Structural determination of the oligosaccharides in the milk of an Asian elephant (Elephas maximus)

Milk of an Asian elephant (Elephas maximus), collected at 11 days post partum, contained 91 g/L of hexose and 3 g/L of sialic acid. The dominant saccharide in this milk sample was lactose, but it also contained isoglobotriose (Glc(α1-3)Gal(β1-4)Glc) as well as a variety of sialyl oligosaccharides. The sialyl oligosaccharides were separated from neutral saccharides by anion exchange chromatography on DEAE-Sephadex A-50 and successive gel chromatography on Bio Gel P-2. They were purified by high performance liquid chromatography (HPLC) using an Amide-80 column and characterized by 1H-NMR spectroscopy. Their structures were determined to be those of 3′-sialyllactose, 6′-sialyllactose, monofucosyl monosialyl lactose (Neu5Ac(α2-3)Gal(β1-4)[Fuc(α1-3)]Glc), sialyl lacto-N-neotetraose c (LST c), galactosyl monosialyl lacto-N-neohexaose, galactosyl monofucosyl monosialyl lacto-N-neohexaose and three novel oligosaccharides as follows: Neu5Ac(α2-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3)Gal(β1-4)Glc, Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3)Gal(β1-4)GlcNAc(β1-3)Gal(β1-4)Glc, and Neu5Ac(α2-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3)Gal(β1-4)Glc. The higher oligosaccharides contained only the type II chain (Gal(β1-4)GlcNAc); this finding differed from previously published data on Asian elephant milk oligosaccharides.