A branched galactoglucan from Lysimachia christinae: Structural characterization, immunoregulatory and anti-oxidant bioactivities in vitro and in vivo

Abstract

Lysimachia christinae, revered as a traditional tea plant in China, is notable for diverse biological activities. However, a comprehensive characterization of its polysaccharides and their biological activities has been largely unexplored. Herein, a galactoglucan was extracted and purified from L. christinae to assess its immunoregulatory and anti-oxidant activities both in vitro and in vivo. The crude polysaccharide was extracted via hot water extraction, ethanol precipitation, and Sevage deproteinization, followed by purification using AB-8, DEAE-52, and Superdex G-200 chromatography to obtain the polysaccharide, namely LCNP. GC–MS and NMR analyses confirmed that LCNP was primarily composed of →4)-Glcp-(1→, accounting for 49.1 % of its structure. In vitro experiments demonstrated that LCNP possesses anti-inflammatory effects, mainly protects L02 and HepA cells from lithocholic acid-induced damage by increasing SOD and GSH contents, protects Caco-2 cells from apoptosis, reduces the production of NO and inflammatory cytokines in macrophages. Furthermore, LCNP stimulated the proliferation of lymphocytes, concurrently leading to upregulating the generation of IL-10 and CD4⁺/CD8⁺ratio in lymphocytes. In mouse, oral administration of LCNP protected the liver and intestines, reduced inflammatory mediators LPS, IL-1β, and IFN-γ, increased the content of IL-10, SOD, CAT, and GSH, and upregulated the CD4⁺/CD8⁺ ratio. Collectively, this study has successfully isolated and characterized a branched galactoglucan from L. christinae, and verified LCNP could protect hepatic cells and reduce the production of inflammatory mediators in macrophages in vitro. Oral administration of LCNP reduced inflammatory mediators and increased the content of IL-10, making it a candidate for practical applications.