Structure Characterization, In Vitro Antioxidant and Anti-Tumor Activity of Sulfated Polysaccharide from Siraitia grosvenorii.

From Siraitia grosvenorii, a natural polysaccharide named SGP-1 was discovered, and its purity was determined to be 96.83%. Its structure is a glucan with 4-, 6- and 4,6-linked glucose units. In this paper, the sulfated derivative S-SGP of SGP-1 was prepared by the chlorosulfonic acid method. The sulfated derivatives were analyzed by Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), and scanning electron microscopy (SEM). The degree of substitution (DS) of the polysaccharide is 0.62, and the weight average molecular weight (Mw) is 1.34 × 104 Da. While retaining the morphological characteristics of polysaccharides, S-SGP appeared a large number of spherical structures and strong intermolecular forces. The in vitro activity study of S-SGP showed that the sulfated derivatives had the ability to scavenge DPPH radicals, hydroxyl radicals and superoxide anions, and the scavenging power tended to increase with the increase in polysaccharide concentration. It can inhibit the growth of human hepatoma cells (HepG2), human breast cancer cells (MDA-MB-231) and human non-small cell lung cancer cells (A549) in vitro. In addition, the treatment of A549 cells with sulfuric acid derivatives can decrease the mitochondrial membrane potential, induce apoptosis, and alter the expression of apoptosis-related mRNA and protein.

In vitro digestion and fecal fermentation of Siraitia grosvenorii polysaccharide and its impact on human gut microbiota.

In this study, the structure of Siraitia grosvenorii polysaccharides (SGPs) changed significantly after digestion. After 48 h of in vitro fecal fermentation, Mw decreased and the content of CR showed a trend of increasing and then decreasing. The monosaccharide composition (glucose) of SGPs showed a trend of decreasing and then stabilizing during fecal fermentation, indicating that SGPs were partially degraded during in vitro fermentation and significantly degraded and utilized by the human intestinal microbiota. In addition, SGPs fermentation for 48 h increased the production of SCFAs especially acetic acid, propionic acid, and butyric acid. Moreover, after in vitro digestion and enzymatic digestion, the in vitro hypoglycemic activity of SGPs remained relatively high afterward, albeit reduced. This study contributes to a better understanding of the potential digestion and enzymatic mechanisms of SGP, which is important for the future development of SGP as a functional food and drug.

Structural Characteristics, Antioxidant and Hypoglycemic Activities of Polysaccharide from Siraitia grosvenorii.

The structural characterization, the in vitro antioxidant activity, and the hypoglycemic activity of a polysaccharide (SGP-1-1) isolated from Siraitia grosvenorii (SG) were studied in this paper. SGP-1-1, whose molecular weight is 19.037 kDa, consisted of Gal:Man:Glc in the molar ratio of 1:2.56:4.90. According to the results of methylation analysis, GC-MS, and NMR, HSQC was interpreted as a glucomannan with a backbone composed of 4)-ß-D-Glcp-(1→4)-, α-D-Glcp-(1→4)-, and 4)-Manp-(1 residues. α-1,6 linked an α-D-Galp branch, and α-1,6 linked an α-D-Glcp branch. The study indirectly showed that SGP-1-1 has good in vitro hypoglycemic and antioxidant activities and that these activities may be related to the fact that the SGP-1-1's monosaccharide composition (a higher proportion of Gal and Man) is the glycosidic-bond type (α- and ß-glycosidic bonds). SGP-1-1 could be used as a potential antioxidant and hypoglycemic candidate for functional and nutritional food applications.

Hypoglycemic effect of a novel polysaccharide from Lentinus edodes on STZ-induced diabetic mice via metabolomics study and Nrf2/HO-1 pathway.

Objective: With the rising prevalence of diabetes worldwide, increased attention is focused on natural drug candidates that can treat diabetes with high efficacy but without undesired side effects. Lentinus edodes is an edible and medicinal fungus, whose polysaccharides are one of the main components that have been reported to have hypoglycemic ability. However, the detailed underlying hypoglycemic mechanism of Lentinus edodes polysaccharides is still unknown. In this study, we extracted and prepared a novel polysaccharide from Lentinus edodes, which was named LNT-1. Methods: The aim of this study was to evaluate the hypoglycemic effect of LNT-1 on mice with type 2 diabetes that was induced by a high fat and high sugar diet and streptozotocin. To explore the possible mechanism, metabolomics analysis based on UPLC-Q-TOF/MS and molecular methods were performed. Results: Data showed that treatment with LNT-1 could ameliorate the damage in diabetic mice, including physiological and biochemical indexes, oxidative parameters and histopathological changes. Moreover, 36 potential biomarkers were screened using metabolomics analysis based on UPLC-Q-TOF/MS. Among them, the main metabolic pathways were glycerophospholipid metabolism, arachidonic acid metabolism and arginine biosynthesis, thereby suggesting that oxidative stress may be involved in the occurrence of diabetes. Both the mRNA and protein expression of the Nrf2/HO-1 signaling pathway was upregulated after treatment with LNT-1, indicating that the hypoglycemic effect of LNT-1 may be related to the activation of the Nrf2/HO-1 pathway. Conclusion: LNT-1 may be a potential natural drug candidate for the prevention and treatment of diabetes by regulating the oxidative stress response. Our study aimed to provide new insights into the application of Lentinus edodes and its polysaccharide as a drug candidate and as an active ingredient in functional foods.

Advances in Chemical Composition, Extraction Techniques, Analytical Methods, and Biological Activity of Astragali Radix.

Astragali Radix (AR) is one of the well-known traditional Chinese medicines with a long history of medical use and a wide range of clinical applications. AR contains a variety of chemical constituents which can be classified into the following categories: polysaccharides, saponins, flavonoids, amino acids, and trace elements. There are several techniques to extract these constituents, of which microwave-assisted, enzymatic, aqueous, ultrasonic and reflux extraction are the most used. Several methods such as spectroscopy, capillary electrophoresis and various chromatographic methods have been developed to identify and analyze AR. Meanwhile, this paper also summarizes the biological activities of AR, such as anti-inflammatory, antioxidant, antitumor and antiviral activities. It is expected to provide theoretical support for the better development and utilization of AR.

A novel polysaccharide obtained from Siraitia grosvenorii alleviates inflammatory responses in a diabetic nephropathy mouse model via the TLR4-NF-κB pathway.

The inflammatory and antioxidant effects of a novel Siraitia grosvenorii polysaccharide (SGP-1-1) were investigated in an inflammation-suppressed diabetic nephropathy (DN) mouse model, and the underlying molecular mechanisms of inflammation and oxidative stress in SGP-1-1-treated mouse models were elucidated. The results demonstrated that DN mouse models treated with SGP-1-1 (50, 100, and 200 mg kg-1 d-1) exhibited good inflammation-modulating activity. In addition, histopathological analysis showed that glomerular atrophy, severe glomerular thylakoid hyperplasia, tubular endothelial detachment, basement membrane exposure, cytoplasmic infiltration with inflammatory cells, and interstitial oedema were all alleviated in DN mice after treatment with SGP-1-1. Metabolomics analysis based on UPLC-Q-TOF/MS revealed that a close relationship between the occurrence of DN and the potential 39 biomarkers, especially, leukotriene E3 and arachidonic acid,of which the main invloved metabolic pathways may beglycerophospholipid metabolism, arachidonic acid metabolism and primary bile acid biosynthesis. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis results demonstrated that SGP-1-1 downregulates mRNA and the protein expression of the G protein-coupled cell membrane receptor TLR4 and its downstream protein kinase (NF-κB p65). This, resulted in the inhibition of the TLR4-NF-κB pathway in the peritoneum of DN mice by regulating inflammation, while stimulating the production of superoxide dismutase (SOD) and reducing the production of cytokine (IL-6, TNF-α) and malondialdehyde (MDA).

Integrated metabolomics coupled with pattern recognition and pathway analysis to reveal molecular mechanism of cadmium-induced diabetic nephropathy.

Diabetic nephropathy (DN) is becoming a worldwide public health problem and its pathophysiological mechanism is not well understood. Emerging evidences indicated that cadmium (Cd), an industrial material but also an environmental toxin, may be involved in the development and progression of diabetes and diabetes-related kidney disease. However, the underlying mechanism is still unclear. Herein, a DN animal model was constructed by exposing to Cd, the metabolomic profiling of DN mice were obtained by using ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS), pattern recognition and pathway analysis were performed to screen potential biomarker. Moreover, western blotting was employed to verify the possible mechanism involved in the occurrence of Cd-induced DN. A total of 66 metabolites in serum have been screened out and identified as biomarkers, including free fatty acids, phospholipids, sphingomyelins, glycerides, and others. Significant differences were demonstrated between the metabolic profiles, including decreased levels of phospholipid and increased content of triglyceride, diacylglycerols, ceramide, lysophosphatidylcholine in Cd-induced DN mice compared with control. Protein expression level of p38 MAPK and Wnt/ß-catenin were significantly increased. UPLC-Q-TOF/MS-based serum metabolomics coupled with pattern recognition methods and pathway analysis provide a powerful approach to identify potential biomarkers and is a new strategy to predict the underlying mechanism of disease caused by environmental toxicant.