page_title: Cyclopamine
section_title: Source and structure
hierarchical_section_title: Cyclopamine / Source and structure
caption_attribution_description: English: Cyclopamine as metabolized by the body in the stomach, information interpreted from [1].
context_page_description: Cyclopamine is a naturally occurring chemical that belongs in the family of steroidal alkaloids. It is a teratogen isolated from the corn lily that causes fatal birth defects. It prevents the embryonic brain from separating into two lobes, which in turn causes the development of a single eye. The chemical was named after this effect, as it was originally noted by Idaho lamb farmers who contacted the US Department of Agriculture after their herds gave birth to cycloptic lambs in 1957. It then took more than a decade to identify the corn lily as the culprit. Later work suggested that different rain patterns caused the sheep to graze differently, impacting the amount of corn lily ingested by pregnant sheep. The poison interrupts the sonic hedgehog signaling pathway during development, thus causing birth defects.
context_section_description: The biosynthesis of cyclopamine begins with cholesterol. A steroid skeleton has a classic 6-member ring, adjacent to another 6, 6, then a five or “6-6-6-5”.  Veratrum was determined to contain five types of alkaloids, each of which had a common cholesterol precursor: (1) solanidine alkaloids, (2) verazine alkaloids, (3) vertramine alkaloids, (4) jervine alkaloids, and (5) the cevanine alkaloids. In biosynthesis, Cyclopamine has a solanide (1) precursor, which itself is made from cholesterol. This was determined by initial studies which isolated alkaloids from corn lily (Veratrum californium), and introduced these to embryonic sheep. At the time, jervine was an already known alkaloid which was isolated from corn lily alongside two other alkaloids: the unknown cyclopamine and veratramine; each with different toxicities. Later studies then demonstrated that jervine degraded to cyclopamine upon a Wolff-Kishner reduction, which helped identify the unknown compound.
  It was also demonstrated that treatment of cyclopamine with a Lewis acid (pH < 2) leads to the production of veratramine. The stomach provides these conditions, and thus only a small amount of cyclopamine passes through the stomach after ingestion. And even though only a small amount of ingested cyclopamine passes the stomach, it remains unaffected afterwards.
  Veratramine is highly toxic, even if it does not impact development, as it excites the central nervous system and can cause seizures – similarly to serotonin. The mechanism for the production of veratramine focuses on the cleavage of a carbon-oxygen bond, which leads to the formation of a new double bond. From there, this ring is almost aromatic. The driving force to become aromatic then pushes an elimination reaction, creating a third double bond and producing aromaticity, as depicted in the figure below.
caption: Production of Veratramine from Cyclopamine in stomach conditions.[3]
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