Composition and immunomodulatory activity of neutral and acidic polysaccharides isolated from Epimedii Folium

Abstract

Epimedii Folium possesses many pharmacological activities including immunomodulation, anti-oxidation, and anti-tumor. Polysaccharides are the main components of Epimedii Folium, and their activities are closely related to the structure. The present study isolated a neutral polysaccharide(EPS-1-1) and an acidic polysaccharide(EPS-2-1) from the aqueous extract of Epimedii Folium through DEAE-52 cellulose anion-exchange chromatography and Sephadex G-100. The structures were characterized by chemical composition analysis, high-performance gel permeation chromatography(HPGPC), Fourier-transform infrared spectrometry(FT-IR), 1-phenyl-3-methyl-5-pyrazolone(PMP) derivatization, scanning electron microscopy(SEM), Congo red test, etc. The immunomodulatory activity of polysaccharides in vitro was determined by investigating the effects on the maturation of bone marrow-derived dendritic cells(BMDCs) and the release of inflammatory cytokines. According to the structural characterization analysis, EPS-1-1 was composed of fructose(Fuc), mannose(Man), ribose(Rib), rhamnose(Rha), glucose(Glc), galactose(Gal), xylose(Xyl), and arabinose(Ara) at 1.90∶0.67∶0.05∶0.08∶3.29∶1.51∶0.05∶0.37(molar ratio), while EPS-2-1 was mainly composed of Fuc, Man, Rha, glucuronic acid(GlcA), galacturonic acid(GalA), Glc, Gal, Xyl, and Ara at 5.25∶0.18∶0.32∶0.13∶1.14∶0.16∶0.55∶0.08∶0.2. EPS-1-1 and EPS-2-1 could promote the maturation and function of BMDCs through up-regulating the expression of MHC-Ⅱ, CD86, CD80, and CD40, and increasing the levels of inflammatory cytokines(IL-6, IL-12, and TNF-α) in vitro experiments, which suggested that EPS-1-1 and EPS-2-1 possessed good immunomodulatory activity.