Preparation and characterization of four new variously deacetylated lysogangliosides, breakdown products of GM1.

Four new deacylated lysogangliosides were obtained through alkaline hydrolysis of either C18 or C20 sphingosine homologues of GM1. By this procedure, both the fatty acids residue and the N-acetyl group of sialic acid were removed to give mono-N-acetyl-lysoGM1 (C18 and C20); the additional loss of the N-acetyl group of the acetylgalactosamine moiety gave de-N-acetyl-lysoGM1 (C18 and C20) with three free amino groups. The structures of four deacetylated lysogangliosides were unambiguously characterized by chemical analysis and 1H and 13C NMR spectroscopy as well as by negative ion FABMS. The aim of this study was to isolate pure breakdown products of gangliosides, enabling the evaluation of the mechanism of action of glycosphingolipids through their cleavage and identification of structures of potential pharmacological activity. These new substances were prepared as candidates to influence eicosanoid production and the mechanisms dependent on protein kinase C and phospholipase A2.