Halaweish F, Kronberg S, Rice J A
Department of Chemistry & Biochemistry, South Dakota State University, Brookings, South Dakota 57007, USA.
J Chem Ecol. 2003 May;29(5):1073-82. doi: 10.1023/a:1023869220586.
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.
乳浆大戟，俗称叶状大戟，对其可能会使啮齿动物和牛减少食草行为的厌恶性植物化学物质进行了化学评估。中层提取物和初始甲醇提取物的石油醚提取物一样，会引起大鼠的食物厌恶反应。从中间层残留物中分离并鉴定出了山奈酚-3-O-β-葡萄糖醛酸和槲皮素-3-O-β-葡萄糖醛酸。本研究是叶状大戟中槲皮素-3-O-β-葡萄糖醛酸的首次报道。这些黄酮糖苷一起对大鼠有轻微的厌恶作用，但单独测试时厌恶活性较低。中层提取物对牛没有引起厌恶反应，而石油醚提取物在牛身上引起了强烈的厌恶反应。叶状大戟中对单胃哺乳动物大鼠有厌恶作用的黄酮类化合物，对反刍动物牛没有厌恶作用。与大鼠相比，这些化合物在到达肠道并被吸收进入血液之前被微生物降解，这可能是牛的一个关键优势。
