Characterization of Glycosyl Inositol Phosphoceramides from Panax ginseng using Nanospray Tandem Mass Spectrometry

Korean ginseng (Panax ginseng C. A. Meyer) is one of the most popular medicinal herbs in the world. This plant is known to have many health benefits and contain a wide variety of bioactive components. However, the knowledge on its lipid compound is still far from being fully explored. Although glycosyl inositol phosphoceramides (GIPCs) are the main sphingolipids in plant tissues, GIPCs of P. ginseng are unknown. The present study employed nanoESI-MSSUPn/SUP, which generated characteristic fragmentation pattern that were used for the structural identification of P. ginseng GIPCs. In addition to detecting a typical mass fragmentation pattern for GIPC in positive ion mode, novel fragmentation correlating with cleavage of the last carbohydrate and fatty acyl chain of the ceramide moiety was identified. In total, 42 GIPC species were detected in P. ginseng. The major P. ginseng GIPC structure was hexose (R₁)-hexuronic acid-inositol phosphoceramide, with three types of R₁ (amine, N-acetylamine, or hydroxyl). The most intense peak was found at m/z 1136.3 ([M+H]SUP+/SUP ion), corresponding to a GIPC (d18:0/h16:0, R₁ = OH). Only three GIPC subtypes showed significantly different levels in five- and six-year-old P. ginseng tap roots.