A Narrative Review of Potential Future Antidiabetic Drugs: Should We Expect More?

Trends in Antidiabetic Drug Discovery: FDA Approved Drugs, New Drugs in Clinical Trials and Global Sales

Type 2 diabetes mellitus (T2DM) continues to be a substantial medical problem due to its increasing global prevalence and because chronic hyperglycemic states are closely linked with obesity, liver disease and several cardiovascular diseases. Since the early discovery of insulin, numerous antihyperglycemic drug therapies to treat diabetes have been approved, and also discontinued, by the United States Food and Drug Administration (FDA). To provide an up-to-date account of the current trends of antidiabetic pharmaceuticals, this review offers a comprehensive analysis of the main classes of antihyperglycemic compounds and their mechanisms: insulin types, biguanides, sulfonylureas, meglitinides (glinides), alpha-glucosidase inhibitors (AGIs), thiazolidinediones (TZD), incretin-dependent therapies, sodium-glucose cotransporter type 2 (SGLT2) inhibitors and combinations thereof. The number of therapeutic alternatives to treat T2DM are increasing and now there are nearly 60 drugs approved by the FDA. Beyond this there are nearly 100 additional antidiabetic agents being evaluated in clinical trials. In addition to the standard treatments of insulin therapy and metformin, there are new drug combinations, e.g., containing metformin, SGLT2 inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors, that have gained substantial use during the last decade. Furthermore, there are several interesting alternatives, such as lobeglitazone, efpeglenatide and tirzepatide, in ongoing clinical trials. Modern drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists, DPP4 inhibitors and SGLT2 inhibitors have gained popularity on the pharmaceutical market, while less expensive over the counter alternatives are increasing in developing economies. The large heterogeneity of T2DM is also creating a push towards more personalized and accessible treatments. We describe several interesting alternatives in ongoing clinical trials, which may help to achieve this in the near future.

Inhibition of the carbohydrate-hydrolyzing enzymes α-amylase and α-glucosidase by hydroxylated xanthones

Xanthones are oxygen-containing heterocyclic compounds that exhibit a wide range of biological and pharmacological properties. Some natural and synthetic derivatives have been identified for their antidiabetic profile, mainly as α-glucosidase...

Comparison of Efficacy and Safety Profile of Sodium-Glucose Cotransporter-2 Inhibitors as Add-On Therapy in Patients With Type 2 Diabetes

Background Type 2 diabetes is a chronic metabolic disorder that is escalating at an alarming rate worldwide. Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are recent oral antihyperglycemic drugs (OADs) with a unique mechanism of action. Objectives This study aimed compared the efficacy and safety profiles of two SGLT-2 inhibitors, empagliflozin and dapagliflozin, in patients with type 2 diabetes as add-on therapy to traditional first-line OADs. Methods We conducted a randomized controlled trial comparing empagliflozin and dapagliflozin in patients with type 2 diabetes. Patients were included in the study if they had type 2 diabetes with inadequate glycemic control, defined as glycated hemoglobin (HbA1c) of 7.5% to 11.0%, treated with conventional first-line OADs. Study participants were randomly assigned into two groups. Group A patients received oral empagliflozin, 10 to 25 mg, and Group B patients received oral dapagliflozin, 5 to 10 mg, for 12 weeks. The primary endpoint was the efficacy profile for each SGLT-2 agent in terms of body weight changes, body mass index (BMI), fasting blood glucose (FBG), and HbA1c. The secondary endpoint was to determine the safety and tolerability profiles of each SGLT-2 agent. Results After 12 weeks of treatment, the mean body weight was reduced significantly in both groups from baseline (empagliflozin: -3.2 kg ± 5.5 kg, p = 0.003; dapagliflozin -2.1 kg ± 4.6 kg, p = 0.008). However, the mean body weight reduction between groups was not statistically significant (p = 0.078). BMI was significantly reduced in both groups (empagliflozin from 28.5 ± 4.9 kg/m2 to 25.8 ± 5.2 kg/m2, p = 0.002; dapagliflozin from 29 ± 5.2 kg/m2 to 27.7 ± 4.8 kg/m2, p = 0.003). However, the patients who received empagliflozin experienced a significantly greater reduction in BMI than patients who received dapagliflozin (p = 0.007). The mean FBG was also reduced in both study groups (empagliflozin: -88.5 mg/dL ± 39.7 mg/dl, p = 0.003; dapagliflozin: -59.8 mg/dL ± 48.5 mg/dL; p = 0.007). However, the patients who received empagliflozin experienced a significantly greater reduction in mean FBG than patients who received dapagliflozin (p = 0.001). HbA1c was also significantly reduced in both groups (empagliflozin: -2.1% ± 1.1%, p = 0.002; dapagliflozin: -1.4% ± 0.9%; p = 0.004). However, patients who received empagliflozin experienced a significantly greater reduction in HbA1c than patients who received dapagliflozin (p = 0.001). The tolerability profiles of both SGLT-2 agents were quite good, and no major adverse effects were reported in the study groups. Urinary infection occurred more often in patients who received dapagliflozin (9.3%) than in patients who received empagliflozin (4.5%; p = 0.002). Patients in the dapagliflozin group also had a higher incidence of genital infections (7.3%) than those in the empagliflozin group (3.8%; p = 0.001). Conclusion Both empagliflozin and dapagliflozin demonstrated excellent efficacy and safety profiles in our study. These agents should be considered as add-on therapy in patients with type 2 diabetes taking conventional first-line OADs.

Flavonoids as potential agents in the management of type 2 diabetes through the modulation of α-amylase and α-glucosidase activity: a review

Type 2 diabetes (T2D) is one of the most prevalent metabolic diseases worldwide and is characterized by increased postprandial hyperglycemia (PPHG). α-Amylase and α-glucosidase inhibitors have been shown to slow the release of glucose from starch and oligosaccharides, resulting in a delay of glucose absorption and a reduction in postprandial blood glucose levels. Since current α-glucosidase inhibitors used in the management of T2D, such as acarbose, have been associated to strong gastrointestinal side effects, the search for novel and safer drugs is considered a hot topic of research. Flavonoids are phenolic compounds widely distributed in the Plant Kingdom and important components of the human diet. These compounds have shown promising antidiabetic activities, including the inhibition of α-amylase and α-glucosidase. The aim of this review is to provide an overview on the scientific literature concerning the structure-activity relationship of flavonoids in inhibiting α-amylase and α-glucosidase, including their type of inhibition and experimental procedures applied. For this purpose, a total of 500 compounds is covered in this review. Available data may be considered of high value for the design and development of novel flavonoid derivatives with effective and potent inhibitory activity against those carbohydrate-hydrolyzing enzymes, to be possibly used as safer alternatives for the regulation of PPHG in T2D.

ASBT(SLC10A2): A promising target for treatment of diseases and drug discovery

Bile acids has gradually become a new focus in various diseases, and ASBT as a transporter responsible for the reabsorption of ileal bile acids, is a key hinge associated to the bile acids-cholesterol balance and bile acids of enterohepatic circulation. The cumulative studies have also shown that ASBT is a promising target for treatment of liver, gallbladder, intestinal and metabolic diseases. This article briefly reviewed the process of bile acids enterohepatic circulation, as well as the regulations of ASBT expression, covering transcription factors, nuclear receptors and gut microbiota. In addition, the relationship between ASBT and various diseases were discussed in this paper. According to the structural classification of ASBT inhibitors, the research status of ASBT inhibitors and potential ASBT inhibitors of traditional Chinese medicine (such resveratrol, jatrorrhizine in Coptis chinensis) were summarized. This review provides a basis for the development of ASBT inhibitors and the treatment strategy of related diseases.

Structural Specificity of Flavonoids in the Inhibition of Human Fructose 1,6-Bisphosphatase

Liver fructose 1,6-bisphosphatase (FBPase) is a recognized regulatory enzyme of the gluconeogenesis pathway, which has emerged as a valid target to control gluconeogenesis-mediated overproduction of glucose. As such, the management of diabetes with FBPase inhibitors represents a potential alternative for the currently used antidiabetic agents. In this study, the FBPase inhibition of a panel of 55 structurally related flavonoids was tested, through a microanalysis screening system. Then, a subset of seven active inhibitors and their close chemical relatives were further evaluated by molecular dynamics (MD) simulations using a linear interaction energy (LIE) approach. The results obtained showed that D14 (herbacetin) was the most potent inhibitor, suggesting that the presence of -OH groups at the C-3, C-4', C-5, C-7, and C-8 positions, as well as the double bond between C-2 and C-3 and the 4-oxo function at the pyrone ring, are favorable for the intended effect. Furthermore, D14 (herbacetin) is stabilized by a strong interaction with the Glu30 side chain and the Thr24 backbone of FBPase. This is the first investigation studying the in vitro inhibitory effect of a panel of flavonoids against human liver FBPase, thus representing a potentially important step for the search and design of novel inhibitors of this enzyme.

Reducing Glucokinase Activity to Enhance Insulin Secretion: A Counterintuitive Theory to Preserve Cellular Function and Glucose Homeostasis

Pancreatic beta-cells are the only cells in the body that can synthesize and secrete insulin. Through the process of glucose-stimulated insulin secretion, beta-cells release insulin into circulation, stimulating GLUT4-dependent glucose uptake into peripheral tissue. Insulin is normally secreted in pulses that promote signaling at the liver. Long before type 2 diabetes is diagnosed, beta-cells become oversensitive to glucose, causing impaired pulsatility and overstimulation in fasting levels of glucose. The resulting hypersecretion of insulin can cause poor insulin signaling and clearance at the liver, leading to hyperinsulinemia and insulin resistance. Continued overactivity can eventually lead to beta-cell exhaustion and failure at which point type 2 diabetes begins. To prevent or reverse the negative effects of overstimulation, beta-cell activity can be reduced. Clinical studies have revealed the potential of beta-cell rest to reverse new cases of diabetes, but treatments lack durable benefits. In this perspective, we propose an intervention that reduces overactive glucokinase activity in the beta-cell. Glucokinase is known as the glucose sensor of the beta-cell due to its high control over insulin secretion. Therefore, glycolytic overactivity may be responsible for hyperinsulinemia early in the disease and can be reduced to restore normal stimulus-secretion coupling. We have previously reported that reducing glucokinase activity in prediabetic mouse islets can restore pulsatility and enhance insulin secretion. Building on this counterintuitive finding, we review the importance of pulsatile insulin secretion and highlight how normalizing glucose sensing in the beta cell during prediabetic hyperinsulinemia may restore pulsatility and improve glucose homeostasis.

Recent advances in managing/understanding the metabolic syndrome

The metabolic syndrome (MetS) concept gathers in a single entity a set of metabolic abnormalities that have in common a close relationship with ectopic deposit of lipids, insulin resistance, and chronic low-grade inflammation. It is a valuable teaching tool to help health professionals to understand and integrate the consequences of lipotoxicity and the adverse metabolic consequences of insulin resistance. Also, it is useful to identify subjects with a high risk for having incident type 2 diabetes. Systems biology studies have gained a prominent role in understanding the interaction between adipose tissue dysfunction, insulin action, and the MetS traits and co-morbidities (that is, non-alcoholic steatohepatitis, or NASH). This approach may allow the identification of new therapeutic targets (that is, de novo lipogenesis inhibitors for NASH). Treatment targets on MetS are the adoption of a healthy lifestyle, weight loss, and the control of the co-morbidities (hyperglycemia, dyslipidemia, arterial hypertension, among others). The long-term goals are the prevention of type 2 diabetes, cardiovascular events, and other MetS-related outcomes. In the last few decades, new drugs derived from the identification of innovative treatment targets have come on the market. These drugs have positive effects on more than one MetS component (that is, hyperglycemia and weight control). New potential treatment targets are under study.