Analysis of Acanthopanax giraldii Harms Polysaccharide II Composition and Its Immune-Protective Role in a Cyclophosphamide-Induced Immunosuppressive Mice Model

Acanthopanax giraldii Harms is commonly used in traditional Chinese medicine to treat rheumatism, improve joints, and strengthen muscles and bones. The polysaccharides present in A. giraldii Harms contain major bioactive substances, which have antioxidant, anticancer, and antiviral activities. In this study, the structural characterization of the homogeneous polysaccharide isolated from A. giraldii Harms, known as AHP-II, and its immunomodulatory effects in vivo will be studied. High-performance ion chromatography (HPIC) and high-performance gel permeation chromatography (HPGPC) based analyses revealed that AHP-II was composed of various monosaccharides, which included rhamnose, arabinose, galactose, glucose, mannose, galacturonic acid, and glucuronic acid in molar ratios of 29.5 : 24.6 : 23.8 : 4.4 : 5.7 : 8.8 : 3.1, respectively, and had a collective molecular weight of 80.21 × 10 3  Da. Fourier-transform infrared (FTIR) spectroscopy indicated the presence of a pyranose ring and β -type glycosidic linkages in AHP-II. In addition, immunomodulatory effect analyses of AHP-II that used a cyclophosphamide-induced immunosuppressive mouse model demonstrated that its treatment could significantly restore spleen and thymus indices, promote the proliferation of splenic lymphocytes, elevate CD4 + T lymphocyte percentage and CD4 +  : CD8 + ratio in the spleen, promote macrophage phagocytosis, and restore cytokines (IL-6, TNF- α , IgM, and IgG) levels. These results suggested that AHP-II could potentially be used as natural immunomodulator and as an alternative treatment to reduce chemotherapy-induced immunosuppression.