Zygacine
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IUPAC name
(5ξ,8ξ,9ξ,12ξ,14ξ)-4,14,15,16,20-Pentahydroxy-4,9-epoxycevan-3-yl acetate
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| Other names
Cevane-3β,4β,14,15α,16β,20-hexol, 4,9-epoxy-, 3-acetate
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| Properties | |
| C29H45NO8 | |
| Molar mass | 535.68 g·mol−1 |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |
Zygacine is a toxin most commonly found in all parts of the plants in the genus Zigadenus (death camas). It is a steroidal alkaloid, like veratridine and batrachotoxin. Zygacine can be lethal when entering the body orally or intravenously. It was first isolated in 1913, but its structure and configuration remained unknown until 1959.
The discovery of zygacine started with the death of livestock, primarily sheep, in times of food shortage for the livestock. In the fields where the sheep grazed death camas was found, together with Low larkspur (Delphinium bicolor), another toxic plant. Low larkspur has an additive effect on the toxicity of the death camas in mice. However, sheep are thought to be resistant to Low larkspur. This led to the conclusion that death camas was the cause of death of the sheep. Research on death camas lead to the conclusion that zygacine was the toxic compound.
Humans have also been exposed to zygacine via ingestion of death camas. In the nineteenth century, Native Americans sold the death camas as food which resulted in the death of several railroad workers, who ate the bulbs. The estimated fatal dose of the bulb ranges from less than 45 grams for a young child up to 450 grams for an adult. Another example of zygacine poisoning dates from 1994, when a hiker mistook the plant for wild onions. He was treated in the emergency department and recovered.
Humans who eat death camas usually mistake them for camas, which is a type of wild onion. An hour after ingestion, most people will experience vomiting, nausea, diarrhea and abdominal cramping. When they arrive at the emergency department, they are usually bradycardic and hypotensive. Bradycardia is the only reported arrhythmia. Ataxia, hyperactive deep-tendon reflexes and muscle spasms have also been reported. Two cases of pediatric poisoning show that the patients are markedly hypotensive and obtunded, with depressed respiration. However, both patients recovered fully within 24 hours.
Steroidal alkaloids, such as zygacine, are known to cause muscle contraction, repetitive firing of the nerves, and an irregular heart rhythm. This is due to alteration of the voltage-gated sodium channel properties.The sodium permeability is increased, which leads to hyperexcitability and depolarization of the excited membrane.This causes muscle spasms and other symptoms of zygacine poisoning.
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Wikipedia