The extraction and isolation of 2 active cocarcinogenic agents from the seed of Croton tiglium L. and their long-term biologic testing are described. Both materials are potent cocarcinogens at very low dosages. The biologic activity of chemically transformed derivatives of the active materials is also reported. Phorbol myristate acetate, a semisynthetic compound derived from croton resin, showed notable promoting activity. Some aspects of the chemistry of the active materials are discussed.
This work was supported by Grants CA-05946, CA-06989, and ES-00014 from the Department of Health, Education and Welfare, USPHS.