The
polysaccharides of Astragalus membranaceus have received extensive study and attention, but there have been few reports on the extraction of these
polysaccharides using cold water (4 °C). In this study, we fractionated a novel cold-water-soluble
polysaccharide (cAMPs-1A) from Astragalus membranaceus with a 92.00%
carbohydrate content using a
DEAE-cellulose 52
anion exchange column and a
Sephadex G-100 column. Our UV, Fourier-transform infrared spectroscopy (FTIR), high-performance gel permeation chromatography, and ion chromatography analysis results indicated the
monosaccharide composition of cAMPs-1A with 1.23 × 10⁴ Da molecular weight to be
fucose,
arabinose,
galactose,
glucose, and
xylose, with molar ratios of 0.01:0.06:0.20:1.00:0.06, respectively. The UV spectroscopy detected no
protein and
nucleic acid in cAMPs-1A. We used FTIR analysis to characterize the α-d-pyranoid configuration in cAMPs-1A. In addition, we performed animal experiments in vivo to evaluate the antitumor and immunomodulatory effects of cAMPs-1A. The results suggested that cAMPs-1A
oral administration could significantly inhibit
tumor growth with the inhibitory rate of 20.53%, 36.50% and 44.49%, respectively, at the dosage of 75,150, and 300 mg/kg. Moreover, cAMPs-1A treatment could also effectively protect the immune organs, promote macrophage pinocytosis, and improve the percentages of lymphocyte subsets in the peripheral blood of
tumor-bearing mice. These findings demonstrate that the
polysaccharide cAMPs-1A has an underlying application as natural
antitumor agents.