Dietary cancer risk from conditional cancerogens (tumor promoters) in produce of livestock fed on species of spurge (Euphorbiaceae). V. Skin irriitant and tumor-promoting diterpene ester toxins of the tigliane and ingenane type in the herbs Euphorbia nubica and Euphorbia helioscopia contaminating fodder of livestock.

Irritant diterpene ester toxins were isolated from Euphorbia nubica and E. helioscopia, which are contaminants of the green fodder of livestock in Egypt. Fractionations of methanol extracts of aerial parts of both plants were monitored by the irritation unit on the mouse ear.

Dietary cancer risk conditional cancerogens in produce of livestock fed on species of spurge (Euphorbiaceae). I. Skin irritant and tumor-promoting ingenane-type diterpene esters in E. peplus, one of several herbaceous Euphorbia species contaminating fodder of livestock.

The hypothesis was proposed that there is a risk of dietary cancer from conditional cancerogens in produce of livestock polluted with irritants of the diterpene ester type, picked up by feeding on species of Euphorbiaceae (spurge). To challenge this, several herbaceous plants of the genus Euphorbia, widespread as weeds and contaminants of livestock fodder, were identified botanically and extracts of their aerial parts were tested for irritancy on the mouse ear. As compared to a standard probe of croton oil, the extracts of E.