Med. Weter. 71 (10), 602-607, 2015
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Kowalczyk E., Patyra E., Kwiatek K. |
Pyrrolizidine alkaloids as a threat to human and animal health |
Pyrrolizidine alkaloids (PAs) are toxins found naturally in a wide variety of plant species that may affect wildlife, livestock and humans. Many of these alkaloids have been shown to be highly toxic, causing hepatic veno-occlusive disease (VOD), liver cirrhosis and ultimately death. PAs may also have mutagenic and carcinogenic potential. Pyrrolizidine alkaloids occur in many plants, mostly belonging to the families Boraginaceae, Asteraceae and Fabaceae originating from different geographical regions. Plants containing pyrrolizidine alkaloids are usually common weeds occurring world-wide in pastures, grasslands, arable lands and along the borders of rivers and roads.
Due to their bitter taste PA-containing plants are generally unpalatable and, as a result, avoided by grazing animals in the field. In preserved and composed feeds this recognition is lost and the toxic PAs may be consumed by livestock. The most undesirable aspect of the poisoning with pyrrolizidine alkaloids is the fact that the disease develops undetected for a long time, which means that at the moment of onset of its symptoms the process of liver damage is so advanced that the animal drops within a few days. Amongst livestock, pigs, cattle and horses are especially susceptible to the toxic effects of the PAs. Humans can be exposed to toxic alkaloids through honey and pollen products. It has also been shown that products like milk, eggs and meat coming from animals fed with feed containing alkaloids may be contaminated with the toxic substances, posing an additional hazard.
The subject of pyrrolizidine alkaloids in not studied in most of the countries, which is why it is extremely difficult to evaluate the real danger that alkaloids pose to human and animal health.
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Key words: pyrrolizidine alkaloids, toxicity, food chain. |