A new glucomannan from Bletilla striata: Structural and anti-fibrosis effects

A novel water-soluble polysaccharide, designated Bletilla striata polysaccharide b (BSPb), was isolated from a traditional Chinese medicinal herb, Bletilla striate. The crude polysaccharide was obtained by hot water extraction and purified by ion-exchange chromatography. The molecular weight was 260 kDa as determined by HPGPC (high performance gel permeation chromatography). Monosaccharide analysis showed that BSPb contained glucose and mannose with a molar ratio of 3:1. Methylation and spectroscopic analyses with 1D and 2D NMR spectroscopy showed that the backbone of BSPb is mainly composed of (1 -> 2)-linked alpha-D-mannopyranose and (1 -> 4)-linked beta-D-glucopyranose residues. In this study, BSPb plays an important role in protection against the renal fibrosis effect, which is probably mediated by down-regulated TGF-beta RI, TGF-beta RII, and alpha-SMA in vitro. (C) 2013 Elsevier B.V. All rights reserved.