Xudong Gao

Effects of simulated gastrointestinal digestion in vitro on the chemical properties, antioxidant activity, α-amylase and α-glucosidase inhibitory activity of polysaccharides from Inonotus obliquus

This study was aimed to investigate the impacts of gastrointestinal digestion in vitro on the physicochemical properties and the biological activities of polysaccharides from Inonotus obliquus (UIOPS-1). Results showed that the monosaccharides composition, structure and conformation of polysaccharides were remarkably altered, and the molecular weight (Mw) of UIOPS-1 was steadily decreased from 105.02kDa to 88.97kDa and 36.74kDa after simulated digestion. The reducing ends were increased and the free monosaccharides including d-glucose, d-galactose and d-xylose were released suggested that the degradation of UIOPS-1 was caused by disrupting the aggregates and glycosidic bonds. The antioxidant activities of UIOPS-1 were significantly increased after gastric digestion (P<0.05), however, they were decreased after intestinal digestion. The α-amylase and α-glucosidase inhibitory activities of UIOPS-1 were significantly increased after digestion indicating a good control of postprandial hyperglycemia (P<0.001). The results indicated that UIOPS-1 still exhibited antioxidant and antihyperglycemic potential after gastrointestinal digestion, which could be considered as a promising candidate for functional foods.

Preparation, Characterization and Application of Polysaccharide-Based Metallic Nanoparticles: A Review

Polysaccharides are natural biopolymers that have been recognized to be the most promising hosts for the synthesis of metallic nanoparticles (MNPs) because of their outstanding biocompatible and biodegradable properties. Polysaccharides are diverse in size and molecular chains, making them suitable for the reduction and stabilization of MNPs. Considerable research has been directed toward investigating polysaccharide-based metallic nanoparticles (PMNPs) through host–guest strategy. In this review, approaches of preparation, including top-down and bottom-up approaches, are presented and compared. Different characterization techniques such as scanning electron microscopy, transmission electron microscopy, dynamic light scattering, UV-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and small-angle X-ray scattering are discussed in detail. Besides, the applications of PMNPs in the field of wound healing, targeted delivery, biosensing, catalysis and agents with antimicrobial, antiviral and anticancer capabilities are specifically highlighted. The controversial toxicological effects of PMNPs are also discussed. This review can provide significant insights into the utilization of polysaccharides as the hosts to synthesize MPNs and facilitate their further development in synthesis approaches, characterization techniques as well as potential applications.

Effects of polysaccharides from Inonotus obliquus and its chromium (III) complex on advanced glycation end-products formation, α-amylase, α-glucosidase activity and H2O2-induced oxidative damage in hepatic L02 cells

In the present study, the antioxidant activity, anti-glycation activity, α-amylase, α-glucosidase inhibitory activity of polysaccharides from Inonotus obliquus (UIOPS) and its chromium (III) complex (UIOPC) were investigated. Their protective effects against H2O2-induced oxidative damages in hepatic L02 cells were also assessed. Results demonstrated that UIOPC and UIOPS exhibited remarkable DPPH scavenging activity, ferric reducing power and hemolysis inhibitory activity. UIOPC also showed significant inhibitory capacity on α-amylase and α-glucosidase than UIOPS (P < 0.05), suggesting a good regulation of the postprandial hyperglycemia. Three phases of advanced glycation end products (AGEs) formation were effectively inhibited by UIOPC and UIOPS. Moreover, pretreatment with UIOPC and UIOPS markedly attenuated the oxidative damage induced by H2O2 in hepatic L02 cells via enhancing the cell viability, inhibiting the morphology alteration and maintaining the integrity of mitochondria. These results indicated that the anti-diabetic mechanism of UIOPC might involve in the homoeostasis of blood glucose and the recovery of endogenous antioxidant system. The elucidation of the potential anti-diabetic mechanism will facilitate the further study and application of the polysaccharides-metal complex in the functional food industry.

Hypoglycemic effects of polysaccharides from corn silk (Maydis stigma) and their beneficial roles via regulating the PI3K/Akt signaling pathway in L6 skeletal muscle myotubes

In the present study, the physicochemical properties of polysaccharides from corn silk (CSP) with different molecular weights were characterized and their inhibitory actions against α-glucosidase and α-amylase were evaluated. Then their effects on glucose uptake and mechanism of action in PI3K/Akt signaling pathway were also determined in L6 skeletal muscle cells. Results demonstrated that CSP could significantly inhibit α-amylase and α-glucosidase. CSP were non-toxic and they considerably increased the 2-NBDG uptake (P < 0.05) in L6 cells. Additionally, CSP regulated the PI3K/Akt signaling pathway and promoted the translocation of GLUT4 to the plasma membrane that would enhanced the glucose uptake in rat L6 skeletal muscle cells. Among the tested polysaccharides, CSP2 with the molecular weight of 62.16 kDa exerted appreciable hypoglycemic activity. Altogether it was suggested that CSP could be the promising candidate in the treatment of Type 2 Diabetes Mellitus (T2DM). The elucidation of the potential anti-diabetic mechanism of the polysaccharides from corn silk will facilitate their utilization in the functional food industries.

Physicochemical properties of polysaccharides from Lentinus edodes under high pressure cooking treatment and its enhanced anticancer effects

This study was to investigate the physicochemical properties and anticancer effects of polysaccharides from Lentinus edodes extracted under high pressure cooking treatment (HPLPS) in vitro and in vivo. The extraction efficiency was improved. The main molecular weight of HPLPS was about 540 and about 227 kDa. And the inhibitory effects on HepG2 and HeLa cells of HPLPS were significantly increased (p < 0.05). The in vivo anticancer effect on H22 tumor bearing mice model was evaluated. The tumor growth inhibitory rate of HPLPS-H was 67.66%. The activities of ALT and AST were decreased. The activities of SOD, CAT, GSH-Px were notably increased. The expressions of IL-2 and TNF-α were increased while the expression of VEGF was decreased. These results suggested that high pressure-assisted extracted polysaccharides from Lentinus edodes might be effectively used for the treatment of hepatocellular carcinoma through its antioxidant and immunomodulatory effects.

Effect of different drying methods on the physicochemical properties and antioxidant activities of mulberry leaves polysaccharides

This study aimed to optimize the suitable drying method to obtain high yield of polysaccharides from mulberry leaves and to determine their structural characterization and antioxidant activities. The effects of three different drying methods such as air dried, hot air dried (55 °C, 65 °C & 75 °C) and freeze dried on the physicochemical and antioxidant properties of mulberry leaves polysaccharides were studied using gas chromatography, high performance gel permeation chromatography, Fourier transform infrared spectroscopy, scanning electron micrography and antioxidant assays. Results revealed that pre-treatment remarkably influenced the changes in their physicochemical and antioxidant properties. In comparison with the other drying techniques, freeze dried polysaccharides showed more rough morphologies and significant antioxidant property. The yield of polysaccharides from the freeze dried sample was about 28.88% higher than the yield of hot air dried sample. The MDA activity of freeze dried sample was about 95.45%. Overall, the results suggested that the freeze drying technique was the appropriate method to extract polysaccharides from mulberry leaves that offered significant biological properties.