Meta-analysis and critical review on the efficacy and safety of alpha-glucosidase inhibitors in Asian and non-Asian populations

Probing benzenesulfonamide-thiazolidinone hybrids as multitarget directed ligands for efficient control of type 2 diabetes mellitus through targeting the enzymes: α-glucosidase and carbonic anhydrase II

Diabetes mellitus is a chronic metabolic disorder characterized by improper expression/function of a number of key enzymes that can be regarded as targets for anti-diabetic drug design. Herein, we report the design, synthesis, and biological assessment of two series of thiazolidinone-based sulfonamides 4a-l and 5a-c as multitarget directed ligands (MTDLs) with potential anti-diabetic activity through targeting the enzymes: α-glucosidase and human carbonic anhydrase (hCA) II. The synthesized sulfonamides were evaluated for their inhibitory activity against α-glucosidase where most of the compounds showed good to potent activities. Compounds 4d and 4e showed potent inhibitory activities (IC50 = 0.440 and 0.3456 μM), comparable with that of the positive control (acarbose; IC50 = 0.420 μM). All the synthesized derivatives were also tested for their inhibitory activities against hCA I, II, IX, and XII. They exhibited different levels of inhibition against these isoforms. Compound 4d outstood as the most potent one against hCA II with Ki equals to 7.0 nM, more potent than the reference standard (acetazolamide; Ki = 12.0 nM). In silico studies for the most active compounds within the active sites of α-glucosidase and hCA II revealed good binding modes that can explain their biological activities. MM-GBSA refinements and molecular dynamic simulations were performed on the top-ranking docking pose of the most potent compound 4d to confirm the formation of stable complex with both targets. Compound 4d was screened for its in vivo antihyperglycemic efficacy by using the oral glucose tolerance test. Compound 4d decreased blood glucose level to 217 mg/dl, better than the standard acarbose (234 mg/dl). Hence, this revealed its synergistic mode of action on post prandial hyperglycemia and hepatic gluconeogenesis. Thus, these benzenesulfonamide thiazolidinone hybrids could be considered as promising multi-target candidates for the treatment of type II diabetes mellitus.

Biochemical and computational inhibition of α-glucosidase by novel metronidazole-linked 1H-1,2,3-triazole and carboxylate moieties: kinetics and dynamic investigations

In the current study, metronidazole derivatives containing 1H-1,2,3-triazole and carboxylate moieties were evaluated in vitro and by computational methods for their anti-diabetic potential to insight into their medicinal use for the management of type II diabetes mellitus. Interestingly all 14 compounds displayed high to significant inhibitory capability against the key carbohydrate's digestive enzyme α-glucosidase with IC50 values in range of 9.73-56.39 μM, as compared to marketed drug acarbose (IC50 = 873.34 ± 1.67 μM). Compounds 5i and 7c exhibited the highest inhibition, therefore, these two compounds were further evaluated for their mechanistic studies to explore its type of inhibition. Compounds 5i and 7c both displayed a concentration-dependent (competitive type of inhibition) with Ki values 7.14 ± 0.01, 6.15 ± 0.02 μM, respectively, which conclude their favourable interactions with the active site residues of the α-glucosidase. Interestingly all compounds are non-cytotoxic against BJ cell line. To further validate our findings, in-silico approaches like molecular docking, and molecular dynamic simulations were applied to investigate the mode of bindings of compounds with the enzyme and identifies their inhibition mechanism, which strongly complements our experimental findings.Communicated by Ramaswamy H. Sarma.

Evaluation of lupeol-chitosan nanoparticles infused cellulose acetate membranes for enhanced in-vitro anticancer and antidiabetic activities

This study utilizes the abundance of pharmacologically active compounds found in natural products and concentrates on the promising anticancer agent lupeol (LUP). The limited water solubility and bioavailability of lupeol have limited its therapeutic utility. To test their potential for treating diabetes and cancer, we synthesized lupeol@chitosan (LUP@CS) nanoparticles encapsulated in cellulose acetate (CA) membranes (LUP@CS/CA). Extensive characterization, including Scanning electron microscopy, Thermogravimetric analysis, X-ray photoelectron spectroscopy, and mechanical strength analysis, confirmed the membrane's structural integrity and drug release capacity. Notably, in vitro experiments utilizing A431 human skin cancer cells revealed remarkable anticancer activity, positioning the membrane as a potential novel therapeutic agent for the treatment of skin cancer. Inhibiting carbohydrate-digesting enzymes effectively, as evidenced by IC50 values as low as 54.56 mg/mL, the membrane also exhibited significant antidiabetic potential. These results demonstrate the multifarious potential of the membrane, which offers promise for both the treatment of skin cancer and the management of diabetes, and has significant implications for nano biological applications.

Treatment of type 2 diabetes mellitus with stem cells and antidiabetic drugs: a dualistic and future-focused approach

Type 2 Diabetes Mellitus (T2DM) accounts for more than 90% of total diabetes mellitus cases all over the world. Obesity and lack of balance between energy intake and energy expenditure are closely linked to T2DM. Initial pharmaceutical treatment and lifestyle interventions can at times lead to remission but usually help alleviate it to a certain extent and the condition remains, thus, recurrent with the patient being permanently pharmaco-dependent. Mesenchymal stromal cells (MSCs) are multipotent, self-renewing cells with the ability to secrete a variety of biological factors that can help restore and repair injured tissues. MSC-derived exosomes possess these properties of the original stem cells and are potentially able to confer superior effects due to advanced cell-to-cell signaling and the presence of stem cell-specific miRNAs. On the other hand, the repository of antidiabetic agents is constantly updated with novel T2DM disease-modifying drugs, with higher efficacy and increasingly convenient delivery protocols. Delving deeply, this review details the latest progress and ongoing studies related to the amalgamation of stem cells and antidiabetic drugs, establishing how this harmonized approach can exert superior effects in the management and potential reversal of T2DM.

An insight on medicinal attributes of 1,2,3- and 1,2,4-triazole derivatives as alpha-amylase and alpha-glucosidase inhibitors

Diabetes Mellitus (DM) is the globe's common leading disease which is caused by high consumption of glucose. DM compiles groups of metabolic disorders which are characterized by inadequate secretion of insulin from pancreas, resulting in hyperglycemia condition. Many enzymes play a vital role in the metabolism of carbohydrate known as α-amylase and α-glucosidase which is calcium metalloenzyme that leads to breakdown of complex polysaccharides into glucose. To tackle this problem, search for newer antidiabetic drugs is the utmost need for the treatment and/or management of increasing diabetic burden. The inhibition of α-amylase and α-glucosidase is one of the effective therapeutic approaches for the development of antidiabetic therapeutics. The exhaustive literature survey has shown the importance of medicinally privileged triazole specifically 1,2,3-triazol and 1,2,4-triazoles scaffold tethered, fused and/or clubbed with other heterocyclic rings structures as promising agents for designing and development of novel antidiabetic therapeutics. Molecular hybrids namely pyridazine-triazole, pyrazoline-triazole, benzothiazole-triazole, benzimidazole-triazole, curcumin-triazole, (bis)coumarin-triazole, acridine-9-carboxamide linked triazole, quinazolinone-triazole, xanthone-triazole, thiazolo-triazole, thiosemicarbazide-triazole, and indole clubbed-triazole are few examples which have shown promising antidiabetic activity by inhibiting α-amylase and/or α-glucosidase. The present review summarizes the structure-activity relationship (SAR), enzyme inhibitory activity including IC50 values, percentage inhibition, kinetic studies, molecular docking studies, and patents filed of the both scaffolds as alpha-amylase and alpha-glucosidase inhibitors, which may be used for further development of potent inhibitors against both enzymes.

Imidazo[1,2-c]quinazolines as a novel and potent scaffold of α-glucosidase inhibitors: design, synthesis, biological evaluations, and in silico studies

α-Glucosidase inhibition is an approved treatment for type 2 diabetes mellitus (T2DM). In an attempt to develop novel anti-α-glucosidase agents, two series of substituted imidazo[1,2-c]quinazolines, namely 6a-c and 11a-o, were synthesized using a simple, straightforward synthetic routes. These compounds were thoroughly characterized by IR, 1H and 13C NMR spectroscopy, as well as mass spectrometry and elemental analysis. Subsequently, the inhibitory activities of these compounds were evaluated against Saccharomyces cerevisiae α-glucosidase. In present study, acarbose was utilized as a positive control. These imidazoquinazolines exhibited excellent to great inhibitory potencies with IC50 values ranging from 12.44 ± 0.38 μM to 308.33 ± 0.06 μM, which were several times more potent than standard drug with IC50 value of 750.0 ± 1.5 μM. Representatively, compound 11j showed remarkable anti-α-glucosidase potency with IC50 = 12.44 ± 0.38 μM, which was 60.3 times more potent than positive control acarbose. To explore the potential inhibition mechanism, further evaluations including kinetic analysis, circular dichroism, fluorescence spectroscopy, and thermodynamic profile were carried out for the most potent compound 11j. Moreover, molecular docking studies and in silico ADME prediction for all imidazoquinazolines 6a-c and 11a-o were performed to reveal their important binding interactions, as well as their physicochemical and drug-likeness properties, respectively.

A Comprehensive Review on Weight Loss Associated with Anti-Diabetic Medications

Obesity is a complex metabolic condition that can have a negative impact on one's health and even result in mortality. The management of obesity has been addressed in a number of ways, including lifestyle changes, medication using appetite suppressants and thermogenics, and bariatric surgery for individuals who are severely obese. Liraglutide and semaglutide are two of the five Food and Drug Administration (FDA)-approved anti-obesity drugs that are FDA-approved agents for the treatment of type 2 diabetes mellitus (T2DM) patients. In order to highlight the positive effects of these drugs as anti-obesity treatments, we analyzed the weight loss effects of T2DM agents that have demonstrated weight loss effects in this study by evaluating clinical studies that were published for each agent. Many clinical studies have revealed that some antihyperglycemic medications can help people lose weight, while others either cause weight gain or neutral results. Acarbose has mild weight loss effects and metformin and sodium-dependent glucose cotransporter proteins-2 (SGLT-2) inhibitors have modest weight loss effects; however, some glucagon-like peptide-1 (GLP-1) receptor agonists had the greatest impact on weight loss. Dipeptidyl peptidase 4 (DPP-4) inhibitors showed a neutral or mild weight loss effect. To sum up, some of the GLP-1 agonist drugs show promise as weight-loss treatments.

Clinical pharmacology of antidiabetic drugs: What can be expected of their use?

The pharmacotherapy of type 2 diabetes mellitus (T2DM) has markedly evolved in the last two decades. Classical antidiabetic agents (sulphonylureas, metformin, insulin) are now in competition with new glucose-lowering medications. Alpha-glucosidase inhibitors and thiazolidinediones (glitazones) were not able to replace older agents, because of insufficient efficacy and/or poor tolerability/safety. In contrast, incretin-based therapies, both dipeptidyl peptidase-4 inhibitors (DPP-4is or gliptins, oral agents) and glucagon-like peptide-1 receptor agonists (GLP-1RAs, subcutaneous injections) are a major breakthrough in the management of T2DM. Because they are not associated with hypoglycaemia and weight gain, DPP-4is tend to replace sulphonylureas as add-on to metformin while GLP-1RAs tend to replace basal insulin therapy after failure of oral therapies. Furthermore, placebo-controlled cardiovascular outcome trials demonstrated neutrality for DPP-4is, but cardiovascular protection for GLP-1RAs in patients with T2DM at high cardiovascular risk. More recently sodium-glucose cotransporter 2 inhibitors (SGLT2is or gliflozins, oral agents) also showed cardiovascular protection, especially a reduction in hospitalization for heart failure, as well as a renal protection in patients with and without T2DM, at high cardiovascular risk, with established heart failure and/or with chronic kidney disease. Thus, GLP-1RAs and SGLT2is are now considered as preferred drugs in T2DM patients with or at high risk of atherosclerotic cardiovascular disease whereas SGLT2is are more specifically recommended in patients with or at risk of heart failure and renal (albuminuric) disease. The management of T2DM is moving from a glucocentric approach to a broader strategy focusing on all risk factors, including overweight/obesity, and to an organ-disease targeted personalized approach.

Screening for α-glucosidase inhibitors from Selaginella uncinata based on the ligand fishing combined with ultra-high-performance liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry

Biflavonoids are naturally occurring compounds consisting of two flavonoid moieties that have received substantial attention from researchers. Although many kinds of biflavonoids are typically distributed in Selaginella uncinata with hypoglycemic effect, their anti-α-glucosidase activities are not yet clear. In this study, a ligand fishing strategy for fast screening of α-glucosidase inhibitors from S. uncinata was proposed. α-Glucosidase was first immobilized on Fe₃ O₄ magnetic nanoparticles (MNPs) and then the α-glucosidase-functionalized MNPs were incubated with crude extracts of S. uncinata to fish out the ligands. Furthermore, considering the similarity and easy confusion of the structures of biflavonoids, the fragmentation patterns of different types of biflavonoids were studied. Based on this, 11 biflavonoids ligands with α-glucosidase inhibitory activities were accurately and quickly identified from S. uncinata with ultra-high-performance liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry. Furthermore, these ligands were confirmed to be potential inhibitors through the in vitro inhibitory assay and molecular docking.

Linking Diabetes to Alzheimer's Disease: Potential Roles of Glucose Metabolism and Alpha-Glucosidase

Alzheimer's disease (AD) and type 2 diabetes mellitus (DM) are more prevalent with ageing and cause a substantial global socio-economic burden. The biology of these two conditions is well elaborated, but whether AD and type 2 DM arise from coincidental roots in ageing or are linked by pathophysiological mechanisms remains unclear. Research findings involving animal models have identified mechanisms shared by both AD and type 2 DM. Deposition of β-amyloid peptides and formation of intracellular neurofibrillary tangles are pathological hallmarks of AD. Type 2 DM, on the other hand, is a metabolic disorder characterised by hyperglycaemia and insulin resistance. Several studies show that improving type 2 DM can delay or prevent the development of AD, and hence, prevention and control of type 2 DM may reduce the risk of AD later in life. Alpha-glucosidase is an enzyme that is commonly associated with hyperglycaemia in type 2 DM. However, it is uncertain if this enzyme may play a role in the progression of AD. This review explores the experimental evidence that depicts the relationship between dysregulation of glucose metabolism and AD. We also delineate the links between alpha-glucosidase and AD and the potential role of alpha-glucosidase inhibitors in treating AD.

Pharmacotherapy of type 2 diabetes: An update and future directions

Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.

Pathophysiology, phenotypes and management of type 2 diabetes mellitus in Indian and Chinese populations

Nearly half of all adults with type 2 diabetes mellitus (T2DM) live in India and China. These populations have an underlying predisposition to deficient insulin secretion, which has a key role in the pathogenesis of T2DM. Indian and Chinese people might be more susceptible to hepatic or skeletal muscle insulin resistance, respectively, than other populations, resulting in specific forms of insulin deficiency. Cluster-based phenotypic analyses demonstrate a higher frequency of severe insulin-deficient diabetes mellitus and younger ages at diagnosis, lower β-cell function, lower insulin resistance and lower BMI among Indian and Chinese people compared with European people. Individuals diagnosed earliest in life have the most aggressive course of disease and the highest risk of complications. These characteristics might contribute to distinctive responses to glucose-lowering medications. Incretin-based agents are particularly effective for lowering glucose levels in these populations; they enhance incretin-augmented insulin secretion and suppress glucagon secretion. Sodium-glucose cotransporter 2 inhibitors might also lower blood levels of glucose especially effectively among Asian people, while α-glucosidase inhibitors are better tolerated in east Asian populations versus other populations. Further research is needed to better characterize and address the pathophysiology and phenotypes of T2DM in Indian and Chinese populations, and to further develop individualized treatment strategies.

Comparison of Metformin-sulfonylurea and Metformin-acarbose Combination Therapies on Glycemic Outcomes: A Retrospective Cohort Study

OBJECTIVE

Pharmacological therapy for type 2 diabetes mellitus features various combinations of treatments, with different therapies providing different levels of effectiveness. In clinical settings, choices are driven by cost, effectiveness, and safety considerations, and these choices are still under question in Indonesia. This study aimed to compare the effectiveness of metformin-sulfonylurea and metformin-acarbose combination therapies on glycemic parameters in patients with type 2 diabetes mellitus.

METHODS

This study was carried out at Gatot Soebroto Army Hospital in Jakarta and utilized a retrospective cohort study design. Participants had consumed the same drug without switching for six months and were divided into a metformin-sulfonylurea group (n = 100) and a metformin-acarbose group (n = 100). The effectiveness of treatment was evaluated by considering hemoglobin A1c (HbA1c), two hours postprandial glucose, and fasting blood glucose.

RESULTS

After six months' consumption, there were no statistical differences between results for the metformin-sulfonylurea and metformin-acarbose groups in terms of change of HbA1c (p = 0.062), controlled two hours postprandial blood glucose (p = 0.649), and controlled fasting blood glucose (p = 0.282). Regular exercise was the most significant factor for constant/decreased HbA1c, whereas being male and following a diet were the most significant factors for controlled two hours postprandial blood glucose and fasting blood glucose, respectively.

CONCLUSION

Based on the analysis performed, there was no significant difference in the effectiveness of six months' consumption of metformin-sulfonylurea and metformin-acarbose on HbA1c, two hours postprandial blood glucose, and fasting blood glucose.

Influence of Elicitation and Drying Methods on Anti-Metabolic Syndrome, and Antimicrobial Properties of Extracts and Hydrolysates Obtained from Elicited Lovage (Levisticum officinale Koch)

This research aims to investigate the influence of elicitation and drying methods (natural, convection, microwave, and freeze-drying), with jasmonic acid (JA) and yeast extract (YE) on the biological activity of extracts and hydrolysates from lovage (Levisticum officinale Koch) leaves. The results indicate that the highest TPC was determined for hydrolysates obtained from JA-elicited microwave-dried lovage (24.96 mg/gDW). The highest ACE and lipase inhibitory activity was noted for PBS extract obtained from JA-elicited lovage after microwave drying (EC₅₀ = 0.16 and 0.12 mg/mL, respectively). Ethanolic extract from JA-elicited lovage after freeze-drying was characterized by the highest α-amylase inhibitory activity (EC₅₀ = 3.92 mg/mL) and the highest α-glucosidase inhibitory activity (EC₅₀ = 1.43 mg/mL) was noted for hydrolysates from control plants subjected to freeze-drying. The highest antimicrobial activity towards C. albicans yeasts was observed for microwave ethanolic extracts with minimal inhibition (MIC) and lethal (MLC) concentrations of 0.625 and 1.25 mg/mL, respectively.

Synthesis of 1,2,3,triazole modified analogues of hydrochlorothiazide via click chemistry approach and in-vitro α-glucosidase enzyme inhibition studies

The current study was aimed to discover potent inhibitors of α-glucosidase enzyme. A 25 membered library of new 1,2,3-triazole derivatives of hydrochlorothiazide (1) (HCTZ, a diuretic drug also being used for the treatment of high blood pressure) was synthesized through click chemistry approach. The structures of all derivatives 2-26 were deduced by MS, IR, ¹H-NMR, and ¹³C-NMR spectroscopic techniques. All the compounds were found to be new. Compounds 1-26 were evaluated for α-glucosidase enzyme inhibition activity. Among them, 18 compounds showed potent inhibitory activity against α-glucosidase with IC₅₀ values between 24 and 379 µM. α-Glucosidase inhibitor drug acarbose (IC₅₀ = 875.75 ± 2.08 μM) was used as the standard. Kinetics studies of compounds 6, 9, 11, 12, 15, 20, 23, and 24 revealed that only compound 15 as a mixed-type of inhibitor, while others were non-competitive inhibitors of α-glucosidase enzyme. All the compounds were found to be non-cytotoxic when checked against mouse fibroblast 3T3 cell line.

Recent Advances in the Development of Type 2 Sodium-Glucose Cotransporter Inhibitors for the Treatment of Type 2 Diabetes Mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is one of the most serious and prevalent diseases worldwide. In the last decade, type 2 sodium-glucose cotransporter inhibitors (iSGLT2) were approved as alternative drugs for the pharmacological treatment of T2DM. The anti-hyperglycemic mechanism of action of these drugs involves glycosuria. In addition, SGLT2 inhibitors cause beneficial effects such as weight loss, a decrease in blood pressure, and others.

OBJECTIVE

This review aimed to describe the origin of SGLT2 inhibitors and analyze their recent development in preclinical and clinical trials.

RESULTS

In 2013, the FDA approved SGLT2 inhibitors as a new alternative for the treatment of T2DM. These drugs have shown good tolerance with few adverse effects in clinical trials. Additionally, new potential anti-T2DM agents based on iSGLT2 (O-, C-, and N-glucosides) have exhibited a favorable profile in preclinical evaluations, making them candidates for advanced clinical trials.

CONCLUSION

The clinical results of SGLT2 inhibitors show the importance of this drug class as new anti-T2DM agents with a potential dual effect. Additionally, the preclinical results of SGLT2 inhibitors favor the design and development of more selective new agents. However, several adverse effects could be a potential risk for patients.

Glucosidase Inhibitors Screening in Microalgae and Cyanobacteria Isolated from the Amazon and Proteomic Analysis of Inhibitor Producing Synechococcus sp. GFB01

Microalgae and cyanobacteria are good sources for prospecting metabolites of biotechnological interest, including glucosidase inhibitors. These inhibitors act on enzymes related to various biochemical processes; they are involved in metabolic diseases, such as diabetes and Gaucher disease, tumors and viral infections, thus, they are interesting hubs for the development of new drugs and therapies. In this work, the screening of 63 environmental samples collected in the Brazilian Amazon found activity against β-glucosidase, of at least 60 min, in 13.85% of the tested extracts, with Synechococcus sp. GFB01 showing inhibitory activity of 90.2% for α-glucosidase and 96.9% against β-glucosidase. It was found that the nutritional limitation due to a reduction in the concentration of sodium nitrate, despite not being sufficient to cause changes in cell growth and photosynthetic apparatus, resulted in reduced production of α and β-glucosidase inhibitors and differential protein expression. The proteomic analysis of cyanobacteria isolated from the Amazon is unprecedented, with this being the first work to evaluate the protein expression of Synechococcus sp. GFB01 subjected to nutritional stress. This evaluation helps to better understand the metabolic responses of this organism, especially related to the production of inhibitors, adding knowledge to the industrial potential of these cyanobacterial compounds.

Reduced postprandial bone resorption and greater rise in GLP-1 in overweight and obese individuals after an α-glucosidase inhibitor: a double-blinded randomized crossover trial

When taken with a meal, α-glucosidase inhibitors (α-GI) reduce the rise in postprandial glucose and increase glucagon-like peptide-1 (GLP-1), and this may lower bone turnover. In this study, a salacinol-type α-GI increased GLP-1 and markedly reduced postprandial bone resorption compared to placebo, suggesting it could have implications for bone health.

INTRODUCTION

Animal and clinical trials indicate that α-glucosidase inhibitors attenuate postprandial glycemic indices and increase secretion of GLP-1. In addition, GLP-1 acts on bone by inhibiting resorption. The goal in this study was to determine if a salacinol α-GI alters postprandial bone turnover and can be explained by changes in serum GLP-1.

METHODS

In this double-blind, placebo-controlled crossover study, healthy overweight/obese adults (body mass index 29.0 ± 3.8 kg/m²; 21-59 years; n = 21) received a fixed breakfast and, in random order, were administered Salacia chinensis (SC; 500 mg) or placebo. A fasting blood sample was taken before and at regular intervals for 3 h after the meal. Serum was measured for bone turnover markers, C-terminal telopeptide of type I collagen (CTX) and osteocalcin, and for glycemic indices and gut peptides.

RESULTS

Compared to placebo, SC attenuated the bone resorption marker, CTX, at 60, 90, and 120 min (p < 0.05) after the meal, and decreased osteocalcin, at 180 min (p < 0.05). As expected, SC attenuated the postprandial rise in glucose compared with placebo, whereas GLP-1 was increased at 60 min (p < 0.05) with SC. Serum GLP-1 explained 41% of the variance for change in postprandial CTX (p < 0.05).

CONCLUSION

This study indicates that attenuating postprandial glycemic indices, with an α-GI, markedly decreases postprandial bone resorption and can be explained by the rise in GLP-1. Future studies should determine whether longer term α-GI use benefits bone health.

Effects of alpha-glucosidase-inhibiting drugs on acute postprandial glucose and insulin responses: a systematic review and meta-analysis

Background/objectives

Despite considerable literature supporting the potential health benefits of reducing postprandial glucose (PPG), and insulin (PPI) exposures, the size of a clinically relevant reduction is currently unknown. We performed a systematic review and meta-analysis to quantify effects of alpha-glucosidase-inhibiting (AGI) drugs on acute PPG and PPI responses.

Methods

We searched EMBASE and MEDLINE until March 13, 2018 for controlled studies using AGI drugs together with a standardized carbohydrate load or mixed meal. The mean incremental PPG and PPI levels were calculated as outcomes. Meta-analyses, stratified by diabetes state, were performed by using random effects models.

Results

The 66 included publications comprised 127 drug-control comparisons for PPG, and 106 for PPI, mostly testing acarbose or miglitol. The absolute effects on PPG were larger among individuals with diabetes (−1.5 mmol/l mean PPG [95% CI −1.9, −1.1] by acarbose, and −1.6 [−1.9, −1.4] by miglitol) as compared to individuals without diabetes (−0.4 [95% CI −0.5, −0.3] by acarbose, and −0.6 [−0.8, −0.4] by miglitol). Relative reductions in PPG by both drugs were similar for diabetic and non-diabetic individuals (43−54%). Acarbose and miglitol also significantly reduced mean PPI, with absolute and relative reductions being largest among individuals without diabetes.

Conclusions

The present meta-analyses provide quantitative estimates of reductions of PPG and PPI responses by AGI drugs in diabetes and non-diabetic individuals. These data can serve as benchmarks for clinically relevant reductions in PPG and PPI via drug or diet and lifestyle interventions.

Do East Asians With Normal Glucose Tolerance Have Worse β-Cell Function? A Meta-Analysis of Epidemiological Studies

BACKGROUND

The difference in the relationship between β-cell function and insulin resistance among Africans, Caucasians and East Asians with normal glucose tolerance (NGT) was not well investigated.

METHODS

We searched PubMed and Web of Science with keywords and identified studies that used the homeostasis model assessment (HOMA) model to evaluate β-cell function (HOMA-B) and insulin sensitivity/resistance (HOMA-S/HOMA-IR) in certain ethnic groups. We used random-effect model to pool data of HOMAs and compared the combined data among the three ethnic groups using subgroup analysis. Linear regression analysis was used to estimate the coefficient of HOMA-S on HOMA-B in these ethnic groups.

RESULTS

We evaluated pooled data of HOMAs in eight African, 26 Caucasian, and 84 East Asian cohorts with NGT, and also 2,392, 6,645 and 67,317 individuals, respectively. The three ethnic groups had distinct HOMA-B but similar HOMA-IR. The regression coefficient of lnHOMA-B on lnHOMA-S was different between Africans and Caucasians (-1.126 vs -0.401, P = 0.0006) or East Asian (-1.126 vs -0.586, P = 0.0087), but similar between Caucasians and East Asians (-0.401 vs -0.586, P = 0.1282). The coefficient in all ethnic groups was similar when age, BMI, and gender were adjusted (African vs Caucasian P = 0.0885, African vs East Asian P = 0.1092, and Caucasian vs East Asian P = 0.6298).

CONCLUSIONS

In subjects with NGT, East Asians had lower HOMA-B but similar β-cell response relative to insulin resistance with Caucasians and Africans when age, BMI, and gender were controlled. This result may challenge the allegation that there was an Asian-specific diabetes phenotype with worse β-cell function.

Integrated metabolomics and ligand fishing approaches to screen the hypoglycemic ingredients from four Coptis medicines

Rhizoma Coptidis, which is mainly originated from the rhizomes of Coptis chinensis, C. deltoidea, C. omeiensis and C. teeta, has been proved to possess a superior anti-diabetic effect in clinic. However, the metabolic characterization and the hypoglycemic ingredients among these Coptis species remain unclear. In this study, we employed an integrated strategy to screen the bioactive ingredients based on metabolomics and ligand fishing approaches. First, the ultra high-performance liquid chromatography coupled to quadruple time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) was used for qualitative identification of four Coptis rhizomes. After prescreening by α-glucosidase inhibition assay, an affinity ultrafiltration system was constructed to fish out hypoglycemic ingredients from the fractions with superior activity, and verified by molecular docking on a virtual platform. The distribution of major compounds suggested the four Coptis rhizomes possess similar metabolic profiles, mainly including alkaloids and phenylpropanoids. Besides, eight compounds (magnoflorine, groenlandicine, jatrorrhizine, epiberberine, columbamine, coptisine, palmatine and berberine) from the n-butanol fraction were specifically bound to α-glucosidase, and considered as hypoglycemic ingredients of Rhizoma Coptidis. Molecular docking revealed that the inhibitors bound to α-glucosidase mainly by hydrophobic interaction, hydrogen bond interaction and π-π interaction. Summary, this research leads a more systematic and comprehensive study on metabolic characterization and hypoglycemic ingredients of Rhizoma Coptidis, which can provide a theoretical basis for the further clinical application.

Cardiovascular outcomes with SGLT-2 inhibitors and GLP-1 receptor agonist in Asians with type 2 diabetes: A systematic review and meta-analysis of cardiovascular outcome trials

BACKGROUND AND AIMS

Both type 2 diabetes and cardiovascular (CV) disease develops at a younger age in Asians and often have a higher risk of mortality. Both sodium-glucose co-transport-2 inhibitors (SGLT-2Is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) have shown a significant reduction in CV end-points in CV outcome trials (CVOTs). Whether similar CV benefit exists in Asians, is not yet clearly known.

METHODS

We systematically searched relevant medical database up to January 31, 2020 and retrieved all the dedicated CVOTs conducted with SGLT-2Is and GLP-1RAs. Subsequently, we meta-analyzed the pooled data of hazard ratio (HR) of major adverse cardiac events (MACE) in Asians. We additionally analyzed the data of heart failure hospitalization (HHF) or CV-death with SGLT-2Is in Asians.

RESULTS

The meta-analysis of three CVOTs conducted with SGLT-2Is (N = 4987), did not find any significant reduction in MACE (HR, 0.88; 95% CI, 0.67 to 1.15; P = 0.35) and HHF or CV-death (HR, 0.86; 95% CI, 0.55 to 1.36; P = 0.53) in Asians, compared to the placebo. In contrast, the meta-analysis of seven CVOTs conducted with GLP-1RAs (N = 4298) demonstrated a significant reduction in MACE, compared to the placebo (HR, 0.71; 95% CI, 0.59 to 0.86; P < 0.0001).

CONCLUSIONS

This meta-analysis found a significant reduction in MACE with GLP-1RAs but not with SGLT-2Is in Asians. No significant reduction in HHF or CV-death demonstrated either with SGLT-2Is in Asians. Whether these results are related to an inadequate statistical power, or due to underrepresentation of Asians, or a true ethnic difference, remains to be established.

The effect of voglibose on metabolic profiles in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of clinical trials

OBJECTIVE

The effect of voglibose on metabolic homeostasis is not well characterized. Therefore, we conducted a systematic review and meta-analysis of clinical trials assessing the effect of voglibose on metabolic profile in patients with type 2 diabetes mellitus (T2DM).

METHODS

Systematic searches were conducted in PubMed, Scopus, Embase, Google Scholar, Web of Science and Cochrane Library to identify clinical trials assessing the effects of voglibose supplementation on cardio-metabolic profile from incept up to 29 July 2019. Data was pooled using fixed- or random-effect models and weighted mean difference (WMD) as the effect size.

RESULTS

Eight clinical trials from 1094 reports, were eligible for inclusion. Pooled findings identified significant reductions in hemoglobin A1c (HbA1c) (WMD= -0.27; 95 %CI -0.49 to -0.05; P = 0.01; I² = 64.8 %) and an increase in LDL-cholesterol levels (WMD=5.97 mg/dl, 95 % CI 0.88, 11.06, P = 0.02; I² = 0.0 %). However, no evidence of effect for voglibose intake on T2DM patients was observed for: fasting blood sugar (FBS) (WMD -7.43 mg/dl; 95 %CI -16.56 to 1.71; P = 0.110; I² = 69.3 %), serum insulin (WMD= -0.15 μU/mL; 95 %CI -0.89 to 0.60; P = 0.70; I² = 0.0 %), total-cholesterol (WMD=2.82 mg/dl, 95 %CI -2.36 to 8.01, P = 0.70; I² = 49.7 %), triglycerides (WMD= -7.07 mg/dl, 95 %CI -21.76 to 7.62, P = 0.34; I² = 0.0 %), HDL-cholesterol levels (WMD= -2.10 mg/dl, 95 %CI -4.48 to 0.27, P = 0.08; I² = 0.0 %,), body mass index (BMI) (WMD=0.09 kg/m², 95 %CI -0.70 to 0.87; P = 0.87; I² = 0.0 %), body weight (WMD= -0.42 kg, 95 %CI -0.84 to 0.00; P = 0.05; I² = 0.0 %), and adiponectin levels (WMD = 0.32 μg/mL, 95 %CI -0.74 to 1.38; P = 0.55; I² = 0.0 %).

CONCLUSIONS

The current meta-analysis identified a decrease in HbA1c and an increase in LDL-cholesterol with administration of voglibose. However, no significant effect was observed on FBS, insulin, bodyweight, BMI, adiponectin, triglycerides, total- and HDL-cholesterol levels.

Recent Developments in Alpha-Glucosidase Inhibitors for Management of Type-2 Diabetes: An Update

The incidence of diabetes has increased globally in recent years and figures of diabetic patients were estimated to rise up to 642 million by 2040. The disorder is accompanied with various complications if not managed at the early stages, and interlinked high mortality rate and morbidity with time. Different classes of drugs are available for the management of type 2 diabetes but were having certain limitations of their safety. Alphaglucosidase is a family of enzyme originated from the pancreas which plays a role in the anabolism of 80-90% of carbohydrate consumed into glucose. This glucose is absorbed into the blood and results in frank postprandial hyperglycemia and worsens the conditions of diabetic patients which precipitate complications. Inhibition of these enzymes helps to prevent postprandial hyperglycemia and the formation of glycated end products. Alphaglucosidase inhibitors are reported to be more important in adequate control of type 2, but marketed drugs have various side effects, such as poor patient compliance and also expensive. This proves the needs for other class of drugs with better efficacy, safety, patient compliance and economic. In this review, we have emphasized the recent advances in the field of new alpha-glucosidase inhibitors with improved safety and pharmacological profile.

Vildagliptin Versus α-Glucosidase Inhibitor as Add-On to Metformin for Type 2 Diabetes: Subgroup Analysis of the China Prospective Diabetes Study

INTRODUCTION

The effect of dipeptidyl peptidase-4 (DDP-4) inhibitors versus α-glucosidase inhibitors (AGIs) on the treatment of type 2 diabetes mellitus (T2DM) in a real-world setting is unknown. The aim of this real-world study was to compare the glucose-lowering effect and tolerability of vildagliptin as add-on to metformin monotherapy (VM) and AGI as add-on to metformin monotherapy (AM) in Chinese patients with T2DM.

METHODS

This was a subgroup analysis of the China Prospective Diabetes Study, a post-marketing, prospective, observational, real-world study conducted at 52 centers in China. T2DM patients with inadequate glycemic control on metformin monotherapy who received VM or AM were included. The composite primary endpoint was glycemic control (hemoglobin A1c [HbA1c] < 7%) after 12 months in the absence of tolerability events (hypoglycemia, weight gain ≥ 3%, or gastrointestinal events leading to treatment discontinuation). Propensity score matching (PSM) was used to balance the two groups.

RESULTS

The success rates of the composite endpoint were higher in the VM group (n = 604/159 before/after PSM) than in the AM group (n = 159/157 before/after PSM), but the difference was not statistically significant (before PSM: 53.0 vs. 46.5%, P = 0.148; after PSM: 56.7 vs. 45.9%, P = 0.055). The glycemic control rate and HbA1c reduction were similar between groups at 3, 6, and 12 months. Compared with the AM group, the VM group had lower risks of any tolerability event (relative risk [RR] 0.53, 95% confidence interval [CI] 0.33-0.83, P = 0.006), of any adverse event (AE) (RR 0.64, 95% CI 0.41-1.00, P = 0.049), and of any serious AE (RR  0.45, 95% CI 0.25-0.81, P = 0.007).

CONCLUSION

The results of this real-world study suggest that vildagliptin as add-on to metformin monotherapy had a similar glucose-lowering effect to AGI as add-on to metformin monotherapy, but with better safety.

Rapid gastric emptying in diabetes mellitus: Pathophysiology and clinical importance

Although slow gastric emptying (gastroparesis) is a well-known complication of chronic hyperglycemia in diabetes mellitus (DM), it recently has become clear that rapid gastric emptying also is a frequent and important diabetic complication. In contrast, acute hyperglycemia causes slow gastric emptying, and acute hypoglycemia causes rapid gastric emptying. Rapid gastric emptying is frequent in T2DM; however, it may also occur in T1DM, particularly in the early stages of the disease, but may persist even into late stages. Recent studies suggest that usually, the stomach restricts the emptying of nutrients to 1-4 kcals/min. This restriction is due to the action of the gastric 'braking' hormones such as GLP-1, leptin, and amylin acting via the gastric inhibitory vagal motor circuit (GIVMC). Disruption of this braking system leads to rapid gastric emptying. Acute hyperglycemia also slows gastric emptying by stimulating the GIVMC, while acute hypoglycemia causes rapid gastric emptying by stimulating the gastric excitatory vagal motor circuit (GEVMC). In contrast, chronic hyperglycemia causes rapid gastric emptying by inducing oxidative stress in the stomach wall that disrupts inhibitory neuromuscular transmission and increases the contractility of the smooth muscle, while chronic hyperglycemia may also cause slow gastric emptying via severe inflammatory stress caused by proinflammatory macrophages and reduce contractility of the smooth muscle. There is a bidirectional relationship between blood glucose and gastric emptying. Thus, rapid gastric emptying may lead to a sizeable postprandial spike, and slow gastric emptying may blunt it. Postprandial hyperglycemia is involved in the development, progression, and complications of DM. Correction of fast gastric emptying involves agents that activate GIVMC and the use of gastric 'braking' hormones or their analogs. Recognition and treatment of rapid gastric emptying may contribute to better management of postprandial hyperglycemia and prevention of some diabetic complications.

Diet-Induced Obese Mice and Leptin-Deficient Lepob/ob Mice Exhibit Increased Circulating GIP Levels Produced by Different Mechanisms

As glucose-dependent insulinotropic polypeptide (GIP) possesses pro-adipogenic action, the suppression of the GIP hypersecretion seen in obesity might represent a novel therapeutic approach to the treatment of obesity. However, the mechanism of GIP hypersecretion remains largely unknown. In the present study, we investigated GIP secretion in two mouse models of obesity: High-fat diet-induced obese (DIO) mice and leptin-deficient Lep^ob/ob mice. In DIO mice, plasma GIP was increased along with an increase in GIP mRNA expression in the lower small intestine. Despite the robust alteration in the gut microbiome in DIO mice, co-administration of maltose and the α-glucosidase inhibitor (α-GI) miglitol induced the microbiome-mediated suppression of GIP secretion. The plasma GIP levels of Lep^ob/ob mice were also elevated and were suppressed by fat transplantation. The GIP mRNA expression in fat tissue was not increased in Lep^ob/ob mice, while the expression of an interleukin-1 receptor antagonist (IL-1Ra) was increased. Fat transplantation suppressed the expression of IL-1Ra. The plasma IL-1Ra levels were positively correlated with the plasma GIP levels. Accordingly, although circulating GIP levels are increased in both DIO and Lep^ob/ob mice, the underlying mechanisms differ, and the anti-obesity actions of α-GIs and leptin sensitizers may be mediated partly by the suppression of GIP secretion.

Head-to-Head Comparison of the Hypoglycemic Efficacy and Safety Between Dipeptidyl Peptidase-4 Inhibitors and α-Glucosidase Inhibitors in Patients With Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

Background: The α-glucosidase inhibitors (AGIs) are commonly prescribed in Asian patients with type 2 diabetes mellitus (T2DM), but with a high incidence of gastrointestinal side effects. This study was aimed to compare the efficacy and safety of dipeptidyl peptidase-4 (DPP4) inhibitors and AGIs in T2DM patients in a meta-analysis.

Methods: Randomized controlled trials were identified via systematic search of PubMed, Embase, and Cochrane’s Library databases from inception to February, 2019. Meta-analyses were performed via a random or a fixed effect model according to the heterogeneity.

Results: Eighteen studies with a total of 4,051 patients with T2DM were included. The DPP4 inhibitors were associated with lower reduction of glycosylated hemoglobin (HbA1c) as compared with AGIs [weighed mean difference (WMD): −0.37%, p < 0.001]. Subgroup analyses indicated that the benefit of DPP4 inhibitors as compared with AGIs on HbA1c were independent of study design, scale, baseline HbA1c, with or without concurrent medications, or follow-up durations. Moreover, compared to AGIs, DPP4 inhibitors was associated with lower reductions of fasting blood glucose (WMD: −0.53 mmol/L, P < 0.001) and postprandial glucose at 2h (WMD: −0.60 mmol/L, P = 0.04), moderately increased body weight (WMD: 0.34 kg, P = 0.02), and decreased risk of gastrointestinal adverse events [risk ratio (RR): 0.48, P < 0.001], but unaffected risk of symptomatic hypoglycemia (RR: 0.96, P = 0.90).

Conclusions: The DPP4 inhibitors are superior to AGIs in T2DM patients for better glycemic control and lower risks of gastrointestinal side effects.

Diabesity and antidiabetic drugs

The prevalence of "diabesity" - diabetes related to obesity - has increased tremendously over the past few decades because of the global obesity epidemic. Although bariatric surgery is the best treatment option for patients with diabesity, a majority of patients are managed only with antidiabetic drugs for various reasons. Diabetes control with antidiabetic agents may affect diabesity outcomes positively or negatively because of their effects on body weight and other metabolic parameters. For this reason, rational use of anti-diabetic medications is imperative to optimise long-term management of diabesity. Understanding the molecular mechanisms of antidiabetic drugs and/or drug combinations on diabesity outcomes are therefore important not only for the basic scientists but also for clinicians. This review explores the molecular signalling cascades of antidiabetic medications in the management of diabesity.