What poisonous alkaloid group is found in yew trees?

The poisonous alkaloid group found in yew trees is taxine. Taxines are not one single molecule but a family of toxic alkaloids concentrated throughout most parts of Taxus species, including the English yew (Taxus baccata). Taxine A and taxine B are the major members, with taxine B generally regarded as the more cardiotoxic component.

The name has a long history. Chemists first isolated a bitter yew substance in the 19th century and called it taxine. In 1956, researchers established that the material was a mixture rather than a single compound. That distinction explains why “taxines” or “taxine alkaloids” is more chemically precise than treating taxine as one substance.

These compounds disrupt cardiac electrical activity by antagonizing sodium and calcium channels, potentially causing bradycardia, conduction problems, arrhythmias, cardiac arrest, or respiratory failure. Yew poisoning is not the same as exposure to paclitaxel: paclitaxel is a separate taxane derivative from yew that became an anticancer drug. The fleshy red aril around a yew seed is generally less toxic than the seed and foliage, but the seeds themselves remain dangerous.