DIETARY CANCER RISK FROM CONDITIONAL CANCEROGENS IN PRODUCE OF LIVESTOCK FED ON SPECIES OF SPURGE (EUPHORBIACEAE) III - MILK OF LACTATING GOATS FED ON THE SKIN IRRITANT HERB EUPHORBIA-PEPLUS IS POLLUTED BY TUMOR PROMOTERS OF THE INGENANE DITERPENE ESTER-TYPE

Special procedures were developed to investigate poisonous milk of lac tating goats fed experimentally on aerial parts of the herb Euphorbia peplus L. In extracts of the milk, weakly irritant in the mouse-ear as say, three diterpene ester toxins were detected by techniques of high- performance liquid chromatography. They are of the ingenane structural type: Euphorbia factor Pel (ingenol 20-acetate 3-angelate), Euphorbia factor Pe2 (20-deoxyingenol 3-angelate) and Euphorbia factor Pe4 (20- deoxyingenol-6 alpha,7 alpha-epoxide 3-angelate). From goats milk coll ected 15 days after cessation of the experimental feeding period, extr acts were completely free of diterpene ester toxins. The toxins pollut ing the milk are identical to diterpene ester entities occurring in th e aerial parts of E. peplus. Of these, Euphorbia factors Pel and Pe2 a re known as promoters of tumors of mouse skin. Apart from the toxic Eu phorbia factors, the non-toxic parent alcohol ingenol was also detecte d in the milk. It is absent in the plant, and may have been generated metabolically from a certain portion of the toxic diterpene esters pic ked up by the goats from their fodder. The results presented here prov ide, for the first time, data for a novel interpretation of the locall y high incidence of esophageal cancer observed in certain areas in the Caspian littoral of Iran, associated with a greater consumption of go at's (and sheep's) milk.