Which plants are neurotoxicants associated with seizures and increased CNS activity?

• A. Milkweed (Asclepias), water hemlock (Cicuta), fitweed (Corydalis), Dutchman's breeches (Dicentra), yellow jessamine (Gelsemium)
• B. Locoweed (Astragalus), morning glory (Ipomoea), yellow star thistle, Russian knapweed
• C. Cannabis, rayless goldenrod, sleepy grass
• D. Belladonna, Datura, Solanum

Answer: (A)

Neurotoxic plant compounds can tip the brain toward overexcitation or reduce inhibition, leading to seizures. Water hemlock is the classic convulsant in this category; cicutoxin in water hemlock directly disrupts neural inhibition, producing rapid, generalized seizures and severe CNS hyperactivity. The other plants in this group are all known to contain potent alkaloids that can affect the CNS and, in sufficient exposure, contribute to convulsions or marked hyperactivity, which is why this set fits best for seizures-associated neurotoxicity.

Milkweed contains cardiac glycosides, and while its primary danger is cardiotoxic, high exposures can produce neurological signs, including tremors or seizures in some animals. Fitweed and Dutchman’s breeches carry isoquinoline alkaloids with CNS activity that can contribute to convulsant effects. Yellow jessamine contains gelsemine, a strong alkaloid with pronounced CNS effects and potential to cause seizures in overdose.

The other answer choices point to plants whose toxic effects are more characteristic of movement disorders, sedation, anticholinergic delirium, or other CNS outcomes rather than primary seizure activity, so they are not the best match for seizure-prone neurotoxicity.