Beier R C, Norman J O
Veterinary Toxicology and Entomology Research Laboratory, US Department of Agriculture, College Station, TX 77840.
Vet Hum Toxicol. 1990;32 Suppl:81-8.
White snakeroot (Eupatorium rugosum Houtt) has been known to cause trembles in animals and milk sickness in humans since the American Revolution. It still continues to poison animals. Horses and goats are particularly sensitive to white snakeroot poisoning. Resurgence of livestock production on small farm units, and utilization of fresh raw milk may result in milk sickness; if the animals have white snakeroot exposure. The goat is the only animal with good toxicity threshold data. In other animals and humans the toxicity thresholds of white snakeroot are not known, and that until responsible toxic principles are identified and their fate in animals and milk studied, such an assessment will not be possible. The toxic component(s) in white snakeroot has not been identified. The mechanism of action of the toxin in animals or humans remains unknown. However, metabolic studies in chicks initially suggest that a specific metabolic enzyme may be the target of the toxic principle. Components of white snakeroot that are toxic after microsomal activation have been isolated. Cytochrome P-450 is responsible for this activation. Activation in vitro can be totally inhibited by the cytochrome P-450 specific autocatalytic inhibitor, 1-aminobenzotriazole. In view of the importance of white snakeroot in the history of the United States and the ongoing problems today, it would be most unfortunate if studies were not pursued expeditiously to identify the toxicant(s) responsible, and to understand the mechanism(s) of action and toxicity thresholds.
自美国独立战争以来，人们就知道白蛇根草（Eupatorium rugosum Houtt）会导致动物颤抖和人类乳毒病。它至今仍在毒害动物。马和山羊对白蛇根草中毒尤为敏感。小型农场单位牲畜生产的复苏以及新鲜生牛奶的利用可能会导致乳毒病；如果动物接触过白蛇根草的话。山羊是唯一具有良好毒性阈值数据的动物。在其他动物和人类中，白蛇根草的毒性阈值尚不清楚，而且在确定其主要有毒成分及其在动物和牛奶中的情况之前，无法进行这样的评估。白蛇根草中的有毒成分尚未确定。毒素在动物或人类中的作用机制仍然未知。然而，对雏鸡的代谢研究初步表明，一种特定的代谢酶可能是有毒成分的作用靶点。已分离出经微粒体激活后有毒的白蛇根草成分。细胞色素P - 450负责这种激活。体外激活可被细胞色素P - 450特异性自催化抑制剂1 - 氨基苯并三唑完全抑制。鉴于白蛇根草在美国历史上的重要性以及当今持续存在的问题，如果不迅速开展研究以确定相关有毒物质、了解其作用机制和毒性阈值，那将是非常不幸的。
