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United States Department of Agriculture

Agricultural Research Service

Title: Toxic and Aversive Diterpenes of Euphorbia Esula

Authors
item Halaweish, Fathi - SDSU, BROOKINGS, SD
item Kronberg, Scott
item Hubert, Mindy - SDSU, BROOKINGS, SD
item Rice, James - SDSU, BROOKINGS, SD

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 17, 2002
Publication Date: August 1, 2002
Citation: HALAWEISH, F.T., KRONBERG, S.L., HUBERT, M.B., RICE, J.A. TOXIC AND AVERSIVE DITERPENES OF EUPHORBIA ESULA. JOURNAL OF CHEMICAL ECOLOGY. 2002. v. 28(8). p. 1599-1611.

Interpretive Summary: The noxious weed leafy spurge, which was introduced into the Great Plains of North America from Europe, has become a serious economic and ecological threat to the productivity of agricultural and natural areas. Cattle, the predominant livestock species on the Great Plains, as well as common wild ruminant species in this region appear to consume little if any leafy spurge. This is likely because they experience a toxic response after the consume small amounts of this plant and consequently learn to avoid it. Domestic sheep and goats can consume considerable amounts of leafy spurge and are used to help control it, but even these species may suffer a toxic response at high levels of intake. Toxic compounds called diterpene ingenols have been isolated from leafy spurge tissues, but compounds in this plant have not been evaluated in respect to their toxicity and capacity to cause ruminants to avoid consuming the plant (form feeding aversions to it). We conducted chemical fractionations of leafy spurge that were guided by biological assays with rats, brine shrimp and cells in an attempt to isolate toxic and aversive compounds in the plant. These bioassay-guided fractionations led to identification of ingenol and one of its diesters as two toxic compounds in leafy spurge.

Technical Abstract: Leafy spurge (Euphorbia esula L.), a plant introduced into the Great Plains of North America from Europe, has become a serious economic and ecological threat to the productivity of agricultural and natural areas. Cattle, the predominant livestock species on the Great Plains, as well as common wild ruminant species in this region appear to consume little if any leafy spurge. This is likely because they experience a toxic response after the consume small amounts of this plant and consequently learn to avoid it. Domestic sheep and goats can consume considerable amounts of leafy spurge and are used to help control it, but even these species may suffer a toxic response at high levels of intake. Toxic diterpene ingenols have been isolated from leafy spurge tissues, but compounds in this plant have not been evaluated in respect to their capacity to induce food aversion learning in mammals. We conducted bioassay-guided fractionations of leafy spurge in an attempt to isolate toxic and aversive compounds in the plant. These bioassay-guided fractionations led to identification of ingenol and one of its diesters as two toxic and aversive compounds in leafy spurge.

Last Modified: 7/24/2014
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