Miglitol: a review of its therapeutic potential in type 2 diabetes mellitus

TCM theory-inspired discovery of DNJ-flavonoid conjugates as broad-spectrum anti-SARS-CoV-2 agents by primarily targeting ER-associated glycoprotein folding process

The global COVID-19 pandemic caused by SARS-CoV-2 has underscored the urgent need for the development of new broad-spectrum antivirals to combat its high mutation rate and the emerging variants. Host ER α-glucosidases I/II are promising host-targeted therapeutic targets for the development of broad-spectrum antivirals against viral strains that depend on ERQC for infectivity. Herein, we designed and synthesized a series of TCM theory-inspired DNJ-flavonoid conjugates as novel α-glucosidase inhibitors, which were screened against their in vitro antiviral activities in non-replicative SARS-CoV-2 pseudovirus (PsV) assay. Remarkably, DNJ-20 not only demonstrated remarkable inhibition activity against α-glucosidase and viral entry process, but also exerted potent and broad-spectrum anti-coronaviral activity against SARS-CoV-2 pseudovirus (PsV), several SARS-CoV-2 variants, as well as HCoV-229E and HCoV-OC43, with EC50 values up to 1.49 μM, which is more potent than the benchmark α-glucosidase inhibitor UV-4 (DNJ-3). Besides, it had no observable cytotoxicity in HeLa-ACE2, HEK-293T and Beas-2B cells. Therefore, TCM theory-inspired DNJ-flavonoid conjugates can be served as promising drug leads for pan-coronavirus therapeutic development to combat current and future coronavirus pandemics.

Synthesis, structural insights and bio-evaluation of N-phenoxyethylisatin hydrazones as potent α-glucosidase inhibitors

Effective α-glucosidase inhibitors are vital for managing type 2 diabetes, emphasizing the need for novel and potent compounds. A series of novel N-phenoxyethylisatin hydrazones 1(a-l) have been synthesized and characterized by their spectral data, and in the case of 1l by its single crystal X-ray analysis. All the synthesized compounds were in vitro evaluated for their inhibition potential against the α-glucosidase enzyme. Interestingly, most of these compounds exhibited significant inhibitory activity against the α-glucosidase enzyme, with IC50 values ranging from 3.64 ± 0.13 to 94.89 ± 0.64 μM compared to the standard drug, acarbose (IC50 = 873.34 ± 1.67 μM). The compound 1e was found to be the most active compound of the series having an IC50 value of 3.64 ± 0.13 μM. Molecular docking studies revealed a binding score of -9.7 kcal mol-1 for 1e, slightly surpassing that of acarbose (-9.4 kcal mol-1). Unlike acarbose, which primarily relies on hydrogen bonding, the binding interactions of 1e are dominated by π-interactions. ADMET profiling confirmed favourable pharmacokinetics for these compounds, including good oral bioavailability, balanced hydrophilicity, and minimal predicted toxicity. These findings highlight the potential of these compounds as promising candidates for the development of more effective treatments for hyperglycemia.

Research progress and perspectives of dual-target inhibitors

The occurrence and development of diseases are complex, and single-target drugs that affect only a single target or pathway often fail to achieve the expected therapeutic effect. The simultaneous effect on two key targets could not only increase patient tolerance but also accelerate disease remission. Dual-target inhibitors have already been studied the most intensively in the development of dual-target drugs. This article briefly introduces the function of drug therapy targets, and mainly summarizes the design strategies and research progress of dual-target inhibitors in neurodegenerative diseases, infectious diseases, metabolic diseases and cardiovascular diseases.

Synthesis of a di-O-acylated deoxynojirimycin (DNJ) derivative and evaluation of its antibacterial and antibiofilm activity against Staphylococcus aureus and Stenotrophomonas maltophilia

Herein we report the synthesis of a novel di-O-acylated DNJ derivative, conceived to study whether iminosugar derivatization with a lipophilic acyl moiety could positively affect its antibacterial properties. The well-known PS-TPP/I2/ImH activating system was used to readily install the acyl chains on the iminosugar, leading to the desired compound in high yield. Biological assays revealed that a di-O-lauroyl DNJ derivative enhanced the antibacterial effect of gentamicin and amikacin against S. aureus and S. maltophilia strains, respectively, suggesting a potential role as antibiotic adjuvant. Furthermore, even though this compound displayed only a weak concentration-dependent inhibitory effect on biofilm formation in S. aureus, it was able to significantly reduce the viability of S. aureus and S. maltophilia preformed biofilms. The results confirm the antibacterial potential of piperidine iminosugars and open the way to further studies involving novel lipophilic derivatives to optimize the antibacterial adjuvant effect herein observed for iminosugar 12.

Synthesis of modified Schiff base appended 1,2,4-triazole hybrids scaffolds: elucidating the in vitro and in silico α-amylase and α-glucosidase inhibitors potential

The current study involves the synthesis of Schiff bases based on 1,2,4-triazoles skeleton and assessing their α-amylase and α-glucosidase profile. Furthermore, the precise structures of the synthesized derivatives were elucidated using various spectroscopic methods such as 1H-NMR, 13C-NMR and HREI-MS. Using glimepiride as the reference standard, the in vitro α-glucosidase and α-amylase inhibitory activities of the synthesized compounds were evaluated in order to determine their potential anti-diabetic properties. All analogues showed varied range of inhibitory activity having IC50 values ranging from 17.09 ± 0.72 to 45.34 ± 0.03 μM (α-amylase) and 16.35 ± 0.42 to 42.31 ± 0.09 μM (α-glucosidase), respectively. Specifically, the compounds 1, 7 and 8 were found to be significantly active with IC50 values of 17.09 ± 0.72, 19.73 ± 0.42, and 23.01 ± 0.04 μM (against α-amylase) and 16.35 ± 0.42, 18.55 ± 0.26, and 20.07 ± 0.02 μM (against α-glucosidase) respectively. The obtained results were compared with the Glimepiride reference drug having IC50 values of 13.02 ± 0.11 μM (for α-glucosidase) and 15.04 ± 0.02 μM (for α-amylase), respectively. The structure-activity relationship (SAR) studies were conducted based on differences in substituent patterns at varying position of aryl rings A and B may cause to alter the inhibitory activities of both α-amylase and α-glucosidase enzymes. Additionally, the molecular docking study was carried out to explore the binding interactions possessed by most active analogues with the active sites of targeted α-amylase and α-glucosidase enzymes.

A Supramolecular Gel-Based Protocol for the Detection of α-Glycosidases for Screening Potential Drugs

α-Glycosidases are carbohydrate-digesting enzymes that catalyze the hydrolysis of α-1,4-glycopyranoside bonds from oligosaccharides and disaccharides. α-Glucosidase is an important biomarker for the diagnosis of type-II diabetes, Azoospermia and Pompe diseases. Additionally, the mutations in α-galactosidase lead to Fabry disease. Inhibitors targeting these enzymes are prescribed as anti-diabetic medications and as effective chaperones for Fabry disease. Comprehending the function - regulation of α-glycosidases requires accurate quantification methods. In this work, we highlight the design of a simple luminescent 'turn-on' assay for sensing these two α-glycosidases in a supramolecular TbCh hydrogel matrix using 1-α-glycosides as pro-sensitizers. The protocol offers a cost-effective method for selectively sensing α-glycosidases in the detection limit of the subnanomolar range. Importantly, the developed enzyme sensors functioned as a platform for rapid screening of drug molecules based on their inhibition potency. Therefore, the protocol is useful for facilitating the advancement of therapeutics and diagnostics targeting this important class of enzymes.

Exploring Thiazolidinedione-Naphthalene Analogues as Potential Antidiabetic Agents: Design, Synthesis, Molecular Docking and In-vitro Evaluation

Thiazolidinedione-naphthalene analogues were synthesized and evaluated for antidiabetic activity as Pancreatic α-Amylase (PAA) and intestinal α-glucosidase (IAG) inhibitors. The activity of the compounds (14a-g,17a-k) is compared with acarbose as the standard drug and all the compounds shows good to moderate antidiabetic activity. In-vitro PAA and IAG inhibition assay is performed for the all compounds, the compounds 17e shows superior PAA and IAG inhibitory activity with respective to standard (IC50 = 12.455 ± 0.04 μM and 9.145 ± 0. 01 μM). The molecular interaction with PAA and IAG protein was also studied with the help of molecular docking studies using AutoDock software. while SwissADME and Osiris property explorer tools computed in-silico drug likeliness and toxicity properties. The in-silico results confirmed the 17e molecule as a superior drug with high binding affinity and good drug likeness against PAA and IAG, confirming in-vitro results. We also studied antioxidant activity (AOA) of all synthesized compounds and results confined that the compound 14g and 17e has good antioxidant potential IC50 = 8.04 ± 0.02 μM and 6.36 ± 0.03 μM respectively among all compounds. In conclusion, in-vitro, in-silico antidiabetic and antioxidant studies revealed 17e compound was found to be potential compound.

The synthesis and bioactivity of apigenin derivatives

BACKGROUND

Apigenin, a naturally occurring compound with a flavone core structure, is known for its diverse bioactivities, including anti-inflammation, anti-toxicant, anti-cancer and so on. There has been significant interest in the medicinal chemistry community. To address these challenges, researchers have developed various derivatives of apigenin to address challenges such as poor water-solubility and low intestinal absorption, aiming to enhance the pharmacological activities and pharmacokinetic properties of this compound.

OBJECTIVE

In recent years, there has been a proliferation of apigenin derivatives with enhanced bioactivity. However, there is a lack of comprehensive reviews on the function-based modification of these derivatives. In this paper, we provide an overview of the apigenin derivatives with varying bioactivities and explored their structure activity relationships. And the functions of different groups of apigenin derivatives were also analyzed.

CONCLUSION

This review summarized the current achievements that could provide some clues for further study of apigenin-based drugs.

The combined effects of bisphenol S and hexavalent chromium on alpha-glucosidase: Intermolecular interaction, structural and functional changes

The co-contamination of heavy metal ions and organic pollutants has posed a threat to human health. Herein, this study investigated the intermolecular interactions of bisphenol S (BPS) and hexavalent chromium (Cr(VI)) under both individual and coexisting conditions, with alpha-glucosidase (AG), a key enzyme in carbohydrate metabolism, and the corresponding effects on the structure and function of AG. Multiple spectroscopic and molecular docking methods were employed to conduct the investigation in vitro and in silico. The results indicated that both BPS and Cr(VI) quenched the fluorescence of AG via a combined static and dynamic quenching processes. At 310 K, the binding constants of AG with BPS in the AG-BPS and (AG-Cr(VI))-BPS systems were 1.84 × 104 and 2.03 × 104 L mol-1, and the binding constants of AG with Cr(VI) in the AG-Cr(VI) and (AG-BPS)-Cr(VI) systems were 6.14 × 103 and 4.35 × 103 L mol-1. Cr(VI) could significantly affect the binding site of BPS in AG, while BPS had a minimal impact on the binding site of Cr(VI) in AG. BPS and Cr(VI) caused varied structural alterations of AG, and the impact of their coexistence on the structure of AG was related to the order in which they were added. Both BPS and Cr(VI) had a concentration-related effect on AG activity. This study provides valuable insights into the molecular mechanisms underlying the combined toxic effects of BPS and Cr(VI) on AG, highlighting the potential health risks associated with their environmental co-exposure.

Severe Acute Interstitial Nephritis Induced by α-glucosidase Inhibitor Miglitol in an Elderly Patient with Type 2 Diabetic Nephropathy

A 79-year-old male patient with type 2 diabetic nephropathy and hypertension was admitted to our hospital because of acute kidney injury with significantly elevated serum creatinine (8.12 mg/dL) and urinary β2-microglobulin (β2MG, 31,748 μg/L) levels. α-glucosidase inhibitor (α-GI) miglitol, started two weeks prior to presentation, was discontinued because drug-induced acute interstitial nephritis (AIN) was suspected. Renal biopsy revealed AIN and diabetic nephropathy. The drug-induced lymphocyte stimulation test for miglitol was also positive. After the discontinuation of miglitol, the urinary β2MG levels decreased to the normal range. This case raises the possibility that α-GI miglitol can worsen the renal function in patients with underlying renal dysfunction.

Inhibition of α-glucosidase activity by potential peptides derived from fermented spent coffee grounds

The control of α-glucosidase activity has been associated with managing diabetes. We previously identified three peptides with high bioactive indices derived from protein hydrolysates of fermented spent coffee grounds. In this study, the peptides YGF, GMCC, and RMYRY were synthesized and tested in vitro for their α-glucosidase inhibition activity, complemented by in silico analyses. Two of the three peptides significantly inhibited α-glucosidase activity, with the more efficient peptides being YGF and GMCC (0.42 mg/mL), resulting in decreased enzymatic activity of 95.31% and 89.79%, respectively. These peptides exhibited binding free energies with the α-glucosidase complex of -8.5 and - 6.6 kcal/mol, respectively, through hydrogen bonds and van der Waals interactions with amino acids from the active site. Pharmacokinetic analysis indicated that YGF and GMCC profiles were unrelated to toxicity. These results underscore the importance of focusing on food waste bioprocessing products to expand the range of alternatives that could aid in diabetes treatment.

In Silico Investigation against Inhibitors of Alpha-Amylase Using Structure-based Screening, Molecular Docking, and Molecular Simulations Studies

Type-II diabetes mellitus is a chronic disorder that results from fluctuations in the glucose level leading to hyperglycemia with severe adverse effects increasing worldwide. Alpha-Amylase is the key enzyme involved in the mechanism of glucose formation therefore Alpha-Amylase inhibitors have become a therapeutic target in the development of new leads as they have the potential to suppress glucose levels. Existing drugs targeting Alpha-Amylase highlight major drawbacks in terms of poor absorption rate that causes several gastrointestinal issues. So, this research is aimed to develop novel inhibitors interacting with Alpha-Amylase's active site using structural-based screening, binding pattern analysis, and molecular dynamic simulation. Hence, to search for a potential lead, we analyzed a total of 133 valiolamine derivatives and 535 desoxynojirimycin derivatives that exhibited drug-like properties screened through Lipinski filters. Virtual screening followed by binding interaction analysis we identified ten compounds that exhibited better binding energy scores compared to the standard drugs voglibose and miglitol, used in our study. The docking analysis, ADMET and metabolic site prediction estimated the best top two compounds with good drug profiles. Further, top compounds VG9 and VG15 were promoted to simulation study using the Biovia Discovery study to access the stability at a time interval of 100 ns. MD simulation results revealed that our compound VG9 possesses better conformational stability in the complex to the active site residues of Alpha-Amylase target protein than standard drug voglibose. Thus, our investigation revealed that compound VG9 also exhibits the best pharmacokinetic as well as binding affinity results and could act as a potential lead compound targeting Alpha-Amylase for Type II diabetes.

Synthesis and glycosidase inhibition of 3,4,5-trihydroxypiperidines using a one-pot amination-cyclisation cascade reaction

Trihydroxypiperidines are a therapeutically valuable class of iminosugar. We applied a one-pot amination-cyclisation cascade reaction to synthesise 3,4,5-trihydroxypiperidine stereoisomers in three steps from commercially available pentoses and in excellent overall yields. Using our methodology, the yields of the syntheses of meso-1, meso-2 and 3L are the highest reported to date. The synthetic methodology was readily extended to the three-step synthesis of N-alkyl derivatives by replacing the ammonia nitrogen source with a primary amine. The trihydroxypiperidines and N-alkyl analogues were screened for enzyme inhibitory activity using Fabrazyme (Fabry disease), GCase (Gaucher's disease), Agrobacterium sp. β-glucosidase, and Escherichia coli β-galactosidase. N-Phenylethyl 3,4,5-trihydroxypiperidine (N-phenylethyl-1-(3R,4R,5S)-piperidine-3,4,5-triol) showed good inhibitory activity of Fabrazyme (Ki = 46 μM). This activity was abolished when the N-phenylethyl group was removed or replaced with a non-aromatic alkyl chain.

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.

Proprotein convertase cleavage of Ictalurid herpesvirus 1 spike-like protein ORF46 is modulated by N-glycosylation

Viral spike proteins undergo a special maturation process that enables host cell receptor recognition, membrane fusion, and viral entry, facilitating effective virus infection. Here, we investigated the protease cleavage features of ORF46, a spike-like protein in Ictalurid herpesvirus 1 (IcHV-1) sharing similarity with spikes of Nidovirales members. We noted that during cleavage, full-length ORF46 is cleaved into ∼55-kDa and ∼100-kDa subunits. Moreover, truncation or site-directed mutagenesis at the recognition sites of proprotein convertases (PCs) abolishes this spike cleavage, highlighting the crucial role of Arg506/Arg507 and Arg668/Arg671 for the cleavage modification. ORF46 cleavage was suppressed by specific N-glycosylation inhibitors or mutation of its specific N-glycosylation sites (N192, etc.), suggesting that glycoprotein ORF46 cleavage is modulated by N-glycosylation. Notably, PCs and N-glycosylation inhibitors exhibited potent antiviral effects in host cells. Our findings, therefore, suggested that PCs cleavage of ORF46, modulated by N-glycosylation, is a potent antiviral target for fish herpesviruses.

Novel molecular hybrids of EGCG and quinoxaline: Potent multi-targeting antidiabetic agents that inhibit α-glucosidase, α-amylase, and oxidative stress

Diabetes mellitus is a multifactorial disease and its effective therapy often demands several drugs with different modes of action. Herein, we report a rational design and synthesis of multi-targeting novel molecular hybrids comprised of EGCG and quinoxaline derivatives that can effectively inhibit α-glucosidase, α-amylase as well as control oxidative stress by scavenging ROS. The hybrids showed superior inhibition of α-glucosidase along with similar α-amylase inhibition as compared to standard drug, acarbose. Most potent compound, 15c showed an IC50 of 0.50 μM (IC50 of acarbose 190 μM) against α-glucosidase. Kinetics studies with 15c revealed a competitive inhibition against α-glucosidase. Binding affinity of 15c (-9.5 kcal/mol) towards α-glucosidase was significantly higher than acarbose (-7.7 kcal/mol). 15c exhibited remarkably high antioxidant activity (IC50 = 18.84 μM), much better than vitamin C (IC50 = 33.04 μM). Of note, acarbose shows no antioxidant activity. Furthermore, α-amylase activity was effectively inhibited by 15c with an IC50 value of 16.35 μM. No cytotoxicity was observed for 15c (up to 40 μM) in MCF-7 cells. Taken together, we report a series of multi-targeting molecular hybrids capable of inhibiting carbohydrate hydrolysing enzymes as well as reducing oxidative stress, thus representing an advancement towards effective and novel therapeutic approaches for diabetes.

Protein engineering of transaminase facilitating enzyme cascade reaction for the biosynthesis of azasugars

Azasugars, such as 1-deoxynojirimycin (1-DNJ), exhibit unique physiological functions and hold promising applications in medicine and health fields. However, the biosynthesis of 1-DNJ is hindered by the low activity and thermostability of the transaminase. In this study, the transaminase from Mycobacterium vanbaalenii (MvTA) with activity toward d-fructose was engineered through semi-rational design and high-throughput screening method. The final mutant M9-1 demonstrated a remarkable 31.2-fold increase in specific activity and an impressive 200-fold improvement in thermostability compared to the wild-type enzyme. Molecular dynamics (MD) simulations revealed that the mutation sites of H69R and K145R in M9-1 played crucial roles in the binding of the amino acceptor and donor, leading to the stable conformation of substrates within the active pocket. An enzyme cascade reaction was developed using M9-1 and the dehydrogenase from Paenibacillus polymyxa (GutB1) for the production of mannojirimycin (MJ), which provided a new idea for the in vitro biosynthesis of 1-DNJ.

Synthesis and Biological Evaluation of New Dihydrofuro[3,2-b]piperidine Derivatives as Potent α-Glucosidase Inhibitors

Inhibition of glycoside hydrolases has widespread application in the treatment of diabetes. Based on our previous findings, a series of dihydrofuro[3,2-b]piperidine derivatives was designed and synthesized from D- and L-arabinose. Compounds 32 (IC50 = 0.07 μM) and 28 (IC50 = 0.5 μM) showed significantly stronger inhibitory potency against α-glucosidase than positive control acarbose. The study of the structure-activity relationship of these compounds provides a new clue for the development of new α-glucosidase inhibitors.

A comprehensive review of small-molecule drugs for the treatment of type 2 diabetes mellitus: Synthetic approaches and clinical applications

Type 2 diabetes mellitus (T2DM) is a long-term metabolic disorder characterized by the body's resistance to insulin and inadequate production of insulin. Small molecule drugs to treat T2DM mainly control blood sugar levels by improving insulin sensitivity, increasing insulin secretion, or reducing liver glycogen production. With the deepening of research on the pathogenesis of diabetes, many drugs with new targets and mechanisms of action have been discovered. The targets of the drugs for T2DM are mainly dipeptidyl peptidase IV inhibitors (DPP4), sodium/glucose cotransporter 2 inhibitors (SGLT2), sulfonylurea receptor modulators (SUR), peroxisome proliferator-activated receptor γ agonists (PPARγ), etc. We are of the opinion that acquiring a comprehensive comprehension of the synthetic procedures employed in drug molecule production will serve as a source of inventive and pragmatic inspiration for the advancement of novel, more potent, and feasible synthetic methodologies. This review aims to outline the clinical applications and synthetic routes of some representative drugs to treat T2DM, which will drive the discovery of new, more effective T2DM drugs.

Pharmacological properties of Ensete glaucum seed extract: Novel insights for antidiabetic effects via modulation of oxidative stress, inflammation, apoptosis and MAPK signaling pathways

ETHNOPHAMACOLOGICAL RELEVANCE

Medicinal plants are increasingly making important contributions to diabetic treatment. Ensete glaucum seeds have been widely used in folk medicine to treat diabetes.

AIM OF THE STUDY

The study was aimed to investigate the protective effect and active mechanisms of E. glaucum seed extract (EGSE) against streptozotocin (STZ)-induced hyperglycemia.

MATERIALS AND METHODS

Hyperglycemic mice were treated with EGSE (25 and 50 mg/kg) or glibenclamide (5 mg/kg) once daily for 7 d. The effects of these treatments on changes in blood biochemical parameters, pancreatic, liver, and kidney histopathology, oxidative stress and inflammatory marker levels in pancreatic, hepatic, and renal tissues were assessed. Expression of several proteins in MAPK signaling pathway related to apoptosis in pancreatic tissue were investigated. Furthermore, ex vivo, in vitro, and in silico biological activities of EGSE and its compounds were also examined.

RESULTS

EGSE and glibenclamide increased notably insulin, reduced significantly glucose, AST, ALT, BUN and creatinine levels in blood. Pancreatic islets, hepatic and renal tissue structure were restored by EGSE or glibenclamide. EGSE showed significant anti-oxidative stress and anti-inflammatory effects by enhancing GSH level and dropping MDA, NF-κB, TNF-α and IL-6 levels in these tissues. Particularly, EGSE exhibited pancreatic protective effect against STZ-induced apoptosis through the MAPK signaling pathway by down-regulation of p-p38 MAPK, ERK1/2, JNK1, p-AMPK, Bax, Bax/Bcl-2, cytochrome c, cleaved-caspase 3 and PARP expression, and slight up-regulation of Bcl-2 expression. Moreover, EGSE inhibited intestinal glucose absorption, PTP1B, α-amylase, and α-glucosidase activities. Its isolated compounds (Afzelechin and coniferaldehyde) showed PTP1B and α-glucosidase inhibitory activities, and potent structure-activity relationships.

CONCLUSION

These findings indicated the hypoglycemic and protective effects of E. glaucum seed extract against the STZ diabetogenic action. E. glaucum seed is a potential candidate for further studies to confirm its activities as a therapeutic agent for diabetic patients.

Discovery of N-(phenylsulfonyl)thiazole-2-carboxamides as potent α-glucosidase inhibitors

In a search for novel nonsugar α-glucosidase inhibitors for diabetes treatment, a series of N-(phenylsulfonyl)thiazole-2-carboxamide derivatives were designed and synthesized, the α-glucosidase inhibitory activities were then evaluated. Several compounds with promising α-glucosidase inhibitory effects were identified. Among these, compound W24 which shows low cytotoxicity and good α-glucosidase inhibitory activity with an IC50 value of 53.0 ± 7.7 μM, is more competitive compared with the commercially available drug acarbose (IC50  = 228.3 ± 9.2 μM). W24 was identified as a promising candidate in the development of α-glucosidase inhibitors. Molecular docking studies and molecular dynamics simulation were also performed to reveal the binding pattern of the active compound to α-glucosidase, and the binding free energy of the best compound W24 was 36.3403 ± 3.91 kcal/mol.

Molecular Basis for Inhibition of Heparanases and β-Glucuronidases by Siastatin B

Siastatin B is a potent and effective iminosugar inhibitor of three diverse glycosidase classes, namely, sialidases, β-d-glucuronidases, and N-acetyl-glucosaminidases. The mode of inhibition of glucuronidases, in contrast to sialidases, has long been enigmatic as siastatin B appears too bulky and incorrectly substituted to be accommodated within a β-d-glucuronidase active site pocket. Herein, we show through crystallographic analysis of protein-inhibitor complexes that siastatin B generates both a hemiaminal and a 3-geminal diol iminosugar (3-GDI) that are, rather than the parent compound, directly responsible for enzyme inhibition. The hemiaminal product is the first observation of a natural product that belongs to the noeuromycin class of inhibitors. Additionally, the 3-GDI represents a new and potent class of the iminosugar glycosidase inhibitor. To substantiate our findings, we synthesized both the gluco- and galacto-configured 3-GDIs and characterized their binding both structurally and kinetically to exo-β-d-glucuronidases and the anticancer target human heparanase. This revealed submicromolar inhibition of exo-β-d-glucuronidases and an unprecedented binding mode by this new class of inhibitor. Our results reveal the mechanism by which siastatin B acts as a broad-spectrum glycosidase inhibitor, identify a new class of glycosidase inhibitor, and suggest new functionalities that can be incorporated into future generations of glycosidase inhibitors.

Intestinal Morphology and Glucose Transporter Gene Expression under a Chronic Intake of High Sucrose

Sucrose is a disaccharide that is degraded into fructose and glucose in the small intestine. High-sucrose and high-fructose diets have been reported, using two-dimensional imaging, to alter the intestinal morphology and the expression of genes associated with sugar transport, such as sodium glucose co-transporter 1 (SGLT1), glucose transporter 2 (GLUT2), and glucose transporter 5 (GLUT5). However, it remains unclear how high-fructose and high-sucrose diets affect the expression of sugar transporters and the intestinal morphology in the whole intestine. We investigate the influence of a chronic high-sucrose diet on the expression of the genes associated with sugar transport as well as its effects on the intestinal morphology using 3D imaging. High sucrose was found to increase GLUT2 and GLUT5 mRNA levels without significant changes in the intestinal morphology using 3D imaging. On the other hand, the delay in sucrose absorption by an α-glucosidase inhibitor significantly improved the intestinal morphology and the expression levels of SGLT1, GLUT2, and GLUT5 mRNA in the distal small intestine to levels similar to those in the proximal small intestine, thereby improving glycemic control after both glucose and sucrose loading. These results reveal the effects of chronic high-sugar exposure on glucose absorption and changes in the intestinal morphology.

A Review on Indole-triazole Molecular Hybrids as a Leading Edge in Drug Discovery: Current Landscape and Future Perspectives

Molecular hybridization is a rational design strategy used to create new ligands or prototypes by identifying and combining specific pharmacophoric subunits from the molecular structures of two or more known bioactive derivatives. Molecular hybridization is a valuable technique in drug discovery, enabling the modulation of unwanted side effects and the creation of potential dual-acting drugs that combine the effects of multiple therapeutic agents. Indole-triazole conjugates have emerged as promising candidates for new drug development. The indole and triazole moieties can be linked through various synthetic strategies, such as click chemistry or other coupling reactions, to generate a library of diverse compounds for biological screening. The achievable structural diversity with indole-triazole conjugates offers avenues to optimize their pharmacokinetic and pharmacodynamic attributes, amplifying their therapeutic efficacy. Researchers have extensively tailored both indole and triazole frameworks with diverse modifications to comprehend their impact on the drug's pharmacokinetic and pharmacodynamic characteristics. The current review article endeavours to explore and discuss various research strategies to design indoletriazole hybrids and elucidate their significance in a variety of pathological conditions. The insights provided herein are anticipated to be beneficial for the researchers and will likely encourage further exploration in this field.

A Review on the Development of Novel Heterocycles as α-Glucosidase Inhibitors for the Treatment of Type-2 Diabetes Mellitus

One of the most effective therapeutic decencies in the treatment of Type 2 Diabetes Mellitus is the inhibition of α-glucosidase enzyme, which is present at the brush border of the intestine and plays an important role in carbohydrate digestion to form mono-, di-, and polysaccharides. Acarbose, Voglibose, Miglitol, and Erniglitate have been well-known α-glucosidase inhibitors in science since 1990. However, the long synthetic route and side effects of these inhibitors forced the researchers to move their focus to innovate simple and small heterocyclic scaffolds that work as excellent α-glucosidase inhibitors. Moreover, they are also effective against the postprandial hyperglycemic condition in Type 2 Diabetes Mellitus. In this aspect, this review summarizes recent progress in the discovery and development of heterocyclic molecules that have been appraised to show outstanding inhibition of α-glucosidase to yield positive effects against diabetes.

Bioequivalence Study of Miglitol Orally Disintegrating Tablets in Healthy Chinese Volunteers Under Fasting Condition Based on Pharmacodynamic and Pharmacokinetic Parameters

To investigate the bioequivalence of miglitol orally disintegrating tablets in healthy Chinese volunteers based on pharmacodynamic (PD) and pharmacokinetic (PK) parameters. Additionally, the safety profile was estimated. Two randomized, open-label, single-dose, crossover trials were conducted under fasting conditions. In the PD trial (CTR20191811), 45 healthy volunteers were randomly divided into 3 groups in a 1:1:1 ratio and administered sucrose alone or coadministered with 50 mg of miglitol orally disintegrating tablet test or reference formulation/sucrose. In the PK trial (CTR20191696), 24 healthy volunteers were randomized (1:1) to receive the test or reference formulation (50 mg). Blood samples were collected at 15 and 17 sampling points per cycle in the PD and PK trials, respectively. Plasma miglitol and serum glucose concentrations were analyzed using a validated liquid chromatography-tandem mass spectrometry method. Serum insulin concentrations were measured using electrochemiluminescent immunoassay. Statistical analyses for the PD and PK parameters were subsequently performed. The volunteers' physical indicators were monitored and documented during the entire study to estimate drug safety. The PD and PK parameters of the two formulations were similar. The main PD and PK end points were both within the prespecified range of 80%-125%. The incidences of treatment-emergent adverse events (TEAEs) and drug-related TEAEs were similar between the test and reference formulation groups, and no serious TEAEs or deaths occurred during the 2 trials. These 2 formulations were demonstrated to be bioequivalent and well tolerated in healthy Chinese volunteers under fasting condition.

Glycosidase-targeting small molecules for biological and therapeutic applications

Glycosidases are ubiquitous enzymes that catalyze the hydrolysis of glycosidic linkages in oligosaccharides and glycoconjugates. These enzymes play a vital role in a wide variety of biological events, such as digestion of nutritional carbohydrates, lysosomal catabolism of glycoconjugates, and posttranslational modifications of glycoproteins. Abnormal glycosidase activities are associated with a variety of diseases, particularly cancer and lysosomal storage disorders. Owing to the physiological and pathological significance of glycosidases, the development of small molecules that target these enzymes is an active area in glycoscience and medicinal chemistry. Research efforts carried out thus far have led to the discovery of numerous glycosidase-targeting small molecules that have been utilized to elucidate biological processes as well as to develop effective chemotherapeutic agents. In this review, we describe the results of research studies reported since 2018, giving particular emphasis to the use of fluorescent probes for detection and imaging of glycosidases, activity-based probes for covalent labelling of these enzymes, glycosidase inhibitors, and glycosidase-activatable prodrugs.

Synthesis, biological evaluation and molecular modelling of 3-Formyl-6-isopropylchromone derived thiosemicarbazones as α-glucosidase inhibitors

Type-2 Diabetes Mellitus (T2DM) is one of the most common metabolic disorders in the world and over the past three decades its incidence has increased drastically. α-Glucosidase inhibitors are used to control the hyperglycemic affect of T2DM. Herein, we report the synthesis, α-glucosidase inhibition, structure activity relationship, pharmacokinetics and docking analysis of various novel chromone based thiosemicarbazones 3(a-r). The derivatives displayed potent activity against α-glucosidase with IC50 in range of 0.11 ± 0.01-79.37 ± 0.71 µM. Among all the synthesized compounds, 3a (IC50 = 0.17 ± 0.026 µM), 3 g (IC50 = 0.11 ± 0.01 µM), 3n (IC50 = 0.55 ± 0.02 µM), and 3p (IC50 = 0.43 ± 0.025 µM) displayed higher inhibitory activity as compared to the standard, acarbose. Moreover, we have developed a statistically significant 2D-QSAR model (R2tr:0.9693; F: 50.4647 and Q2LOO:0.9190), which can be used in future to further design potent thiosemicarbazones as inhibitors of α-glucosidase.

Bioprospecting of Sea Anemones (Cnidaria, Anthozoa, Actiniaria) for β-Defensin-like α-Amylase Inhibitors

Diabetes mellitus is one of the most serious diseases of our century. The drugs used are limited or have serious side effects. The search for new sources of compounds for effective treatment is relevant. Magnificamide, a peptide inhibitor of mammalian α-amylases, isolated from the venom of sea anemone Heteractis magnifica, can be used for the control of postprandial hyperglycemia in diabetes mellitus. Using the RACE approach, seven isoforms of magnificamide were detected in H. magnifica tentacles. The exon-intron structure of magnificamide genes was first established, and intron retention in the mature peptide-encoding region was revealed. Additionally, an α-amylase inhibitory domain was discovered in the mucins of some sea anemones. According to phylogenetics, sea anemones diverge into two groups depending on the presence of β-defensin-like α-amylase inhibitors and/or mucin-inhibitory domains. It is assumed that the intron retention phenomenon leads to additional diversity in the isoforms of inhibitors and allows for its neofunctionalization in sea anemone tentacles. Bioprospecting of sea anemones of the order Actiniaria for β-defensin-like α-amylase inhibitors revealed a diversity of inhibitory sequences that represents a starting point for the design of effective glucose-lowering drugs.

Evaluation of a digital tool supporting therapeutic decision making for the personalized management of patients with type 2 diabetes not treated with insulin: A pilot study

AIMS

To investigate the benefits of using the Personalized Treatment Tool (PTT), a web-based clinical decision support tool assisting the diabetologist in the evaluation of patient's clinical characteristics and SMBG data, in the management of patients with non-insulin treated type 2 diabetes and inadequate glucose control.

METHODS

We conducted a single-center, 16-week, cluster-randomized controlled trial.

RESULTS

Eighty-two patients with 64.3 ± 9.4 years of age, disease duration 13.2 ± 9.1 years and HbA1c 7.8 ± 0.6%, 41 in the PTT group and 41 in the control group, completed the study. At follow-up, changes in indicators of glucose control and variability were not statistically different between the two groups. However, when considering the subgroup of patients on a single anti-diabetes drug at baseline (9 in the PTT group, 14 in the control group), changes in HbA1c and CGM-derived TIR 70-140 mg/dl, 24-hour MSG, GRADE, and HBGI were significantly improved in the PTT group compared to the control group.

CONCLUSION

When performed in a structured manner and used to modify the diabetes therapy through an algorithm-driven digital tool, SMBG can lead to significant improvements of glycemic control and variability in patients with type 2 diabetes not treated with insulin.

Multicomponent diastereoselective synthesis of tetrahydropyridines as α-amylase and α-glucosidase enzymes inhibitors

Background: Researchers seeking new drug candidates to treat diabetes mellitus have been exploring bioactive molecules found in nature, particularly tetrahydropyridines (THPs). Methods: A library of THPs (1-31) were synthesized via a one-pot multicomponent reaction and investigated for their inhibition potential against α-glucosidase and α-amylase enzymes. Results: A nitrophenyl-substituted compound 5 with IC50 values of 0.15 ± 0.01 and 1.10 ± 0.04 μM, and a Km value of 1.30 mg/ml was identified as the most significant α-glucosidase and α-amylase inhibitor, respectively. Kinetic studies revealed the competitive mode of inhibition, and docking studies revealed that compound 5 binds to the enzyme by establishing hydrophobic and hydrophilic interactions and a salt bridge interaction with His279. Conclusion: These molecules may be a potential drug candidate for diabetes in the future.

Synthesis, α-Glucosidase inhibitory activity and docking studies of Novel Ethyl 1,2,3-triazol-4-ylmethylthio-5,6-diphenylpyridazine-4-carboxylate derivatives

In this work, a novel series of pyridazine-triazole hybrid molecules were prepared and evaluated as inhibitors of rat intestinal α-glucosidase enzyme. Amongst all newly synthesized compounds, 10k showed good inhibition in the series with IC₅₀ value of 1.7 µM which is 100 folds stronger than positive control, acarbose. The cytotoxicity revealed that this compound is not toxic against normal cell line, HDF. The docking studies showed that triazole ring plays an important role in the binding interactions with the active site. The insertion of compound 10k into the active pocket of α-glucosidase and formation of hydrogen bonds with Leu677 was observed from docking studies. The kinetic studies revealed that this compound has uncompetitive mode of inhibition against α-glucosidase enzyme.

Relationships among Postprandial Plasma Active GLP-1 and GIP Excursions, Skeletal Muscle Mass, and Body Fat Mass in Patients with Type 2 Diabetes Treated with Either Miglitol, Sitagliptin, or Their Combination: A Secondary Analysis of the MASTER Study

BACKGROUND

We previously conducted a pilot randomized controlled trial "the MASTER study" and demonstrated that alpha-glucosidase inhibitor miglitol and a dipeptidyl peptidase-4 inhibitor sitagliptin modified postprandial plasma excursions of active glucagon-like peptide-1 (aGLP-1) and active gastric inhibitory polypeptide (aGIP), and miglitol treatment decreased body fat mass in patients with type 2 diabetes (T2D). However, the details regarding the relationships among postprandial plasma aGLP-1 and aGIP excursions, skeletal muscle mass, and body fat mass are unclear.

METHODS

We conducted a secondary analysis of the relationships among skeletal muscle mass index (SMI), total body fat mass index (TBFMI), and the incremental area under the curves (iAUC) of plasma aGLP-1 and aGIP excursions following mixed meal ingestion at baseline and after 24-week add-on treatment with either miglitol alone, sitagliptin alone, or their combination in T2D patients.

RESULTS

SMI was not changed after the 24-week treatment with miglitol and/or sitagliptin. TBFMI was reduced and the rates of aGIP-iAUC change were lowered in the two groups treated with miglitol, although their correlations did not reach statistical significance. We observed a positive correlation between the rates of aGIP-iAUC and TBFMI changes and a negative correlation between the rates of TBFMI and SMI changes in T2D patients treated with sitagliptin alone whose rates of aGIP-iAUC change were elevated.

CONCLUSIONS

Collectively, although T2D patients treated with miglitol and/or sitagliptin did not show altered SMI after 24-week treatment, the current study suggests that there are possible interrelationships among postprandial plasma aGIP excursion modified by sitagliptin, skeletal muscle mass, and body fat mass.

Carbohydrate-Small Molecule Hybrids as Lead Compounds Targeting IL-6 Signaling

In the past 25 years, a number of efforts have been made toward the development of small molecule interleukin-6 (IL-6) signaling inhibitors, but none have been approved to date. Monosaccharides are a diverse class of bioactive compounds, but thus far have been unexplored as a scaffold for small molecule IL-6-signaling inhibitor design. Therefore, in this present communication, we combined a structure-based drug design approach with carbohydrate building blocks to design and synthesize novel IL-6-signaling inhibitors targeting glycoprotein 130 (gp130). Of this series of compounds, LS-TG-2P and LS-TF-3P were the top lead compounds, displaying IC50 values of 6.9 and 16 µM against SUM159 cell lines, respectively, while still retaining preferential activity against the IL-6-signaling pathway. The carbohydrate moiety was found to improve activity, as N-unsubstituted triazole analogues of these compounds were found to be less active in vitro compared to the leads themselves. Thus, LS-TG-2P and LS-TF-3P are promising scaffolds for further development and study as IL-6-signaling inhibitors.

Pyrazole scaffold-based derivatives: A glimpse of α-glucosidase inhibitory activity, SAR, and route of synthesis

The α-glucosidase is a validated target to develop drugs for treating type 2 diabetes mellitus. The existing α-glucosidase inhibitors have certain shortcomings related to side effects and route of synthesis. Accordingly, it is inevitable to develop new chemical templates as α-glucosidase inhibitors. Pyrazole derivatives have a special place in medicinal chemistry because of various biological activities. Recently, pyrazole-based heterocyclic compounds have emerged as a promising scaffold to develop α-glucosidase inhibitors. This study focuses on the recently reported pyrazole-based α-glucosidase inhibitors, including their biological activity (in vivo, in vitro, and in silico), structure-activity relationship, and ways of synthesis. The literature revealed the development of several promising pyrazole-based α-glucosidase inhibitors and new synthetic routes for their preparation. The encouraging α-glucosidase inhibitory results of the pyrazole-based heterocyclic compounds make them an attractive target for further research. The authors also foresee the arrival of the pyrazole-based α-glucosidase inhibitors in clinical practice.

Preparation of iminosugars from aminopolyols via selective oxidation using galactose oxidase

Minimally protected aminopolyols are novel substrates for the galactose oxidase variant F₂. Site-selective oxidation proceeds at the terminal primary alcohol, followed by spontaneous cyclisation to afford stable hemiaminal/hemiacetal anomers of the piperidine and azepane scaffolds, with isolated yields of up to 94%. Simultaneous deprotection and reduction occured readily to afford valuable and biologically relevant iminosugars.

Optimization of Extraction Process of Polysaccharides MAP-2 from Opuntia Milpa Alta by Response Surface Methodology and Evaluation of Its Potential as α-Glucosidase Inhibitor

The α-glucosidase inhibitors play an important role in blood glucose control in patients with type 2 diabetes. At present, the development of new α-glucosidase inhibitors is an urgent clinical need. Our previous studies have found that the polysaccharide MAP-2 in the cactus Opuntia Milpa Alta has significantly better activity than acarbose (one of the most widely used first-line α-glucosidase inhibitors in clinical practice), but its optimal extraction process parameters and inhibition kinetic characteristics are not clear, and whether it has the potential to become a new α-glucosidase inhibitors is also unclear. In this study, based on previous research, we used the combination of single factor experiments and the response surface method (RSM) to identify the optimal extraction conditions for MAP-2 as follows: solid-liquid ratio 1:4, extraction temperature 90 °C, extraction time 1 h. Under these conditions, the extraction yield of MAP-2 was 3.47 ± 0.062%. When the concentration of MAP-2 was 16 mg/mL, the inhibition rate of α-glucosidase was 91.13 ± 0.62%. In addition, the results of inhibition kinetics showed that the inhibition rate of MAP-2 on α-glucosidase was the highest at pH 7.4 for 30 min, and showed a good dose-effect relationship, which was a reversible competitive inhibition. Meanwhile, we also compared the activities of MAP-2 and acarbose on the side effects of acarbose related enzymes. Compared with acarbose, MAP-2 not only had a better activation effect on lactase, but also inhibited the activity of hyaluronidase, and the activation and inhibition rate were positively correlated with the concentration. However, under the same conditions, the effect of acarbose on hyaluronidase was opposite to that of MAP-2. At low concentration, acarbose had a certain activation effect on lactase, but gradually attained an inhibitory effect with the increase in concentration. In contrast, MAP-2 not only activates lactase activity, improves diarrhea, abdominal distension, and abdominal pain, but also inhibits hyaluronidase activity, to solve the side effects of allergic reactions, suggesting that MAP-2 has the potential to become a novel and effective inhibitor of α-glucosidase with fewer side effects.

In Vitro and In Vivo Evaluation of the Antidiabetic Activity of Solidago virgaurea Extracts

Background

Solidago virgaurea (Asteraceae) has been used for more than 700 years for treating cystitis, chronic nephritis, urolithiasis, rheumatism, and inflammatory diseases. However, the antidiabetic activity of Solidago virgaurea has been rarely studied.

Methods

Three extracts of Solidago virgaurea were prepared, and their antidiabetic potentials were evaluated by various cell-free, cell-based, and in vivo studies.

Results

We found that the Solidago virgaurea contained multiple bioactive phytochemicals based on the GC-MS analysis. The Solidago virgaurea extracts effectively inhibited the functions of the carbohydrate digestive enzyme (α-glucosidase) and protein tyrosine phosphatase 1B (PTP1B), as well as decreased the amount of advanced glycation end products (AGEs). In the L6 myotubes, the Solidago virgaurea methanolic extract remarkably enhanced the glucose uptake via the upregulation of glucose transporter type 4 (GLUT4). The extract also significantly downregulated the expression of PTP1B. In the streptozotocin-nicotinamide induced diabetic mice, the daily intraperitoneal injection of 100 mg/kg Solidago virgaurea methanolic extract for 24 days, substantially lowered the postprandial blood glucose level with no obvious toxicity. The extract's anti-hyperglycemic effect was comparable to that of the glibenclamide treatment.

Conclusion

Our findings suggested that the Solidago virgaurea extract might have great potential in the prevention and treatment of diabetes.

Carbohydrate-based drugs launched during 2000-2021

Carbohydrates are fundamental molecules involved in nearly all aspects of lives, such as being involved in formating the genetic and energy materials, supporting the structure of organisms, constituting invasion and host defense systems, and forming antibiotics secondary metabolites. The naturally occurring carbohydrates and their derivatives have been extensively studied as therapeutic agents for the treatment of various diseases. During 2000 to 2021, totally 54 carbohydrate-based drugs which contain carbohydrate moities as the major structural units have been approved as drugs or diagnostic agents. Here we provide a comprehensive review on the chemical structures, activities, and clinical trial results of these carbohydrate-based drugs, which are categorized by their indications into antiviral drugs, antibacterial/antiparasitic drugs, anticancer drugs, antidiabetics drugs, cardiovascular drugs, nervous system drugs, and other agents.

An Amination-Cyclization Cascade Reaction for Iminosugar Synthesis Using Minimal Protecting Groups

The development of a one-step amination-cyclization cascade reaction for the synthesis of N-substituted iminosugars from iodo-pentoses and hexoses is reported. This novel methodology allows for the stereoselective conversion of easily accessible iodo-aldoses and iodo-ketoses into iminosugars in a single step, in highly efficient yields (63-95%), and in aqueous media. Furthermore, the use of functionalized amines allows for the synthesis of N-functionalized iminosugars without additional steps. To illustrate this methodology, a number of biologically important iminosugars were prepared, including 1-deoxynojirimycin, (3S,4R,5S,6R)-azepane-3,4,5,6-tetraol, and N-functionalized 1-deoxymannojirimycins.

1,6-epi-Cyclophellitol Cyclosulfamidate Is a Bona Fide Lysosomal α-Glucosidase Stabilizer for the Treatment of Pompe Disease

α-Glucosidase inhibitors are potential therapeutics for the treatment of diabetes, viral infections, and Pompe disease. Herein, we report a 1,6-epi-cyclophellitol cyclosulfamidate as a new class of reversible α-glucosidase inhibitors that displays enzyme inhibitory activity by virtue of its conformational mimicry of the substrate when bound in the Michaelis complex. The α-d-glc-configured cyclophellitol cyclosulfamidate 4 binds in a competitive manner the human lysosomal acid α-glucosidase (GAA), ER α-glucosidases, and, at higher concentrations, intestinal α-glucosidases, displaying an excellent selectivity over the human β-glucosidases GBA and GBA2 and glucosylceramide synthase (GCS). Cyclosulfamidate 4 stabilizes recombinant human GAA (rhGAA, alglucosidase alfa, Myozyme) in cell medium and plasma and facilitates enzyme trafficking to lysosomes. It stabilizes rhGAA more effectively than existing small-molecule chaperones and does so in vitro, in cellulo, and in vivo in zebrafish, thus representing a promising therapeutic alternative to Miglustat for Pompe disease.

Introduction of C-alkyl branches to L-iminosugars changes their active site binding orientation

L-ido-Deoxynojirimycin (L-ido-DNJ) itself showed no affinity for human lysosomal acid α-glucosidase (GAA), whereas 5-C-methyl-L-ido-DNJ showed a strong affinity for GAA, comparable to the glucose analog DNJ, with a K_i value of 0.060 μM. This excellent affinity for GAA and enzyme stabilization was observed only when methyl and ethyl groups were introduced. Docking simulation analysis revealed that the alkyl chains of 5-C-alkyl-L-ido-DNJs were stored in three different pockets, depending on their length, thereby the molecular orientation was changed. Comparison of the binding poses of DNJ and 5-C-methyl-L-ido-DNJ showed that they formed a common ionic interaction with Asp404, Asp518, and Asp616, but both the binding orientation and the distance between the ligand and each amino acid residue were different. 5-C-Methyl-L-ido-DNJ dose-dependently increased intracellular GAA activity in Pompe patient fibroblasts with the M519V mutation and also promoted enzyme transport to lysosomes. This study provides the first example of a strategy to design high-affinity ligands by introducing alkyl branches into rare sugars and L-sugar-type iminosugars to change the orientation of binding.

Stereoselective Access to Iminosugar C,C-Glycosides from 6-Azidoketopyranoses

We report the synthesis of iminosugar C,C-glycosides starting from 6-azidoketopyranoses. Their Staudinger-azaWittig-mediated cyclization provided bicyclic N,O-acetals, which were stereoselectively opened with AllMgBr to afford β-hydroxyazepanes with a quaternary carbon α to the nitrogen. Their ring contraction via a β-aminoalcohol rearrangement produced the six-membered l-iminosugars with two functional handles at the pseudoanomeric position. Inversion of the free OH at the azepane level furnished the d-iminosugars.