Herbal medicines, pyrrolizidine alkaloids

Complementary alternative medicine herbal remedies pyrrolizidine alkaloids veno-occlusive disease of the liver natural treatments or therapy... 

In the West Indies especially, pyrrolizidine alkaloid toxicity is a continuing problem, as plants containing pyrrolizidine alkaloids such as Heliotropium, Senecio, and Crotolaria species are used in traditional medicine to make herbal teas. Chronic exposure to low doses of these alkaloids causes liver cirrhosis, and it is estimated that these alkaloids account for one-third of the cirrhosis cases detected at autopsy in Jamaica (see Chapter 6 for more details of these natural toxins). 

As we saw in Chapter 3, pyrrohzidine alkaloid toxicity is a continuing problem, as plants containing pyrrolizidine alkaloids are also used in traditional medicine to make herbal teas, especially in the West Indies. 

Comfrey products have been withdrawn from the market in several countries, including the USA and the UK. The German Federal Health Office has restricted the availability of botanical medicines containing unsaturated pyrrolizidine alkaloids (1,2). Herbal medicines that provide more than Img internally or more than 100 mg externally per day, when used as directed, are not permitted herbal medicines that provide 0.1-1 mg internally or 10-100 mg externally per day, when used as directed, may be applied only for a... 

The German Federal Health Office has restricted the availability of botanical medicines containing unsaturated pyrrolizidine alkaloids (1,2). Herbal medicines that provide over 1 mg/day internally or over 100 mg/day externally are not permitted herbal medicines that provide... 

In the present investigation, supercritical carbon dioxide and carbon dioxide -h co-solvent mixtures were used to extract and isolate a model pyrrolizidine alkaloid from its parent plant. Pyrrolizidine alkaloids have been used in herbal medicine to combat tumors as long ago as the fourth century A.D. (4) and to treat cancer since the tenth century A.D. (5). More recently, they have received increasing attention as chemotherapeutic drugs. Processes for their separation, however, are specific to each alkaloid, and either lead to chemical modification of the alkaloid or require the use of solvents which must then be completely removed from the extract. 

Fu PP, Yang Y, Xia Q, etal. (2002) Pyrrolizidine alkaloids -tumorigenic components in Chinese herbal medicines and dietary supplements. Journal of Food and Drug Analysis 10(4) 198-211. 

Pyrrolizidine alkaloids can be found in numerous plants used in Indian and Chinese medicine (Roeder, 2000 Zhao et al., 1989). For example, a medicinal herbal preparation containing Heliotropium eichwaldii and its... 

Nevertheless, Foster and Johnson emphasize that comfrey also contains toxic pyrrolizidine alkaloids (PAs), as documented in Chapter 6. Although PAs will help stop bleeding, the negative effects outweigh the beneficial, for comfrey has been found to cause liver damage and produce cancerous liver mmors. Despite its long history in herbal medicine, no clinical smdies have documented any positive effects attributable to comfrey. Many studies, however, have demonstrated its liver toxicity. 

AHPA. July 2011. Code of Ethics Business Conduct. Silver Spring, MD American Herbal Products Association. Danninger, T., U. Hagemann, V. Schmidt, and P.S. Schoenhoefer. 1983. Toxicity of pyrrolizidine alkaloid-containing medicinal plants. Pharm. Ztg. 128 289-303. 

Betz, J.M., R.M. Eppley, W.C. Taylor, and D. Andrzejewski. 1994. Determination of pyrrolizidine alkaloids in commercial comfrey products (Symphytum sp.). J. Phann. Sci. 83(5) 649-653. Bradley, P.R. 1992. British herbal compendium A handbook of scientific information on widely used plant drugs. Bournemouth, UK British Herbal Medicine Association. 

Yu, L., Y. Xu, H. Feng, and S.F. Li. 2005. Separation and determination of toxic pyrrolizidine alkaloids in traditional Chinese herbal medicines by micellar electrokinetic chromatography with organic modifier. Electrophoresis 26(17) 3397-3404. 

Denham, A. 1996, Using herbs that contain pyrrolizidine alkaloids , European Journal of Herbal Medicine 2 27-38. 

Pyrrolizidine alkaloids poison animals grazing on toxic wild plants and those fed contaminated feed, causing economic losses. They poison humans through deliberate consumption of certain foods and herbal medicines and through consumption of food contaminated by wild plants, such as via transport of the toxins by bees into honey. Analytical methods are required for different purposes - to detect the presence of pyrrolizidine alkaloids, to quantify the total level of the toxins, or to measure the quantity of individual compounds. The task is made more challenging by the variety of PAs, their widespread nature and their different forms. Analytical methods are based on color reactions, enzyme linked immunosorbent assays (ELlSAs), spectroscopy, and the full range of chromatographic techniques. A lack of reference standards and... 

Yu LJ, Li SPY (2005) Dynamic pH junction-sweeping capillary electrophoresis for online preconcentration of toxic pyrrolizidine alkaloids in Chinese herbal medicine. Electrophoresis 26 4360 367... 

Roeder E, Wiedenfeld H (2011) Pyrrolizidine alkaloids in plants used in the traditional medicine of Madagascar and the Mascarene islands. Pharmazie 66(9) 637-647 Neuman MG, Winkler RE (2008) Veno-occlusive disease of the liver induced by herbal medicine Rmnanian. J Hepatol 4 7-9... 

Purpose The objectives are to encourage recognition and prevention of common morbidity encountered when using complementary and alternative medicine and 2) to review the toxic effect of herbal remedies containing pyrrolizidine alkaloids (PAs). 

Pyrrolizidine alkaloids are poisonous to humans and cause losses in hvestock, especially grazing animals. Humans are exposed to pyrrolizidine alkaloids through consumption of plants containing these toxins, contaminated staple products, herbal teas or medicines, and dietary supplements (Fu et al. 2004). Poisoning by pyrrolizidine alkaloids is endemic in India, Jamaica and parts of Africa. Native American and Hispanic populations in western... 

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