Chemical Structure and Morphological Features of A Polysaccharide BHP-1 Purified from Bulbs of Lilium davidii var. unicolor / 中国实验方剂学杂志

ABSTRACT

Objective:To study the chemical structure and morphological features of a polysaccharide BHP-1 isolated and purified from the bulbs of Lilium davidii var. unicolor. Method:Thermogravimetry (TG) and scanning electron microscopy (SEC) was used to determine the thermal characteristics and the surface morphology changes of the polysaccharide BHP-1, respectively. The chemical structure of BHP-1 was analyzed by gas chromatography-mass spectrometer (GC-MS), partial acid hydrolysis, sodium periodate oxidation-Smith degradation and nuclear magnetic resonance (NMR). Result:The results showed that the backbone of the polysaccharide BHP-1 mainly contained α-(1→4)-linked D-glucopyranosyl and β-(1→4)-linked D-mannopyanosyl, and the branches were probably linked at the O-2 and/or O-3 of the mannosyl and glucosyl residues, with T-α-D-glucopyranosyl as a terminal structure. It was a natural mannoglucose containing a small amount of O-acetyl group. BHP-1 began to degrade at 220 °C, and the degradation ended at 520 ℃, indicating a good thermal stability, smooth surface and a large number of depressions. The depressions were formed by closely interlaced and sunken sheet layers with irregular holes. Conclusion:BHP-1 was a natural mannoglucose with a good thermal stability, smooth surface, a large number of depressions and irregular holes, and contained a small amount of O-acetyl group. Its chemical structure was reported for the first time.