Structural characterisation and bioactivity of polysaccharides isolated from fermented Dendrobium officinale.

Backgound A polysaccharide was purified in this paper, which was acquired from the fermentation broth of Dendrobium officinale Kimura et Migo. This article aims to investigate the structural features and bioactivity of this polysaccharide. RESULTS: The polysaccharide was purified and the main polysaccharide fraction (i.e. DOP-1) was obtained. High-performance gel permeation chromatography (HPGPC) revealed that the molecular weight of DOP-1 is 447.48 KDa. There are galactose, glucose and mannose in DOP-1 via monosaccharide composition analysis, and their ratio was 1:1.79:6.71. Methylation and NMR spectroscopic analysis indicated that the backbone of DOP-1 is: →4)-α-D-Glcp-(1→4)-α-D-Manp-(1→4)-α-D-Manp-(1→4,6)-α-D-Manp-(1→, its repeating units were also preliminarily established. In vitro tests proved that DOP-1 not only protects RAW264.7 macrophages from the cytotoxic effect induced by lipopolysaccharide (LPS), but also inhibits cytokine (i.e. IL-6 and TNF-α) produced which are induced by LPS. DOP-1 demonstrated good scavenging activity in vitro toward 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals, as well as good metal chelating activity. Therefore, DOP-1 has potential applications in antioxidant. CONCLUSION: These findings strengthen that the structural characteristics of DOP-1 support its favourable biological activities and lay a strong foundation for further exploration of its structure-activity relationships and activity development and providing experimental data for the development and utilization of fermentation broth of D. officinale This article is protected by copyright. All rights reserved.