| Definition: |
Any member of a structurally diverse group of hybrid isoprenoid-indole alkaloids, produced solely by members of the Subsection V cyanobacterial strains. The major classes of hapalindole-type molecules include hapalindoles, fischerindoles, welwitindolinones and ambiguines that share a common molecular feature where an indole and an isonitrile group are connected by a carbon-carbon motif (C10-C11) that is appended with a monoterpene unit. Fusion of the exomethylene carbon C-16 with indole backbones in the tricyclic hapalindoles provides tetracyclic hapalindoles and fischerindoles that, on rearrangement, can also lead to the bridged tetracyclic welwitindolinones. Decoration of tetracyclic hapalindoles with a tert-prenyl group at C-2 of the indole ring results in ambiguines, of which many have a fused pentacyclic 6-6-6-5-7 or 6-6-6-5-6 ring system. |