(264f) Synthesis of Water-Soluble Oligosaccharides As Potential Prebiotics Via Non-Enzymatic Sugar Glycosylation

Bioactive oligosaccharides have found promising applications as functional food, prebiotic compounds, immunostimulating agents, and pharmaceuticals. Oligosaccharides synthesis prevalently relies on biological methods such as enzymatic transglycosylation and controlled hydrolysis of polysaccharides. In this study, we demonstrated a novel non-enzymatic glycosylation method to produce water-soluble oligosaccharides in acidic lithium bromide trihydrate from monomeric sugars, in which new glycosidic bonds were formed between the C1 oxocarbenium on a protonated sugar and the hydroxyl groups (C2, C3 or C6) of another sugar. The oligosaccharide products were analyzed using HPIC, MALDI-TOF/MS, and NMR. The results indicated that up to 70% of the glucose could be converted to gluco-oligosaccharides. The resultant gluco-oligosaccharides were linked predominantly through α-1,6-glycosidic bonds with small qantity of β-1,6-, α-1,2-, and α-1,3-glycosidic bonds. Preliminary evaluation indicated that the oligosaccharides could be metabolized by gut microbiota; therefore, the oligosaccharides have the potential as prebiotics.