Egil Ramstad

Biogenetic interrelationships of ergot alkaloids.

Abstract The biogenetic interconversions of clavine alkaloids have been studied by the use of clavine-C14 and clavine-H3 alkaloids labeled biosynthetically in saprophytic culture, and four different ergot strains in saprophytic cultures. Agroclavine was shown to be oxidized irreversibly to elymoclavine. The attack appears to be directly on the methyl group. Agroclavine, but not elymoclavine, was shown to be converted irreversibly to the following clavine alkaloids: festuclavine, pyroclavine, and setoclavine. Elymoclavine was shown to be the precursor of lysergol, isolysergol, penniclavine, and isopenniclavine. These conversion reactions are irreversible. Only three clavine alkaloids were found to be metabolized in ergot strain 47 A, viz., agroclavine, elymoclavine, and lysergene, all of which have a double bond in position 8. Chanoclavine was shown not to be a precursor of the clavine alkaloids. Evidences indicate that it was not a breakdown product of agroclavine or of any other clavine alkaloid derived from agroclavine. Lysergene was shown to be converted to lysergol, isolysergol, penniclavine, and isopenniclavine. No evidence was found suggesting that lysergene is a normal intermediate in the biosynthesis of these compounds from elymoclavine. Each stereoisomer was found to be biosynthesized as such and not to be the result of a chemical or biochemical isomerization process.