Structure and antinociceptive effects of β-D-glucans from Cookeina tricholoma

Structurally different water-insoluble (1 -> 3),(1 -> 6) beta-D-glucans were isolated from aqueous and alkaline extracts of the mushroom-forming ascomycete Cookeina tricholoma, a wild edible mushroom found in Brazilian Amazon forest. The structures showed different substitution patterns, which may influence their extractability and consequently their conformation in solution, and different M-w (4.3 x 10(5) Da, 3.7 x 10(5) Da and 8.2 x 10(5) Da, for ICW-Ct, IHW-Ct and IK2-ct, respectively). The main-chains are composed of (1 -> 3) -linked beta-D-Glcp units 0-6 substituted by side chains with different lengths of (1 -> 6)-linked beta-D-Glcp units (ICW-Ct and IHW-Ct) or by a combination of (1 -> 6) -linked beta-D-Glcp units and single units of beta-D-Glcp (IK2-ct). beta-D-glucans with similar Mw and showing only (1 6) -linked beta-D-Glcp units as side chains (ICW-Ct and IHW-Ct) showed significant inhibition of neurogenic pain, 69 +/- 11 and 57 +/- 11% at the dose of 10 mg kg(-1), respectively, in the model of nociception induced by intraplantar injection of formalin. (C) 2016 Published by Elsevier Ltd.