Gadusol, an enolic derivative of cyclohexane-1,3-dione present in the roes of cod and other marine fish. Isolation, properties and occurrence compared with ascorbic acid

Abstract

Gadusol, C8H12O6, has been isolated from roes of the cod (Gadus morhua L.), i.e., ovaries that contain ripe eggs just before spawning. The concentration is about 4 g/kg dry wt. It has been identified as 1,4,5-trihydroxy-5-hydroxymethyl-2-methoxycyclo-hex-1-en-3-one and this structure was confirmed by synthesis of the anhydro tetra-acetate derivative from methyl 3,5-diacetoxy-4-methoxybenzoate. Concentrations of gadusol in the roes of other marine teleost fish examined are of the same order as in cod roes. Gadusol has some properties similar to ascorbic acid and both compounds, after oxidation, react with 2,4-dinitrophenylhydrazine in the commonly-used assay procedure for ascorbic acid. Specific assays showed that the concentrations of gadusol in the roes of marine fish are severalfold greater than those of ascorbic acid. Gadusol is structurally related to the mycosporines previously reported from a number of different organisms.