Anti-inflammatory activity and conformational behavior of a branched (1 leads to 3)-beta-D-glucan from an alkaline extract of Dictyophora indusiata Fisch.

A (1 leads to 6)-branched (1 leads to 3)-beta-D-glucan (T-5-N), isolated from a M sodium hydroxide extract of the fruit bodies of Dictyophora indusita Fisch., markedly exhibited anti-inflammatory effects on both carrageenan-induced edema and scalded edematous hyperalgesia in rat's hindpaws. The activities of T-5-N (25 mg/kg i.p. X 2) were more potent than those of phenylbutazone (25-50 mg/kg i.p. X 2). The conformational behavior of T-5-N was studied. Its molecular weight in neutral solution was about three times that in 0.25M sodium hydroxide. This finding, in addition to the results of optical rotatory measurement and complex-formation with Congo Red, indicated that T-5-N has an ordered, triple-helical structure in neutral or slightly alkaline solution (less than 0.15M NaOH), and has single chains in highly alkaline solution (greater than 0.25M NaOH). The conformational transition occurs at concentrations of sodium hydroxide in the range of 0.15-0.25M.