Conium maculatum (Umbelliferae/Apiaceae) or poison hemlock is a large biennial herb indigenous to Europe and naturalized in North and South America. As a common poisonous plant, recognition is important, and this plant can be differentiated from most other members of the Umbelliferae/Apiaceae by its smooth purple-spotted stem. The dried unripe fruits were formerly used as a pain reliever and sedative, but have no medicinal use now. The ancient Greeks are said to have executed condemned prisoners, including Socrates, using poison hemlock. The poison causes gradual muscular paralysis followed by convulsions and death from respiratory paralysis. All parts of the plant are poisonous due to the alkaloid content, though the highest concentration of alkaloids is found in the green fruit (up to 1.6%). The major alkaloid (about 90%) is the volatile liquid coniine (Figure 115), with smaller amounts of structurally related piperidine alkaloids, including N-methylconiine and ?-coniceine (Figure 115). In North America, the name hemlock refers to species of Tsuga (Pinaceae), a group of coniferous trees, which should not be confused with the poison hemlock.
© 2018 Biocyclopedia | All rights reserved.