Structural determination of glucosylceramides isolated from marine sponge by fast atom bombardment collision‐induced dissociation linked scan at constant B/E

Abstract

Five glucosylceramides (GlcCers) were isolated by reversed phase high-performance liquid chromatography from the MeOH extracts of a marine sponge, Haliclona (Reniera) sp., collected from the coast of Ulleung Island, Korea, and analyzed by fast atom bombardment mass spectrometry (FAB-MS) in positive-ion mode. FAB-mass spectra of these compounds included protonated molecules [M + H](+) and abundant sodiated molecules [M + Na](+) from a mixture of m-NBA and NaI. The structures of these GlcCers, which were similar, were elucidated by FAB-linked scan at constant B/E. To find diagnostic ions for their characterization, the GlcCers were analyzed by collision-induced dissociation (CID) linked scan at constant B/E. The CID-linked scan at constant B/E of [M + H](+) and [M + Na](+) precursor ions resulted in the formation of numerous characteristic product ions via a series of dissociative processes. The product ions formed by charge-remote fragmentation provided important information for the characterization of the fatty N-acyl chain moiety and the sphingoid base, commonly referred to as the long-chain base. The product ions at m/z 203 and 502 were diagnostic for the presence of a sodiated sugar ring and beta-D-glucosylsphinganine, respectively. For further confirmation of the structure of the fatty N-acyl chain moiety in each GlcCer, fatty acid methyl esters were obtained from the five GlcCers by methanolysis and analyzed by FAB-MS in positive-ion mode. On the basis of these dissociation patterns, the structures of the five GlcCers from marine sponge were elucidated. In addition, the accurate mass measurement was performed to obtain the elemental composition of the GlcCers isolated from marine sponge.

Sphingolipidomics: An Important Mechanistic Tool for Studying Fungal Pathogens

“…Several different ionization methods have been used in sphingolipid analysis, for example, the ESI ( Han and Gross, 1994 ), MALDI ( Jones et al, 2014 ), and FAB ( Ahn et al, 2009 ). These ionization techniques are coupled with mass analyzers like MS/MS ( Shaner et al, 2009 ), MS n ( Ito et al, 2013 ), TOF ( Jia et al, 2015 ), FT-ICR ( Guo et al, 2012 ), and QqTOF MS ( Ejsing et al, 2006 ).…”

Natural Products from the Marine Sponge Subgenus Reniera

“…This was the first report on the isolation of isomeric pairs of glucocerebrosides containing saturated C 15 and C 19 acyl chains. Lately, the structural determination of compounds 109 – 112 , 115 , 116 , 120 , and 121 were well established using fast atom bombardment mass spectrometry (FAB-MS) in positive-ion mode by Hong and coworkers [ 53 ]. In addition, one ceramide ( 123 ) was separated from the same sponge SPV06/12/13 collected off Samalona Island, and its absolute structure was determined by HyperChem computational techniques [ 49 ].…”

Mass Spectrometry Methodology in Lipid Analysis

“…Fast atom bombardment (FAB) has been widely used to identify the structure of nonvolatile lipids, including fatty acids [40], monoacylglycerols [41], glycerophospholipids [42,43] and sphingolipids [44,45]. However, given the complexity of lipid extracts and the inconvenience when conjugating the chromatography and FAB MS, intensive efforts need to be carried out to effectively quantitatively analyze lipids by FAB MS.…”