New Ceramides and Cerebrosides from the Deep-Sea Far Eastern Starfish Ceramaster patagonicus .

Three new ceramides ( 1 - 3 ) and three new cerebrosides ( 4 , 8 , and 9 ), along with three previously known cerebrosides (ophidiocerebrosides C ( 5 ), D ( 6 ), and CE-3-2 ( 7 )), were isolated from a deep-sea starfish species, the orange cookie starfish Ceramaster patagonicus . The structures of 1 - 4,   8 , and 9 were determined by the NMR and ESIMS techniques and also through chemical transformations. Ceramides 1 - 3 contain iso- C 21 or C 23 Δ 9 -phytosphingosine as a long-chain base and have C 16 or C 17 (2 R )-2-hydroxy-fatty acids of the normal type. Cerebroside 4 contains C 22 Δ 9 -sphingosine anteiso- type as a long-chain base and (2 R )-2-hydroxyheptadecanoic acid of the normal type, while compounds 8 and 9 contain saturated C-17 phytosphingosine anteiso- type as a long-chain base and differ from each other in the length of the polymethylene chain of (2 R )-2-hydroxy-fatty acids of the normal type: C 23 in 8 and C 24 in 9 . All the new cerebrosides ( 4 , 8 , and 9 ) have β-D-glucopyranose as a monosaccharide residue. The composition of neutral sphingolipids from C. patagonicus was described for the first time. The investigated compounds 1 - 3 , 5 - 7 , and 9 exhibit slight to moderate cytotoxic activity against human cancer cells (HT-29, SK-MEL-28, and MDA-MB-231) and normal embryonic kidney cells HEK293. Compounds 2 , 5 , and 6 at a concentration of 20 µM inhibit colony formation of MDA-MB-231 cells by 68%, 54%, and 68%, respectively. The colony-inhibiting activity of compounds 2 , 5 , and 6 is comparable to the effect of doxorubicin, which reduces the number of colonies by 70% at the same concentration.