Isolation, purification, and structural elucidation of polysaccharide CALB-1 from Aurantii Fructus and study on its immunoregulatory activity / 中草药

ABSTRACT

To separate and purify the crude polysaccharide from Aurantii Fructus to obtain CALB-1 and to study the structure of CALB-1 and immunoregulatory activity. A refined CALB-1 was obtained from F. aurantii by hot water extraction, then separated and purified by ion exchange resin and ion exchange agarose gel. The molecular weight of CALB-1 was measured by HPLC. The chemical structure and molecular morphology of CALB-1 were determined by IR, periodate oxidation, methylation analysis, scanning electron microscopy (SEM), and atomic force microscope (AFM). The immunoregulatory activity of CALB-1 was evaluated by splenocyte proliferation and mononuclear-macrophage phagocytic function in hypo-immunologic mice. CALB-1 was a homogeneous polysaccharide measured by HPLC and the molecular weight of CALB-1 was estimated to be 3.28 × 107. Chemical and spectroscopic analyses illustrated that CALB-1 was highly branched acidic polysaccharides, contained Ara, Man, and Gal as monosaccharide constitutes, and it consisted of backbone chain of 1→ and 1→4 linkages. Through SEM and AFM observations, we indicated that the molecular morphology of CALB-1 was amorphous solid. Besides, CALB-1 significantly stimulated the splenocyte proliferation in vitro and improved the K value of expurgation index and α value of phagocytic index in hypo-immunologic mice. CALB-1 is highly branched acidic polysaccharides and uniform relative molecular mass. Moreover, CALB-1 could present the certain immune regulation in vivo and in vitro. Our study provides a theoretical basis for the development and utilization of CALB-1.