Isolation, NMR and mass spectral studies of a novel pentasaccharide from goat milk

Carbohydrates are the most abundant and diverse biomolecules that play important roles in various biological processes, including inflammation and immune response, angiogenesis and metastasis of cancer cells, viral and bacterial infections, and many other cell-cell communications. Oligosaccharides are the carbohydrate that contains 2-10 units of monosaccharides and have varied biological activities such as biological recognition, anti-complementary, anti-coagulant, anti-inflammatory, anti-viral, anti-bacterial, anti-tumor, anti-oxidant, lipid lowering, immunological, prebiotic and hypoglycemic activities. Goat milk oligosaccharides have anti-inflammatory properties and are involved in the repairing process after a dextran sodium sulphate-induced colitis. Keeping in mind the biological importance of goat milk oligosaccharides, in the present studies, goat milk was analyzed for its oligosaccharide content which led to the isolation of a novel oligosaccharide, nubiose, C36H61O26N3. The structure of the isolated oligosaccharide was elucidated by chemical transformation, chemical degradation, 1H, 13C, 2D-NMR (COSY, TOCSY, HMBC and HSQC) and mass spectrometry as under.