title: Isotopic labeling of milk disialogangliosides (GD3).
abstract: The most abundant ganglioside group in both human milk and bovine milk during the first postnatal week is ganglioside GD3. This group of disialogangliosides forms up to 80% of the total ganglioside content of colostrum. Although dietary gangliosides have shown biological activity such as improvement of cognitive development, gastrointestinal health, and immune function, there is still a gap in our understanding of the molecular mechanisms governing its uptake and the metabolic processes affecting its bioavailability. The use of isotopically labeled ganglioside to track the bioavailability, absorption, distribution, and metabolism of gangliosides may provide key information to bridge this gap. However, isotope labeled GD3 is not commercially available and its preparation has not been described. We report for the first time the preparation of labeled GD3 with stable isotopes. Using alkaline hydrolysis, we were able to selectively remove both acetyl groups from the tetrasaccharide portion of GD3 without promoting significant hydrolysis of the ceramide portion of the molecule to generate N-deacetyl-GD3 (Neu5α2-8Neu5-GD3). The N-deacetyl-GD3 was then chemoselectively re-acetylated in aqueous medium using deuterated acetic anhydride in the presence of Triton X 100 to produce2H6-GD3 {GD3[(Neu5Ac-11-2H3)-(Neu5Ac-11-2H3)]}. This method provided2H6-GD3 with approximately 60% yield. This compound was characterized by proton nuclear magnetic resonance (1H NMR) and liquid chromatography mass spectrometry (LC-MS). The oral absorption of the2H6-GD3 was demonstrated using a Sprague-Dawley weaning rats. Our results indicate that some ingested labeled milk gangliosides are absorbed and transported into the bloodstream without modification.
authors: Dairy Foods Team, Food & Bio-based Products Group, AgResearch Ruakura, Hamilton 3240, New Zealand. Electronic address: Mariza.GomesReis@agresearch.co.nz.
authors: Mariza Gomes
authors: MG
authors: Reis
authors: Food Nutrition & Health Team, Food & Bio-based Products Group, AgResearch Grasslands, Palmerston North 4442, New Zealand.
authors: Rodrigo
authors: R
authors: Bibiloni
authors: Fonterra Research and Development Centre, Palmerston North 4442, New Zealand.
authors: Paul
authors: P
authors: McJarrow
authors: Fonterra Research and Development Centre, Palmerston North 4442, New Zealand.
authors: Alastair
authors: A
authors: MacGibbon
authors: Fonterra Research and Development Centre, Palmerston North 4442, New Zealand.
authors: Bertram
authors: B
authors: Fong
authors: Food Nutrition & Health Team, Food & Bio-based Products Group, AgResearch Grasslands, Palmerston North 4442, New Zealand.
authors: Shalome
authors: S
authors: Bassett
authors: Food Nutrition & Health Team, Food & Bio-based Products Group, AgResearch Grasslands, Palmerston North 4442, New Zealand; Riddet Institute, Massey University, Palmerston North 4442, New Zealand.
authors: Nicole
authors: N
authors: Roy
authors: Food Assurance & Meat Quality Team, Food & Bio-based Products Group, AgResearch Ruakura, Hamilton 3240, New Zealand.
authors: Marlon Martins
authors: MM
authors: Dos Reis
mesh_terms: D065966:Absorption, Physicochemical; D000284:Administration, Oral; D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid; D005732:Gangliosides / Q000008:administration & dosage / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D007553:Isotope Labeling; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005732:Gangliosides; C025447:sialogangliosides
keywords: Absorption; Deuterium; GD3; Ganglioside; Isotopic labeling; Milk; Oral