Characterization of the covalent binding of cyanidin-3-glucoside to bovine serum albumin and its inhibition mechanism for advanced nonenzymatic glycosylation reactions.

Nonenzymatic glycosylation of proteins can generate advanced glycosylation end products, which are closely associated with the pathogenesis of certain chronic physiological diseases and aging. In this study, we characterized the covalent binding of cyanidin-3-glucoside (C3G) to bovine serum albumin (BSA) and investigated the mechanism by which this covalent binding inhibits the nonenzymatic glycosylation of BSA. The results indicated that the covalent interaction between C3G and BSA stabilized the protein's secondary structure. Through liquid chromatography-electrospray ionization tandem mass spectrometry analysis, we identified the covalent binding sites of C3G on BSA as lysine, arginine, asparagine, glutamine, and cysteine residues. This covalent interaction significantly suppressed the nonenzymatic glycosylation of BSA, consequently reducing the formation of nonenzymatic glycosylation products. C3G competitively binds to nonenzymatic glycosylation sites (e.g., lysine and arginine) on BSA, thereby impeding the glycosylation process and preventing the misfolding and structural alterations of BSA induced by fructose. Furthermore, the covalent attachment of C3G to BSA preserves the secondary structure of BSA and hinders subsequent nonenzymatic glycosylation events.

Green Tea Extract Decreases Arg-Derived Advanced Glycation Endproducts but Not Lys-Derived AGEs in UHT Milk during 1-Year Storage.

Epigallocatechin gallate (EGCG)-enriched green tea extract (GTE) was added to lactose-reduced UHT-treated milk to evaluate its role in perturbing the Maillard reaction and the formation of advanced glycation endproducts (AGEs) during 1-year storage. The UHT processing caused epimerization of EGCG into gallocatechin gallate (GCG). For milk samples with added 0.1% w/v GTE, a EGCG/GCG loss of 26% was found soon after the UHT treatment and the loss increased to 64% after the 1-year of storage. LC-MS/MS analysis revealed the presence of various EGCG/GCG-α-dicarbonyl adducts and EGCG/GCG-hydroxymethylfurfural adducts in milk samples, while EGCG/GCG-amino acid adducts were not detected. Although EGCG/GCG trapped α-dicarbonyl compounds including glyoxal, methylglyoxal, 3-deoxyglucosone/3-deoxygalactosone, and diacetyl, it did not lower their net steady-state concentrations, except of 3-deoxyglucosone. The addition of GTE reduced the formation of Arg-derived AGEs by 2- to 3-fold, but surprisingly enhanced the accumulation of furosine and lysine-derived AGEs [Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine)] by 2-4-fold depending on the concentration of the added GTE and storage time. The present study shows that trapping of α-dicarbonyl compounds by EGCG may not be the major pathway for inhibiting the formation of AGEs in milk.

Lycopene Ameliorated Oxidative Stress and Inflammation in Type 2 Diabetic Rats.

We aim to study the antioxidative and anti-inflammatory effects of lycopene on type 2 diabetes mellitus (T2DM) rats, anticipating a complementary strategy for the prevention of long-term complications of T2DM. In this study, rats with streptozotocin-induced diabetes were divided into four groups, receiving a 10-week lycopene intervention: DM, DM + low dose of lycopene (L), DM + medium dose of lycopene (M), and DM + high dose of lycopene (H) group with 0, 5, 10, and 15 mg/kg BW lycopene, respectively. At the end of intervention, fasted blood glucose (FBG) level, oxidative stress indicators, including glycosylated hemoglobin (GHb), glycosylated low-density lipoprotein, oxidized low-density lipoprotein (ox-LDL). and malondialdehyde (MDA), as well as antioxidants, that is, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), and inflammatory factors like tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were determined. The results indicated that oxidative stress and inflammatory factors were elevated in DM rats. Lycopene intervention decreased the FBG level in DM rats compared with the untreated ones. It revealed a dose-dependent effect on decreasing serum oxidative stress biomarkers, including GHb, ox-LDL, and MDA. Inflammatory factors (TNF-α and CRP) in DM rats were also decreased by lycopene intervention. Total antioxidative capacity as well as the activities of antioxidants in DM rats including CAT, SOD, and GPx were increased after lycopene intervention. We conclude that lycopene protects against diabetic progression and prevents further complications of diabetic rats through ameliorating oxidative stress and inflammation, as well as improving the systemic antioxidative capacity. PRACTICAL APPLICATION: According to our study, lycopene intakes at experimental dosages appear to have beneficial effects on ameliorating oxidative stress and inflammation in type 2 diabetes mellitus (T2DM) rats, suggesting that lycopene might help improving T2DM progression when its daily intake is up to about 0.79 mg/kg BW in humans, which approximately equals to 5 mg/kg BW in rats. However, more clinical trials are needed to provide a more reliable and convincing conclusion in humans.

Optimization of Polysaccharide Ultrasonic Extraction Conditions Using Purple Sweet Potato Tubers Based on Free Radical Scavenging and Glycosylation Inhibitory Bioactivities.

BACKGROUND: The purple sweet potato, Ipomoea batatas, belongs to the family Convolvulaceae. It is one of the most widely consumed tubers in Asia and is found in many dishes. Many people with diabetes eat purple sweet potato tubers to help reduce blood glucose in China. OBJECTIVE: To predict the ultrasonic conditions for getting the optimal in vitro antioxidant and antiglycated activity of ultrasonic extracted polysaccharides from purple sweet potato (I. batatas) tubers, the artificial neural network (ANN) regression models was used in this study. MATERIALS AND METHODS: The antioxidant activity of polysaccharides was quantified by evaluating the hydroxyl radical scavenging effect after ultrasonic extraction, and the data were used in conjunction with optimized extraction conditions to train the predictive ANN models. RESULTS: The following conditions were predicted to yield optimal hydroxyl scavenging activity: 200 W, 22°C, and 40 min. In contrast, conditions of 230 W, 22°C, and 50 min yielded the greatest inhibitory effect on albumin nonenzymatic glycosylation. The accuracy and predictive ability of the models ranged from good to excellent, as indicated by R2 values ranging from 0.953 to 0.998. CONCLUSION: The results of the present study showed that ANN predictive models are useful in ultrasonic processing, which can rapidly and accurately predict the optimum extraction conditions for polysaccharides based on their antioxidant and antiglycated activities. In addition, the results of the present study suggest that the consumption of sweet potatoes may help reduce free radicals in the body and prevent or treat diabetes. SUMMARY: Ultrasonic extraction conditions were simulated and optimized using artificial neural networkBioactivities showed nonlinear relationship with ultrasonic conditionsThe optimal extraction conditions were 200 W, 22°C, and 40 min for the highest antioxidant capacityThe optimal extraction conditions were 230 W, 22°C, and 50 min for the highest antiglycated effect. Abbreviations used: IBP: Polysaccharide of Ipomoea batatas; RSM: response surface methodology; ANN: Artificial neural network; BSA: Bovine serum albumin.

Patenting strategies, the authentication US fiscal methodology, discovery and development of imidazole-containing peptide compounds with free-radical scavenging and transglycating properties acting as targeted drug regulators and homeostatic agents with diverse therapeutic activities for pharmacy of diabetes and metabolic diseases.

INTRODUCTION: Diabetes mellitus is the seventh-leading cause of death in the US and diabetic complications are interlaced with specific diverse microvascular and macrovascular pathologies resulting from hyperglycemia. The society should expand prowess and patenting of biotechnology to cure disease and complications. AREAS COVERED: The work summarizes biological activities of patented carnosine mimetics resistant in formulations to enzymatic hydrolysis with human carnosinases that are acting as a universal form of antioxidant, deglycating and transglycating agents that inhibit sugar-mediated protein crosslinking, chelate or inactivate a number of transition metal ions (including ferrous and copper ions), possess lipid peroxidase type of activity and protection of antioxidant enzymes from inactivation. L-Carnosine released systemically from N-acetylcarnosine lubricant eye drops or from skeletal muscle during exercise is transported into hypothalamic tuberomammillary nucleus-histamine neurons and hydrolyzed. The resulting L-histidine is subsequently converted into histamine acting as metabolic fuel feeding for the hypothalamic histaminergic system. This mechanism is responsible for the effects of L-carnosine on autonomic neurotransmission and physiological function of pancreas, stimulating in vivo regeneration of insulin-producing ß cells. EXPERT OPINION: Therapeutic benefits for imidazole-containing antioxidants (nutraceutical non-hydrolyzed carnosine, carcinine, D-carnosine, ophthalmic prodrug N-acetylcarnosine, leucyl-histidylhydrazide and patented formulations thereof) are an essential part of diabetes treatment.

PAMAM dendrimers: destined for success or doomed to fail? Plain and modified PAMAM dendrimers in the context of biomedical applications.

PAMAM (polyamidoamine) dendrimers are commonly considered promising polymers that can be successfully used in various biomedical applications. Nevertheless, direct clinical adaptations of plain unmodified PAMAM dendrimers may be limited at present, mainly because of their toxicity, unpredictable behavior in living organisms, unknown bioavailability, biocompatibility or pharmacokinetic profile, problematic therapeutic dose selection, or high cost of production. On the basis of our studies concerning the possible use of unmodified PAMAM dendrimers as the scavengers of glucose and carbonyl stress in animal models of human pathology, as well as considering available literature on experimental data of other researchers, we have prepared the brief critical review of the biomedical activities of these unmodified compounds and their most alluring derivatives, especially in the context of possible future perspectives of PAMAMs. Thus, on the pages of this review, we made an attempt to briefly summarize obstacles, emerging from experimental, technical, and human limitations, that may, to some extent, restrain our belief in a brighter future of plain amine-terminated PAMAM dendrimers.

Remodeling of retinal microvessels in STZ-induced diabetic rats and medical influence / 第二军医大学学报

Objective: To observe the remodeling of diabetic microvessels in diabetic rats. Methods: Diabetic animal models were induced by STZ on SD rats. The rats were treated with nonenzymatic glycosylation inhibitor and blood flow activating and stasis removing traditional Chinese medicine to evaluate the remodeling of diabetic retinal microvessels by trypsin digestion and figure analysis. Results: At 8 weeks, significant alteration of retinal capillary width in diabetic rats were observed( P

A Simplified Colorimetric Assay of Nonenzymatic Glycosylation of Human low Density Lipoproteins in Normal and Diabetes Mellitus

A simplified colorimetric method for measurement of the levels of glycosylation of proteins was developed by a modification of an existing method. Employing this method, the extent of nonenzymatic glycosylation of apolipoprotein B subspecies(B-100, B-74, B-26), LDL, VLDL and total serum proteins in human plasma obtained from patients with diabetes mellitus and control subjects was compared. Plasma LDL (1.019 < d < 1.063) and VLDL(d < 1.006) were separated using the sequential ultracentrifugation method, and the subspecies of apolipoprotein B were isolated by extracting them from polyacrylamide gels after they were separated by preparative SDS-polyacrylamide gel electrophoresis. Increases in the level of glycosylation of serum proteins, LDL, VLDL, and apo B subspecies obtained from diabetic patients were observed. Among them, the increases of glycosylated LDL and apo B-26 were most significant (p < .001). Also, good correlations were found between glycosylations of apo B-26 and LDL (r=.88), and glycosylation of LDL and LDL cholesterol level(r=.79). The results also showed an excellent correlation between levels of HbA1c and glycosylated apo B-26(r=.93).

Aortic Collagen Nonenzymatic Glycosylation Level in Streptozotocin-induced Diabetic Rats / 第二军医大学学报

Aortic collagen advanced glycosylation endproduct (AGE) and collagen contents were determined in 8 streptozotocin-induced diabetic rats and 8 control rats. Ten weeks after a peritoneal injection of streplozotocin, the AGE and collagen contents were significantly increased in diabetic rats (P