Determination of stereochemical configuration of the glycerol moieties in glycoglycerolipids by chiral phase high-performance liquid chromatography.
This study reports a simple and sensitive method for determining the absolute configuration of the glycerol moieties in glycoglycerolipids. The method is based on chiral phase high-performance liquid chromatography (HPLC) separations of enantiomeric di- and monoacylglycerols released from glycosyldi- and monoacylglycerols, respectively, by periodate oxidation followed by hydrazinolysis. The released di- and monoacylglycerols were chromatographed as their 3,5-dinitrophenylurethane (3,5-DNPU) and bis(3,5-DNPU) derivatives, respectively. The derivatives were separated on two chiral phases of opposite configuration, (R)- and (S)-1-(1-naphthyl)ethylamine polymers for diacylglycerols and N-(R)- -(1-naphthyl)ethylaminocarbonyl-(S)-valine and N-(S)-1 -(1-naphthyl)ethylamino-carbonyl-(R)-valine for monoacylglycerols. Clear enantiomer separations, which permit the assignment of the glycerol configuration, were achieved for sn-1,2(2,3)-diacyl- and sn-1(3)-monoacylglycerols generated from linseed oil triacylglycerols by partial Grignard degradation on all the chiral stationary phases employed. Using the method, we have determined the glycerol configuration in the glycosyldiacylglycerols (monogalactosyl-, digalactosyl-, and sulfquinovosyldiacylglycerols) and glycosylmonoacylglycerols (monogalactosyl-, digalactosyl-, and sulfoquinovosylmonoacylglycerols) isolated from spinach leaves and the coralline red alga Corallina pilulifera. The results clearly showed that the glycerol moieties in all the glycoglycerolipids examined have S-configuration (sn-1,2-diacyl- and sn-1-monoacylglycerols). The new method demonstrates that chiral phase HPLC provides unambiguous information on the configuration of the glycerol backbone in natural glycosyldi- and monoacylglycerols, and that the two-step liberation of the free acylglycerols does not compromise glycerol chirality.
Takahashi
Y
Y
Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan.
Itabashi
Y
Y
Suzuki
M
M
Kuksis
A
A
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004075:Diglycerides / Q000737:chemistry; D038983:Galactolipids; D005989:Glycerides / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry* / Q000302:isolation & purification; D006017:Glycolipids / Q000737:chemistry*; D008968:Molecular Conformation; D000461:Rhodophyta / Q000737:chemistry; D018724:Spinacia oleracea / Q000737:chemistry; D013237:Stereoisomerism
D004075:Diglycerides; D038983:Galactolipids; D005989:Glycerides; D006017:Glycolipids; C007388:digalactosyldiacylglycerol; C009909:monogalactosyldiacylglycerol; C013694:sulfoquinovosyl diglyceride; D005990:Glycerol