Prevention of type 2 Diabetes Mellitus: Potential of pharmacological agents

Hypoglycemic and Hypolipidemic Effects of Triterpenoid Standardized Extract of Agave durangensis Gentry

Diabetes mellitus is a chronic, degenerative, and multifactorial disease characterized by hyperglycemia, and at least 537 million people suffered from diabetes in 2021. Agave durangensis Gentry, a species of agave native to the state of Durango, reports phenolic compounds, flavonols, flavonoids, and saponins and could be an alternative for the treatment of diabetes. The aim of this work was to identify the compounds in the leaves of Agave durangensis Gentry and their potential activity in diabetes. The leaf extract of Agave durangensis Gentry (EAD) was characterized by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), and different families of bioactive compounds were quantified by analytical methods. Probable pharmacological targets were identified in silico, and the inhibition of dipeptidyl peptidase-4 (DPP4) was validated in vitro. A model of hyperglycemia was established with streptozotocin in male Wistar rats, and we administered EAD intragastrically at a dose of 300 mg/kg, as well as combinations of the extract with metformin and sitagliptin over 30 days. Biochemical and histological parameters were analyzed. We identified thirty-six major compounds, where triterpenes represented 30% of the extract. Molecular docking showed that the extract could interact with α-glucosidases and DPP4 since a large number of compounds in the extract have a Δ G lower than that reported for the controls, and DPP4 inhibition was confirmed by in vitro assays. In vivo assays demonstrated that the administration of the extract was able to significantly decrease glucose levels by 56.75% and glycosylated hemoglobin by 52.28%, which is higher than that reported for sitagliptin with a decrease of 35.22%. In addition, the extract decreased triglycerides by 59.28% and very-low-density lipoprotein (VLDL) cholesterol by 60.27%, and when administered in combination with metformin, it decreased them more than when metformin was administered alone. For all the above reasons, Agave durangensis Gentry extract could be used for the development of phytomedicine for the treatment of diabetes.

Bioactive Polyphenolic Compounds from Propolis of Tetragonula carbonaria in the Gibberagee Region, New South Wales, Australia

Stingless bee propolis has emerged globally as a new source of bioactive molecules that can advance human health. However, limited research has been conducted on Australian stingless bee propolis. This study investigated the chemical composition and biological activity of the propolis produced by the stingless bees Tetragonula carbonaria from Gibberagee, a distinct region of New South Wales state in Australia. Using bioassay-guided fractionation, twelve compounds were isolated, including six A-ring methylated flavonoids. Nine of these compounds demonstrated strong scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radicals, with five exhibiting greater potency than vitamin C. Chemical structures of seven additional minor flavonoids were determined through an intensive MS/MS data analysis. In silico screening of these 19 compounds revealed that all, except for gallic acid, displayed a higher binding affinity to α-glucosidase than the antidiabetic drug, voglibose. This study showed that the Gibberagee stingless bee propolis is a promising source for nutraceutical and cosmeceutical applications owing to its strong antioxidant and antidiabetic properties. The unique profile of A-ring C-methylated flavonoids potentially provides valuable insights into its botanical origin.

Exploring the anti-diabetic potential of Aloe vera: isolation and characterization of bioactive compounds

We investigated the anti-diabetic effects of the ethyl acetate fraction of Aloe vera and its isolated compounds using both in vitro and in vivo study models. In vitro tests showed that the ethyl acetate part of A. vera and its separate compounds had better activity blocking α-glucosidase, α-amylase, and α-lipase. The ethyl acetate fraction and its active constituents, barbaloin and gallic acid, significantly (p < 0.01) normalised blood glucose levels and serum biochemical parameters compared to those of STZ-induced controls. Both barbaloin and gallic acid exhibited maximum glucose-lowering effects in diabetic rats. Ethyl acetate fraction, barbaloin, and gallic acid also showed a significant increase in serum insulin and restoration of the biochemical and antioxidant status of STZ-induced diabetic rats. Therefore, the ethyl acetate fraction of A. vera, barbaloin, and gallic acid demonstrated remarkable anti-diabetic activity in STZ-induced diabetic rats.

Impact of Drying Methods on Phenolic Composition and Bioactivity of Celery, Parsley, and Turmeric-Chemometric Approach

Drying is one of the most commonly used methods for food preservation, and in spice processing, it has a significant impact on quality. In this paper, the influences of drying at room temperature, 60 °C, and 90 °C and freeze-drying on celery and parsley roots and turmeric rhizomes were examined. The highest content of total phenolics was found in celery dried at 60 °C (C60), parsley at room temperature (PRT), and freeze-dried turmeric (TFD) (1.44, 1.58, and 44.92 mg GAE/gdm, respectively). Celery dried at room temperature (CRT), PRT, and TFD showed the highest antioxidant activity regarding the DPPH and ABTS radicals and FRAP. The analysis of color parameters revealed that celery dried at 90 °C (C90); PFD and TFD showed the most similar values to control samples. The drying process was optimized using a combination of standard score (SS) and artificial neural network (ANN) methods. The ANN model effectively evaluated the significance of drying parameters, demonstrating high predictive accuracy for total phenolics, total flavonoids, total flavonols, total flavan-3-ols, IC50ABTS, and FRAP. TFD showed the strongest α-glucosidase inhibitory potential. Also, TFD extract showed good antibacterial activity against Staphylococcus aureus but not against Escherichia coli. C90 and PFD extracts did not show antibacterial activity against the tested microorganisms.

Hypoglycemic Ability of Sericin-Derived Oligopeptides (SDOs) from Bombyx mori Yellow Silk Cocoons and Their Physiological Effects on Streptozotocin (STZ)-Induced Diabetic Rats

Patients with diabetes require daily medication to maintain blood sugar levels. Nevertheless, the long-term use of antidiabetics can lose efficacy and cause degeneration in some patients. For long-term diabetes care, integrating natural dietary foods and medicine is being considered. This study investigated the impact of SDOs on blood sugar levels and their physiological effects on diabetic rats. We induced diabetes in male Wistar rats with STZ (50 mg/kg) and then administered an oral glucose tolerance test to determine the SDO dosage comparable to glibenclamide. The rats were divided into nine groups: normal, diabetic, and diabetic with insulin (10 U/kg), glibenclamide (0.6 mg/kg), bovine serum albumin (BSA; 200 mg/kg), soy protein isolate (200 mg/kg), or SDOs (50, 100, and 200 mg/kg). Diabetic rats administered SDOs had a higher body weight and serum insulin but a lower blood sugar than diabetic control rats. Biochemical assays indicated lower AST/SGOT, ALT/SGPT, BUN, and triglycerides but higher HDL in the SDO groups. Immunohistochemistry showed that SDOs reduced damaged islet cells, increased beta-cell size, and improved insulin levels while decreasing alpha cell size and glucagon. The vascular effects of SDOs were like those of normal control treatment and insulin treatment in diabetic rats. SDOs, a yellow silk protein, show potential for long-term diabetes care.

Identification of reversible and druggable pathways to improve beta-cell function and survival in Type 2 diabetes

Targeting β-cell failure could prevent, delay or even partially reverse Type 2 diabetes. However, development of such drugs is limited as the molecular pathogenesis is complex and incompletely understood. Further, while β-cell failure can be modeled experimentally, only some of the molecular changes will be pathogenic. Therefore, we used a novel approach to identify molecular pathways that are not only changed in a diabetes-like state but also are reversible and can be targeted by drugs. INS1E cells were cultured in high glucose (HG, 20 mM) for 72 h or HG for an initial 24 h followed by drug addition (exendin-4, metformin and sodium salicylate) for the remaining 48 h. RNAseq (Illumina TruSeq), gene set enrichment analysis (GSEA) and pathway analysis (using Broad Institute, Reactome, KEGG and Biocarta platforms) were used to identify changes in molecular pathways. HG decreased function and increased apoptosis in INS1E cells with drugs partially reversing these effects. HG resulted in upregulation of 109 pathways while drug treatment downregulated 44 pathways with 21 pathways in common. Interestingly, while hyperglycemia extensively upregulated metabolic pathways, they were not altered with drug treatment, rather pathways involved in the cell cycle featured more heavily. GSEA for hyperglycemia identified many known pathways validating the applicability of our cell model to human disease. However, only a fraction of these pathways were downregulated with drug treatment, highlighting the importance of considering druggable pathways. Overall, this provides a powerful approach and resource for identifying appropriate targets for the development of β-cell drugs.

Large scale application of the Finnish diabetes risk score in Latin American and Caribbean populations: a descriptive study

Background

The prevalence of type 2 diabetes (T2D) continues to increase in the Americas. Identifying people at risk for T2D is critical to the prevention of T2D complications, especially cardiovascular disease. This study gauges the ability to implement large population-based organized screening campaigns in 19 Latin American and Caribbean countries to detect people at risk for T2D using the Finnish Diabetes Risk Score (FINDRISC).

Methods

This cross-sectional descriptive analysis uses data collected in a sample of men and women 18 years of age or older who completed FINDRISC via eHealth during a Guinness World Record attempt campaign between October 25 and November 1, 2021. FINDRISC is a non-invasive screening tool based on age, body mass index, waist circumference, physical activity, daily intake of fruits and vegetables, history of hyperglycemia, history of antihypertensive drug treatment, and family history of T2D, assigning a score ranging from 0 to 26 points. A cut-off point of ≥ 12 points was considered as high risk for T2D.

Results

The final sample size consisted of 29,662 women (63%) and 17,605 men (27%). In total, 35% of subjects were at risk of T2D. The highest frequency rates (FINDRISC ≥ 12) were observed in Chile (39%), Central America (36.4%), and Peru (36.1%). Chile also had the highest proportion of people having a FINDRISC ≥15 points (25%), whereas the lowest was observed in Colombia (11.3%).

Conclusions

FINDRISC can be easily implemented via eHealth technology over social networks in Latin American and Caribbean populations to detect people with high risk for T2D. Primary healthcare strategies are needed to perform T2D organized screening to deliver early, accessible, culturally sensitive, and sustainable interventions to prevent sequelae of T2D, and reduce the clinical and economic burden of cardiometabolic-based chronic disease.

Dipeptidyl peptidase-4 inhibitor sitagliptin induces vasorelaxation via the activation of Kv channels and PKA

The present study investigated the vasorelaxant effects of sitagliptin, which is a dipeptidyl peptidase-4 (DPP-4) inhibitor in aortic rings pre-contracted with phenylephrine (Phe). Sitagliptin induced vasorelaxation in a concentration-dependent manner but the inhibition of voltage-dependent K⁺ (Kv) channels by pretreatment with 4-aminopyridine (4-AP) effectively reduced this effect. By contrast, the inhibition of inward rectifier K⁺ (Kir) channels by pretreatment with barium (Ba²⁺), large-conductance calcium (Ca²⁺)-activated K⁺ (BK_Ca) channels with paxilline, and adenosine triphosphate (ATP)-sensitive K⁺ (K_ATP) channels with glibenclamide did not change this effect. Although the application of SQ 22536, which is an adenylyl cyclase inhibitor, also did not change this effect, treatment with KT 5720, a protein kinase A (PKA) inhibitor, effectively reduced the vasorelaxant effects of sitagliptin. ODQ, which is a guanylyl cyclase inhibitor, and KT 5823, a protein kinase G (PKG) inhibitor, did not impact the effect. Furthermore, neither the inhibition of Ca²⁺ channels by pretreatment with nifedipine nor the inhibition of sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) pumps by pretreatment with thapsigargin changed the effect. Similarly, the effects of sitagliptin were not altered by eliminating the endothelium, by pretreatment with a nitric oxide (NO) synthase inhibitor (L-NAME), or by inhibition of small- and intermediate-conductance Ca²⁺-activated K⁺ channels (SK_Ca and IK_Ca) using apamin and TRAM-34. Taken together, these results suggest that sitagliptin induces vasorelaxation by inhibiting both membrane potential (Em)-dependent and -independent vasoconstriction and activating PKA and Kv channels independently of PKG signaling pathways, other K⁺ channels, SERCA pumps, and the endothelium.

A complete review of empagliflozin: Most specific and potent SGLT2 inhibitor used for the treatment of type 2 diabetes mellitus

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are the latest class of drugs to be introduced for the treatment of type 2 diabetes mellitus (T2DM). They reduce hyperglycemia by increasing urinary glucose excretion and exert favorable effects beyond glucose control with consistent body weight, blood pressure, and serum uric acid reductions. Empagliflozin is a potent SGLT2 inhibitor used to improve glycemic control in adults with T2DM. It has the highest SGLT2 specificity among all the clinically used or currently tested SGLT2 inhibitors. Low risk of hypoglycemia, absence of weight gain and demonstrated cardiovascular risk reduction support its consideration as a first line medication in addition to metformin for patients with T2DM and cardiovascular disease. Mostly reported adverse events are genital mycotic infections, while urinary tract infections and events linked to volume depletion are rather rare. This review covers the complete information on empagliflozin including the history of its development, synthesis, pharmacology and different methods which have been reported for its analysis.

Diet and prevention of type 2 diabetes mellitus: beyond weight loss and exercise

INTRODUCTION

Insulin resistance (IR) and pancreatic beta-cell dysfunction are core pathophysiologic features of type 2 diabetes mellitus (T2DM). Select lifestyle and pharmacologic interventions, including weight loss, physical activity, a Mediterranean diet intervention, and hypoglycemic agents, have been shown to prevent or delay T2DM. However, dietary factors other than weight loss may also impact risk, mainly through effects to enhance insulin sensitivity, although some may also directly or indirectly impact pancreatic beta-cell function.

AREAS COVERED

A literature review of observational studies and randomized controlled trials (RCTs) was conducted, and the research indicates dietary factors showing promise for reducing T2DM risk include higher intakes of cereal fibers, unsaturated fatty acids, magnesium, and polyphenols (e.g. anthocyanins), while reducing dietary glycemic load, added sugars, and high-sugar beverages.

EXPERT COMMENTARY

While these dietary factors are mainly supported by evidence from observational studies and RCTs of surrogate markers for T2DM, they are consistent with current recommendations to emphasize consumption of whole grains, nuts, seeds, legumes, seafood, fruits, and vegetables, while limiting intakes of saturated fatty acids, refined carbohydrates, and processed meats. Additional dietary intervention RCTs are needed to assess the efficacy of these promising dietary interventions for delaying or preventing the onset of T2DM.

Punicic acid: A potential compound of pomegranate seed oil in Type 2 diabetes mellitus management

Diabetes is one of the most prevalent diseases in the worldwide. Type 2 diabetes mellitus (T2DM), the most common form of the disease, has become a serious threat to public health and is a growing burden on global economies. Due to the unexpected adverse effects of antidiabetic medicines, the use of nutraceuticals as a complementary therapy has drawn extensive attention by investigators. In this issue, a novel nutraceutical, Punicic acid (PA)-the main ingredient of pomegranate seed oil (PSO) that has potential therapeutic effects in T2DM-has been investigated. PA is a peroxisome proliferator-activated receptor gamma agonist, and unlike synthetic ligands, such as thiazolidinediones, it has no side effects. PA exerts antidiabetic effects via various mechanisms, such as reducing inflammatory cytokines, modulating glucose homeostasis, and antioxidant properties. In this review, we discussed the potential therapeutic effects of PSO and PA and represented the related mechanisms involved in the management of T2DM.

Predictors of weight reduction and maintenance in a large cohort of overweight and obese adults in a community setting

AIM

In overweight/obese individuals, modest 5% weight loss and its maintenance promotes health; however, it is challenging and typically unachievable, especially in community settings. Established predictors of weight loss outcome in a community setting are lacking, hindering the development of practical interventions and prevention tools. Our aim was to identify predictors associated with 5% weight reduction (initial 6 months) and maintenance (1 year) in overweight and obese adults undergoing weight reduction treatment, free of charge, in a community setting.

METHODS

Computerised medical files of 11 842 adults aged 50.6 ± 16.3 years, attending 162 primary clinics, were analysed retrospectively. Thirty medical, biochemical and demographic independent variables were tested as potential predictors using multiple logistic regression models.

RESULTS

Significant predictors of high successful weight reduction were: not being treated with insulin (odds ratio (OR) = 0.53), higher baseline body mass index (OR = 1.05) and younger age (OR = 0.98). Weight maintenance predictors were: successful initial weight reduction (OR = 1.26), short time intervals between weighings (OR = 0.88) and frequent weighing (OR = 0.95). Visits to a dietitian were significantly associated with success during both periods: each visit raised the probability of success by 13.4 and 7.6%, respectively. Type 2 diabetes or use of hypoglycaemic drugs were not significant predictors.

CONCLUSIONS

In a community-based setting, number of visits to a dietitian is a strong predictor of successful weight reduction and maintenance. Initial success is a critical predictor of weight loss maintenance. Subgroup of older, diabetic patients treated with insulin has a dramatically lower probability of weight reduction success.

The vasorelaxant effect of mitiglinide via activation of voltage-dependent K+ channels and SERCA pump in aortic smooth muscle

AIMS

The vasorelaxant effects of the anti-diabetic drug, mitiglinide in phenylephrine (Phe)-pre-contracted aortic rings were examined.

MATERIALS AND METHODS

Arterial tone measurement was performed in aortic smooth muscle cells.

KEY FINDINGS

Mitiglinide dose-dependently induced vasorelaxation. Application of the large-conductance Ca²⁺-activated K⁺ (BK_Ca) channel blocker paxilline, inwardly rectifying K⁺ (Kir) channel blocker Ba²⁺, and ATP-sensitive K⁺ (K_ATP) channel blocker glibenclamide did not affect the vasorelaxant effect of mitiglinide. However, application of the voltage-dependent K⁺ (Kv) channel blocker 4-AP, effectively inhibited mitiglinide-induced vasorelaxation. Although pretreatment with the Ca²⁺ channel blocker nifedipine did not alter the mitiglinide-induced vasorelaxation, pretreatment with the sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) pump inhibitor thapsigargin and cyclopiazonic acid reduced the vasorelaxant effect of mitiglinide. In addition, the vasorelaxant effect of mitiglinide was not affected by the inhibitors of adenylyl cyclase, protein kinase A, guanylyl cyclase, or protein kinase G. Elimination of the endothelium and inhibition of endothelium-dependent vasorelaxant mechanisms also did not change the vasorelaxant effect of mitiglinide.

SIGNIFICANCE

We proposed that mitiglinide induces vasorelaxation via activation of Kv channels and SERCA pump. However, the vasorelaxant effects of mitiglinide did not involve other K⁺ channels, Ca²⁺ channels, PKA/PKG signaling pathways, or the endothelium.