Macrophage activation induced by the polysaccharides isolated from the roots of Sanguisorba officinalis

Abstract

Context: Macrophage, involved at all stages of immune response, is an important component of the host defense system. Polysaccharides exist almost ubiquitously in medical plants and most of them possess immunomodulation and macrophage activation properties.Objective: This study elucidates the effects on macrophage activation and molecular mechanism induced by the polysaccharides (SOPs) from the roots of Sanguisorba officinalis Linne (Rosaceae).Materials and methods: Polysaccharides (SOPs) from the roots of S. officinalis were obtained by water extraction and ethanol precipitation. Physicochemical characterization of SOPs was analyzed by phenol–sulfuric acid, m-hydroxydiphenyl, Bradford method, and gas chromatography. Phagocytic capacity of RAW 264.7 macrophages incubated with SOPs (25 and 100 μg/ml) was determined by the aseptic neutral red method. Macrophages were incubated with SOPs (25 and 100 μg/ml), and the TNF-α and NO the secretion were measured using ELISA kit and Griess reagent, respectively. In addition, TNF-α and iNOS transcripts were evaluated by semi-quantitative RT-PCR, and NF-κB signaling activation was detected by Western blot assay.Results: SOPs enhanced the phagocytosis capacity of macrophages to aseptic neutral red solution and increased TNF-α and NO secretion. The amounts of TNF-α and iNOS transcript were increased significantly at the mRNA level when macrophages were exposed to SOPs. Meanwhile, the stimulation of macrophages by SOPs induced phosphorylation of p65 at serine 536 and a marked decrease of IκB expression.Discussion and conclusion: These results suggested that SOPs exhibited significant macrophage activation properties through NF-κB signaling pathway and could be considered as a new immunopotentiator.