Jackson J A, Hemken R W, Bush L P, Boling J A, Siegel M R, Zavos P M
Department of Animal Sciences, University of Kentucky, Lexington 40546-0215.
Drug Chem Toxicol. 1987;10(3-4):369-79. doi: 10.3109/01480548709042993.
Three trials involving 184 male Sprague Dawley rats were conducted to identify the biologically active fraction of endophyte-infected tall fescue seed. In trial 1, seed infected (greater than 95%) with the endophytic fungus Acremonium coenophialum and shown to be toxic to cattle, was serially extracted with hexane, ethylacetate, and methanol, respectively. A second sample of this seed was extracted with chloroform only. Controls included a solvent treatment (spraying the various solvents on endophyte-free seed and carrying the mixture to dryness), the seed post-extraction, endophyte-infected seed and endo-phyte-free seed. Laboratory chow was mixed with all diets to provide 50% of the mix. Trial 2 examined the same treatments as trial 1 except that the chloroform treatment was omitted. Dosages 3 times (equivalent to 22.5 g seed) those used in trial 1 were applied to endophyte-free seed (7.5 g) in an attempt to accentuate any differences. Trial 3 examined the methanol fraction extracted serially, a methanol fraction extracted batchwise, and a water fraction extracted batchwise. Controls included seed residues post-extraction, solvent residue from methanol sprayed on endophyte-free seed, and endophyte-infected seed. Lowered feed intake and weight gains, and depressed serum prolactin concentrations were used as indicators of toxicity. Feed intake was lower in all three trials for rats fed the methanol fraction. In all three trials mean serum prolactin concentrations in rats fed the methanol extracts were not different from those fed endophyte-infected fescue seed. Rats fed the water extract in trial 3 had lower feed intakes than rats fed endophyte-free seed. However, rats fed the seed, post-water extraction, had serum prolactin concentrations similar to that of the negative control. Results suggest that the toxic factor(s) may be concentrated in the methanol extract.
进行了三项涉及184只雄性斯普拉格-道利大鼠的试验，以确定内生真菌感染的高羊茅种子的生物活性成分。在试验1中，用内生真菌Acremonium coenophialum感染（感染率大于95%）且已证明对牛有毒性的种子，分别用己烷、乙酸乙酯和甲醇依次进行提取。该种子的第二个样本仅用氯仿进行提取。对照组包括溶剂处理（将各种溶剂喷洒在无内生真菌的种子上并将混合物干燥）、提取后的种子、内生真菌感染的种子和无内生真菌的种子。将实验室饲料与所有日粮混合，使其占混合物的50%。试验2除省略氯仿处理外，研究了与试验1相同的处理方法。将试验1中使用剂量3倍（相当于22.5克种子）的剂量应用于无内生真菌的种子（7.5克），以试图突出任何差异。试验3研究了依次提取的甲醇馏分、分批提取的甲醇馏分和分批提取的水馏分。对照组包括提取后的种子残渣、喷洒在无内生真菌种子上的甲醇溶剂残渣以及内生真菌感染的种子。采食量和体重增加降低以及血清催乳素浓度降低被用作毒性指标。在所有三项试验中，喂食甲醇馏分的大鼠采食量较低。在所有三项试验中，喂食甲醇提取物的大鼠血清催乳素平均浓度与喂食内生真菌感染的羊茅种子的大鼠无差异。试验3中喂食水提取物的大鼠采食量低于喂食无内生真菌种子的大鼠。然而，喂食水提取后种子的大鼠血清催乳素浓度与阴性对照组相似。结果表明，毒性因子可能集中在甲醇提取物中。
