1(Key Laboratory of Carbohydrate Chemistry and Biotechnology(Jiangnan University), Ministry of Education, Wuxi 214122,China); 2(School of Biotechnology, Jiangnan University, Wuxi 214122, China); 3(Department of Radiology,Wuxi Second Hospital Affiliated to Nanjing Medical University,Wuxi 214002,China)
Abstract: A water-soluble crude polysaccharide named as APS was isolated from the roots of Mongolia Astragalus membranaceus by hot water extraction and its in vitro prebiotic activity was tested. After purification, two main polysaccharides (APS-1 and APS-2) with relative molecular masses of 38.4 kDa and 5.2 kDa were collected. Their structural characteristics were investigated by high performance gel filtration chromatography (HPGFC), ion chromatography (IC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy(1H-NMR). Based on the data obtained, APS-1 was mainly composed of galactose and glucose with a molar ratio of 1:49.76. APS-2 was mainly composed of rhamnose, galactose and glucose with a molar ratio of 1:2.99:16.26. APS-1 was found to be mainly composed of α-type glycosidic bonds while APS-2 contained both α-type glycosidic bonds and β-type glycosidic bonds. When APS (5 g/L) was fermented by human feces, the pH of the medium decreased from 7.49 (0 h) to 5.88 (48 h), and the contents of total short-chain fatty acids (SCFA), acetic acid, propionic acid, and butyric acid were all significantly increased. The results showed that APS had great prebiotic activity to human intestinal microbes.
GIBSON G R, PROBERT H M, LOO J V, et al. Dietary modulation of the human colonic microbiota: updating the concept of prebiotics[J]. Nutrition Research Reviews, 2004, 17(2): 259-275.
LAYDEN B T, ANGUEIRA A R, BRODSKY M, et al. Short chain fatty acids and their receptors: new metabolic targets[J]. Translational Research, 2013, 161(3): 131-140.
[6]
GULLON B, GULLON P, TAVARIA F, et al. In vitro assessment of the prebiotic potential of Aloe vera mucilage and its impact on the human microbiota[J]. Food Function, 2015, 6(2): 525-531.
[7]
GAO B B, WANG R J,PENG Y,et al. Effects of a homogeneous polysaccharide from Sijunzi decoction on human intestinal microbes and short chain fatty acids in vitro[J]. Journal of Ethnopharmacology, 2018, 224(2018): 465-473.
[8]
CHEN C, HUANG Q,FU X, et al.In vitro fermentation of mulberry fruit polysacchrides by human fecal inocula and impact on microbiota[J].Food Function,2016,7(11):4 637-4 643.
[9]
FU Y S, ZHANG J N, CHEN K N, et al. An in vitro fermentation study on the effects of Dendrobium officinale polysaccharides on human intestinal microbiota from fecal microbiota transplantation donors[J]. Journal of Functional Foods, 2019, 53: 44-53.
[10]
NERURKAR P V, MIYAMOTO J, WATANABE K, et al. Barley β-glucan improves metabolic condition via short-chain fatty acids produced by gut microbial fermentation in high fat diet fed mice[J]. Plos One, 2018, 13(4): e0196579.
[11]
LUO J, ZHANG C, LIU R, et al. Ganoderma lucidum polysaccharide alleviating colorectal cancer by alteration of special gut bacteria and regulation of gene expression of colonic epithelial cells[J]. Journal of Functional Foods, 2018, 47: 127-135.
[12]
CHEN R Z, TAN L, JIN C G, et al. Extraction, isolation, characterization and antioxidant activity of polysaccharides from Astragalus membranaceus[J]. Industrial Crops and Products, 2015, 77: 434-443.
[13]
WANG Y F, YANG X F, CHENG B, et al. Protective effect of Astragalus polysaccharides on ATP binding cassette transporter A1 in THP-1 derived foam cells exposed to tumor necrosis factor-alpha[J]. Phytotherapy research, 2010, 24(3): 393-398.
[14]
ZHAO L H, MA Z X, ZHU J, et al. Characterization of polysaccharide from Astragalus radix as the macrophage stimulator[J]. Cell Immunol, 2011, 271(2): 329-334.
YAN H, XIE Y, SUN S, et al.Chemical analysis of Astragalus mongholicus polysaccharides and antioxidant activity of the polysaccharides[J].Carbohydrate Polymers,2010,82(3): 636-640.
[18]
PHAM T, TEOH K T, SAVARY B J,et al.In vitro fermentation patterns of rice bran components by human gut microbiota[J]. Nutrients, 2017, 9(11):1 237.
[19]
LAM K L, KO K C, LI X, et al.In vitro infant faecal fermentation of low viscosity barley beta-glucan and its acid hydrolyzed derivatives: evaluation of their potential as novel prebiotics[J]. Molecules, 2019, 24(828):doi:10.3390/molecules 24050828.
[20]
LI S G, ZHANG Y Q, Characterization and renal protective effect of a polysaccharide from Astragalus membranaceus[J]. Carbohydrate Polymers,2009,78(2):343-348.
LIAO J Z, LI C Y, HUANG J, et al. Structure characterization of honey-processed Astragalus polysaccharides and its anti-inflammatory activity in vitro[J]. Molecules, 2018,23(1):168.
[23]
LIU Y M, LIU W, LI J, et al. A polysaccharide extracted from Astragalus membranaceus residue improves cognitive dysfunction by altering gut microbiota in diabetic mice[J]. Carbohydrate polymers, 2019, 205: 500-512.
[24]
WIOLETA W A K, LUCYNA D, JERZY H, et al. Fibres from flax overproducing β-1,3-glucanase show increased accumulation of pectin and phenolics and thus higher antioxidant capacity[J]. BMC Biotechnology, 2013, 13(1): 10.
[25]
PHUKAN M M, CHUTIA R S, KONWAR B K, et al.Microalgae chlorella as a potential bio-energy feedstock[J]. Applied Energy, 2011, 88(10): 3 307-3 312.
[26]
LI R, CHEN W C, WANG W P, et al. Extraction, characterization of Astragalus polysaccharides and its immune modulating activities in rats with gastric cancer[J]. Carbohydrate polymers, 2009, 78(4): 738-742.
[27]
SCHENZEL K, FISCHER S. FT Raman spectroscopy-a rapid analytical tool for detecting the transformation of cellulose polymorphs[J]. Cellulose, 2001, 8(1): 49-57.
[28]
FU J, HUANG L F, ZHANG H T, et al. Structural features of a polysaccharide from Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao[J]. Journal of Asian Natural Products Research,2013,15(6):687-692.
[29]
OLIVERIRA D L, COSTABILE A, WILBEY R A, et al. In vitro evaluation of the fermentation properties and potential prebiotic activity of caprine cheese whey oligosaccharides in batch culture systems[J]. Biofactors, 2012, 38(6): 440-449.
[30]
KOK N M D A N. Effects of fructans-type prebiotics on lipid metabolism[J]. American Society for Clinical Nutrition, 2001, 73(2): 456S-458S.
[31]
WE R. Role of anaerobic bacteria in the metabolic welfare of the colonic mucosa in man[J]. Gut, 1980, 21: 793-798.
[32]
LAPARRA J M, SANZ Y. Interactions of gut microbiota with functional food components and nutraceuticals[J]. Pharmacological Research, 2010, 61(3): 219-225.
2020, Vol. 46 
