Asclepias syriaca L. (common milkweed) is known to contain sufficient amounts of cardiac glycosides, which are known to be toxic to humans. Nonetheless, it is traditionally used for food by Native Americans, including the Myaamia people of Indiana and Oklahoma. In order to test the hypothesis that traditional horticultural and culinary practices prevent the Myaamia from ingesting toxic levels of cardiac glycosides, we have determined the level of glycosides (digitoxin equivalent) in A. syriaca 1) in various parts of the plant, 2) at various heights for pre-reproductive plants, and 3) before and after cooking according to traditional Myaamia procedures. Plants were grown, harvested, dried, ground, and extracted twice with ethanol. The amount of digitoxin-equivalent glycoside in plant extract was determined spectrophotometrically using 2,2’,4,4’-tetranitrodiphenyl, a selective derivatizing agent. We find that all parts of the plant contain significant levels of cardiac glycosides at all stages of growth. Plants harvested as young shoots for food, the common practice of the Myaamia, contain slightly lower levels of cardiac glycosides when compared to the leaves and stems of older, taller plants. Moreover, the toxicity is significantly reduced by the traditional Myaamia cooking procedure—a repeated boiling with several changes of water. Therefore, it appears as though the risk of glycoside poisoning from traditional Myaamia use of milkweed for food is moderated by their harvesting practice and traditional cooking procedure.

中文翻译：

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根据Myaamia传统收获和煮熟的乳草有何毒性？

众所周知，Aslerpias syriaca L.（普通乳草）含有足够量的强心苷，已知对人体有毒。尽管如此，传统上它还是由印第安人，包括印第安纳州和俄克拉荷马州的Myaamia人用作食物。为了检验以下假设，即传统的园艺和烹饪习惯会阻止Myaamia摄入强心苷的毒性水平，我们确定了植物A. syriaca中1），2）中的A. syriaca中的苷（洋地黄毒当量）水平。生殖植物的高度不等，以及3）按照传统的Myaamia程序烹饪前后。植物生长，收获，干燥，研磨并用乙醇萃取两次。使用2,2'，4，分光光度法测定植物提取物中洋地黄毒苷当量的糖苷含量。4'-四硝基二苯基，选择性衍生剂。我们发现植物的所有部分在生长的各个阶段都含有大量的强心苷。与幼龄，高大植物的叶子和茎相比，作为幼芽采食的植物是Myaamia的常见做法，其强心苷含量略低。此外，通过传统的Myaamia烹饪程序可显着降低毒性-通过多次换水反复煮沸。因此，似乎通过传统的Myaamia将马利筋用作食品，使糖苷中毒的风险似乎通过其收割方法和传统烹饪程序得以缓解。与幼龄，高大植物的叶子和茎相比，作为幼芽采食的植物是Myaamia的常见做法，其强心苷含量略低。此外，通过传统的Myaamia烹饪程序可显着降低毒性-通过多次换水反复煮沸。因此，似乎通过传统的Myaamia将马利筋用作食品，使糖苷中毒的风险似乎通过其收割方法和传统烹饪程序得以缓解。与幼小的高等植物的叶子和茎相比，作为幼芽采食的植物是Myaamia的常见做法，其强心苷的含量略低。此外，通过传统的Myaamia烹饪程序可显着降低毒性-通过多次换水反复煮沸。因此，似乎通过传统的Myaamia将马利筋用作食品，使糖苷中毒的风险似乎通过其收割方法和传统烹饪程序得以缓解。