Chemical composition and immuno-stimulating properties of polysaccharide biological response modifier isolated from Radix Angelica sinensis

To investigate the immunomodulating activity of Radix Angelica sinensis, three different Radix A. sinensis polysaccharide fractions (APFs, namely APF1, APF2 and APF3) were isolated by fractionation using gel filtration and were identified as the immunomodulators of murine peritoneal macrophages. In the present study, it was found that various APFs induced a significant increase in cellular lysosomal enzyme activity, nitric oxide (NO) formation, reactive oxygen species (ROS) production and tumor necrosis factor-α (TNF-α) secretion in macrophages in vitro. Furthermore, APFs dose-dependently stimulated macrophages to produce NO through the up-regulation of inducible NO synthase (iNOS) activity and the maximal effect occurred at a concentration of 500 μg/ml by APF2, followed by APF3 and APF1 in decreasing order. Moreover, the predominant sugars in various APFs were identified as rhamnose, arabonose, glucose, galactose and the ratio of these monosaccharides differed from one polysaccharide fraction to another, which also affected the cellular effector molecule production in macrophages.