Structural characterization and immunoregulatory activity of a novel heteropolysaccharide from bergamot (Citrus medica L. var. sarcodactylis) by alkali extraction

摘要

Bergamot is an ornamental plant and important traditional Chinese herbal medicine of tremendous value in economic and medicinal applications, mainly distributed in southern and southeastern China. Polysaccharide is one of active components of bergamot. In this study, CMSPB80 was extracted from bergamot by alkali solution and purified by DEAE Sepharose fast flow and Sephadex G-75 column to obtain a homogeneous heteropolysaccharide (CMSPB80-1), with a molecular weight of 103 kDa. Ion chromatography analysis indicated that CMSPB80-1 was composed of -> 3)-alpha-L-Rhap-(1 ->, -> 5)-alpha-L-Araf-(1 ->, -> 3,6)-alpha-D-Manp.(1 ->, -> 3)-beta-D-Galp-(1 ->, -> 4,6)-alpha-D-Glcp-(1 ->, -> 6)-beta-D-Galp-(1 -> and a terminal alpha-D-Glcp. Scanning electron microscope (SEM) demonstrated that CMSPB80-1 was rough with a sheet-like and irregular structure. Atomic force microscopy (AFM) displayed CMSPB80-1 was branched and entangled with globular aggregates instead of a triple-helix structure. In addition, in vitro activity of CMSPB80-1 was evaluated by neutral red up-take assay and production of nitric oxide (NO) assay, which provided evidence that CMSPB80-1 could enhance macrophage phagocytiosis and promote splenocyte lymphocytes proliferation. The results proposed that CMSPB80-1 was suitable for health care and food/pharmaceutical industries as an immunoregulatory activity ingredient.