Isolation and structure of four new ceramides from the starfish Luidia maculata.  A new sphingosine-type ceramide LMCer-1-1 (1) and three new phytosphingosine-type ceramides, LMCer-2-1 (2), LMCer-2-6 (3), and LMCer-2-7 (4), were isolated from the anti-hyperglycemic active ceramide molecular species LMCer-1 and LMCer-2, obtained from the less polar fraction of the chloroform-methanol extract of the whole bodies of Luidia maculata. The structures of these ceramides were determined on the basis of chemical and spectroscopic evidence as: (2S,3R,4E,2''R)-2-(2-hydroxyhexadecanoylamino)-16-methyl-4-octadecene-1,3-diol (1), (2S,3S,4R,2''R)-2-(2-hydroxyhexadecanoylamino)-16-methyl-octadecane-1,3,4-triol (2), (2S,3S,4R,2''R)-2-(2-hydroxydocosanoylamino)-hexadecane-1,3,4-triol (3), and (2S,3S,4R,2''R)-2-(2-hydroxydocosanoylamino)-14-methyl-hexadecane-1,3,4-triol (4).