Α-glycosidase Inhibitors Research Articles

Effect of different hypoglycemic drugs and insulin on the risk of new-onset atrial fibrillation in people with diabetes: a network meta-analysis

ObjectiveDiabetes is considered a significant risk factor for the development of atrial fibrillation/flutter (AF/AFL). However, there is still insufficient evidence to determine the varying effects of different hypoglycemic drugs (HDs) on the incidence of new-onset AF/AFL in diabetic patients. To address this gap, we conducted a network meta-analysis to investigate whether various HDs have different effects on the risk of new-onset AF/AFL compared with insulin.MethodWe conducted a comprehensive search in PubMed, EMBASE, Cochrane Library, and Web of Science to identify all clinical trials investigating the association between various HDs or insulin and incident AF/AFL up until April 1, 2024. Bayesian random-effects model was used for network meta-analysis, and the results were expressed as relative risk (RR) and 95% confidence interval (CI).ResultAfter searching 2070 articles, a total of 12 studies (2,349,683 patients) were included in the network meta-analysis. The treatment regimen comprised insulin and 8 HDs hypoglycemic drugs, which are sodium-dependent glucose transporters 2 inhibitor (SGLT2i), glucagon-like peptide 1 receptor agonist (GLP-1RA), dipeptidyl peptidase 4 inhibitors (DPP4i), metformin (Met), sulfonylureas (SU), non-sulfonylureas (nSU), thiazolidinedione (TZD) and α-glycosidase inhibitors (AGI). The use of SGLT2i [RR 0.23, 95%CI (0.11, 0.49)], GLP-1RA [RR 0.28, 95%CI (0.13, 0.57)], and DPP4i [RR 0.34, 95%CI (0.17, 0.67)] demonstrated significant efficacy in reducing the incidence of new-onset AF/AFL when compared to insulin. When HDs were compared in pairs, SGLT2i is more effective than Met [RR 0.35, 95% CI (0.19, 0.62)], SU (RR 0.27, 95% CI (0.14, 0.51)], nSU [RR 0.28, 95% CI (0.08, 0.95)], TZD [RR 0.34, 95% CI (0.17, 0.7)], GLP-1RA is more effective Met [RR 0.42, 95% CI (0.25, 0.71)], SU (RR 0.33, 95% CI (0.18, 0.6)], TZD [RR 0.41, 95% CI (0.21, 0.82)], while Met[RR 1.98, 95% CI (1.23, 3.23)], SU [RR 2.54, 95% CI (1.46, 4.43)], TZD [RR 2.01, 95% CI (1.05, 3.79)] was not as effective as DPP4i.ConclusionSGLT-2i, GLP-1RA, and DPP4i showed a superior efficacy in reducing the risk of new-onset AF/AFL compared to insulin therapy.

New tetrahydro-isoquinoline derivatives as cholinesterase and α-glycosidase inhibitors: Synthesis, characterization, molecular docking & dynamics, ADME prediction, in vitro cytotoxicity and enzyme inhibition studies

In the presented work, it was reported about the synthesis procedure of new isoquinoline derivatives starting from chalcones and acetoacetanilide, a multi-step synthesis pathway yielded four isoquinoline derivatives (5a-d). At the first stage of our research, corresponding cyclohexanone derivatives are synthesized from the Michael addition reaction of chalcones with acetoacetanilide. After that, on the based cyclohexanone derivative was obtained novel isoquinoline derivatives. According to the structures, a plausible reaction mechanism was suggested. The structure of the synthesized compounds was confirmed by NMR spectroscopy method and X-Ray analysis. Additionally, to determine cholinesterase and α-glycosidase inhibition activity compounds 5(a-d) were tested against AChE, BChE and α-Gly as in vitro. In this work, the novel isoquinoline derivatives 5(a-d) demonstrated encouraging inhibitory action against α-glucosidase, as seen by their IC50 values ranging from 9.95 to 19.25 nM. This indicates that they were approximately 1–3 times more active than acarbose (IC50 = 23.07 nM). Also, the molecular docking IFD XP Gscores, dynamics simulations and MM-GBSA ΔG binding free energies of the isoquinoline derivatives on hAChE, hBChE and α-Gly are determined. The molecular dynamics (MD) simulations conducted in this study provided valuable insights into the dynamic behaviors, stabilities, and interaction profiles of ligand–protein complexes involving the R and S isomers of compounds 5c-hAChE, 5c-hBChE, and 5a-αGly. The MD simulations were crucial for understanding the complex stabilities and dynamic mechanisms of the ligand–protein interactions, shedding light on the potential inhibitory roles of these compounds..

Dauresorcinols A and B, two pairs of merosesquiterpenoid enantiomers with new carbon skeletons from Rhododendron dauricum

Five pairs of new merosesquiterpenoid enantiomers, named dauresorcinols A−E (1−5), were isolated from the leaves of Rhododendron dauricum. Their structures were elucidated by comprehensive spectroscopic data analysis, quantum chemical calculations, Rh2(OCOCF3)4-induced ECD, and single-crystal X-ray diffraction analysis. Dauresorcinols A (1) and B (2) possess two new merosesquiterpene skeletons bearing an unprecedented 2,6,7,10,14-pentamethyl-11-oxatetracyclo[8.8.0.02,7.012,17]octadecane and a caged 15-isohexyl-1,5,15-trimethyl-2,10-dioxatetracyclo[7.4.1.111,14.03,8]pentadecane motif, respectively. Plausible biosynthetic pathways of 1−5 are proposed involving key oxa-electrocyclization and Wagner−Meerwein rearrangement reactions. (+)/(−)-1 and 3−5 showed potent α-glucosidase inhibitory activity, 3 to 22 times stronger than acarbose, an antidiabetic drug targeting α-glucosidase. Docking results provide a basis to design and develop merosesquiterpenoids as potent α-glycosidase inhibitors.

Effective α-glycosidase inhibitors based on polyphenolic benzothiazole heterocycles

α-Glycosidase inhibition is one of the main approaches to treat Diabetes mellitus. Polyphenolic moieties are known to be responsible for yielding exhibit potent α-glycosidase inhibitory effects. In addition, compounds containing benzothiazole and Schiff base functionalities were previously reported to show α-glycosidase inhibition. In this paper, the synthesis of seven new phloroglucinol-containing benzothiazole Schiff base derivatives through the reaction of 6-substituted-2-aminobenzothiazole compounds with 2,4,6-trihydroxybenzaldehyde using acetic acid as a catalyst was reported. The synthesized compounds were characterized using spectroscopic methods such as FT-IR, 1H NMR, 13C NMR, and elemental analysis. The synthesized compounds were evaluated for their inhibitory effects on α-glycosidase, compounds 3f and 3g were found to show significant inhibitory properties when compared to the positive control. The IC50 values of 3f and 3g were calculated as 24.05 ± 2.28 and 18.51 ± 1.19 µM, respectively. Kinetic studies revealed that compounds 3f and 3g exhibited uncompetitive mode of inhibition against α-glycosidase. Molecular modeling predicted druglikeness for the title compounds and underpinned the importance of phloroglucinol hydroxyls for interacting with the key residues of α-glycosidase.

Synthesis of zinc phthalocyanine complex containing tetra propanoic acid groups: Electronic properties and inhibitory effects on some metabolic enzymes

In the new study, first the synthesis and characterization of 2, 10, 16, 24-Tetrakis-3-(phenoxy) propanoic acid phthalocyaninato zinc (II)(4) and its starting compound are presented. The aggregation properties of compound (4) were investigated with the UV–visible spectrum, and the excitation and emission properties were investigated with the fluorescence spectra. The new compounds were characterized by IR, UV-visible, Mass and 1H NMR spectroscopy. These 3-(3,4-dicyanophenoxy) propanoic acid (3) and compound (4) had effective inhibition against α-glycosidase, α-amylase, butyrylcholinesterase and acetylcholinesterase. IC50 values were found as 4.21–6.57 µM for AChE, 0.32–1.88 µM for BChE, 47.14–62.07 µM for α-amylase, and 13.41–21.82 µM for α-glycosidase. By molecular docking study, compared to reference compounds (tacrine and acarbose) of compound (4) [-9.25 kcal/mol for AChE; -9.30 kcal/mol for BChE; -6.50 kcal/mol for α-amylase and -8.49 kcal/mol for α-glycosidase seem to be more effective and promising. Drug development for the treatment of diabetes, hyperglycemia, and obesity has as one of its design goals the creation of molecules that are α-amylase and α-glycosidase inhibitors. As a result, compound (4) can have promising anti Alzheimer drug potential and record as novel anti-diabetic inhibitors.

Functionally substituted derivatives of novel thiourea and phenylthiourea as potent aldose reductase, α-amylase, and α-glycosidase inhibitors: in vitro and in silico studies

Functionally substituted derivatives of novel thiourea and phenylthiourea as potent aldose reductase, α-amylase, and α-glycosidase inhibitors: in vitro and in silico studies

Innovation of 6-sulfonamide-2H-chromene derivatives as antidiabetic agents targeting α-amylase, α-glycosidase, and PPAR-γ inhibitors with in silico molecular docking simulation.

A new series of 2-imino or 2-oxo-2H-chromene-6-sulfonamide derivatives 2-9 with potential anti-diabetic activity were designed and synthesized. The new 6-sulfonamide chromenes were synthesized by reacting 3-formyl-4-hydroxybenzenesulfonyl chloride with activated methylene derivatives in the presence of ammonium acetate as a catalyst. The structure of the products was confirmed by spectroscopic analysis. All the designed derivatives 2-9 were evaluated for their activity against α-amylase and exhibited inhibitory percentage values higher than 93% at 100 μg mL-1. Additionally, the IC50 values represented a variable degree of activity with two derivatives 2 and 9 exhibiting the most promising derivative results with IC50 values of 1.76 ± 0.01 and 1.08 ± 0.02 μM, respectively, compared to Acarbose (IC50 = 0.43 ± 0.01 μM). Additionally, these derivatives showed potency against the α-glucosidase enzyme with IC50 values of 0.548 ± 0.02 and 2.44 ± 0.09 μg mL-1, compared to Acarbose (0.604 ± 0.02 μg mL-1). Moreover, the in vitro PPAR-γ transactivation assay revealed that chromene-6-sulfonamide derivatives 2 and 9 exhibited potential PPAR-γ activity with IC50 values of 3.152 ± 0.03 and 3.706 ± 0.32 μg mL-1, respectively, compared to Pioglitazone (4.884 ± 0.29 μg mL-1). This indicates that these derivatives have insulin sensitivity and glucose metabolism activity. The in silico ADMET prediction showed that these derivatives have an acceptable range of oral bioavailability, drug-likeness, and a safe toxicity profile, including being non-cytotoxic, non-mutagenic, non-immunotoxic, and non-carcinogenic. Finally, computational docking analysis demonstrated the ability of these derivatives to interact with α-amylase, α-glucosidase, and PPAR-γ enzymes, with confirmed successful placement due to good binding energy values and various interactions within the pocket.

Effect of Teneligliptin in comparison with Voglibose as an add on therapy in reducing microvascular complications in type II Diabetes Mellitus patients – A Prospective randomized control trial

Background: The strict glycaemic control postpones all the microvascular and macrovascular complications. In type 2 diabetes the initiation of metformin is the cornerstone in reducing blood sugar. The next option is either insulin or oral hypoglycaemic agents. The DPP-4 inhibitors like gliptins have the advantages of less incidence of hypoglycaemia, good safety profile and can be combined to any oral hypoglycaemics. The meta-analysis showed that teneligliptin has less adverse profile in number of Japanese and Korean studies. It was proved that the fasting glucose and postprandial glucose substantially reduced with a potential benefit of reducing cholesterol, thereby reducing the risk of cardiovascular diseases. The advantage of using this drug as is does not worsen the hepatic and renal status. Voglibose an α-glycosidase inhibitors delay the glucose absorption from GIT hence effective in reducing postprandial hyperglycaemia. Methods: This prospective randomized controlled study was designed to compare the efficacy of teneligliptin and voglibose as an add on therapy on patients with uncontrolled blood sugar in addition to metformin 500mg BD and glimepiride 2 mg OD. Totally 80 patients were included between the age groups of 40 to 70 years. Patients were divided into two groups 40 patients each, group A were given teneligliptin and group B patients were given voglibose for a period of 6 months. At the end of 3rd month and 6th month investigations were done for FBS, PPBS and HbA1c.Statisticalmethods: Data were tabulated and results were analysed by using Analysis of Variance. AP value of <0.05 was considered as statistically significant. Results: At the end ofsix months group II showed significant reduction in fasting blood sugar and post-prandial blood sugar level. A significant reduction in FBS, PPBS, HbA1c is seen in both the groups, where teneligliptin has a favourable glucose reduction along with voglibose. Conclusions: Our study concludes that teneligliptin is better than voglibose as the 2nd line add on therapy to sulphonylureas, metformin or insulin.

Tetrazoles and Related Heterocycles as Promising Synthetic Antidiabetic Agents.

Tetrazole heterocycle is a promising scaffold in drug design, and it is incorporated into active pharmaceutical ingredients of medications of various actions: hypotensives, diuretics, antihistamines, antibiotics, analgesics, and others. This heterocyclic system is metabolically stable and easily participates in various intermolecular interactions with different biological targets through hydrogen bonding, conjugation, or van der Waals forces. In the present review, a systematic analysis of the activity of tetrazole derivatives against type 2 diabetes mellitus (T2DM) has been performed. As it was shown, the tetrazolyl moiety is a key fragment of many antidiabetic agents with different activities, including the following: peroxisome proliferator-activated receptors (PPARs) agonists, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase (AR) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) agonists, G protein-coupled receptor (GPCRs) agonists, glycogen phosphorylases (GP) Inhibitors, α-glycosidase (AG) Inhibitors, sodium glucose co-transporter (SGLT) inhibitors, fructose-1,6-bisphosphatase (FBPase) inhibitors, IkB kinase ε (IKKε) and TANK binding kinase 1 (TBK1) inhibitors, and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). In many cases, the tetrazole-containing leader compounds markedly exceed the activity of medications already known and used in T2DM therapy, and some of them are undergoing clinical trials. In addition, tetrazole derivatives are very often used to act on diabetes-related targets or to treat post-diabetic disorders.

Novel hydrazones derived from anthranilic acid as potent cholinesterases and α-glycosidase inhibitors: Synthesis, characterization, and biological effects.

N-substitued anthranilic acid derivatives are commonly found in the structure of many biologically active molecules. In this study, new members of hydrazones derived from anthranilic acid (1-15) were synthesized and investigated their effect on some metabolic enzymes such as acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glycosidase (α-Gly). Results indicated that all the molecules exhibited potent inhibitory effectsagainst all targets as compared to the standard inhibitors, revealed by IC50 values. Ki values of compounds for AChE, BChE, and α-Glyenzymes were obtained in the ranges 66.36 ± 8.30-153.82 ± 13.41, 52.68 ± 6.38-113.86, and 2.13 ± 0.25-2.84 nM, respectively. The molecular docking study was performed for the most active compounds to the determination of ligand-enzyme interactions. Binding affinities of the most active compound were found at the range of -9.70 to-9.00 kcal/mol for AChE, -11.60to-10.60 kcal/mol for BChE, and -10.30 to-9.30 kcal/mol for α-Gly. Molecular docking simulations showed that the novel compounds had preferential interaction with AChE, BChE, and α-Gly. Drug-likeness properties and ADMET (absorption, distribution, metabolism, excretion, and toxicity) analyzes of all synthesized compounds (1-15) were estimated and their toxic properties were evaluated as well as their therapeutic properties. Moreover, molecular dynamics simulations were carried out to understand the accuracy of the most potent derivatives of docking studies.

Novel coumarin-chalcone derivatives: Synthesis, characterization, antioxidant, cyclic voltammetry, molecular modelling and biological evaluation studies as acetylcholinesterase, α-glycosidase, and carbonic anhydrase inhibitors

In this study, a total of 12 coumarin-chalcone derivatives, 6 of which are original were synthesized. The structures of the newly synthesized compounds were elucidated by 1H NMR, 13C NMR, IR, and elemental analysis methods (7g-7l). The antioxidant potencies measured by using CUPRAC method (Trolox equivalent total antioxidant capacity) were as follows: 7j > 7i > 7c > 7d > 7k > 7l > 7f > 7h > 7e > 7g > 7a >7b. Furthermore, the compounds were evaluated against human carbonic anhydrases I, II, acetylcholinesterase and α-glycosidase enzymes. Compounds 7c, 7e, 7g, 7i, 7j and 7l showed promising human carbonic anhydrase I inhibition compared to the standard Acetazolamide (Ki: 16.64 ± 4.72–49.82 ± 5.82 nM vs Ki: 57.64 ± 5.41 nM). In addition, all compounds exhibited strong inhibition against acetylcholinesterase and α-glycosidase. Ki values were between 2.39 ± 0.97–9.35 ± 3.95 nM (Tacrine Ki: 13.78 ± 4.36 nM) for acetylcholinesterase, and 14.49 ± 8.51–75.67 ± 26.38 nM (Acarbose Ki: 12600 ± 78.00 nM) for α-glycosidase. Binding of 7g was predicted using molecular docking and stability of the complex was confirmed with molecular dynamics simulations which shed a light on the observed activity against acetylcholinesterase. Finally, cyclic voltammetry was also used for the electrochemical characterization of the synthesized compounds.

Total Synthesis and Absolute Configuration Determination of the α-Glycosidase Inhibitor (3S,4R)-6-Acetyl-3-hydroxy-2,2-dimethylchroman-4-yl (Z)-2-Methylbut-2-enoate from Ageratina grandifolia.

Herein, we report the first total synthesis of α-glycosidase inhibitor (3R, 4S)-6-acetyl-3-hydroxy-2,2-dimethylchroman-4-yl (Z)-2-methylbut-2-enoate as well as its enantiomer. Our synthesis confirms the chromane structure separately proposed by Navarro-Vazquez and Mata, on the basis of DFT computations. Furthermore, our synthesis allowed us to determine the absolute configuration of the natural compound as (3S, 4R) and not (3R, 4S).

Formulation and Evaluation of Mucoadhesive Tablets of Acarbose for Type 2 Diabetes

The objective of the study was to develop mucoadhesive tablet of Acarbose (α-glycosidase inhibitor) to enhance the bioavailability and to further reduce the dosing frequency of administration. The Mucoadhesive tablets of Acarbose were prepared by using three different Mucoadhesive polymers such as HPMC E5 LV, Sodium alginate and Guar Gum in varying concentrations and by direct compression technique. The micromeritics evaluation such as angle of repose, bulk density, tapped density, compressibility index and Hausner's ratio showed good to satisfactory flow properties. Swelling index was calculated with respect to time. The swelling index profile of all formulations, prepared as per the experimental design showed an increase in the value of swelling index as the amount of polymer increased. Maximum swelling index was found seen with formulations containing Sodium alginate, the value increases with increasing the amount of sodium alginate. The highest adhesion force i.e. highest strength of mucoadhesive bond was observed with Formulation F9 containing Guar gum as 18.02±0.17 this followed by F6 containing Sodium alginate as 16.33±0.56 and formulation F8 containing Guar gum in the ratio 1:2 as 14.26±0.11. The Adhesion Force increases with increasing the concentration of Mucoadhesive polymers used. The Tablets containing HPMC E5 LV showed least adhesive force than tablets of other formulations. The formulation F6 containing Sodium alginate was taken as optimized formulation based on its mucoadhesive strength and in vitro release was found to be optimum. The optimized formulation was subjected to kinetic drug release studies. The formulation best fitted into zero order kinetics. The drug release was dominated by the erosion and swelling of the polymer. From the release exponent in the Korsmeyer-Peppas model it could be suggested that the mechanism that leads to the release of drug was non-Fickian diffusion. Keywords: mucoadhesive tablet, Acarbose, Gastroretentive

Voglibose Regulates the Secretion of GLP-1 Accompanied by Amelioration of Ileal Inflammatory Damage and Endoplasmic Reticulum Stress in Diabetic KKAy Mice.

Voglibose is an α-glycosidase inhibitor that improves postprandial hyperglycemia and increases glucagon-like peptide-1 (GLP-1) secretion in patients with type 2 diabetes. Recently, there has been increasing interest in the anti-inflammatory effects of voglibose on the intestine, but the underlying mechanism is not clear. This study evaluated the effects and mechanisms of voglibose on glycemic control and intestinal inflammation. Type 2 diabetic KKAy mice were treated with voglibose (1 mg/kg) by oral gavage once daily. After 8 weeks, glucose metabolism, levels of short-chain fatty acids (SCFAs), systematic inflammatory factors, intestinal integrity and inflammation were evaluated using hematoxylin and eosin staining, immunohistochemistry, immunofluorescence and Western blot analysis. Voglibose ameliorated glucose metabolism by enhancing basal- and glucose-dependent GLP-1 secretion. Several beneficial SCFAs, such as acetic acid and propionic acid, were increased by voglibose in the fecal sample. Additionally, voglibose notably decreased the proportion of pro-inflammatory macrophages and the expression of nuclear factor kappa B but increased the expression of tight junction proteins in the ileum, thus markedly improving intestinal inflammatory damage and reducing the systematic inflammatory factors. Ileal genomics and protein validation suggested that voglibose attenuated inositol-requiring protein 1α-X-box binding protein 1-mediated endoplasmic reticulum stress (ERS). Together, these results showed that voglibose enhanced the secretion of GLP-1, which contributed to the glycemic control in KKAy mice at least in part by regulating intestinal inflammation and the expression of ERS factors.

An Insight into Pyrazole-containing Compounds: Synthesis and Pharmacological Activities

Background: Heterocyclic scaffolds have gained exceptional devotion in the recent years due to their marked utility in bio-organic field. Among these, pyrazole remains a privileged scaffold as broad array of medicinally active agents encompasses this heterocycle as a core nucleus. Pyrazole is a five-membered, aromatic ring containing two nitrogen atoms at adjacent positions are readily able to show interactions with numerous receptor (s), enzymes located on the target cells in biological system. Pyrazole-containing compounds are acknowledged with anticyclooxygenases (anti-inflammatory), carbonic anhydrase inhibitor, α-glycosidase inhibitor, and cholinesterase enzymes inhibitor and anti-DNA gyrases activities. Noticeably, rimonabant, phenylbutazone, fipronil, difenamizole, celecoxib, antipyrine, fezolamide and betazole are few representatives of pyrazole containing drugs. Objectives: The manuscript aims to review the detailed synthetic approaches applied for the synthesis of pyrazole derivatives. In particular, we examine recent scientific finding on antimicrobial, anti-tubercular, antiviral, anticancer and anti-inflammatory perspectives of pyrazole containing analogues. Methods: Pyrazole analogues have been widely explored by scientific community as large number of papers has been published in this regard. Numerous pyrazole-containing analogues have been designed, synthesized, and screened for their in vitro and in vivo bio-efficacy and many of them endowed with commendable pharmacological activities. Pyrazole analogues with superior applications as antiviral, anticancer, and anti-inflammatory efficacy have also been well documented in patents granted to this heterocyclic nucleus. Results: This review outlines the recent advances in medicinal chemistry of pyrazole analogues with a special emphasize of structure-activity relationships to afford ideas for the rational drug-design and discovery and their impact on desired pharmacological applications. Conclusion: The information provided in this manuscript may help the medicinal chemists to generate robust pyrazole analogues with high efficacy.

Isolation of Chalcomoracin as a Potential α-Glycosidase Inhibitor from Mulberry Leaves and Its Binding Mechanism.

Diabetes is a chronic metabolic disease, whereas α-glucosidases are key enzymes involved in the metabolism of starch and glycogen. There is a long history of the use of mulberry leaf (the leaf of Morus alba) as an antidiabetic herb in China, and we found that chalcomoracin, one of the specific Diels–Alder adducts in mulberry leaf, had prominent α-glucosidase inhibitory activity and has the potential to be a substitute for current hypoglycemic drugs such as acarbose, which have severe gastrointestinal side effects. In this study, chalcomoracin was effectively isolated from mulberry leaves, and its α-glucosidase inhibition was studied via enzymatic kinetics, isothermal titration (ITC) and molecular docking. The results showed that chalcomoracin inhibited α-glucosidase through both competitive and non-competitive manners, and its inhibitory activity was stronger than that of 1-doxymycin (1-DNJ) but slightly weaker than that of acarbose. ITC analysis revealed that the combination of chalcomoracin and α-glucosidase was an entropy-driven spontaneous reaction, and the molecular docking results also verified this conclusion. During the binding process, chalcomoracin went into the “pocket” of α-glucosidase via hydrophobic interactions, and it is linked with residues Val544, Asp95, Ala93, Gly119, Arg275 and Pro287 by hydrogen bonds. This study provided a potential compound for the prevention and treatment of diabetes and a theoretical basis for the discovery of novel candidates for α-glycosidase inhibitors.

Synthesis of novel thiosemicarbazone derivatives as antidiabetic agent with enzyme kinetic studies and antioxidant activity

Novel thiosemicarbazone derivatives were synthesized via condensation reactions between the corresponding thiosemicarbazides and 4-(methylsulfonyl)acetophenone. The chemical structures of all compounds were elucidated by infrared (IR), 1H-NMR and 13C-NMR spectroscopy and mass spectrometry. Antioxidant studies of all compounds were performed by using CUPRAC, FRAP, DPPH methods. 2-{1-[4-(Methylsulfonyl)phenyl]ethylidene}-N-phenylhydrazinecarbothioamide (1) possessed good antioxidant activity with an SC50 value of 15.70 µM which also is higher than standard drug, ascorbic acid. All compounds were evaluated for their antidiabetic properties as α-glycosidase and α-amylase inhibitors. Compound 1 was found to be the most active compound against α-glucosidase and α-amylase with IC50 values of 1.58 µM and 3.24 µM, respectively. The enzyme kinetic studies demonstrated that compound 1 has a competitive mode of binding. Furthermore, molecular docking studies have elucidated the binding mechanism at the molecular level by examining the molecular interactions between compound 1 and these enzymes.

In silico and in vitro studies of thiosemicarbazone-indole hybrid compounds as potent α-glycosidase inhibitors

It is essential to study α-glucosidase enzyme (EC 3.2.1.20) inhibitors because of their physiological role as well as their clinical relevance. In previous research, a novel series of thiosemicarbazone-indole hybrid compounds were synthesized and reported. In the current research, α-glucosidase inhibitory activity of the derivatives was evaluated and then in silico studies were carried out on screened compounds. All derivatives exhibited a magnificent α-glucosidase inhibitory activity (IC50 = 27.0 ± 1.0–97.4 ± 1.5 µM) toward the acarbose as reference drug (IC50 = 750.0 ± 1.5 µM). Compound 1i having phenyl ring at the thiosemicarbazone moiety and the trimethoxymethyl substituent at phenyl moiety of C2 position of indole ring was the most potent compound (IC50 = 27.0 ± 1.0 µM) among other compounds. A kinetic study of 1i revealed that is a competitive inhibitor against α-glucosidase. Moreover, the molecular docking studies established that screened derivatives interacted with the essential amino acids in the active site. Finally, based on the molecular dynamics simulations and free binding energy calculations, complexes 1d, 1i and 1k with α-glucosidase showed a good stability in the active site. Van der Waals and electrostatic interactions also exhibited the most contributions to the stability of these complexes. Moreover, all the screened compounds showed agreeable ADME properties for oral bio-availability, and good drug-likeness.

Iboga-type alkaloids with Indolizidino[8,7-b]Indole scaffold and bisindole alkaloids from Tabernaemontana bufalina Lour

Phytochemical investigation on the aerial parts of Tabernaemontana bufalina Lour. (Apocynaceae) led to the identification of four undescribed monoterpenoid indole alkaloids named taberbufamines A−D, an undescribed natural product, and fourteen known indole alkaloids. The structures of the undescribed alkaloids were established by spectroscopic and computational methods, and their absolute configurations were further determined by quantum chemical TDDFT calculations and the experimental ECD spectra. Taberbufamines A and B possessed an uncommon skeleton incorporating an indolizidino [8,7-b]indole motif with a 2-hydroxymethyl-butyl group attached at the pyrrolidine ring. Biosynthetically, Taberbufamines A and B might be derived from iboga-type alkaloid through rearrangement. Vobatensine C showed significant bioactivity against A-549, Bel-7402, and HCT-116 cells with IC50 values of 2.61, 1.19, and 1.74 μM, respectively. Ervahanine A showed antimicrobial activity against Bacillus subtilis, Mycobacterium smegmatis, and Helicobacter pylori with MIC values of 4, 8, and 16 μg/mL, respectively. 19(S)-hydroxyibogamine was shown as butyrylcholinesterase inhibitor (IC50 of 20.06 μM) and α-glycosidase inhibitor (IC50 of 17.18 μM), while tabernamine, ervahanine B, and ervadivaricatine B only showed α-glycosidase inhibitory activities with IC50 values in the range of 0.95–4.61 μM.

Screening of probiotics with efficient α-glucosidase inhibitory ability and study on the structure and function of its extracellular polysaccharide

Inhibition of α-glucosidase activity is an important strategy in lowering the concentration of blood sugar. In this paper, using domestic and foreign characteristic food-derived substances as the sources of lactobacillus, the performance of them were evaluated by measuring the strains’ α-glucosidase inhibitory ability. Finally, the cell-free extracellular supernatants (CFS) of Lactobacillus rhamnosus LB1lac10 was determined to have the highest α-glucosidase inhibition ability. Based on the Nanopore third-generation sequencing technology platform, the genome of LB1lac10 was sequenced and functional gene annotation was performed. After that, the biological activity and structural composition of the exopolysaccharide produced by L. rhamnosus LB1lac10 were studied. The purified exopolysaccharide EPS1-1 also showed efficient α-glucosidase inhibitory ability. The structure and conformation characteristics of EPS1-1 were further analyzed. The EPS1-1 from L. rhamnosus LB1lac10 had a molecular weight of 88,650 Da, and it was mainly composed of mannose, glucuronic acid, glucose, xylose, galactose, and arabinose. From the FT-IR and NMR analyses, EPS1-1 had functional groups of a typical polysaccharide structure and contained two types of glycosidic bonds with α-configuration pyranose. The main glycosidic bond corresponded to → 4)-α- d-Glcp-(1→, which might be an important reason why EPS1-1 could inhibit α-glycosidase. Thermodynamic studies showed that EPS1-1 had high heat resistance to meet the needs of food processing. The results suggested that L. rhamnosus LB1lac10 could be used as a potential probiotic to lower blood sugar, and the EPS1-1 has the potential to serve as a natural α-glycosidase inhibitor to regulate the concentration of blood glucose.