Chemical characterisation of the oligosaccharides in hooded seal (Cystophora cristata) and Australian fur seal (Arctocephalus pusillus doriferus) milk

Carbohydrates were extracted from hooded seal milk, Crystophora cristata (f amily Phocidae). Free oligosaccharides were separated by gel filtration and then purified by ion exchange chromatography, gel filtration and preparati ve thin layer or paper chromatography and their structures determined by H- 1-NMR. The hooded seal milk was found to contain inositol and at least nine oligosaccharides, most of which had lacto-N-neotetraose or lacto-N-neohexa ose as core units, similar to those in milk of other species of Carnivora s uch as bears (Ursidae). Their structures were as follows: Gal(beta1-4)Glc ( lactose); Fuc(alpha1-2)Gal(beta1-4)Glc (2'-fucosyllactose); Gal(beta1-4)Glc NAc(beta1-3)Gal(beta1-4)Glc (lacto-N-neotetraose); Fuc(alpha 1-2)Gal(beta 1 -4)GlcNAc(beta 1-3)Gal(beta1-4)Glc (lacto-N-fucopentaose IV); Gal(beta1-4)G lcNAc(beta1 3)[Gal(beta1-4)GlcNAc(beta1-6)]Gal(1-4)Glc (lacto-N-neohexaose) ; Fuc(alpha1-2)Gal(beta1-4)GIcNAc(beta1-3)[Gal(beta1-4)GlcNAc(beta1-6)]Gal( beta1-4)Glc (monofucosyl lacto-N-neohexaose a); Gal(beta1-4)GlcNAc(beta1-3) [Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-6)]Gal(beta1-4)Glc (monofucosyl lact o-N-neohexaose b); Fuc(alpha1-2)Gal(beta1-4)GlcNAc(beta1-3)[Fuc(alpha1-2)Ga l(beta1-4)GlcNAc(beta1-6)Gal(beta1-4)Glc (difucosyl lacto-neohexaose);Gal(b eta1-4)GlcNAc(beta1-3)Gal(beta1-4)GlcNAc(beta1-3)Gal 4)Glc(para lacto-N-neo hexaose); Fuc(alpha1-2)Gal(beta1-4)GLcNAc(beta1-3)Gal(beta1-4)GlcNAc(beta1- 3)Gal(beta1-4)Glc (monofucosyl para lacto-N-neohexaose). Milk of the Austra lian fur seal, Arctophalus pusillus doriferus (family Otariidae) contained inositol but no lactose or free oligosaccharides. These results, therefore, support the hypothesis that the milk of otariids, unlike that of phocids, contains no free reducing saccharides, (C) 2001 Elsevier Science Inc. All r ights reserved.