Production and identification of intricate bioactive oligosaccharides from Nyctanthesarbor-tristis leaves by a combination of enzymatic, HPAEC and MALDI-TOF-MS techniques

Abstract

Nondigestible oligosaccharides are associated with positive health outcomes; however, hemicellulosic oligosaccharides of N. arbor-tristis have not been studied. Herein we report production hemicellulosic oligosaccharides from its leaves and their identification. A series of complex neutral oligosaccharides (1-16), produced by endo-(1,4)-b-d-cellulase digestion of the alkali extracted xyloglucan, were identified by chemical, HPAE chromatographic and MALDI mass spectrometric techniques. Additionally, xylan enriched hemicellulose-A fraction upon endo-(1,4)-b-d-xylanase digestion yielded several acidic and neutral xylo-oligosaccharides (17-24), each containing a backbone of b-(1,4)-d-Xylp units substituted at position 2 with a single stub of d-Xylp and 4-O-Me-d-GlcpA residues. The structural diversity and high-water solubility of these enzyme-generated oligosaccharides implied promising health implication.