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

β-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. β-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) β-glucan. In addition, the β-(1-6)-linked branches of β-glucan from Chamsong-I mushroom were specifically hydrolyzed by enzymatic treatments to produce β-glucan samples with various DB from 19 to 50%. As the DB of β-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 β-glucan plays a crucial role in its antitumor effect and the antitumor effect could be enhanced by modulating critical branching structure of β-glucan.

► Branching degree (DB) of Chamsong-I mushroom β-glucan is enzymatically modified ► All β-glucans produce nitric oxide and inhibit cancer cell growth dose-dependently ► Modified β-glucan with 32% DB exhibits the most impressive anti-tumor activity ► Branching structure of β-glucan plays a crucial role in its antitumor activity