基于斑马鱼生物模型评价青钱柳的降糖作用

该研究以5 dpf斑马鱼为对象,系统研究了其对葡萄糖（GLU）和四氧嘧啶（ALX）耐受性的影响,研究了GLU与ALX联合建立糖尿病斑马鱼生物模型的可行性和有效性。以此为基础,研究了斑马鱼对青钱柳（CP）的耐受性并指导开展了CP的降糖作用评价。结果发现,以10 mg/mL GLU与3.60或7.20 μg/mL ALX联合诱导24 h,可显著增加斑马鱼GLU值,分别增加了51.52%（p<0.05）和68.32%（p<0.05）。经200、400和800 μg/mL阿卡波糖治疗处理后斑马鱼GLU值分别降低了27.28%、33.69%和38.75%,差异均显著（p<0.05）,表明以10 mg/mL GLU与3.60 μg/mL ALX联合孵育24 h可以有效建立糖尿病斑马鱼模型。另外,研究发现,400和800 μg/mL CP可以显著降低10 mg/mL GLU溶液诱导的斑马鱼GLU值,分别降低了37.59%（p<0.05）和38.57%（p<0.05）;200、400和800 μg/mL CP可以显著降低糖尿病斑马鱼GLU值,分别降低了27.43%、32.75%和29.20%,差异均显著（p<0.05）。结果表明,基于正常生理和病理生理的斑马鱼生物模型评价,CP具有明显的降糖效应,其在辅助降糖功能饮品开发上具有广阔的应用前景。     

槲皮素通过Nrf2通路对糖尿病大鼠胰腺氧化损伤的拮抗作用机制

目的：探讨槲皮素是否通过核因子E2相关因子2（nuclear factor erythroid 2-related factor 2, Nrf2）通路拮抗糖尿病大鼠胰腺氧化损伤。方法：选取SPF级SD大鼠48 只,随机选取10 只大鼠作为正常对照组,其余38 只大鼠饲喂高脂饲料联合注射30 mg/kg mb链脲佐菌素建立2型糖尿病（type 2 diabetes mellitus,T2DM）模型。以大鼠随机血糖浓度不低于16.7 mmol/L作为造模成功判断标准,按血糖浓度分层将大鼠随机分为T2DM模型组、低剂量槲皮素（L-QU）、高剂量槲皮素（H-QU）干预组,每组10 只,连续灌胃12 周。测定大鼠胰腺组织匀浆液的氧化损伤和抗氧化指标,运用Western Blot、实时定量聚合酶链式反应测定Nrf2、血红素氧合酶1（heme oxygenase 1,HO-1）、谷胱甘肽硫转移酶（glutathione S-transferase,GST）、NADP(H):醌氧化还原酶1（NADP(H):quinone oxido-reductase 1,NQO1）蛋白及其mRNA表达量。结果：与T2DM模型组相比,低、高剂量槲皮素干预显著降低了大鼠血糖浓度和胰腺丙二醛含量（P＜0.05）,减轻胰岛素抵抗,显著提高超氧化物歧化酶等抗氧化酶活力（P＜0.05）,Nrf2以及下游抗氧化酶HO-1、NQO1的蛋白含量和mRNA表达量均显著上升（P＜0.05）。结论：槲皮素可能是通过激活胰腺组织Nrf2信号通路,上调下游抗氧化酶表达,进而减轻T2DM大鼠胰腺氧化损伤,改善胰岛素抵抗,调节血糖水平,从而发挥防治糖尿病的作用。     

花椒精油对链脲佐菌素诱导的糖尿病小鼠糖代谢的影响

目的：研究花椒精油对1型糖尿病机体糖代谢的影响及可能机制。方法：将50 只健康雄性昆明小鼠（KM小鼠）分为空白对照,糖尿病模型组,花椒精油高（15 mg/（kg mb·d））、中（9 mg/（kg mb·d））、低（3 mg/（kg mb·d））剂量组,每组10 只。采用链脲佐菌素诱导建立1型糖尿病模型。空白组和糖尿病模型组灌胃等剂量的大豆油,给药28 d后,检测血清胰岛素、糖化血清蛋白（glycosylated serum protein,GSP）及糖化血红蛋白（glycosylated hemoglobin,GHb）、肌糖原和肝糖原水平;应用实时荧光定量聚合酶链式反应测定肝脏磷酸肌醇3激酶（phosphoinositide 3-kinase,PI3K）、蛋白激酶B（protein kinase B,PKB）、葡萄糖转运子2（glucose transporter 2,GLUT2）和骨骼肌葡萄糖转运子4（glucose transporter 4,GLUT4）mRNA相对表达量;Western blot检测肝脏PI3K（p110）、PKB和p-PKB（Ser473）的蛋白表达量。实验期间每周测定其空腹血糖浓度及体质量,给药28 d后进行葡萄糖耐量测定。结果：与模型组相比,花椒精油剂量组的摄食量、饮水量、空腹血糖浓度、GHb质量浓度、GSP质量浓度最高分别下降38.91%、35.93%、28.60%、30.76%、37.29%,胰岛素、肝糖原与肌糖原水平最高分别提高22.56%、23.61%、149.75%;PI3K、PKB、GLUT2、GLUT4 mRNA相对表达量最高分别上调87.5%、53.4%、77.05%、133.3%;花椒精油高、中、低剂量组PI3K（p110）蛋白表达量分别上调了3.20、2.51 倍和1.67 倍,p-PKB（Ser473）蛋白表达量分别上调了7.64、6.12 倍和2.73 倍。结论：花椒精油对1型糖尿病小鼠具有降糖效果,其可能机制是激活PI3K/PKB途径,使GLUT2/4移位,促进细胞对葡萄糖的吸收和利用。     

Inhibitory properties of polyphenols in Malus “Winter Red” crabapple fruit on α-glucosidase and α-amylase using improved methods

To explore the inhibitory activity of polyphenols on α-glucosidase and α-amylase, 16 polyphenols were isolated, identified, and quantified in an edible Malus “Winter Red” crabapple fruit. The limitations of two traditional methods for α-glucosidase and α-amylase activity assay in vitro were assayed. An improved method based on an HPLC assay for α-glucosidase and a colorimetric method coupled with a custom-made mini-column for α-amylase were established. Compared with positive controls, acarbose and miglito, most polyphenols, especially the four aglycones (cyanidin, quercetin, phloretin, and 3-hydroxyphloretin) showed higher inhibition rates on α-glucosidase. None of the polyphenols showed higher inhibition rates on α-amylase than acarbose, but most, especially the four aglycones, showed higher inhibition rates on α-amylase than miglito. The Malus Winter Red fruit has great potential for postprandial blood glucose management as a potential diet therapy for diabetic patients.     

Effect of camel milk protein hydrolysates against hyperglycemia,hyperlipidemia, and associated oxidative stress in streptozotocin (STZ)-induced diabetic rats

This study investigated the effect of camel milk protein hydrolysates (CMPH) at 100, 500 and 1,000 mg/kg of body weight (BW) for 8 wk on hyperglycemia, hyperlipidemia, and associated oxidative stress in streptozotocin-induced diabetic rats. Body weights and fasting blood glucose levels were observed after every week until 8 wk, and oral glucose tolerance test (OGTT) levels and biochemical parameters were evaluated after 8 wk in blood and serum samples. Antioxidant enzyme activity and lipid peroxidation in the liver were estimated, and histological examination of the liver and pancreatic tissues was also conducted. Results showed that CMPH at 500 mg/kg of BW [camel milk protein hydrolysate, mid-level dosage (CMPH-M)] exhibited potent hypoglycemic activity, as shown in the reduction in fasting blood glucose and OGTT levels. The hypolipidemic effect of CMPH was indicated by normalization of serum lipid levels. Significant improvement in activity of superoxide dismutase and catalase, and reduced glutathione levels were observed, along with the attenuation of malondialdehyde content in groups fed CMPH, especially CMPH-M, was observed. Decreased levels of liver function enzymes (aspartate aminotransferase and alanine aminotransferase) in the CMPH-M group was also noted. Histology of liver and pancreatic tissue displayed absence of lipid accumulation in hepatocytes and preservation of β-cells in the CMPH-M group compared with the diabetic control group. This is the first study to report anti-hyperglycemic and anti-hyperlipidemic effect of CMPH in an animal model system. This study indicates that CMPH can be suggested for its therapeutic benefits for hyperglycemia and hyperlipidemia, thus validating its use for better management of diabetes and associated comorbidities.     

Molecular basis of the anti-diabetic properties of camel milk through profiling of its bioactive peptides on dipeptidyl peptidase IV (DPP-IV) and insulin receptor activity

The molecular basis of the anti-diabetic properties of camel milk reported in many studies and the exact active agent are still elusive. Recent studies have reported effects of camel whey proteins (CWP) and their hydrolysates (CWPH) on the activities of dipeptidyl peptidase IV (DPP-IV) and the human insulin receptor (hIR). In this study, CWPH were generated, screened for DPP-IV binding in silico and inhibitory activity in vitro, and processed for peptide identification. Furthermore, pharmacological action of intact CWP and their selected hydrolysates on hIR activity and signaling and on glucose uptake were investigated in cell lines. Results showed inhibition of DPP-IV by CWP and CWPH and their positive action on hIR activation and glucose uptake. Interestingly, the combination of CWP or CWPH with insulin revealed a positive allosteric modulation of hIR that was drastically reduced by the competitive hIR antagonist. Our data reveal for the first time the profiling and pharmacological actions of CWP and their derived peptides fractions on hIR and their pathways involved in glucose homeostasis. This sheds more light on the anti-diabetic properties of camel milk by providing the molecular basis for the potential use of camel milk in the management of diabetes.