Discovery and preclinical profile of teneligliptin (3-[(2S,4S)-4-[4-(3-methyl-1-phenyl-1H-pyrazol-5-yl)piperazin-1-yl]pyrrolidin-2-ylcarbonyl]thiazolidine): A highly potent, selective, long-lasting and orally active dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes

Identification of a Novel Scaffold for Inhibition of Dipeptidyl Peptidase-4

Dipeptidyl peptidase-4 (DPP-4) is considered a major drug target for type 2 diabetes mellitus (T2DM). In addition to T2DM, a regulatory role of DPP-4 was also found in cardiovascular diseases. Existing DPP-4 inhibitors have been reported to have several adverse effects. In this study, a computer-aided drug design approach and its use to detect a novel class of inhibitor for DPP-4 are reported. Through structure and pharmacophore-based screening, we identified 13 hit compounds from an ∼4-million-compound library. Physical interactions of these hits with DPP-4 were studied using docking and explicit solvent molecular dynamics (MD) simulations. Later, MMPBSA binding energy was calculated for the ligand/protein simulation trajectories to determine the stability of compounds in the binding cavity. These compounds have a novel scaffold and exhibited a stable binding mode. "Best-in-screen" compounds (or their closest available analogs) were resourced and their inhibition of DPP-4 activity was experimentally validated using an in vitro enzyme activity assay in the presence of 100 and 10 μM compounds. These assays identified a compound with a spirochromanone center with 53% inhibition activity at a 100 μM concentration. A further five spirochromanone compounds were synthesized and examined in silico and in vitro; again, one compound showed 53% inhibitory activity action at 100 μM. Overall, this study identified two novel "spirochromanone" compounds that lowered DPP-4 activity by more than ∼50% at 100 μM. This study also showed the impact of fast in silico drug design techniques utilizing virtual screening and MD to identify novel scaffolds to bind and inhibit DPP-4. Spirochromanone motif identified here may be used to design molecules to achieve drug-like inhibitory action against DPP-4.

Teneligliptin inhibits lipopolysaccharide-induced cytotoxicity and inflammation in dental pulp cells

Diabetes mellitus is one of the most common health threatening disorders. Patients with chronic diabetes are at high risk of contracting oral diseases, including dental pulp damage. In this study, we reviewed how Teneligliptin, a commonly used anti-diabetic agent, protected dental pulp cells from lipopolysaccharide (LPS)-induced cytotoxicity and improved their viability. The dental pulp cells treated with Teneligliptin were resistant to LPS-induced reactive oxygen species (ROS) and its byproduct 4-hydroxynonenal (4-HNE) generation. The Teneligliptin recovered LPS-induced a reduction of cellular glutathione and produced cytokine including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Mechanistically, we found that Teneligliptin suppressed LPS- that caused an expression of the cell surface receptor toll like receptor 4 (TLR-4) and the activation of JNK kinase and activator protein 1 (AP1) as well as the nuclear factor-κB (NF-κB) signal pathways. Collectively, our study demonstrates that the molecular mechanism Teneligliptin is a protective anti-diabetic agent in dental pulp cells and it has the potential to treat diabetes-associated dental pulp diseases.

Synthesis, In Vitro Antimicrobial and Cytotoxic Activities of Some New Pyrazolo[1,5-a]pyrimidine Derivatives

A new series of pyrazole 4⁻7 and pyrazolo[1,5-a]pyrimidine 8⁻13 were synthesized by using a simple, efficient procedure, and screened for their in-vitro antimicrobial and antitumor activities. Symmetrical and asymmetrical 3,6-diarylazo-2,5,7-triaminopyrazolo[1,5-a]pyrimidine were synthesized by the conventional method and also subjected to microwave irradiation and under ultrasound conditions. The biological results revealed that most of the tested compounds proved to be active as antibacterial and antifungal agents. The antitumor activity of the synthesized compounds was evaluated against human cancer cell lines, MCF-7, HCT-116, and HepG-2, as compared with Doxorubicin as a control.

Teneligliptin versus sitagliptin in Korean patients with type 2 diabetes inadequately controlled with metformin and glimepiride: A randomized, double-blind, non-inferiority trial

AIM

To assess the efficacy and safety of add-on therapy with the dipeptidyl peptidase-4 inhibitor teneligliptin compared with sitagliptin in patients with type 2 diabetes (T2DM) inadequately controlled with metformin and glimepiride.

MATERIALS AND METHODS

This was a phase 3, randomized, double-blind, non-inferiority study of adult Korean subjects with T2DM (n = 201), with HbA1c ranging from 7.0% to 11.0%, on stable doses of metformin plus glimepiride. Subjects were randomized in a 1:1 fashion to receive either oral teneligliptin 20 mg or sitagliptin 100 mg for 24 weeks. The primary endpoint was change from baseline in HbA1c.

RESULTS

At baseline, mean age was 60.56 ± 9.41 years, body mass index was 25.23 ± 2.85 kg/m² and HbA1c was 8.11% ± 0.79%. At 24 weeks, both groups achieved significant reductions from baseline in HbA1c (teneligliptin, -1.03% ± 0.10% [P < 0.0001]; sitagliptin, -1.02% ± 0.10% [P < 0.0001]). The inter-group difference was -0.01% (95% confidence interval [CI]: -0.28, 0.26; P = 0.9497); the upper limit of the 95% CI was within the preset limit for non-inferiority (0.4%). There were no significant differences between groups in the proportion of patients achieving HbA1c targets, or changes from baseline in fasting plasma glucose, body weight or lipid levels at 24 weeks. Rates of adverse events (teneligliptin, n = 63 [61.76%]; sitagliptin, n = 61 [62.24%]; P = 0.9442) and hypoglycaemia (teneligliptin, n = 32 [31.37%]; sitagliptin, n = 28 [28.57%]; P = 0.6656) were similar.

CONCLUSION

Teneligliptin was non-inferior to sitagliptin in the context of triple therapy for T2DM and is an important option in this setting.

Evaluation of Teneligliptin Effects on Transcriptional Activity of PPARγ in Cell-Based Assays

BACKGROUND

The antidiabetic drug teneligliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor with a thiazolidine-specific structure. This study aimed to investigate whether teneligliptin can activate PPARγ directly and/or indirectly in cell-based assays.

METHODS

Promoter assays using the reporter construct driven under the control of the SV40 promoter and the PPAR response element (PPRE) were performed. Luciferase activity was measured after a 3-day incubation of vector-transduced cells with various concentrations of teneligliptin.

RESULTS

Treatment of the cells with 50 μM teneligliptin significantly transactivated a reporter gene. The presence of the PPARγ antagonist, GW9662, did not affect the activation of PPRE-reporter expression by teneligliptin.

CONCLUSION

We found that teneligliptin could increase PPARγ activity in cell-based assays irrespective of the PPARγ ligand-binding domain.

Efficacy and Safety of Teneligliptin in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Teneligliptin is a 3rd-generation dipeptidyl peptidase-4 (DPP-4) inhibitor. There is a limited evidence regarding the effect of teneligliptin. Therefore, this study is to assess the efficacy and safety of teneligliptin in type 2 diabetes mellitus (T2DM) patients with inadequately glycemic controlled. Methods: A search of PubMed, Medline, Embase, and The Cochrane Library during 2000.01-2018.03 was performed for randomized controlled trials of teneligliptin compared to placebo in patients with T2DM with monotherapy or add-on treatment. Results: Ten trials with 2119 patients were analyzed. Teneligliptin produced absolute reductions in glycated hemoglobin A1c (HbA1c) levels (weighted mean difference (WMD) 0.82%, 95% confidence interval (CI) [-0.91 to -0.72], p < 0.00001) compared with placebo. However, after 36-42 weeks of follow-up (open-label), HbA1c level rise higher than duration (double-blind) in teneligliptin group. Teneligliptin led to greater decrease of fasting plasma glucose (FPG) level (vs. placebo, WMD -18.32%, 95% CI [-21.05 to -15.60], p < 0.00001). Teneligliptin also significantly decreased the 2 h post-prandial plasma glucose (2 h PPG) (WMD -46.94%, 95% CI [-51.58 to -42.30], p < 0.00001) and area under the glucose plasma concentration-time curve from 0 to 2 h (AUC0-2h) for PPG (WMD -71.50%, 95% CI [-78.09 to -64.91], p < 0.00001) compared with placebo. Patients treated with teneligliptin achieved increased homeostasis model assessment of β cell function (HOMA-β) with 9.31 (WMD, 95% CI [7.78-10.85], p < 0.00001). However, there was no significant difference between teneligliptin and placebo in overall adverse effects (0.96 risk ratio (RR), 95% CI [0.87, 1.06], p = 0.06). The risks of hypoglycemia were not significantly different between teneligliptin and placebo (1.16 RR, 95% CI [0.59, 2.26], p = 0.66). Conclusions: Teneligliptin improved blood glucose levels and β-cells function with low risk of hypoglycemia in patients with T2DM. Common adverse effects of teneligliptin including hypoglycemia were identified and reviewed. Risks of cardiovascular events are less certain, and more data for long-term effects are needed.

Activity and selectivity cliffs for DPP-IV inhibitors: Lessons we can learn from SAR studies and their application to virtual screening

The inhibition of dipeptidyl peptidase-IV (DPP-IV) has emerged over the last decade as one of the most effective treatments for type 2 diabetes mellitus, and consequently (a) 11 DPP-IV inhibitors have been on the market since 2006 (three in 2015), and (b) 74 noncovalent complexes involving human DPP-IV and drug-like inhibitors are available at the Protein Data Bank (PDB). The present review aims to (a) explain the most important activity cliffs for DPP-IV noncovalent inhibition according to the binding site structure of DPP-IV, (b) explain the most important selectivity cliffs for DPP-IV noncovalent inhibition in comparison with other related enzymes (i.e., DPP8 and DPP9), and (c) use the information deriving from this activity/selectivity cliff analysis to suggest how virtual screening protocols might be improved to favor the early identification of potent and selective DPP-IV inhibitors in molecular databases (because they have not succeeded in identifying selective DPP-IV inhibitors with IC₅₀ ≤ 100 nM). All these goals are achieved with the help of available homology models for DPP8 and DPP9 and an analysis of the structure-activity studies used to develop the noncovalent inhibitors that form part of some of the complexes with human DPP-IV available at the PDB.

Efficacy and Safety of Teneligliptin 40 mg in Type 2 Diabetes: A Pooled Analysis of Two Phase III Clinical Studies

INTRODUCTION

Teneligliptin, an antihyperglycemic agent belonging to the dipeptidyl peptidase-4 inhibitor class, is usually prescribed at a dose of 20 mg/day. In Japan, the dose can be increased to 40 mg/day if needed. We examined the treatment response when the teneligliptin dose was increased from 20 to 40 mg in a post hoc pooled analysis of data from two 52-week, open-label, phase III clinical trials of teneligliptin 20-40 mg/day as monotherapy or combination treatment in Japanese patients with type 2 diabetes.

METHODS

In both studies, patients received teneligliptin 20 mg for at least 28 weeks; thereafter the dose was increased if glycemic control was inadequate. The data set for this post hoc analysis comprised those patients whose teneligliptin dose was increased to 40 mg at week 28 (N = 204). We assessed (i) the proportion of patients achieving HbA1c reduction after teneligliptin dose increase [≤ - 0.1% change in HbA1c during weeks 28-52 (24 weeks); responders] and (ii) the response to teneligliptin 40 mg according to whether or not patients experienced HbA1c re-elevation (≥ 0.1% increase) during 28 weeks of teneligliptin 20 mg.

RESULTS

Of 204 patients, 108 (52.9%) showed a response to teneligliptin 40 mg (HbA1c change ≤ - 0.1% during weeks 28-52) and had mean (± SD) HbA1c reduction of 0.50 ± 0.44%. Of patients showing re-elevation of HbA1c during treatment with teneligliptin 20 mg, 89/143 (62.2%) achieved HbA1c reduction after dose increase to 40 mg. Logistic regression analyses suggested that change in body weight is one of the parameters linked to HbA1c reduction after dose increase to teneligliptin 40 mg. The incidence of adverse events was not changed after teneligliptin dose increase.

CONCLUSION

Increasing the dosage of teneligliptin from 20 to 40 mg/day has potential as a well-tolerated and effective option for treating type 2 diabetes.

FUNDING

Mitsubishi Tanabe Pharma Corporation.

Crystal structures of a bacterial dipeptidyl peptidase IV reveal a novel substrate recognition mechanism distinct from that of mammalian orthologues

Dipeptidyl peptidase IV (DPP IV, DPP4, or DAP IV) preferentially cleaves substrate peptides with Pro or Ala at the P1 position. The substrate recognition mechanism has been fully elucidated for mammalian DPP IV by crystal structure analyses but not for bacterial orthologues. Here, we report the crystal structures of a bacterial DPP IV (PmDAP IV) in its free form and in complexes with two kinds of dipeptides as well as with a non-peptidyl inhibitor at 1.90 to 2.47 Å resolution. Acyl-enzyme intermediates were observed for the dipeptide complexes of PmDAP IV, whereas tetrahedral intermediates were reported for the oligopeptide complexes of mammalian DPP IVs. This variation reflects the different structural environments of the active site Arg residues, which are involved in the recognition of a substrate carbonyl group, of mammalian and bacterial enzymes. A phylogenetic analysis revealed that PmDAP IV is a closer relative of dipeptidyl peptidases 8 and 9 (DPP8 and DPP9, DPP IV-family enzymes) than DPP IV. These results provide new insights into the substrate recognition mechanism of bacterial DAP IVs and may assist in the development of selective inhibitors for DAP IVs from pathogenic asaccharolytic bacteria, which utilise proteins or peptides as an energy source.

Synthesis and Pharmacological Activities of Pyrazole Derivatives: A Review

Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesis methods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported.

Synthesis and Pharmacological Activities of Pyrazole Derivatives: A Review

Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesis methods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported.

Evaluation of treatment satisfaction, efficacy and safety of dipeptidyl peptidase-4 inhibitors in geriatric patients with type 2 diabetes mellitus: A cross-sectionalcomparative study

Introduction

Dipeptidyl peptidase 4 (DPP4) inhibitors are attractive agents to be used in the elderly patients with Type 2 diabetes mellitus (T2DM) because of their beneficial effects.

Methods

In this cross-sectional, observational study, we evaluated and compared the treatment satisfaction using Diabetes Treatment Satisfaction Questionnaire (DTSQ) in two groups (i.e., regimens containing DPP4 inhibitors vs. other regimens). Efficacy was evaluated by assessing and comparing the glycosylated hemoglobin (HbA1c) values and the percentage of patients who achieved the glycemic control (HbA1c <7%). The adverse drug reactions (ADRs) were also recorded and compared among two groups.

Results

A total of 115 patients participated in the study (42 in Group 1 and 73 in Group 2). Significantly better DTSQ scores were observed among Group 1 patients in terms of DTSQ score total (P = 0.01) and DTSQ score for perception of hyperglycemia (P = 0.008) as compared to Group 2 patients. Significant difference was observed in HbA1c values among two groups (P = 0.02, 95% confidence interval [CI], 0.06-1.14). Also, significantly higher proportion of patients had achieved glycemic control, i.e., HbA1c <7% in Group 1 as compared to Group 2 (P = 0.002, 95% CI, 11.8%-48.1%). Significantly higher number of ADRs were observed among Group 1 patients as compared to Group 2 (P = 0.003).

Conclusion

DPP4 inhibitors seem to offer better treatment satisfaction and efficacy in geriatric T2DM patients but at the expense of increased frequency of ADRs; however, further research is warranted.

Diastereoselective One Pot Five-Component Reaction toward 4-(Tetrazole)-1,3-Oxazinanes

A diastereoselective one pot five-component reaction toward the synthesis of 4-(tetrazole)-1,3-oxazinanes has been reported. The sonication-accelerated, catalyst-free, simple, general and highly time efficient, Asinger-Ugi-tetrazole reaction was used for the synthesis of diverse 4-(tetrazole)-1,3-oxazinanes. The reaction exhibit excellent diastereoselectivity and broad substrate scope.

Unique binding mode of Evogliptin with human dipeptidyl peptidase IV

Evogliptin ((R)-4-((R)-3-amino-4-(2,4,5-trifluorophenyl)butanoyl)-3-(tert-butoxymethyl) piperazine-2-one)) is a highly potent selective inhibitor of dipeptidyl peptidase IV (DPP4) that was approved for the treatment of type 2 diabetes in South Korea. In this study, we report the crystal structures of Evogliptin, DA-12166, and DA-12228 (S,R diastereomer of Evogliptin) complexed to human DPP4. Analysis of both the structures and inhibitory activities suggests that the binding of the trifluorophenyl moiety in the S₁ pocket and the piperazine-2-one moiety have hydrophobic interactions with Phe357 in the S₂ extensive subsite, and that the multiple hydrogen bonds made by the (R)-β-amine group in the S₂ pocket and the contacts made by the (R)-tert-butyl group with Arg125 contribute to the high potency observed for Evogliptin.

Synthesis of substituted 2H-benzo[e]indazole-9-carboxylate as a potent antihyperglycemic agent that may act through IRS-1, Akt and GSK-3β pathways

Based on high throughput screening of our chemical library, we identified two 4,5-dihydro-2H-benzo[e]indazole derivatives (5d and 5g), which displayed a significant effect on glucose uptake in L6 skeletal muscle cells. Based on these lead molecules, a series of benzo[e]indazole derivatives were prepared. Among all the synthesized dihydro-2H-benzo[e]indazoles, 8-(methylthio)-2-phenyl-6-p-tolyl-4,5-dihydro-2H-benzo[e]indazole-9-carboxylate (5e) showed significant glucose uptake stimulation in L6 skeletal muscle cells, even better than lead compounds. Additionally, 5e decreased glucagon-induced glucose release in HepG2 hepatoma cells. The 2H-benzo[e]indazole 5e exerted an antihyperglycemic effect in normal, sucrose challenged streptozotocin-induced diabetic rats and type 2 diabetic db/db mice. Treatment with 5e at a dose of 30 mg kg-1 in db/db mice caused a significant decrease in triglyceride and total cholesterol levels and increased the HDL-C level in a significant manner. The mechanistic studies revealed that the 2H-benzo[e]indazole 5e significantly stimulated insulin-induced signaling at the level of IRS-1, Akt and GSK-3β in L6 skeletal muscle cells, possibly by inhibiting protein tyrosine phosphatase-1B. This new 2H-benzo[e]indazole derivative has potential for the treatment of diabetes with improved lipid profile.

Teneligliptin, a Chemotype Prolyl-Thiazolidine-Based Novel Dipeptidyl Peptidase-4 Inhibitor with Insulin Sensitizing Properties

BACKGROUND AND OBJECTIVES

Teneligliptin, a chemotype prolyl-thiazolidine-based novel dipeptidyl peptidase (DPP)-4 inhibitor, was preliminarily shown to reduce insulin resistance in patients with type 2 diabetes mellitus (T2DM). The objective of this study is to further investigate the insulin sensitising properties of teneligliptin in comparison to those of sitagliptin.

METHODS

Treatment-naïve subjects with T2DM were administered 20 mg/day teneligliptin monotherapy (n = 45). As a comparator, 25-50 mg/day sitagliptin monotherapy was performed in a non-randomized manner (n = 71). No other drugs were administered. At 3 months, levels of diabetic parameters were compared with those at baseline.

RESULTS

At 3 months, while similar reductions of glycated hemoglobin (HbA1c) levels were observed with these two drugs, indexes for insulin sensitivity [homeostasis model assessment (HOMA)-R and 20/(C-peptide × fasting blood glucose (FBG)) levels] ameliorated only with teneligliptin. Then, the subjects were divided into two groups representing distinct degrees of insulin resistance; high HOMA-R (≥4) and low HOMA-R (<2) groups. With teneligliptin, similar decreases of HbA1c levels were observed in high (9.85-7.66 %, p < 0.0005) and low (10.12-8.51 %, p < 0.01) HOMA-R groups. HOMA-R (-32.6 %, p < 0.05) and non-high density lipoprotein cholesterol (non-HDL-C, -6 %, p < 0.05) levels significantly decreased and 20/(C-peptide × FBG) levels significantly increased (53 %, p < 0.001) in high HOMA-R group. HOMA-B levels increased in both groups with significant inter-group differences (+101.7 % in low HOMA-R group vs. +55.4 % in high HOMA-R group). Group 2. With sitagliptin, similar decreases of HbA1c levels were observed from those of teneligliptin in either high or low HOMA-R group, but no changes of HOMA-R, non-HDL-C or 20/(C-peptide × FBG) levels were noted. Increases of HOMA-B levels with sitagliptin were comparable to those with teneligliptin in either high or low HOMA-R group.

CONCLUSIONS

These results indicate that: (i) teneligliptin ameliorates insulin sensitivity and non-HDL-C levels in subjects with high degrees of insulin resistance. This is not the case with sitagliptin, though similar glycemic efficacies were observed. (ii) glycemic efficacy of teneligliptin may be determined by the balance of its capacity in modulating insulin resistance and beta-cell function depending on the degrees of baseline insulin resistance.

Comparative Binding Analysis of Dipeptidyl Peptidase IV (DPP-4) with Antidiabetic Drugs - An Ab Initio Fragment Molecular Orbital Study

Dipeptidyl peptidase IV (DPP-4) enzyme is responsible for the degradation of incretins that stimulates insulin secretion and hence inhibition of DPP-4 becomes an established approach for the treatment of type 2 diabetics. We studied the interaction between DPP-4 and its inhibitor drugs (sitagliptin 1, linagliptin 2, alogliptin 3, and teneligliptin 4) quantitatively by using fragment molecular orbital calculations at the RI-MP2/cc-pVDZ level to analyze the inhibitory activities of the drugs. Apart from having common interactions with key residues, inhibitors encompassing the DPP-4 active site extensively interact widely with the hydrophobic pocket by their hydrophobic inhibitor moieties. The cumulative hydrophobic interaction becomes stronger for these inhibitors and hence linagliptin and teneligliptin have larger interaction energies, and consequently higher inhibitory activities, than their alogliptin and sitagliptin counterparts. Though effective interaction for both 2 and 3 is at [Formula: see text] subsite, 2 has a stronger binding to this subsite interacting with Trp629 and Tyr547 than 3 does. The presence of triazolopiperazine and piperazine moiety in 1 and 4, respectively, provides the interaction to the S2 extensive subsite; however, the latter's superior inhibitory activity is not only due to a relatively tighter binding to the S2 extensive subsite, but also due to the interactions to the S1 subsite. The calculated hydrophobic interfragment interaction energies correlate well with the experimental binding affinities (KD) and inhibitory activities (IC50) of the DPP-4 inhibitors.

Teneligliptin in management of type 2 diabetes mellitus

Teneligliptin is a recently developed oral dipeptidyl peptidase 4 inhibitor indicated for the management of type 2 diabetes mellitus (T2DM) in adults along with diet and exercise. Teneligliptin has been recently available in Japan (Teneria(®)), Argentina (Teneglucon(®)), and India (Tenepure; Teneza) at relatively affordable price. This is a positive step toward the management of T2DM in developing countries, where the cost of medicine is out-of-pocket expenditure and is a limiting factor for health care. This review evaluates the efficacy and safety of teneligliptin in the management of T2DM. Teneligliptin has been systematically evaluated in T2DM as monotherapy with diet and exercise and in combination with metformin, glimepiride, pioglitazone, and insulin in short-term (12 weeks) and long-term (52 weeks) studies. These studies have reported a reduction in HbA1c of 0.8%-0.9% within 12 weeks of therapy. Two 52-week studies reported sustained improvement in glycemic control with teneligliptin. Teneligliptin has been found to be well tolerated, and the safety profile is similar to other dipeptidyl peptidase 4 inhibitors. Hypoglycemia and constipation are the main adverse events. Teneligliptin can be administered safely to patients with mild, moderate, or severe renal impairment or end-stage renal disease without dose adjustment. Similarly, it can be used in patients with mild-to-moderate hepatic impairment. Teneligliptin is effective and well tolerated and may have an important role in the management of T2DM.

DPP-4 inhibitors in diabetic complications: role of DPP-4 beyond glucose control

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are an emerging class of antidiabetic drugs that constitutes approximately fifty percent of the market share of the oral hypoglycemic drugs. Its mechanism of action for lowering blood glucose is essentially via inhibition of the rapid degradation of incretin hormones, such as glucagon-like peptide (GLP)-1 and gastric inhibitory polypeptide (GIP), thus the plasma concentration of GLP-1 increases, which promotes insulin secretion from the pancreatic β cells and suppresses glucagon secretion from the α cells. In addition to the direct actions on the pancreas, GLP-1 exhibits diverse actions on different tissues through its action on GLP-1 receptor, which is expressed ubiquitously. Moreover, DPP-4 has multiple substrates besides GLP-1 and GIP, including cytokines, chemokines, neuropeptides, and growth factors, which are involved in many pathophysiological conditions. Recently, it was suggested that DPP-4 is a new adipokine secreted from the adipose tissue, which plays an important role in the regulation of the endocrine function in obesity-associated type 2 diabetes. Consequently, DPP-4 inhibitors have been reported to exhibit cytoprotective functions against various diabetic complications affecting the liver, heart, kidneys, retina, and neurons. This review outlines the current understanding of the effect of DPP-4 inhibitors on the complications associated with type 2 diabetes, such as liver steatosis and inflammation, dysfunction of the adipose tissue and pancreas, cardiovascular diseases, nephropathy, and neuropathy in preclinical and clinical studies.

Comprehensive analysis of the Co-structures of dipeptidyl peptidase IV and its inhibitor

Background

We comprehensively analyzed X-ray cocrystal structures of dipeptidyl peptidase IV (DPP-4) and its inhibitor to clarify whether DPP-4 alters its general or partial structure according to the inhibitor used and whether DPP-4 has a common rule for inhibitor binding.

Results

All the main and side chains in the inhibitor binding area were minimally altered, except for a few side chains, despite binding to inhibitors of various shapes. Some residues (Arg125, Glu205, Glu206, Tyr662 and Asn710) in the area had binding modes to fix a specific atom of inhibitor to a particular spatial position in DPP-4. We found two specific water molecules that were common to 92 DPP-4 structures. The two water molecules were close to many inhibitors, and seemed to play two roles: maintaining the orientation of the Glu205 and Glu206 side chains through a network via the water molecules, and arranging the inhibitor appropriately at the S2 subsite.

Conclusions

Our study based on high-quality resources may provide a necessary minimum consensus to help in the discovery of a novel DPP-4 inhibitor that is commercially useful.

Electronic supplementary material

The online version of this article (doi:10.1186/s12900-016-0062-8) contains supplementary material, which is available to authorized users.

Comparative Analysis of Binding Kinetics and Thermodynamics of Dipeptidyl Peptidase-4 Inhibitors and Their Relationship to Structure

The binding kinetics and thermodynamics of dipeptidyl peptidase (DPP)-4 inhibitors (gliptins) were investigated using surface plasmon resonance and isothermal titration calorimetry. Binding of gliptins to DPP-4 is a rapid electrostatically driven process. Off-rates were generally slow partly because of reversible covalent bond formation by some gliptins, and partly because of strong and extensive interactions. Binding of all gliptins is enthalpy-dominated due to strong ionic interactions and strong solvent-shielded hydrogen bonds. Using a congeneric series of molecules which represented the intermediates in the lead optimization program of linagliptin, the onset of slow binding kinetics and development of the thermodynamic repertoire were analyzed in the context of incremental changes of the chemical structures. All compounds rapidly associated, and therefore the optimization of affinity and residence time is highly correlated. The major contributor to the increasing free energy of binding was a strong increase of binding enthalpy, whereas entropic contributions remained low and constant despite significant addition of lipophilicity.

Teneligliptin: a review in type 2 diabetes

Oral teneligliptin [Teneglucon® (Argentina)], a dipeptidyl peptidase-4 inhibitor, is indicated for the treatment of adults with type 2 diabetes (T2DM). This article reviews the pharmacology, therapeutic efficacy and tolerability of teneligliptin in the treatment of adults with T2DM. In 12- or 16-week, placebo-controlled phase 2 and 3 trials, oral teneligliptin 20 or 40 mg once daily, as monotherapy or in combination with metformin, glimepiride or pioglitazone improved glycaemic control, including in patients with end-stage renal disease, and was generally well tolerated. Most treatment-emergent adverse events were of mild intensity and relatively few patients discontinued treatment because of these events. Improvements in glycaemic control observed in short-term trials were maintained at 52 weeks in extension phases of these trials and in 52-week interventional studies, with no new safety concerns identified during this period. In the absence of direct head-to-head clinical trials, the position of teneligliptin relative to other antidiabetic agents in the management of T2DM remains to be determined. In the meantime, teneligliptin is a useful treatment option for adults with T2DM who have not responded adequately to diet and exercise regimens, or the addition of antidiabetic drugs.

Clinical pharmacology of dipeptidyl peptidase 4 inhibitors indicated for the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycaemic control without causing weight gain or increasing hypoglycaemic risk in patients with type 2 diabetes mellitus (T2DM). The eight available DPP-4 inhibitors, including alogliptin, anagliptin, gemigliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin, and vildagliptin, are small molecules used orally with identical mechanism of action and similar safety profiles in patients with T2DM. DPP-4 inhibitors may be used as monotherapy or in double or triple combination with other oral glucose-lowering agents such as metformin, thiazolidinediones, or sulfonylureas. Although DPP-4 inhibitors have the same mode of action, they differ by some important pharmacokinetic and pharmacodynamic properties that may be clinically relevant in some patients. The main differences between the eight gliptins include: potency, target selectivity, oral bioavailability, elimination half-life, binding to plasma proteins, metabolic pathways, formation of active metabolite(s), main excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. The off-target inhibition of selective DPP-4 inhibitors is responsible for multiorgan toxicities such as immune dysfunction, impaired healing, and skin reactions. As a drug class, the DPP-4 inhibitors have become accepted in clinical practice due to their excellent tolerability profile, with a low risk of hypoglycaemia, a neutral effect on body weight, and once-daily dosing. It is unknown if DPP-4 inhibitors can prevent disease progression. More clinical studies are needed to validate the optimal regimens of DPP-4 inhibitors for the management of T2DM when their potential toxicities are closely monitored.

Comparative review of dipeptidyl peptidase-4 inhibitors and sulphonylureas

Type 2 diabetes (T2DM) is a progressive disease, and pharmacotherapy with a single agent does not generally provide durable glycaemic control over the long term. Sulphonylurea (SU) drugs have a history stretching back over 60 years, and have traditionally been the mainstay choice as second-line agents to be added to metformin once glycaemic control with metformin monotherapy deteriorates; however, they are associated with undesirable side effects, including increased hypoglycaemia risk and weight gain. Dipeptidyl peptidase (DPP)-4 inhibitors are, by comparison, more recent, with the first compound being launched in 2006, but the class now globally encompasses at least 11 different compounds. DPP-4 inhibitors improve glycaemic control with similar efficacy to SUs, but do not usually provoke hypoglycaemia or weight gain, are relatively free from adverse side effects, and have recently been shown not to increase cardiovascular risk in large prospective safety trials. Because of these factors, DPP-4 inhibitors have become an established therapy for T2DM and are increasingly being positioned earlier in treatment algorithms. The present article reviews these two classes of oral antidiabetic drugs (DPP-4 inhibitors and SUs), highlighting differences and similarities between members of the same class, as well as discussing the potential advantages and disadvantages of the two drug classes. While both classes have their merits, the choice of which to use depends on the characteristics of each individual patient; however, for the majority of patients, DPP-4 inhibitors are now the preferred choice.

Natural Products as Sources of New Drugs from 1981 to 2014

This contribution is a completely updated and expanded version of the four prior analogous reviews that were published in this journal in 1997, 2003, 2007, and 2012. In the case of all approved therapeutic agents, the time frame has been extended to cover the 34 years from January 1, 1981, to December 31, 2014, for all diseases worldwide, and from 1950 (earliest so far identified) to December 2014 for all approved antitumor drugs worldwide. As mentioned in the 2012 review, we have continued to utilize our secondary subdivision of a "natural product mimic", or "NM", to join the original primary divisions and the designation "natural product botanical", or "NB", to cover those botanical "defined mixtures" now recognized as drug entities by the U.S. FDA (and similar organizations). From the data presented in this review, the utilization of natural products and/or their novel structures, in order to discover and develop the final drug entity, is still alive and well. For example, in the area of cancer, over the time frame from around the 1940s to the end of 2014, of the 175 small molecules approved, 131, or 75%, are other than "S" (synthetic), with 85, or 49%, actually being either natural products or directly derived therefrom. In other areas, the influence of natural product structures is quite marked, with, as expected from prior information, the anti-infective area being dependent on natural products and their structures. We wish to draw the attention of readers to the rapidly evolving recognition that a significant number of natural product drugs/leads are actually produced by microbes and/or microbial interactions with the "host from whence it was isolated", and therefore it is considered that this area of natural product research should be expanded significantly.

Tissue distribution of teneligliptin in rats and comparisons with data reported for other dipeptidyl peptidase-4 inhibitors

We investigated the tissue distribution of teneligliptin, a dipeptidyl peptidase (DPP)-4 inhibitor, in rats, and compared it with tissue distributions previously reported for other DPP-4 inhibitors. Following the oral administration of [¹⁴ C]teneligliptin to Sprague-Dawley rats, it was predominantly distributed to the kidney and liver, followed by the lung, spleen, and pituitary gland. The elimination half-life (t_1/2 ) of [¹⁴ C]teneligliptin was 68.3 and 69.0 h in the kidney and liver, respectively; these values were about 10 times greater than the plasma t_1/2 . Of note, the elimination of [¹⁴ C]teneligliptin from tissues with high DPP-4 activity (kidney, liver, and lung) was slower in wild-type rats than in DPP-4-deficient rats, especially in the kidney. By contrast, in the heart and pancreas, which weakly express DPP-4, we observed no difference in [¹⁴ C]teneligliptin concentrations between the two animal strains. In the kidney, most radioactivity was attributable to unchanged teneligliptin from 0.5 to 72 h after administration. The marked difference in the distribution of [¹⁴ C]teneligliptin between the two strains suggests that the high binding affinity of teneligliptin for DPP-4 is involved in its tissue distribution. The currently marketed DPP-4 inhibitors are highly distributed to the liver, kidney, and lung, but the extent of tissue distribution varies greatly among the drugs. The differences in the tissue distributions of DPP-4 inhibitors might be related to differences in their pleiotropic effects. This article is protected by copyright. All rights reserved.

Synthesis, Biological Evaluation, and Molecular Docking of (R)-2-((8-(3-aminopiperidin-1-yl)-3-methyl-7-(3-methylbut-2-en-1-yl)-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-1-yl)methyl)benzonitrile as Dipeptidyl Peptidase IV Inhibitors

Type 2 diabetes (T2D) is classified as a major metabolic disorder, which has affected approximately 194 million people worldwide. DPP-IV inhibitors as a new therapy have shown several advantages over traditional antidiabetic drugs. Based on the similar binding modes of Alogliptin and Linagliptin, molecular operation was conducted via combining pharmacophore hybridization with structural optimization between the two market drugs and racemic compounds 40 and 43 were reported as DPP-IV inhibitors in our previous studies. But the majority of DPP-IV inhibitors have developed into a small molecule with certain conformation; in this study, we described the synthesis, biological evaluation, and molecular docking of corresponding enantiomers of compounds 40 and 43. The most potent inhibitor is (R)-40 (IC50  = 23.5 nm, F = 74.67%, T1/2  = 4 h), which exhibited moderate antihyperglycemic activity as compared to the standard antidiabetic drug Linagliptin in OGTT. In addition, compound (R)-40 effectively improved the pathological state of DIO mice. Molecular docking studies clarified the favorable binding affinity between compound (R)-40 and DPP-IV active site. Thus, compound (R)-40 would be entitled to further development as a drug candidate on the basis of the suitable pharmacokinetic (PK) and desirable pharmacodynamic (PD) profiles.

Pharmacokinetic and protein binding profile of peptidomimetic DPP-4 inhibitor - Teneligliptin in rats using liquid chromatography-tandem mass spectrometry

The aim of the present study is to explore pharmacokinetic and protein binding characteristics of a novel dipeptidylpeptidase-4 (DPP-4) inhibitor, teneligliptin in rats using an ultra high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). It is required for demonstrating the high protein binding nature of teneligliptin which can be extended for drug repositioning to brain disorders. Sample preparation was accomplished through a protein precipitation procedure using acetonitrile. Separation of teneligliptin and sitagliptin (IS) from endogenous components with high selectivity and sensitivity (0.5ng/mL) was achieved within 4min using Poroshell 120 EC-C18 column (100×3.0mm, 2.7μ). A gradient mobile phase consisting of 10mM ammonium formate and acetonitrile was applied at a flow rate of 0.45mL/min. Detection of target ions [M+H](+) at m/z 427.2274 for teneligliptin and m/z 408.1258 for IS was performed in selective ion mode using positive ion electrospray ionization high resolution accurate mass spectrometry. The linearity of the method was found to be in the range of 0.5-1000ng/mL. The matrix effect was 88.7-94.5% for teneligliptin. Plasma samples were found to stable under different storage conditions. It was successfully applied to pharmacokinetic and plasma protein binding study of drug in rats. Results showed linear dose proportionality of pharmacokinetics at 0.1 and 1mg/kg and relatively high protein binding of teneligliptin (85.46 ± 0.24 %) compared with other DPP-4 inhibitors.

Navigating the chemical space of dipeptidyl peptidase-4 inhibitors

This study represents the first large-scale study on the chemical space of inhibitors of dipeptidyl peptidase-4 (DPP4), which is a potential therapeutic protein target for the treatment of diabetes mellitus. Herein, a large set of 2,937 compounds evaluated for their ability to inhibit DPP4 was compiled from the literature. Molecular descriptors were generated from the geometrically optimized low-energy conformers of these compounds at the semiempirical AM1 level. The origins of DPP4 inhibitory activity were elucidated from computed molecular descriptors that accounted for the unique physicochemical properties inherently present in the active and inactive sets of compounds as defined by their respective half maximal inhibitory concentration values of less than 1 μM and greater than 10 μM, respectively. Decision tree analysis revealed the importance of molecular weight, total energy of a molecule, topological polar surface area, lowest unoccupied molecular orbital, and number of hydrogen-bond donors, which correspond to molecular size, energy, surface polarity, electron acceptors, and hydrogen bond donors, respectively. The prediction model was subjected to rigorous independent testing via three external sets. Scaffold and chemical fragment analysis was also performed on these active and inactive sets of compounds to shed light on the distinguishing features of the functional moieties. Docking of representative active DPP4 inhibitors was also performed to unravel key interacting residues. The results of this study are anticipated to be useful in guiding the rational design of novel and robust DPP4 inhibitors for the treatment of diabetes.

Anagliptin, a potent dipeptidyl peptidase IV inhibitor: its single-crystal structure and enzyme interactions

The single-crystal structure of anagliptin, N-[2-({2-[(2S)-2-cyanopyrrolidin-1-yl]-2-oxoethyl}amino)-2-methylpropyl]-2-methylpyrazolo[1,5-a]pyrimidine-6-carboxamide, was determined. Two independent molecules were held together by intermolecular hydrogen bonds, and the absolute configuration of the 2-cyanopyrrolidine ring delivered from l-prolinamide was confirmed to be S. The interactions of anagliptin with DPP-4 were clarified by the co-crystal structure solved at 2.85 Å resolution. Based on the structure determined by X-ray crystallography, the potency and selectivity of anagliptin were discussed, and an SAR study using anagliptin derivatives was performed.

Teneligliptin : expectations for its pleiotropic action

INTRODUCTION

The main aim in the management of diabetes mellitus is to prevent the development of its complications. Large fluctuations in glucose levels may increase the risk of complications, so improved control of glucose fluctuations, in addition to management of chronic hyperglycemia, could represent an important goal in diabetes pharmacotherapy.

AREAS COVERED

Pre-clinical and clinical studies suggest that poor control of blood glucose fluctuations contributes to progression of diabetic vascular complications. Dipeptidyl peptidase (DPP)-4 inhibitors are one of several drug classes used to manage diabetes, and the potential vasoprotective effects of DPP-4 inhibition have attracted attention in recent years. The DPP-4 inhibitor teneligliptin was approved in Japan in 2012 and in Korea in 2014. Teneligliptin differs in its structural and pharmacokinetic characteristics compared with other drugs in the same class. It appears to have potent, sustained effects on glycemic control, thereby reducing the complications of hypoglycemia and postprandial hyperglycemia. Because of its effects on vascular function, teneligliptin may be beneficial in patients at high risk of cardiovascular disease.

EXPERT OPINION

The possible pleiotropic effects of teneligliptin, such as those on endothelial function and metabolic syndrome, are of great interest. This review examines these effects and their potential clinical relevance.

Scaffold-based design of xanthine as highly potent inhibitors of DPP-IV for improving glucose homeostasis in DIO mice

Diabetes mellitus, commonly characterized by hyperglycemia, is a group of metabolic diseases. Some oral anti-diabetic drugs show poor tolerability during chronic treatment, and associate with undesired side effects. Recent advances in the understanding of physiological functions of incretins and their degrading enzyme dipeptidyl peptidase DPP-IV have led to the discovery of DPP-IV inhibitors as a new class of oral anti-diabetic drugs. Several DPP-IV inhibitors have different chemical structures of which the xanthine scaffold has specific advantages. Combining previous work with the research strategy of pharmacophore hybridization, we retained this scaffold and synthesized a new series of amino-alcohol or diamino-modified xanthine compounds. Some xanthines exhibited submicromolar inhibitory activities against DPP-IV. The most potent compound 40 [Formula: see text] exhibits a good in vivo efficacy in reducing glucose excursion at a single dose and a better chronic effect in reducing body weight than metformin in DIO mice. In other words, the combined effect improved the pathological state of DIO mice.

Novel DPP-4 inhibitors against diabetes

DPP-4 specifically degrades the incretin hormone GLP-1 and GIP, both of which are vital modulators of blood glucose homeostasis. Attributed to its potential biological function, DPP-4 inhibition has presently represented an attractive therapeutic strategy for treating diabetes and aroused a significant interest in the pharmaceutical industry. Chemical stability, selectivity and pharmacokinetic properties have been continuously emphasized during the long journey of R&D centered on DPP-4 inhibitors. The current landscape of the development of DPP-4 inhibitors is outlined in this review, with a focus on rational drug design and structural optimization to pursue chemical stability, selectivity and favorable pharmacokinetic properties. In addition, the structure-activity relationships, based on reported DPP-4 inhibitors, will be discussed.

Design, synthesis, biological screening, and molecular docking studies of piperazine-derived constrained inhibitors of DPP-IV for the treatment of type 2 diabetes

Novel piperazine-derived conformationally constrained compounds were designed, synthesized, and evaluated for in vitro Dipeptidyl peptidase-IV (DPP-IV) inhibitory activities. From a library of compounds synthesized, 1-(2-(4-(7-Chloro-4-quinolyl)piperazin-1-yl)acetyl)pyrrolidine (2g) was identified as a potential DPP-IV inhibitor exhibiting better inhibitory activity than P32/98, reference inhibitor. The in vivo studies carried out in STZ and db/db mice models indicated that the compound 2g showed moderate antihyperglycemic activity as compared to the marketed drug Sitagliptin. A two-week repeated dose study in db/db mice revealed that compound 2g significantly declined blood glucose levels with no evidence of hypoglycemia risk. Furthermore, it showed improvement in insulin resistance reversal and antidyslipidemic properties. Molecular docking studies established good binding affinity of compound 2g at the DPP-IV active site and are in favor of the observed biological data. These data collectively suggest that compound 2g is a good lead molecule for further optimization studies.

Comparison of the administration of teneligliptin every day versus every other day in Japanese patients with type 2 diabetes: a randomized non-inferior test

The half life (t1/2 ) of teneligliptin is 24.2 hours. Accordingly, we hypothesized that the administration of teneligliptin every other day might improve glycemic control. In this study, we evaluated the effectiveness of the administration of teneligliptin every other day in Japanese patients with type 2 diabetes. Fifty-one patients were randomly assigned to receive treatment with 20 mg of teneligliptin every day (Group A) or 20 mg of teneligliptin every other day (Group B) for 12 weeks. HbA1c, glycoalbumin (GA), 1,5-anhydroglucitol (1,5-AG), lipid, blood pressure, body weight, urine albumin-to-creatinine ratio, overall treatment satisfaction level, adverse events and drug adherence were all measured. Forty-seven patients completed this study, and the HbA1c, GA, and 1,5-AG levels in group B were found to be decreased to the same extent as those in group A. No distinct differences in the overall treatment satisfaction level, adverse events, or drug adherence were seen between the two groups at 12 weeks. The administration of teneligliptin every other day had a similar efficacy, patient satisfaction level, and safety compared with its administration every day. This information will be useful for reducing the economic load without changing the patients' satisfaction and glycemic control.

Chemical specificity and conformational flexibility in proteinase-inhibitor interaction: scaffolds for promiscuous binding

One of the most important roles of proteins in cellular milieu is recognition of other biomolecules including other proteins. Protein-protein complexes are involved in many essential cellular processes. Interfaces of protein-protein complexes are traditionally known to be conserved in evolution and less flexible than other solvent interacting tertiary structural surface. But many examples are emerging where these features do not hold good. An understanding of inter-play between flexibility and sequence conservation is emerging, providing a fresh dimension to the paradigm of sequence-structure-function relationship. The functional manifestation of the inter-relation between sequence conservation and flexibility of interface is exemplified in this review using proteinase-inhibitor protein complexes.