Carotenoids in Clams, Ruditapes philippinarum and Meretrix petechialis

Carotenoids were investigated in two species of clams, Rudiapes philippinarum and Meretrix petechialis. Fucoxanthin 3-esters and fucoxanthinol 3-esters were found to be major components, along with crassostreaxanthin A 3-acetate, crassostreaxanthin A, crassostreaxanthin B 3-acetate, crassostreaxanthin B, halocynthiaxanthin 3'-acetate, halocynthiaxanthin, alloxanthin, diatoxanthin, diadinoxanthin, and heteroxanthin. Fatty acids esterified with fucoxanthin and fucoxanthinol were identified as C24:6, C22:5, C22:6, C20:5, 020:0, C20:1, 018:0, C18:1, 016:0, 016:1, and C14:0 from fast atom bombardment mass spectrometry (FAB-MS) data. Crassostreaxanthin A 3-acetate and crassostreaxanthin B 3-acetate were first isolated and completely characterized by spectroscopic data. Furthermore, possible metabolic pathways of fucoxanthin in clams were proposed.