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Polysaccharide extracted from okra (Abelmoschus esculentus (L.) Moench), a traditional functional food, is a biologically active substance reported to possess hypoglycemic and anti-oxidative qualities. However, it is unknown which polysaccharides play a role and have the potential mechanism. This present study is to assess the possible impacts of a novel polysaccharide isolated from okra (OP) on mice fed with a high-fat diet (HFD) combined with an intraperitoneal injection (i.p.) of 100 mg/kg streptozotocin (STZ) twice, to induce type 2 diabetes mellitus (T2DM). We found that an eight-week administration of OP at 200 or 400 mg/kg body weight significantly alleviated the symptoms, with elevations in blood glucose, triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), as well as reducing high-density lipoprotein cholesterol (HDL-C), body weight, food, and water consumption. The OP treatment increased the hepatic glycogen and decreased the mussy hepatic cords and liver fibrosis in the T2DM mice. The decreases of ROS and MDA and the increases of SOD, GSH-Px and CAT in liver were observed after administration of OP. OP alleviated the T2DM characteristics through the activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3 beta (GSK3β) pathway, and enhanced the nuclear factor erythroid-2 (Nrf2) expression and promoted Nrf2-medicated heme oxygenase-1(HO-1) and superoxide dismutase 2 (SOD2) expression. OP also relieved mitochondrial dysfunction by inhibiting NOX2 activation. Taken together, these findings suggest that a polysaccharide isolated from okra exerts anti-T2DM effects partly by modulating oxidative stress through PI3K/AKT/GSK3β pathway-medicated Nrf2 transport. We have determined that a polysaccharide possesses hypoglycemic activity, as well as its underlying mechanism.

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INTRODUCTIONDiabetes mellitus (DM) is a highly prevalent disease all over the world. Its long-term tissue complications that affect small and large blood vessels are directly connected with the time of patients suffering from hyperglycemia. Chitosan is a polycationic copolymer consisting of β-1, 4-linked 2-acetamido-D-glucose and β-1, 4-linked 2-amino-D-glucose units. Crab and shrimp shell wastes are currently utilized as the major industrial source of biomass for large-scale production of chitosan. Chitosan which is biodegradable, non-toxic and biocompatible has been shown to be particularly useful in many fields [1] , including food, cosmetics, biomedicine, agriculture and environmental protection. Furthermore, it can be used as a bioactive material due to its biodegradable, non-toxic and non-allergenic natures. However, chitosan shows its biological activity only in acidic medium because of its poor solubility at pH above 6.5 and low absorbability of non-digestible and high molecular polysaccharides. Therefore, recent studies on chitosan have attracted interest in converting it to chitooligosaccharides(COS), because COS not only are water-soluble but also possess versatile functional properties such as antitumor enhancing properties [2,3] , immunostimulating effects [2,4] , antimicrobial activity [5] , free radical scavenging activity [6][7][8] , protective effects against infections [9] , arthritis controlling activity [10] , plant disease controlling activity [11,12] and angiotensin I converting enzyme inhibitory activity [13] . However, little attention has been paid to its activity in diabetes mellitus and related mode of action.In the present study, soluble chitooligosaccharides with low molecular weight were prepared by enzymatic hydrolysis of chitosan with chitosanase as previously described [14] . The purpose of this study was to examine the effect of chitooligosaccharides on proliferation of pancreatic islet cells and release of insulin in vitro. MATERIALS AND METHODS MaterialsChitosan (minimum 90% deacetylated, Mr: 500 000) was purchased from Jinan Haidebei Marine Bioengineering Abstract AIM: To investigate the effect of chitooligosaccharides on proliferation of pancreatic islet cells, release of insulin and 2 h plasma glucose in streptozotocin-induced diabetic rats. METHODS:In vitro , the effect of chitooligosaccharides on proliferation of pancreatic islet cells and release of insulin was detected with optical microscopy, colorimetric assay, and radioimmunoassay respectively. In vivo , the general clinical symptoms, 2 h plasma glucose, urine glucose, oral glucose tolerance were examined after sixty days of feeding study to determine the effect of chitooligosaccharides in streptozotocin-induced diabetic rats. RESULTS:Chitooligosaccharides could effectively a c c e l e ra t e t h e p r o l i f e ra t i o n o f p a n c r e a t i c i s l e t cells. Chitooligosaccharides (100 mg/L) had direct and prominent effect on pancreastic β cells and insulin release from islet cells. All concentrations of chitooli...

Background and Purpose Acute kidney injury is a common clinical problem with no definitive or specific treatment. Therefore, the molecular mechanisms of acute kidney injury must be fully understood to develop novel treatments. Nuciferine, a major bioactive compound isolated from the lotus leaf, possesses extensive pharmacological activities. Its effect on folic acid‐induced acute kidney injury, however, remains unknown. Here, we aimed to clarify the pharmacological effects of nuciferine and its mechanisms of action in acute kidney injury. Experimental Approach The effects of nuciferine on folic acid‐induced acute kidney injury in mice were investigated. HK‐2 human proximal tubular epithelial cells and HEK293T HEK cells were used to evaluate the protective effect of nuciferine on RSL3‐induced ferroptosis. Key Results Nuciferine treatment mitigated the pathological alterations, ameliorated inflammatory cell infiltration and improved kidney dysfunction in mice with folic acid‐induced acute kidney injury. In HK‐2 and HEK293T cells, nuciferine significantly prevented RSL3‐induced ferroptotic cell death. Mechanistically, nuciferine significantly inhibited ferroptosis by preventing iron accumulation and lipid peroxidation in vitro and in vivo. Moreover, knockdown of glutathione (GSH) peroxidase 4 (GPX4) abolished the protective effect of nuciferine against ferroptosis. Conclusion and Implications Nuciferine ameliorated renal injury in mice with acute kidney injury, perhaps by inhibiting the ferroptosis. Nuciferine may represent a novel treatment that improves recovery from acute kidney injury by targeting ferroptosis.

Open fires such as those within forests and grasslands, as well as crop residue burning in fields, contribute considerable amounts of trace gases and particulate matter to the atmosphere and therefore play an important role in climate change and atmospheric chemistry. Emissions from open fires in China are estimated at a medium resolution of 1 km2 from April 2000 to March 2007 (seven fire years). Burned areas and land use types at 1 km spatial resolution are defined using the L3JRC product from the Systeme Probatoire pour l'Observation de la Terre (SPOT) satellite and the Global Land Cover 2000 data sets for China, respectively. The 500‐m burned area product (MCD45A1) from the Moderate Resolution Imaging Spectroradiometer (MODIS) is compared with the L3JRC burned area product in China. On an average, the total burned areas from L3JRC product are 16 times those from MCD45A1 product. Interannual changes of burned area are in accordance with the records reported in official statistics. Aboveground biomass densities are characterized by vegetation type and province. Fuel moisture content is considered to calculate the combustion factors by using time series of normalized difference vegetation index (MOD13A3). Crop residue burning accounts for the most biomass burning in China, but we find that it is not detected efficiently by the available burned area algorithms. Both burned area and emission data reveal significant spatial patterns and seasonal variation during the seven fire years. Total nonagricultural fire emissions are concentrated in north and southwest China, especially in the spring and autumn. Forest fires are determined to be the primary contributor to nonagricultural fire emissions. The annual emissions are estimated as follows for China during the seven study years: 137.8 (range from 108.8 to 172.9) Tg a−1 CO2, 7.0 (5.5–8.7) Tg a−1 CO, 0.25 (0.22–0.34) Tg a−1 NOx, 0.90 (0.71–1.1) Tg a−1 PM2.5, 0.06 (0.05–0.07) Tg a−1 BC, and 0.56 (0.44–0.7) Tg a−1 OC.