Aplysiadione and aplysiaenal: Truncated biosynthetic intermediates of aplysiatoxins from a cyanobacterium

Abstract

Aplysiatoxin and its derivatives have been isolated from marine cyanobacteria. The biosynthesis of their characteristic bicyclic skeletons from a linear polyketide intermediate has been proposed. Two polyketides, aplysiadione (1) and aplysiaenal (2), were isolated from the marine cyanobacterium Moorea producens (formerly Lyngbya majuscula) collected in the Okinawan coastal area. The polyketide chemical structures were elucidated from HR ESI-MS and NMR spectra. Aplysiadione (1) corresponds to a decarboxylated analog of the proposed biosynthetic intermediate of aplysiatoxins. Aplysiaenal (2) is a truncated analog of the linear intermediate. The isolation of aplysiadione (1) strongly supports the proposed ring formation mechanisms for the aplysiatoxins, and this compound is a rare example of a biosynthetic intermediate of polyketide secondary metabolites from marine cyanobacteria.

Keywords

• Aplysiatoxins
• Biosynthetic intermediates
• Polyketides
• Cyanobacteria