Gardner D R, Molyneux R J, Ralphs M H
Poisonous Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, 1150 East 1400 North, Logan, Utah 84341, USA.
J Agric Food Chem. 2001 Oct;49(10):4573-80. doi: 10.1021/jf010596p.
An analytical method has been developed to measure the locoweed toxin, swainsonine, in locoweed plant material. Dry ground plant samples were extracted using a small-scale liquid/liquid extraction procedure followed by isolation of the swainsonine by solid phase extraction with a cation-exchange resin. Detection and quantitation of the swainsonine were accomplished using reversed phase high-performance liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry (LC-MS(2)). The limit of quantitation was estimated to be 0.001% swainsonine by weight in dry plant material, which corresponds to the lower threshold for toxicity of locoweeds. The method of analysis was applied to the analysis of Oxytropis sericea (white locoweed) and Oxytropis lambertii (Lambert locoweed) plant samples to measure the variability of individual plant swainsonine levels within populations and within species. Individual plant variability was found to be highly significant for both O. sericea and O. lambertii populations. The combined three-year mean swainsonine values taken from three populations of O. sericea ranged from 0.046% in Utah to 0.097% in a New Mexico population. Sixteen individual populations of O. lambertii were sampled from eight different U.S. states. Swainsonine was detected at levels >0.001% in only 5 of the 16 collection sites. Those populations of O. lambertii found to contain higher swainsonine levels were restricted to the most southern and western portion of its distribution, and all were identified as belonging to var. bigelovii, whereas var. articulata and var. lambertii samples contained swainsonine at levels <0.001%.
已开发出一种分析方法，用于测定疯草植物材料中的疯草毒素苦马豆素。将干燥的磨碎植物样品采用小规模液/液萃取程序进行萃取，然后用阳离子交换树脂通过固相萃取法分离苦马豆素。苦马豆素的检测和定量通过反相高效液相色谱与大气压化学电离串联质谱联用（LC-MS(2)）来完成。估计定量限为干燥植物材料中苦马豆素重量的0.001%，这与疯草毒性的下限相对应。该分析方法应用于绢毛棘豆（白花疯草）和宽叶棘豆（兰伯特疯草）植物样品的分析，以测量种群内和物种内单个植物苦马豆素水平的变异性。发现绢毛棘豆和宽叶棘豆种群的单个植物变异性都非常显著。从绢毛棘豆的三个种群获取的三年苦马豆素平均值组合范围从犹他州的0.046%到新墨西哥州一个种群的0.097%。从美国八个不同州采集了16个宽叶棘豆的单个种群。在16个采集地点中，只有5个检测到苦马豆素水平>0.001%。那些发现含有较高苦马豆素水平的宽叶棘豆种群仅限于其分布最南部和最西部的部分，并且都被鉴定为属于大花变种，而关节变种和兰伯特变种样品中的苦马豆素水平<0.001%。
