title: Rodent and ruminant ingestive response to flavonoids in Euphorbia esula.
abstract: Euphorbia esula, common name leafy spurge, was chemically evaluated for aversive phytochemicals that appear to minimize herbivory by rodents and cattle. A middle-layer extract elicited food aversions in rats as did the petroleum ether extract of the initial methanol extract. Kaempferol-3-0-beta-glucuronic acid and quercetin-3-0-beta-glucuronic acid were separated and identified from the middle-layer residue. This study is the first report of quercetin-3-0-beta-glucuronic acid in leafy spurge. Together these flavonoidal glucosides were mildly aversive to rats but showed less aversive activity when tested separately. The middle-layer extract produced no aversive response from cattle, while the petroleum ether extract elicited strong aversions in cattle. Flavonoidal compounds from leafy spurge that were aversive to rats, a monogastric mammal, were not aversive to cattle, a ruminant. Microbial degradation of the compounds before they reach the intestines and are absorbed into the bloodstream is likely a key advantage for cattle compared to rats.
authors.affiliation: Department of Chemistry & Biochemistry, South Dakota State University, Brookings, South Dakota 57007, USA. fathi_halaweish@sdstate.edu
authors.forename: F
authors.initials: F
authors.lastname: Halaweish
authors.forename: S
authors.initials: S
authors.lastname: Kronberg
authors.forename: J A
authors.initials: JA
authors.lastname: Rice
mesh_terms: D000818:Animals; D002417:Cattle; D028481:Euphorbia / Q000737:chemistry*; D005247:Feeding Behavior; D005419:Flavonoids / Q000378:metabolism / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves; D051381:Rats
chemical_list: D005419:Flavonoids; D010936:Plant Extracts