Novel 10-hydroxydocosapolyenoic acids from deep-water scleractinian corals

The new 10-hydroxydocosapolyenoic acids (10R,7Z,11E,13E,16Z,19Z)-10-hydroxy docosa-7,11,13,16,19-pentaenoic acid (1a) and (10R*,4Z,7Z,11E,13Z,16Z,19Z)- 10-hydroxydocosa-4,7,11,13,16,19-hexaenoic acid (2a) were isolated as methy l esters 1b and 2b, respectively, following CH2N2 treatment of the EtOH ext ract of the scleractinian coral Madrepora oculata from deep-water of the so uthern Indian Ocean. From the same species from the Norwegian Sea, 1b and t he methyl ester 3b of the new (10R,7Z,11E,13Z,16Z)-10-hydroxydocosa-7, 11,1 3,16-tetraenoic acid (3a) were analogously isolated, while from the untreat ed extract, the free acid 3a itself could be isolated. The absolute configu ration of 1a and 3a was established by the chiral exciton coupling of the C (10) benzoate esters 1c and 3c. Other known 10-hydroxydocosapolyenoic acids and 8-hydroxyeicosapolyenoic acid were also isolated from M. oculata from both locations. These results imply the intervention of a rare lipooxygenas e with high omega 13 specificity. In an examination of several other deep-w ater scleractinians, hydroxypolyenoic acids were found only in Lophelia per tusa from the northeastern Atlantic Ocean.