Inhibitory effect of CDP, a polysaccharide extracted from the mushroom Collybia dryophila, on nitric oxide synthase expression and nitric oxide production in macrophages

The effect of Collybia dryophila polysaccharide (CDP), a (1→3), (1→4)-β-d-glucan extracted from the mushroom C. dryophila, was evaluated on nitric oxide (NO) production induced by lipopolysaccharide (LPS) and gamma interferon (IFNγ) or by LPS alone in RAW 264.7 cells. CDP significantly inhibited NO production in a dose-dependent manner without affecting cell viability. The inhibition of NO by CDP was consistent with decreases in both inducible nitric oxide synthase (iNOS) protein and mRNA expression suggesting that CDP exerts its effect by inhibiting iNOS gene expression. In addition, CDP at concentrations of 400 and 800 μg/ml was shown to significantly increase prostaglandin E2 (PGE2) production in LPS- and IFNγ-induced macrophages when compared to the control.