Cerebrosides and tocopherol trimers from the seeds of Euryale ferox

Two new cerebrosides, ferocerebrosides A (1) [(2S,3R,4E,8E,2'R)-1-O-(beta-glucopyranosyl)-N-(2'-hydroxydocosanoyl)-4,8-sphingadienine] and B (2) [(2S,3R,4E,8E,2'R)-1-O-(beta-glucopyranosyl)-N-(2'-hydroxytetracosanoyl)-4,8-sphingadienine], two new tocopherol trimers, ferotocotrimers C (5) and D (6), and two known tocopherol trimers, IVb (3) and IVa (4), were isolated from the seeds of Euryale ferox. Their structures were determined on the basis of spectroscopic data, especially 1D and 2D NMR experiments. Compounds 1 and 2 showed cytotoxicity in the brine shrimp lethality bioassay, with LC50 values of 0.17 and 0.20 mM, respectively.