Cardiotoxicity of Plants in Iran: a Review

In this review an attempt has been made to review the cardiotoxic effects of poisonous plants which are found in Iran. Among various plant species growing in different regions of Iran, a large number of plants contain chemical compounds which are toxic to animals and humans. Among those poisonous plants, cardiotoxic plants are important due to the acute nature of their toxicity and frequent lethal livestock and human intoxications. Cardiotoxic plants of Apocynaceae family, Nerium oleander, N. indicum and Thevetia peruviana contain cardiac glycosides including oleandrin, oleandroside and thevetin A-C. Plants of Taxaceae family, Taxus baccata and T. brevifolia contain taxine alkaloids, including taxine A and B. The toxic effects of cardiac glycosides are primarily attributed to inhibition of plasmalemmal Na+/ K+-ATPase which results into the accumulation of intracellular Ca2+ and, depending to its severity, inotropic or arrhythmic effects are seen. Taxine B, the prominent alkaloid in Taxus spp. block sodium and calcium channels preferentially in cardiac myocytes, thus causing conduction abnormalities. Various cardiac arrhythmias in acute cases of poisoning with aforementioned plants result in acute heart failure and death. Post mortem findings are non-diagnostic and toxicological analysis of gastrointestinal tract content or body fluids is used for detection of cardiac glycosides and taxines.