ABSTRACT
The environmental hazards presented by plants which contain tumor-promoting diterpenes were apparent from the classical tumor-promoting experiments carried out by Berenblum. Many of the esterified forms of diterpenes are unstable and either hydrolyze or rearrange during extraction. Human exposure to the naturally occurring tumor-promoting diterpenes can be considered as arising from several sources: first, from the cultivation of species of these families in gardens and greenhouses. Second, as an occupational exposure of workers involved in processing these plants for economic products, third, by the consumption of food products including honey, milk, or meat derived ultimately from a plant source and finally, by the use of these plants in alternative forms of medicine such as homeopathy, herbal, or folk medicine. Diterpene tumor-promoting agents are traditionally known as esters of phorbol. Studies concerning the ethnobotanical uses of plants of the Euphorbiaceae and Thymelaeaceae are of considerable interest to toxicologists involved with environmental aspects of tumor promotion.
