Purification and characterization of a glucan from Bacillus Calmette Guerin and the antitumor activity of its sulfated derivative

A water-soluble glucan, BCG-PASW, with a molecular weight of 2.10 x 10(4) Da, was separated from polysaccharide nucleic acid fraction of Bacillus Calmette Guerin (BCG-PSN) using DEAE-52 cellulose and Sephadex G-200 chromatography. Based on gas chromatography-mass spectrometry (GC-MS), fourier transform infrared (FT-IR) spectra, 1D and 2D nuclear magnetic resonance (NMR) spectroscopy techniques (COSY, HSQC and HMBC), BCG-PASW was found to be an alpha-D-glucan composed of alpha-D-(1 -> 4)-linked glucopyranosyl residues, with branches at O-6 consisting of non-reducing terminal alpha-D-Glcp approximately every eight residues. In vitro antitumor activity by MTS method, its sulfated derivative with a substitution degree of 0.59, could inhibite C666-1 nasopharyngeal carcinoma cells growth significantly. The results indicated that the sulfate content play a decisive role in the bioactivities of the polysaccharides. (C) 2015 Elsevier Ltd. All rights reserved.