In the group given MNAN alone, most esophageal papillomas developed during the first 45 weeks. Both catechol and B. pilosa significantly increased the esophageal papilloma multiplicity (No. of papillomas/rat) induced by MNAN, with a maximum tumor yield of 2.2 times that in the corresponding subgroup treated with MNAN alone. Papilloma multiplicity increased from subgroup A to subgroup C in the MNAN plus B. pilosa group but not in the MNAN plus catechol group. No tumors were induced by the test cocarcinogens given without MNAN. We concluded that a) an increased esophageal [3H]dThd-I indicates potential cocarcinogenicity and b) catechol and B. pilosa were weak esophageal cocarcinogens. These results support the view that catechol in cigarette smoke and B. pilosa as eaten in South Africa contribute to the etiology of human esophageal cancer.

Original languageEnglish (US)
Pages (from-to)1283-1290
Number of pages8
JournalJournal of the National Cancer Institute
Issue number6
Publication statusPublished - Oct 31 1985


ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this