Chromatography of sphingolipids of human brain

Abstract

Sphingolipids of the brain were prepared by solvent extraction of the tissue or from mixed brain extracts subjected to mild alkaline hydrolysis. Their components were separated on silicic-acid columns. Through use of a gradient elution with a number of chloroform-methanol mixtures and pure methanol, satisfactory fractions were obtained in an 8-hour period. The elution patterns were constant and the recoveries of hexose and alkali-stable phosphorus high. Combined chemical, infrared, and paper chromatographic techniques were used for analysis. Pure galactocerebrosides were isolated and in some instances further characterized by gas-liquid chromatography of their fatty acid derivatives. Preliminary results suggest that cerebrosides containing normal acids are eluted earlier from silicic-acid columns than those containing hydroxylated acid. A ceramide was detected in the brain from a patient with multiple sclerosis and significant amounts of glucocerebrosides in the brain of an old patient. Dihydrocerebroside-like fractions and other not characterized sphingosine derivatives were found in some instances. Pure sphingomyelins were isolated from small amounts of brain tissue.