Correlation of branching structure of mushroom β-glucan with its physiological activities

beta-Glucans with a different degree of branching (DB) were prepared from three different mushrooms and their physiological properties were characterized in terms of branching structure. beta-Glucan with 29% DB from shitake mushroom was the most effective in inhibiting the growth of tumor cells and also producing nitric oxide compared to Chamsong-I (67% DB) and cauliflower (16% DB) beta-glucan. In addition, the beta-(1-6)-linked branches of beta-glucan from Chamsong-I mushroom were specifically hydrolyzed by enzymatic treatments to produce beta-glucan samples with various DB from 19 to 50%. As the DB of beta-glucan reduced, the inhibition of cancer cell growth and production of nitric oxide increased when the branching reached up to 32%, then decreased as the DB further reduced. Therefore, these results indicated that the branching structure of beta-glucan plays a crucial role in its antitumor effect and the antitumor effect could be enhanced by modulating critical branching structure of beta-glucan. (C) 2012 Elsevier Ltd. All rights reserved.