Eicosanoids and other hydroxylated fatty acids from the marine alga Gracilariopsis lemaneiformis

Abstract

The fatty acid constituents of the red alga Gracilariopsis lemaneiformis have been investigated and their chemical structures determined by various spectroscopic methods. Three novel compounds were isolated as synthetic peracetate, methyl esters from the derivatized crude extract [methyl 10( S*)-acetoxy-6( Z),8( E),12( Z),15( Z)-octadecatetraenoate, methyl 12-acetoxy-5( Z),8( E),10( E)-dodecatrienoate, and methyl 12( R*),13( S*)-diacetoxy-18-keto-5( Z),8( Z),10( E),14( Z),16( E)-eicosapentaenoate]. Seven known hydroxy fatty acids were also isolated as synthetic derivatives [methyl 12( S*)-acetoxy-5( Z),8( Z),10( E),14( Z)-eicosatetraenoate, methyl 12( S)-acetoxy-5( Z),8( Z),10( E),14( Z), 17( Z)-eicosapentaenoate, methyl 12( R*),13( S*)-diacetoxy-5( Z),8( Z),10( E),14( Z)-eicosatetraenoate, methyl 12( R), 13( S)-diacetoxy-5( Z),8( Z),10( E),14( Z),17( Z)-eicosapentaenoate, methyl 13( S*)-acetoxy-9( Z),11( E)-octadecadienoate, methyl 13-keto-9( Z),11( E)-octadecadienoate, methyl 13( S*)-acetoxy-9( Z),11( E),15( Z)-octadecatrienoate]. The occurrence of these different eicosanoids in G. lemaneiformis suggests that this red alga may contain several oxidative enzymes which differ in their positional specificity.