Phytochemical Studies on Paeoniae Radix (4);Cerebrosides and Other Constituents

A mixture of sixteen cerebrosides, which comprised four cerebroside molecular species (PL-1 ${\sim}$ PL-4) was separated from the roots of Paeonia lactiflora. The structures of cerebrosides were characterized as $1-O-{\beta}$-D-glucopyranosides of phytosphingosines, which comprised a common long-chain base, (2S,3S,4R,8E/Z)-2-amino-8-octadecene-1,3,4-triol with eight fatty acids or 2-hydroxy fatty acids of varying chain lengths ($C_{16}$, $C_{18}$, $C_{20-26}$) linked to the amino group. Aralia cerebroside and its 8Z isomer (PL-1), $1-O-{\beta}$-D-glucopyranosyl-(2S,3S, 4R,8E/Z)-2-[(2'R)-2'-hydroxytetracosanoylamino]-8-octadecene-1,3,4-triol (PL-2), $1-O-{\beta}$-D-glucopyranosyl-(2S,3S,4R, 8E/Z)-2-[(2'R)-2'-hydroxydocosanoylamino]-8-octadecene-1,3,4-triol (PL-3), and $1-O-{\beta}$-D-glucopyranosyl-(2S,3S,4R, 8E/Z)-2-[(2'R)-2'-hydroxytricosanoylamino]-8-octadecene-1,3,4-triol (PL-4) were identified as major components of these cerebroside molecular species. All the major cerebrosides were shown to be a mixture of geometrical isomers (8E and 8Z) of phytosphingosine-type glucocerebrosides possessing 2R-hydroxy fatty acids. In addition, three ${\beta}-sitosterol$ derivatives and adenosine were also separated. The structures of these isolates have been determined on the basis of chemical and spectroscopic evidence.