Polysaccharide from Hovenia dulcis (Guaizao) improves pancreatic injury and regulates liver glycometabolism to alleviate STZ-induced type 1 diabetes mellitus in rats.

Hovenia dulcis is a traditional medicinal and edible plant and has a major geographical presence in China. In this study, a polysaccharide purified from H. dulcis (HDPs-2A) was found to ameliorate type 1 diabetes mellitus (T1DM) in streptozotocin-induced diabetic rat. HDPs-2A treatment resulted in significantly lower fasting blood glucose levels, but higher body weight, plasma insulin, and liver glycogen levels. Moreover, HDPs-2A improved dyslipidemia, pancreatic oxidative stress, and reduced serum pro-inflammatory factors. In addition, HDPs-2A up-regulated PDX-1, activated and up-regulated IRS2 expression, and regulated apoptosis and regeneration of islet ß cells to recover islet ß-cell function injury in TIDM rats. HDPs-2A also up-regulated the expression of pancreatic GK and GLUT2 to improve insulin secretion ability of islet ß-cells, ultimately improving the glucose metabolism disorder of T1DM rats. Moreover, HDPs-2A significantly up-regulated the expression of GK and down-regulated the expression of G6Pase in liver to improve liver glycogen synthesis, inhibit liver gluconiogenesis, and improve liver glucose metabolism disorder of T1DM rats. In summary, the hypoglycemic mechanisms of HDPs-2A may include regulating the regeneration and apoptosis of islet ß-cells and activating liver glycometabolism-related signaling pathways in T1DM rats.

Zanthoxylum alkylamides ameliorate protein metabolism in type 2 diabetes mellitus rats by regulating multiple signaling pathways.

Type 2 diabetes mellitus (T2DM) can easily induce insulin resistance (IR) in skeletal muscle, causing protein metabolism disorder and inflammation. The present study aimed to investigate whether Zanthoxylum alkylamides (ZA) could ameliorate T2DM through regulating protein metabolism disorder by using a rat model of T2DM. The predominant bioactive constituents found in ZA were hydroxyl-α-sanshool, hydroxyl-ß-sanshool and hydroxyl-γ-sanshool. The results showed that ZA improved a series of biochemical indices associated with protein metabolism and inflammation in T2DM rats. Our mechanistic finding indicated that ZA promoted protein anabolism in T2DM rats by up-regulating the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway. ZA also promoted glucose transportation in skeletal muscle to ameliorate skeletal muscle IR and energy metabolism through regulating the AMP-activated protein kinase (AMPK) signaling pathway. Moreover, ZA inhibited protein degradation and improved protein catabolism disorder in T2DM rats by down-regulating the PI3K/Akt/forkhead box O (FoxO) signaling pathway, and ZA further ameliorated inflammation to inhibit protein catabolism via regulating the tumor necrosis factor α (TNF-α)/nuclear factor κB (NF-κB) pathway in the skeletal muscle of T2DM rats. Collectively, the ameliorating effect of ZA on protein metabolism disorder in T2DM rats was the common result of regulating multiple signaling pathways. ZA decreased skeletal muscle IR to promote protein anabolism and inhibit protein catabolism for improving protein metabolism disorder, thus ultimately ameliorating T2DM. In sum, our findings demonstrated that ZA treatment could effectively ameliorate T2DM through improving protein metabolism, providing a new treatment target for T2DM.

Hypoglycemic effect of low-sugar juice derived from Hovenia dulcis on type 1 diabetes mellitus rats.

BACKGROUND: Fruit juice is usually rich in monosaccharides and disaccharides. A reverse osmosis separation machine was used to remove monosaccharides and disaccharides from Hovenia dulcis fruit juice, leaving behind most of the bioactive substances in a low-sugar fruit juice (LSFJ), so as to provide a more effective treatment for diabetic patients. METHOD: This study was carried out with type 1 diabetes mellitus model induced with high dose of streptozotocin (60 mg kg-1 ), and oral administration of LSFJ for 4 weeks. RESULTS: LSFJ treatment led to significant gain in body weight and increased serum insulin level, insulin-like growth factor-1 level, blood urea nitrogen level, creatinine level, and hepatic glycogen level. Meanwhile, fasting blood glucose, fructosamine level, and glucose tolerance were also observably enhanced. Additional, LSFJ treatment significantly improved lipid metabolism, islet quality, and islet oxidative stress. The messenger RNA levels of glucose metabolism genes in the pancreas of diabetic rats decreased in the diabetes model group, whereas messenger RNA expression of these genes was significantly increased with LSFJ treatment. CONCLUSION: These findings indicate that LSFJ can improve symptoms associated with type 1 diabetes mellitus. The research also suggests new strategies for diabetes prevention and treatment. © 2021 Society of Chemical Industry.

Zanthoxylum alkylamides improve amino acid metabolism in type 2 diabetes mellitus rats.

To investigate the effect of Zanthoxylum alkylamides (ZA) on amino acid metabolism of type 2 diabetes mellitus (T2DM), the present study was performed with T2DM rats model induced with high fat and sugar fodder combined with low-dose of streptozotocin. ZA were fed to rats at three different doses of 2, 4, and 8 mg/kg for 28 days and metformin was fed to rats at 135 mg/kg as positive control. The results showed that compared with the normal control, the amino acid levels and the expression of related carrier genes were disordered in T2DM rats. Compared with the model, different doses of ZA could significantly resist (p < .05) the decrease in body weight of T2DM rats and improve hyperglycemia, with the best result observed with the high dose (8 mg/kg). Different doses of ZA could ameliorate the levels of 19 kinds of amino acid in the plasma, jejunum, liver, and skeletal muscle of T2DM rats by regulating the expression of related amino acid transporters including LAT1, SNAT2, CAT1, et al. to thereby ameliorating amino acid metabolism disorder in T2DM rats. PRACTICAL APPLICATIONS: Previous studies showed that Zanthoxylum alkylamides (ZA) could promote the amino acid metabolism in the jejunum of healthy SD rats, improve protein metabolism disorder of type 1 diabetic rats, and also reduce the risk of metabolic syndrome in fat rats model. Herein, we investigated the effect of ZA on amino acid metabolism in type 2 diabetes mellitus (T2DM) rats. The results indicated that ZA could remarkably improve the abnormal expression of amino acid carriers in the jejunum, liver, and skeletal muscle, thereby ameliorating the disorder of amino acid metabolism in the plasma, jejunum, liver, and skeletal muscle of T2DM rats. Therefore, ZA are potential antidiabetic food/medicine product for the T2DM treatment.

High-pressure ultrasonic-assisted extraction of polysaccharides from Hovenia dulcis: Extraction, structure, antioxidant activity and hypoglycemic.

In this study, high-pressure ultrasonic-assisted extraction (HUE) technology was used for polysaccharide extraction from Hovenia dulcis (HDPS). A maximal extraction yield (11.81 ±â€¯0.26%) was obtained using the response surface method (RSM) with optimized HUE conditions (Ultrasound power 330 W, 68 °C, and 22 min). Results showed that HDPS mainly contained neutral sugar (47.81 ±â€¯1.56%), uronic acid (12.52 ±â€¯0.15%), and protein (3.64 ±â€¯0.24%), specifically. HDPS was comprised of mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose in a molar ratio of 3.20%, 20.40%, 4.81%, 11.14%, 27.37% and 33.08%, respectively. And with an average molecular weight of 185.22 kDa for its major component (accounting for 90.13% for HDPS). The result obtained from the X-ray diffraction pattern confirmed a semi-crystalline nature of the sample. HUE-HDPS suggested typical shear thinning behavior and non-Newtonian properties. Additionally, HUE-HDPS exhibited better chemical antioxidant activities in DPPH, ABTS, hydroxyl radical scavenging and Fe2+ chelation activity. The in-vitro and in-vivo experiments indicated that HUE-HDPS had obviously hypoglycemic effects. Accordingly, the polysaccharides from Hovenia dulcis might serve as a natural antioxidant and hypoglycemic agent.

Japanese grape (Hovenia dulcis) polysaccharides: New insight into extraction, characterization, rheological properties, and bioactivities.

In this study, accelerated solvent extraction (ASE) technology was applied to extract Hovenia dulcis polysaccharides (HDPs). The polysaccharide yields, physicochemical properties, rheological properties, antioxidant activities, and hypoglycemic effects were compared between ASE-HDPs and hot water extracted polysaccharides (HWE-HDPs). The maximum ASE-HDPs yield was obtained using a response surface method (RSM) with optimized ASE conditions comprising 2 cycles at 130 °C for 23 min. The maximum ASE-HDPs yield of 8.62 ±â€¯0.29% is significantly higher than the maximum HWE-HDP yield of 6.89 ±â€¯0.21%. The chemical compositions, molecular weight (Mw) distributions, rheological properties, antioxidant activities, and hypoglycemic effects of polysaccharides varied with each extraction method, while the primary structure remained the same. Both HDPs exhibited typical shear thinning behavior and non-Newtonian properties. The storage modulus (G') and loss modulus (G″) of the HDPs solutions were enhanced with increasing oscillation frequency, and displayed gelatinous behavior (G' > G″). ASE-HDPs displayed better antioxidant activities in DPPH and ABTS, as well as superior reducing power and hydroxyl and superoxide anion scavenging ability, whereas HWE-HDPs exhibited higher Fe2+ chelating activity. The in vitro experiments indicated that HDPs have a decidedly hypoglycemic effect.