In the last decade appeared a large number of publications on the therapeutic effectiveness of echinochrome A and drugrnpreparations based on it, and that arouse the interest in the whole world to search and investigate biologically active quinonoidrnpigments of sea urchins. Therefore, the study of the chemical properties of echinochrome A, in particular the stability of itsrnsolutions, is an urgent task for modern pharmaceuticals. To investigate stability of echinochrome A in aqueous solutions, 200rnmg of it was diluted 50-fold with distilled water saturated with atmospheric oxygen (pH 7.2), and was vigorously stirred atrnroom temperature for 48 hours. Echinochrome A was removed from the reaction mixture by extraction with chloroform, itsrnoxidation products were extracted with ethyl acetate and chromatographed on a Toyopearl HW-40 gel in a solvent systemrn20-50% EtOH containing 0.3% HCOOH. As a result, 7-ethyl-2,2,3,3,5,6,8-heptahydroxy-2,3-dihydro-1,4-naphthoquinone,rn2-(carboxycarbonyl)-4-ethyl-3,5,6-trihydroxybenzoic acid, echinolactone A (7-ethyl-5,6-dihydroxy-2,3-dioxo-2,3-rndihydrobenzofuran-4-carboxylic acid), 4-ethyl-3,5,6-trihydroxyphthalic acid and 4-ethyl-2-formyl-3,5,6-trihydroxybenzoicrnacid were isolated. The structures of compounds 2, 3, 5, 6 were established using high-resolution mass spectrometry (HR-ESIMS)rnand NMR, and of compound 4–using X-ray crystallography.
