Structure characterization and antitumor activity of an alpha beta-glucan polysaccharide from Auricularia polytricha

A fraction of a 0.05 M NaOH solution-soluble polysaccharide, termed AAFRC, was obtained from Auricularia polytricha by protease-assisted aqueous extraction followed by precipitation with ethanol and purification with gel filtration chromatography. Analysis by high performance liquid chromatography (HPLC) coupled to a TSK-G5000PW(XL), column and gel filtration chromatography on Sephacryl S-400HR indicated that AAFRC is homogenous with an average molecular weight (Mw) of about 1.20x 10(6) Da. The structure of AAFRC was revealed by chemical methods including Fourier transform infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. Results indicated that AAFRC is a glucan consisting 1,3-beta-glucan, 1,4-alpha-glucan, and 1,3-alpha-glucan backbone with a single 1 ->)-alpha-D-glucopyranosyl side-branching unit on every six residues, on average, along the main chain. The growth of transplantable Sarcoma-180 (S-180) in mice was also significantly inhibited by AAFRC compared with the model controls (P<0.01), with the inhibitory rate being 43.61%. (C) 2011 Elsevier Ltd. All rights reserved.