Poison Hemlock (Conium maculatum L.)
Piperidine (nicotinic) alkaloids in Conium include coniceine, coniine, N-methyl coniine, conhydrine, and pseudoconhydrine. The alkaloid content is variable with the stage of development and the stage of reproduction of the plant. During the first year of growth, the plant alkaloid content tends to be low. Plants in the second year, however, have alkaloid contents of approximately 1% in all plant parts. The alkaloid content is somewhat higher after sunny weather, as compared to rainy weather. The highest concentration of alkaloids occur in the seeds which can contaminate cereal grains. Coniine (2-propylpiperidine) and N-methyl coniine progressively increase in flowers and fruits, while coniceine decreases during plant maturation. In the vegetative stage - i.e. early growth - coniceine (W'-2 propylpiperidine) is the predominant alkaloid. Coniceine and coniine are the primary teratogenic alkaloids of Conium.
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