Stickel F, Seitz H K
Department of Medicine I, Division of Gastroenterology and Hepatology, University of Erlangen-Nuernberg, Krankenhausstrasse 12, 91054 Erlangen, Germany.
Public Health Nutr. 2000 Dec;3(4A):501-8. doi: 10.1017/s1368980000000586.
Herbal medication has gathered increasing recognition in recent years with regard to both treatment options and health hazards. Pyrrolizidine alkaloids have been associated with substantial toxicity after their ingestion as tea and in the setting of contaminated cereals have led to endemic outbreaks in Jamaica, India and Afghanistan. In Western Europe, comfrey has been applied for inflammatory disorders such as arthritis, thrombophlebitis and gout and as a treatment for diarrhoea. Only recently was the use of comfrey leaves recognized as a substantial health hazard with hepatic toxicity in humans and carcinogenic potential in rodents. These effects are most likely due to various hepatotoxic pyrrolizidine alkaloids such as lasiocarpine and symphytine, and their related N-oxides. The mechanisms by which toxicity and mutagenicity are conveyed are still not fully understood, but seem to be mediated through a toxic mechanism related to the biotransformation of alkaloids by hepatic microsomal enzymes. This produces highly reactive pyrroles which act as powerful alkylating agents. The main liver injury caused by comfrey (Symphytum officinale) is veno-occlusive disease, a non-thrombotic obliteration of small hepatic veins leading to cirrhosis and eventually liver failure. Patients may present with either acute or chronic clinical signs with portal hypertension, hepatomegaly and abdominal pain as the main features. Therapeutic approaches include avoiding intake and, if hepatic failure is imminent, liver transplantation. In view of the known serious hazards and the ban on distributing comfrey in Germany and Canada, it is difficult to understand why comfrey is still freely available in the United States.
近年来，草药疗法在治疗选择和健康危害方面都得到了越来越多的认可。吡咯里西啶生物碱在作为茶饮用以及在受污染谷物的情况下摄入后，具有显著毒性，已导致牙买加、印度和阿富汗的地方性疫情爆发。在西欧，紫草已被用于治疗关节炎、血栓性静脉炎和痛风等炎症性疾病以及腹泻。直到最近，人们才认识到使用紫草叶对人类具有严重的健康危害，会导致肝毒性，对啮齿动物具有致癌潜力。这些影响很可能是由于各种肝毒性吡咯里西啶生物碱，如阔叶千里光碱和聚合草碱，以及它们相关的N-氧化物。毒性和致突变性的传递机制仍未完全了解，但似乎是通过一种与肝微粒体酶对生物碱的生物转化相关的毒性机制介导的。这会产生高反应性的吡咯，它们作为强大的烷基化剂起作用。紫草（聚合草）引起的主要肝损伤是肝小静脉闭塞病，这是一种小肝静脉的非血栓性闭塞，会导致肝硬化并最终导致肝衰竭。患者可能表现出急性或慢性临床症状，主要特征为门静脉高压、肝肿大和腹痛。治疗方法包括避免摄入，如果即将发生肝衰竭，则进行肝移植。鉴于已知的严重危害以及德国和加拿大禁止分发紫草，很难理解为什么紫草在美国仍然可以自由获取。
