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Taxines
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
The genus Taxus comprises a group of evergreen plants commonly known as yew trees that produce several types of toxic metabolites such as alkaloidal diterpenoids (taxines or taxine alkaloids), nonalkaloidal diterpenoids, phenolic compounds, flavonoids, bioflavonoids, and glycosides. Representing about 30% of the total alkaloid fraction from T. baccata (English yew or European yew), taxines (particularly taxine B) are Ca+2-channel antagonists that increase cytoplasmic calcium concentrations and cause serious heart-related disease syndromes in humans and animals who accidentally or deliberately ingest yew seeds, leaves (needles), and bark. In addition, recent development and application of taxine-derived compounds (i.e., taxanes) in the treatment of tumors and cancers create the opportunity for taxine poisoning in different population groups. Given the current absence of antidotes to taxines, there is an obvious need to develop novel intervention measures against taxine poisoning. Considering that taxines often form conjugated metabolites in the liver for subsequent excretion in urine, use of medication or a substance that specifically binds or conjugates with taxines may offer a potential approach to eliminate taxines and increase the probability of a patient's survival.
Characteristics of emergency department presentations following ingestion of Taxus baccata (yew)
Published in Clinical Toxicology, 2023
Vanessa Alexandra Buetler, Alexandra Maria Braunshausen, Stefan Weiler, Jolanta Klukowska-Rötzler, Aristomenis K. Exadaktylos, Evangelia Liakoni
The toxicity of Taxus baccata is mediated by two major taxine alkaloids, taxine A and taxine B, that are mainly present in all parts of the plant with the exception of the berries [1,3–7]. The cardiotoxic effects are mostly induced by taxine B and presentations following ingestion can range between asymptomatic cases and life-threatening cardiotoxicity [5,8]. Ingestion of about 50–100 g yew leaves (corresponding to 0.6–1.3 g yew leaves/kg body weight, or 3–6.5 mg taxines/kg body weight, or more than 100 leaves) can be lethal [4,6,9]. However, the exact lethal dose is unknown. The amount of the taxines absorbed can vary with several factors, including the preparation of the material (higher if leaves minced or mashed before ingestion than with untreated leaves) as well as the season of the year (higher taxine concentrations in the plant during winter) [4,10]. First signs of intoxication can be non-specific, such as nausea, emesis and abdominal pain [4]. In severe intoxications, cardiotoxicity can occur, mediated through inhibition of sodium and calcium channels, with potentially fatal outcome [5,6,8,9]. The diagnosis is mainly based on the patient’s history or identification of leaves in the gastrointestinal tract, while detection of specific alkaloids with mass spectrometry can also be used for confirmation [1,6,11]. Treatment is focused on decontamination measures and supportive care, and there is no known antidote available [4,12].