Hepatotoxicity of herbal remedies and mushrooms

Hepatotoxicity of botanicals

OBJECTIVE

Hepatic impairment resulting from the use of conventional drugs is widely acknowledged, but there is less awareness of the potential hepatotoxicity of herbal preparations and other botanicals, many of which are believed to be harmless and are commonly used for self-medication without supervision. The aim of this paper is to examine the evidence for hepatotoxicity of botanicals and draw conclusions regarding their pathology, safety and applications.

DESIGN

Current literature on the hepatotoxicity of herbal drugs and other botanicals is reviewed. The aetiology, clinical picture and treatment of mushroom (Amanita) poisoning are described.

RESULTS

Hepatotoxic effects have been reported for some Chinese herbal medicines (such as Jin Bu Huan, Ma-Huang and Sho-saiko-to), pyrrolizidine alkaloid-containing plants, germander (Teucrium chamaedrys), chaparral (Larrea tridentata), Atractylis gummifera, Callilepsis laureola, and others. The frequency with which botanicals cause hepatic damage is unclear. There is a lack of controlled treatment trials and the few studies published to date do not clarify the incidence of adverse effects. Many plant products do not seem to lead to toxic effects in everyone taking them, and they commonly lack a strict dose-dependency. For some products, such as Sho-saiko-to, the picture is confused further by demonstrations of hepatoprotective properties for some components. Mushroom poisoning is mostly due to the accidental consumption of Amanita species. Treatment with silymarin, thioctic acid, penicillin and liver transplantation have been shown to be effective but require early diagnosis.

CONCLUSIONS

Severe liver injury, including acute and chronic abnormalities and even cirrhotic transformation and liver failure, has been described after the ingestion of a wide range of herbal products and other botanical ingredients, such as mushrooms. It is concluded that in certain situations herbal products may be just as harmful as conventional drugs.

Acute hepatic failure: a Western perspective

Acute hepatic failure (AHF) is an uncommon, devastating syndrome, which results in death or the need for liver transplantation in more than 50% of cases. While AHF has numerous causes, most cases are due to viral hepatitis and drug toxicity or idiosyncratic reactions. A significant group with indeterminate causation remains, despite careful investigation. In many of these cases a viral aetiology is suspected, although yet not proven. Major differences exist in the aetiology of AHF between the West and Eastern countries. A wider range of aetiologies exists in the West. Common causes include acetaminophen toxicity and idiosyncratic drug reactions, while viral hepatitis is less frequent. Hepatitis E infection is rarely seen in Western countries in contrast to its high prevalence in the East. The mainstay of AHF management is supportive care in an intensive care unit. Liver transplantation is now the standard of care in many Western liver units for individuals who have a less than 20% probability of survival. Lack of availability of donor livers at short notice remains a significant problem. Methods of liver support used while waiting for a donor liver or for the native liver to regenerate include bioartificial livers, extracorporeal liver-assist devices, extracorporeal whole organ perfusion (human and transgenic pig) and hepatocyte transplantation. The effectiveness of these methods remains unproven and awaits controlled clinical trials. Both transplantation and liver-support methods require specialized units and expensive and complicated equipment. Further research is necessary to identify modalities of therapy that would be effective as well as widely accessible.

Acute hepatitis induced by greater celandine (Chelidonium majus)

The hepatotoxic potential of conventional drugs is well known, but herbal medicines are often assumed to be harmless. In the last 2 years, we have observed 10 cases of acute hepatitis induced by preparations of greater celandine (Chelidonium majus), which are frequently prescribed to treat gastric and biliary disorders. The course of hepatitis was mild to severe. Marked cholestasis was observed in 5 patients, but liver failure did not occur. Other possible causes of liver disease (viral, autoimmune, hereditary, alcohol, and secondary biliary) were excluded by laboratory tests and imaging procedures, and liver biopsy specimens were consistent with drug-induced damage. After discontinuation of greater celandine, rapid recovery was observed in all patients and liver enzyme levels returned to normal in 2-6 months. Unintentional rechallenge led to a second flare of hepatic inflammation in 1 patient. Greater celandine has to be added to the list of herbs capable of inducing acute (cholestatic) hepatitis. A significant proportion of unexplained cases of hepatitis may be caused by greater celandine.

The toxicology of African herbal remedies

Toxicity related to traditional medicines is becoming more widely recognized as these remedies become popular in developed countries. Accidental herbal toxicity occurs not only as a result of a lack of pharmaceutic quality control in harvesting and preparation but also because herbal remedies are believed to be harmless. Although there is a huge amount of data available documenting the pharmacologically active ingredients of many plants, it is seldom helpful to the toxicologist in an acute situation. Current analytic methods such as high-performance liquid chromatography, gas chromatography--mass spectrometry, and immunoassays can provide identification of the toxin in those few cases in which the history or symptoms give a clear lead, but broad screening methods remain to be developed. In most cases of plant poisoning, treatment continues to be only of symptoms, with few specific antidotes available. It is important that toxicologists in the West be alert to the possibility of encountering poisoning in patients due to traditional African remedies.

Evaluation of abnormal liver function tests

Although the liver can be affected in a wide range of disorders, the differential diagnosis of abnormal liver function tests can be substantially narrowed by a comprehensive history and physical examination and by the recognition of relatively distinct biochemical patterns of liver injury. Although referral to a specialist may be required for the performance of, for example, percutaneous liver biopsy and long-term management of chronic liver disease, a presumptive diagnosis can usually be made in the vast majority of patients who present to primary care physicians with abnormal liver function tests.