Structural characteristics of a hyperbranched acidic polysaccharide from the stems of Ephedra sinica and its effect on T-cell subsets and their cytokines in DTH mice

An acidic hetero-polysaccharide (ESP-B4) was acquired from the stems of Ephedra sinica. Its structure was characterized by periodate oxidation, Smith degradation, partial acid hydrolysis, methylation analysis combined with HPCE, GC–MS and FT-IR spectra. The results indicated that ESP-B4 contained a repeating unit of [→4)-GalpA-(1→2)-Rhap-(1→] as hairy region, substituted by arabinose, xylose, galactose, glucose, mannose and glucuronic acid. To better understand the mechanism of bioactivity for this compound, the quantities of ESP-B4 was further enriched by ion exchange and gel filtration chromatography. Immunological tests in vivo showed that ESP-B4 exhibits compelling immunosuppressive effects by hematoxylin and eosin staining, enzyme-linked immunosorbent assay and flow cytometric analysis. The mechanism of action might be attributed to its inhibition of IL-2 and IL-4 levels in serum, and also effectively suppressed the ratio of CD4+/CD8+ in serum of T cell mediated delayed-type hypersensitivity mice. The results suggest that ESP-B4 could be a valuable lead material for immunosuppressive drug development.