Structure and identification of immune fragments of acid-degraded oligosaccharides from active Astragalus polysaccharides APS-Ⅱ / 药学学报

We previously reported that active Astragalus polysaccharides APS-Ⅱ generate strong immune activity. Here we establish the optimal method for APS-II acid degradation. After preliminary structural studies and separation and preparation of the degradation products, the oligosaccharide active center with the strongest immune activity was identified by in vitro immune cell culture experiments. The optimum acid degradation conditions for APS-II were determined by a single factor experiment and an orthogonal experiment. Astragalus oligosaccharides prepared under the optimal conditions were subjected to structural analysis by hydrophilic interaction chromatography - electrospray ionization source - high resolution time-of-flight mass spectrometry. The products were separated and oligosaccharide fragments with different degrees of polymerization were isolated by preparative purification chromatography. Finally, fragments of the immunologically active centers were identified by in vitro immune cell cultures from multiple perspectives. The results show that the optimal acid hydrolysis conditions for APS-Ⅱ are hydrolysis temperature 80 ℃, trifluoroacetic acid concentration 1.0 mol·L-1, hydrolysis time 1 h. The degradation conditions have good repeatability. The degradation product is a six-carbon aldehyde glycan structure with the main chain 1→4 connected. The immune activity screening experiment for six oligosaccharide fragments showed that larger molecular weight oligosaccharides have stronger immune-promoting effects. It is speculated that the immunologically active center of Astragalus oligosaccharide is located in the sugar chain of DP9-DP19. The animal welfare and the experimental process in this study follow the requirements of the Animal Ethics Committee of Shanxi University. This result suggests a foundation for the structural characterization and structure-activity relationship research of Astragalus oligosaccharides, and may promote the development of Astragalus oligosaccharide drugs.

Establishment of enzymatic hydrolysis method of active Astragalus polysaccharides APS-Ⅱ and study on the immune activity of oligosaccharides after its degradation / 药学学报

italic>Astragalus polysaccharides are the main immunomodulatory substances in Astragali Radix. The structure of polysaccharides is difficult to accurately determine, which limits the in-depth study of the molecular mechanism of Astragalus polysaccharides in vivo. "Polysaccharide receptor theory" believes that there are one or more oligosaccharide fragment "active centers" in immunologically active polysaccharide molecules. Therefore, the degradation of Astragalus polysaccharides into oligosaccharides and the study of the active centers of polysaccharides at the oligosaccharide level provide new ideas in the study of the structure and mechanism of Astragalus polysaccharides. This article adopts endo-α-1,4-glucanase enzymatic hydrolysis, and determines the best degradation conditions through single factor test and orthogonal test to degrade the immunologically active polysaccharide APS-Ⅱ (10 kDa component) into oligomers with different degrees of polymerization. Then through the preparation of polyacrylamide gel chromatography and specific immune and non-specific immune cell tests, the immune activity screening of different oligosaccharide components is carried out. The animal welfare and the experimental process in this study follow the requirements of the Animal Ethics Committee of Shanxi University. The results showed that compared with the immunologically active polysaccharide APS-Ⅱ, different oligosaccharide components have obvious differences in different immunological activities. This paper studies the different immunological activities of Astragalus polysaccharides at the level of oligosaccharides, laying a foundation for further elucidating the structure and function of Astragalus polysaccharides, enriching the theory of polysaccharide receptors, and providing new ideas for the development of Astragalus polysaccharides.

Identification of different Bupleurum varieties based on carbohydrate-specific chromatograms / 药学学报

Characterization of the polysaccharides and monosaccharides of Bupleurum chinense was undertaken to identify differences in the Bupleurum chinense's sugar profiles, so as to provide a basis for the identification of different varieties. High performance liquid chromatography (HPLC) was used to generate chromatograms of the total polysaccharides of Bupleurum using an Evaporation Light Detector (ELSD), and a monosaccharide chromatogram was generated using a UV-detector (UV) following polysaccharide derivatization. The data were analyzed using SIMCA software and SPSS software to distinguish different varieties of Bupleurum. The results show that the yield of polysaccharides from Bupleurum falcatum is the highest, while the yield of polysaccharides from Bupleurum chinense is the lowest. The polysaccharide spectrum shows that the molecular weights of the polysaccharides in different Bupleurum differ, and their percentages of the total peak area are also different. The four Bupleurum polysaccharides are composed of mannose, glucuronic acid, rhamnose, galacturonic acid, glucose, galactose, and arabinose, but differ in length. The ratio of glucose to arabinose in Bupleurum chinense, Bupleurum scorzonerifolium, Bupleurum falcatum and Bupleurum marginatum var. stenophyllum is: 3.0-4.0, 5.5-7.0, 12.0-17.0, 9.0-12.0. In this study, a sugar profile technique was developed to provide a new method for the identification of different varieties of Bupleurum.

Hepatic Cyp1a2 Expression Reduction during Inflammation Elicited in a Rat Model of Intermittent Hypoxia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intermittent hypoxia (IH) is a key element of obstructive sleep apnea (OSA) that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expression of hepatic cytochrome P450 (CYP) and CYP regulators, including nuclear receptors.</p><p><b>METHODS</b>Hematoxylin and eosin staining was conducted to analyze the general pathology of the liver of rats exposed to IH. The messenger RNA (mRNA) expression levels of inflammatory cytokines, CYPs, nuclear factor-κB (NF-κB), and nuclear factors in the liver were measured by quantitative reverse transcription polymerase chain reaction.</p><p><b>RESULTS</b>We found inflammatory infiltrates in the liver of rats exposed to IH. The mRNA expression level of interleukin-1beta was increased in the liver of the IH-exposed rats (0.005 ± 0.001 vs. 0.038 ± 0.008, P = 0.042), whereas the mRNA expression level of Cyp1a2 was downregulated (0.022 ± 0.002 vs. 0.0050 ± 0.0002, P = 0.029). The hepatic level of transcription factor NF-κB was also reduced in the IH group relative to that in the control group, but the difference was not statistically significant and was parallel to the expression of the pregnane X receptor and constitutive androstane receptor. However, the decreased expression of the glucocorticoid receptor upon IH treatment was statistically significant (0.056 ± 0.012 vs. 0.032 ± 0.005, P = 0.035).</p><p><b>CONCLUSIONS</b>These results indicate a decrease in expression of hepatic CYPs and their regulator GR in rats exposed to IH. Therefore, this should be noted for patients on medication, especially those on drugs metabolized via the hepatic system, and close attention should be paid to the liver function of patients with OSA-associated IH.</p>