Search Results (497)

Quercetin is a biologically active flavonoid compound that exerts numerous beneficial effects in humans and animals, including anti-diabetic activity. Its action has been explored in rodent models of type 1 and type 2 diabetes. It was revealed that quercetin mitigated diabetes-related hormonal and metabolic disorders and reduced oxidative and inflammatory stress. Its anti-diabetic effects were associated with advantageous changes in the relevant enzymes and signaling molecules. Quercetin positively affected, among others, superoxide dismutase, catalase, glutathione peroxidase, glucose transporter-2, glucokinase, glucose-6-phosphatase, glycogen phosphorylase, glycogen synthase, glycogen synthase kinase-3β, phosphoenolpyruvate carboxykinase, silent information regulator-1, sterol regulatory element-binding protein-1, insulin receptor substrate 1, phosphoinositide 3-kinase, and protein kinase B. The available data support the conclusion that the action of quercetin was pleiotropic since it alleviates a wide range of diabetes-related disorders. Moreover, no side effects were observed during treatment with quercetin in rodents. Given that human diabetes affects a large part of the population worldwide, the results of animal studies encourage clinical trials to evaluate the potential of quercetin as an adjunct to pharmacological therapies. Full article

Background: The global increase in type 2 diabetes mellitus (T2DM) cases necessitates the need for early detection of metabolic changes. This study investigated variations in liver enzymes, renal markers, electrolytes, and lipid profiles among T2DM patients stratified by hemoglobin A1c (HbA1c) categories to support early identification and better management of diabetes-related complications. Methods: A retrospective observational study at King Khalid University Hospital (KKUH), Riyadh, included 621 adult patients diagnosed with T2DM categorized into four HbA1c groups: normal (<5.7%), prediabetes (5.7–6.4%), controlled diabetes (6.5–7.9%), and uncontrolled diabetes (≥8.0%). Biochemical parameters included the liver profile: alkaline phosphatase (ALP) and bilirubin, renal profile: creatinine, blood urea nitrogen (BUN), glucose, sodium, and chloride, and lipid profile: cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides. Regression models identified predictors of ALP, cholesterol, and LDL. Results: ALP was higher in uncontrolled diabetes (89.0 U/L, Q1–Q3: 106.3–72.0) than in the prediabetes group (75.0 U/L, Q1–Q3: 96.8–62.3). Sodium and chloride were lower in uncontrolled diabetes (Na: 138.3 mmol/L, Q1–Q3: 140.3–136.4; Cl: 101.1 mmol/L, Q1–Q3: 102.9–99.4) compared to the normal group (Na: 139.5 mmol/L, Q1–Q3: 142.4–136.9; Cl: 103.5 mmol/L, Q1–Q3: 106.1–101.7). LDL was lower in uncontrolled diabetes (2.1 mmol/L, Q1–Q3: 2.8–1.7) than in the normal group (2.8 mmol/L, Q1–Q3: 3.7–2.2), while triglycerides were higher in patients with uncontrolled diabetes compared to the normal group (1.45 mmol/L, Q1–Q3: 2.02–1.11 vs. 1.26 mmol/L, Q1–Q3: 1.44–0.94). Regression models showed low explanatory power (R² = 2.1–7.3%), with weight, age, and sex as significant predictors of select biochemical markers. Conclusions: The study observed biochemical variations across HbA1c categories in T2DM patients, likely reflecting insulin resistance. Monitoring these markers in conjunction with HbA1c can enhance early detection and improve the management of complications. Full article

Background: Vaccination effectively reduces the risk of infection, including COVID-19 yet older adults often receive insufficient attention despite their increased vulnerability. The study aimed to correlate serological results with underlying conditions, vaccination status, and COVID-19 history. Methods: This non-interventional, multicenter study aimed to assess vaccination coverage and SARS-CoV-2 antibody levels among residents of eight long-term care facilities (LTCFs) in Southern Poland. Data collection took place between January and June 2022, with 429 participants recruited based on their ability to provide informed consent and their residency in LTCFs. Sociodemographic data, medical history, and COVID-19-related information—including infection history and vaccination status—were collected through surveys. Blood samples were obtained for serological testing using enzyme-linked immunosorbent assays (ELISA) to detect anti-SARS-CoV-2 antibodies. Statistical analysis, including Spearman’s correlation, revealed significant associations between antibody levels and vaccination status, as well as between RT-PCR-confirmed COVID-19 infections and higher antibody titers. Results: Among the seven different qualitative serological, only the Anti-SARS-CoV-2 NCP (IgG) and Anti-SARS-CoV-2 (IgA) tests showed a positive correlation with the Anti-SARS-CoV-2 QuantiVac (IgG) test, which was used as a comparator. A weak correlation was noted with the age of the residents. Conclusions: Our findings suggest that vaccination positively influences antibody responses, underscoring the importance of immunization among LTCF residents. Additionally, certain comorbidities—such as degenerative joint disease and diabetes—showed weak correlations with higher antibody levels. This study provides valuable insights into the humoral immune response to COVID-19 in vulnerable populations residing in LTCFs. Full article

Background/Objective: Metabolic dysfunction-associated fatty liver disease (MAFLD) is defined by the presence of hepatic steatosis, and is associated with obesity, diabetes, and other metabolic alterations. Feeding rats with a high-fat high-fructose (HFHF) diet is a reproducible experimental model of obesity/metabolic syndrome and the related MAFLD. Aronia melanocarpa, Rosa canina, and Alchemilla vulgaris are polyphenol-rich plants with proven health benefits. The aim of this study was to reveal the effects of four Aronia melanocarpa-based fruit juices (AMBFJs) in HFHF-fed rats. Methods: The AMBFJs were AM20 and AM60 (produced from aronia berries at 20 °C and 60 °C, respectively), AMRC (aronia juice with Rosa canina), and AMAV (aronia juice with Alchemilla vulgaris). Male Wistar rats were allocated to 6 groups. Except for the Control, the rest of the groups were fed an HFHF diet for 60 days. Throughout the experiment, each of the AMBFJs was administered to one HFHF-fed group. Results: HFHF-fed rats had an increased calorie intake on the background of increased liquid and decreased food consumption. At the end of the experiment, they had similar body weights, slightly increased fat indices, increased levels of blood lipids and liver enzymes, as well as typical histopathological changes in liver and adipose tissue. AMBFJs-treated animals showed improvement in most of these parameters, especially in triglyceride levels, liver enzymes, and the histopathological changes in the liver and fat. AMAV, the juice with the highest polyphenolic content, had the highest effect on adiposity. Conclusion: In HFHF-fed rats, AMBFJs exerted beneficial effects on MAFLD probably due to their polyphenolic ingredients. Full article

This study describes the synthesis of heterocyclic derivatives containing multiple nitrogen atoms serving as important moieties for developing novel antidiabetics through a simple synthetic pathway. We herein describe the synthesis and characterization of novel pyrimidine derivatives using one-pot reactions in a catalyst-free and efficient manner through a two-stage process involving the synthesis of 2-amino-4-hydrazinyl-6-methoxy pyrimidine, followed by a reaction with phenyl isothiocyanate derivatives. The structures of all the new compounds were confirmed via physical and spectral analysis. Furthermore, we evaluated the synthesized pyrimidine derivatives’ biological activities in relation to their potential roles as novel anti-diabetic agents by testing their activity profiles against the enzymes α-glucosidase and α-amylase. Compound 4 expressed the highest level of activity against α-glucosidase and α-amylase, with a greater inhibitory concentration (IC₅₀ of 12.16 ± 0.12 µM and IC₅₀ 11.13 ± 0.12 µM) compared to that of acarbose (IC₅₀ = 10.60 ± 0.17 µM and IC₅₀ = 11.30 ± 0.12 µM), which is widely used as a standard antidiabetic drug. The primary structure activity relationship analysis identified the impact of an electron- withdrawing group, especially with respect to fluorine on inhibitory activity. This was further confirmed in molecular docking studies, which demonstrated that both compounds exhibited similar inhibition patterns and emphasized the significance of incorporating a lipophilic electron-withdrawing substituent on the phenyl ring, along with the 2,4-diaminopyrimidine scaffold. Full article

Purpose: To investigate the role of the kynurenine pathway (KP) in ocular diseases by evaluating the activity of key enzymes—kynurenine aminotransferase (KAT) and kynurenine monooxygenase (KMO)—and the 3-hydroxykynurenine to kynurenic acid (3-HK/KYNA) ratio in relation to cataract severity, diabetes, glaucoma, and pseudoexfoliation syndrome (PEXS). Methods: Tryptophan metabolite levels were measured in patients undergoing cataract surgery and stratified by SPONCS grading and comorbid conditions. KAT and KMO activities were estimated using metabolite ratios (KYNA/KYN and 3-HK/KYN, respectively). Statistical analyses included Kruskal–Wallis tests with post hoc comparisons and Mann–Whitney U tests. Results: KAT activity declined significantly with increasing SPONCS grade (p = 0.014), suggesting a progressive loss of KYNA production and antioxidative capacity in advanced cataracts. Diabetic patients exhibited higher KMO activity (p = 0.039) and elevated 3-HK/KYNA ratios (p = 0.013), indicating a metabolic shift toward oxidative stress and neurotoxicity. Similarly, glaucoma patients had significantly increased KMO activity (p = 0.032), consistent with enhanced 3-HK-mediated retinal ganglion cell damage. In contrast, PEXS showed no significant alterations in KP markers. Conclusions: The kynurenine pathway is differentially modulated in ocular diseases. A decline in KAT activity correlates with cataract severity, while upregulation of KMO is prominent in diabetes and glaucoma, revealing disease-specific metabolic dysregulation. Targeting KMO to reduce toxic metabolite accumulation or enhancing KYNA synthesis may offer novel therapeutic avenues. These findings also support the potential of KP metabolites as biomarkers for disease monitoring and progression. Full article

Obesity causes lifestyle-related diseases such as hypertension and type 2 diabetes and has become a global health concern. L-fucose (Fuc), a monosaccharide that can be derived from brown algae, has been shown to strongly suppress lipid droplet accumulation in 3T3-L1 murine adipocytes at high concentrations via the activation of AMP-activated kinase (AMPK). Although low concentrations of Fuc also exhibited similar effects, the underlying mechanisms remain unclear. In this study, we investigated the effects of low-level Fuc on lipid metabolism, focusing on the role of fucosylation. Low-level Fuc did not induce AMPK phosphorylation but suppressed lipid droplet accumulation. This suppressive effect was abolished by co-treatment with the fucosylation inhibitor 2F-Peracetyl-Fucose (2F-PAF), suggesting that fucosylation plays a key role in the observed metabolic regulation. Furthermore, proteomic analysis combined with click chemistry pulldown suggested that proteins involved in the regulation of lipid metabolism, such as acetoacetyl-CoA synthetase enzymes and catalytic subunit alpha of cAMP-dependent protein kinase, are fucosylated or interact with fucose. These findings provide novel insights into the anti-obesity mechanisms of Fuc and highlight the physiological significance of protein fucosylation in adipocyte lipid metabolism. Full article

Background/Objectives: Diabetes mellitus is a group of chronic metabolic disorders characterized by persistent hyperglycemia. Aldose reductase, the first enzyme in the polyol pathway, plays a key role in the onset of long-term diabetic complications. Aldose reductase inhibition has been widely established as a potential pharmacotherapeutic approach to prevent and treat diabetes mellitus-related comorbidities. Although several promising aldose reductase inhibitors have been developed over the past few decades, they have failed in clinical trials due to unacceptable pharmacokinetic properties and severe side effects. This paper describes the design, synthesis, and pharmacological evaluation of four novel 5-halogenated N-indolylsulfonyl-2-fluorophenol derivatives (3a-d) as aldose reductase inhibitors. Methods: The design of compounds was based on a previously published lead compound (IIc) developed by our research group to enhance its inhibitory capacity. Compounds 3a-d were screened for their ability to inhibit in vitro partially purified aldose reductase from rat lenses, and their binding modes were investigated through molecular docking. Results: The presence of a sulfonyl linker between indole and o-fluorophenol aromatic rings is mandatory for potent aldose reductase inhibition. The 5-substitution of the indole core with halogens resulted in a slight decrease in the inhibitory power of 3a-c compared to IIc. Among halogens, bromine was the most capable of filling the selectivity pocket through hydrophobic interactions with Thr113 and Phe115 residues. Conclusions: Although our strategy to optimize the inhibitory potency of IIc via inserting halogen atoms in the indole scaffold was not fruitful, aromatic ring halogenation can be still utilized as a promising approach for designing more potent aldose reductase inhibitors. Full article

Arazá (Eugenia stipitata) seeds, which are an abundant byproduct of pulp processing in the Amazon region, represent up to 84% of the fruit’s dry matter and remain underutilized. This study investigates, for the first time, the bioactive potential of hydroethanolic (70:30) extracts from Arazá seeds (ASs) to inhibit key enzymes related to glycemic and cholesterol regulation, specifically α-amylase, α-glucosidase, and HMG-CoA reductase. Additionally, the proximate characterization, antioxidant capacity assessment, and LC-MS analysis of phenolic compound composition were performed. The results demonstrated that the hydroethanolic extracts exhibited the significant inhibition of α-amylase and α-glucosidase, with IC₅₀ values of 47.06 and 49.99 µg/mL, respectively. This inhibitory activity correlates with the total phenolic content (155.88 ± 6.12 mg GAE/g dry weight) and compounds such as epicatechin gallate and p-hydroxybenzoic acid. The extract also showed a high capacity to scavenge the DPPH radicals (IC₅₀ = 46.63 µg/mL), although no inhibition of HMG-CoA reductase or cytotoxicity in blood cells was observed. Proximate analysis revealed that ASs are low in lipids (0.16%), proteins (4.96%), and ash (0.82%) but contain a considerable amount of fiber (27.7%). These findings suggest that ASs represent a valuable byproduct with potential for further research on its application in diabetes management. Full article

Background: Inhibition of intestinal α-glucosidase is a key strategy for controlling postprandial hyperglycemia in diabetes. Astragali Radix (AR), a traditional medicinal and dietary herb widely consumed in China, is rich in flavonoids that are believed to exhibit hypoglycemic properties. Methods: A total of 29 AR-related flavonoids, including both original constituents and metabolites, were screened for α-glucosidase inhibitory activity using in vitro enzymatic assays. Mechanistic investigations were conducted through enzyme kinetics, circular dichroism (CD) spectroscopy, surface plasmon resonance (SPR), and molecular docking. The in vivo hypoglycemic effects were assessed using a postprandial hyperglycemic mouse model. Additionally, potential mixture effects of flavonoid combinations were evaluated. Results: Of the 29 flavonoids, 16 demonstrated significant α-glucosidase inhibitory activity, with five (C3, C17, C19, C28, and C29) identified as novel inhibitors. Structure–activity relationship (SAR) analysis revealed that hydroxylation, particularly at the C-3 position, enhanced activity, while glycosylation and methoxylation reduced it. Mechanistic studies demonstrated that these compounds bind to distinct amino acid residues within the active site of α-glucosidase, inducing conformational changes and exerting different types of inhibition, leading to varying inhibitory mechanisms. Additionally, 15 compounds reduced postprandial blood glucose levels, with C3, C16, C17, C19, and C28 confirmed as novel in vivo inhibitors. Notably, two compositions of flavonoids combined at their individually ineffective concentrations exhibited significant inhibitory effects. Conclusions: This study provides a comprehensive evaluation of AR-related flavonoids as α-glucosidase inhibitors and offers valuable insights for the development of highly effective, low-toxicity, flavonoid-based, antidiabetic therapeutics and functional foods. Full article

The liver’s crucial role in methylglyoxal (MG) metabolism is frequently overlooked in the literature. We present a perspective that enhances the current understanding of the role of methylglyoxal (MG) and the glyoxalase cycle in the pathogenesis of insulin resistance and obesity, ultimately leading to type 2 diabetes mellitus (DM) and cardiovascular disease (CVD). Fructose may be a significant substrate contributing, particularly in contemporary times, to the flux of trioses in the liver, accounting for a substantial portion of MG production. The steady-state concentration of MG—and the subsequent modification of proteins—would then be determined by the flux of trioses, their utilization in lipogenesis, and their decomposition into MG, which is further converted into D-lactate by glyoxalase enzymes GLO1 and GLO2. Consequently, enhancing the activity and/or expression of GLO1 could potentially mitigate the adverse effects of fructose in the liver. Additional research and validation are required to confirm these biological pathways. These arguments are in favor of further research into safe and efficient ways to activate the glyoxalase pathway to lessen the negative effects of fructose metabolism that lead to insulin resistance (IR) and its related repercussions. Full article

Background: N-glycosylation is a post-translational modification involving the attachment of oligosaccharides to proteins and is known to influence immunoglobulin G (IgG) effector functions and even antigen binding. IgG contains an evolutionarily conserved N-glycosylation site in its fragment crystallizable (Fc) region, while during V-D-J recombination and somatic hypermutation processes it can also obtain N-glycosylation sites in its antigen binding fragment (Fab). Our previous study demonstrated altered IgG N-glycosylation in children at type 1 diabetes (T1D) onset, with the most prominent changes involving sialylated glycans, hypothesized to mainly come from the Fab region, however, the analytical method used could not distinguish between Fc and Fab. Methods: IgG was isolated from plasma from 118 children with T1D and 98 healthy controls from the Danish Registry of Childhood and Adolescent Diabetes. Isolated IgG was cleaved into Fc and Fab fragments using IdeS enzyme. N-glycans were enzymatically released from each fragment, fluorescently labelled with procainamide, and analyzed separately using the UPLC-MS method. Structural annotation of resulting chromatograms was performed using MS/MS. Results: T1D related N-glycosylation changes were more pronounced in the Fab glycans compared to Fc glycans, with five Fab glycans (Man5, Man7, FA2BG1S1, A2G2S2, FA2BG2S1) being significantly altered compared to only one in the Fc region (FA2[3]BG1). Comparing Fc and Fab glycosylation overall reveals stark differences in the types of glycans on each region, with a more diverse and complex repertoire being present in the Fab region. Conclusions: These findings suggest that N-glycosylation changes in early onset T1D predominantly originate from the Fab region, underscoring their potential role in modulating (auto)immunity and highlighting distinct glycosylation patterns between Fc and Fab. Full article

Bee pollen is widely recognized for its health benefits, with its nutritional and bioactive properties varying by botanical origin. This study analyzed twelve bee pollen samples collected from six different apiaries in Uruguay during two seasons (spring and autumn) to determine their botanical composition; nutritional profile (protein, lipids, carbohydrates, dietary fiber, ash, and fatty acid profile); bioactive compound content (total phenols, vitamin C, tocopherols, and carotenoids); antioxidant activity (ABTS and ORAC); color; and ability to inhibit enzymes involved in carbohydrate and fat digestion. Among the samples collected in autumn, three were monofloral (one from Casuarina and two from Eucalyptus). The spring samples, however, were all multifloral, except for one monofloral Rapeseed sample. Monofloral samples had higher protein, fiber, tocopherol, and total phenol content, along with higher ABTS and ORAC values, but lower carotenoid levels. In contrast, autumn samples had lower protein and lipid content but higher fiber and vitamin C levels. The predominant fatty acids were palmitic, linolenic, linoleic, and oleic acids, with most samples showing a higher proportion of polyunsaturated fatty acids (40.7–57.9%). Compared to other food matrices, the α-glucosidase inhibition values of Uruguayan bee pollen are similar to those found in raw citrus pomace. This is the first report on bee pollen’s ability to inhibit pancreatic lipase in relation to its in vitro anti-obesity properties. Uruguayan bee pollen shows significant potential for combating metabolic syndrome, obesity, and type 2 diabetes. Full article

Background/Objectives: Growth differentiation factor-15 (GDF-15) is a component of the transforming growth factor beta (TGF-β) family that may act as regulator of inflammation. A possible protective role of GDF-15 against glucose alterations has been hypothesized. The aim of this pilot study was to evaluate the relationship between a circulating concentration of GDF-15 and metabolic/inflammatory parameters, as well as with adverse perinatal outcomes in patients with gestational diabetes mellitus (GDM). Methods: Twenty-four (n = 24) patients with GDM and n = 29 age-matched pregnant women with normal glucose tolerance (NGT) were recruited at the third trimester of gestation. Clinical and biochemical parameters were collected. Serum levels of GDF-15, small dense low density lipoprotein cholesterol (sdLDL), interleukin 6 (IL-6), a Soluble Urokinase Plasminogen Activator Receptor (su-PAR) were measured by an enzyme-linked immunosorbent assay kit. Fetal ultrasound parameters, maternal, delivery, and perinatal outcomes, were assessed. Results: Serum GDF-15 did not differ between GDM and NGT (p = 0.286). However, in linear regression analysis, a significant negative association was observed between GDF-15 and fetal weight percentile at the third trimester, only in patients with GDM (p = 0.013), even after adjustment for age and pre-pregnancy BMI (p = 0.029). GDF-15 positively associated with IL-6, adjusting for pre-pregnancy BMI (p = 0.047). Pregnant women with adverse perinatal outcomes had higher levels of GDF-15 (p = 0.043). In the regression model, higher levels of GDF-15 were associated with an increased likelihood of adverse perinatal outcomes after adjustment for age and pre-pregnancy BMI (p = 0.044). Conclusions: Besides its action as regulator of inflammation, GDF-15 might have a possible protective role against hyperglycemia-related excessive fetal growth in GDM. GDF-15 circulating levels might also be related to adverse perinatal outcomes. Full article

Hyperlipidemia, marked by high levels of fats in the blood, is a major risk factor for non-communicable diseases such as type 2 diabetes, cardiovascular diseases, and cancer. It has been linked to the action of reactive oxygen species and the formation of advanced glycation end products. Current treatments for hyperlipidemia, like orlistat, simvastatin, and atorvastatin, often present undesirable side effects, prompting the need for new therapeutic agents that are safer, more effective, cost-efficient, and have fewer side effects. In this context, new compounds, specifically propano- and butanosulfonic acids with 9-substituted quinobenzothiazinyl substituents, were synthesized through reactions with 9-substituted quinobenzothiazines and propane sultone or butane sultone. These novel quinobenzothiazine derivatives were verified using ¹H NMR, ¹³C NMR, and HR-MS techniques. The research focused on assessing these compounds for their toxicity, ability to prevent glycation, antioxidant properties, and their potential to combat hyperlipidemia. Toxicity was evaluated on the 3T3 L1 fibroblast cell line using the MTT assay. The capacity to prevent glycation was tested with bovine serum albumin–methylglyoxal and bovine serum albumin–glucose systems. This study measured total reactive oxygen species in the 3T3 L1 cell line using 2′,7′-dichlorodihydrofluorescein diacetate staining, and antioxidant capacity was assessed through DPPH scavenging and metal ion chelation tests. The effectiveness against hyperlipidemia was determined by targeting cholesterol esterase and pancreatic lipase activities, with concentrations of the compounds 5 to 12 ranging from 0.0245 to 0.268 μM. Standard drugs such as orlistat, simvastatin, statins, and aminoguanidine were used as positive controls in various assays. Additionally, computational docking studies with AutoDock Vina were performed. The resulting findings indicated that the compounds were non-toxic to cells, effectively inhibited key enzymes related to hyperlipidemia, and showed significant antioxidant properties, including the prevention of advanced glycation end-product formation. Compounds 11 and 12 demonstrated the highest activity levels. These promising results highlight the potential of new quinobenzothiazine derivatives as lead compounds for the development of antihyperlipidemic drugs, although further research is necessary to confirm their efficacy and safety. Full article