Exploring efficacy of indole-based dual inhibitors for α-glucosidase and α-amylase enzymes: In silico, biochemical and kinetic studies

Synthesis and biological evaluation of indole derivatives containing thiazolidine-2,4-dione as α-glucosidase inhibitors with antidiabetic activity

In order to develop potential α-glucosidase inhibitors with antidiabetic activity, twenty-six indole derivatives containing thiazolidine-2,4-dione were synthesized. All compounds presented potential α-glucosidase inhibitory activities with IC50 values ranging from 2.35 ± 0.11 to 24.36 ± 0.79 μM, respectively compared to acarbose (IC50 = 575.02 ± 10.11 μM). Especially, compound IT4 displayed the strongest α-glucosidase inhibitory activity (IC50 = 2.35 ± 0.11 μM). The inhibition mechanism of compound IT4 on α-glucosidase was clarified by the investigation of kinetics studies, fluorescence quenching, CD spectra, 3D fluorescence spectra, and molecular docking. In vivo antidiabetic experiments demonstrated that oral administration of compound IT4 would suppress fasting blood glucose level and ameliorate their glucose tolerance and dyslipidemia in diabetic mice.

Finding structural requirements of structurally diverse α-glucosidase and α-amylase inhibitors through validated and predictive 2D-QSAR and 3D-QSAR analyses

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemic state. The α-glucosidase and α-amylase are considered two major targets for the management of Type 2 DM due to their ability of metabolizing carbohydrates into simpler sugars. In the current study, cheminformatics analyses were performed to develop validated and predictive models with a dataset of 187 α-glucosidase and α-amylase dual inhibitors. Separate linear, interpretable and statistically robust 2D-QSAR models were constructed with datasets containing the activities of α-glucosidase and α-amylase inhibitors with an aim to explain the crucial structural and physicochemical attributes responsible for higher activity towards these targets. Consequently, some descriptors of the models pointed out the importance of specific structural moieties responsible for the higher activities for these targets and on the other hand, properties such as ionization potential and mass of the compounds as well as number of hydrogen bond donors in molecules were found to be crucial in determining the binding potentials of the dataset compounds. Statistically significant 3D-QSAR models were developed with both α-glucosidase and α-amylase inhibition datapoints to estimate the importance of 3D electrostatic and steric fields for improved potentials towards these two targets. Molecular docking performed with selected compounds with homology model of α-glucosidase and X-ray crystal structure of α-amylase largely supported the interpretations obtained from the cheminformatic analyses. The current investigation should serve as important guidelines for the design of future α-glucosidase and α-amylase inhibitors. Besides, the current investigation is entirely performed by using non-commercial open-access tools to ensure easy accessibility and reproducibility of the investigation which may help researchers throughout the world to work more on drug design and discovery.

Synthesis, α-amylase and α-glucosidase inhibition and molecular docking studies of indazole derivatives

Herein, we report the synthesis and inhibitory potential of indazole (Methyl 1H-indazole-4-carboxylate) derivatives (1-13) against α-amylase and α-glucosidase enzymes. The described derivatives demonstrated good inhibitory potential with IC₅₀ values, ranging between 15.04 ± 0.05 to 76.70 ± 0.06 µM ± SEM for α-amylase and 16.99 ± 0.19 to 77.97 ± 0.19 µM ± SEM for α-glucosidase, respectively. In particular, compounds (8-10 and 12) displayed significant inhibitory activities against both the screened enzymes, with their inhibitory potential comparable to the standard acarbose (12.98 ± 0.03 and 12.79 ± 0.17 µM ± SEM, respectively). Additionally, the influence of different substituents on enzyme inhibition activities was assessed to study the structure activity relationships. Molecular docking simulations were performed to rationalize the binding of derivatives/compounds with enzymes. All the synthesized derivatives (1-13) were characterized with the aid of spectroscopic instruments such as ¹H-NMR, ¹³C-NMR, HR-MS, elemental analysis and FTIR.Communicated by Ramaswamy H. Sarma.

Fragment-Based Dynamic Combinatorial Chemistry for Identification of Selective α-Glucosidase Inhibitors

Efforts to combine advantages of fragment-based drug design (FBDD) and dynamic combinatorial chemistry (DCC) for the development of selective α-glucosidase inhibitors were described. Starting from 5 rationally designed fragments, two iterative dynamic combinatorial libraries (DCLs) comprising 29 acylhydrazone products were generated and screened using α-glucosidase and α-amylase as the templates. The optimal ligand identified showed substantial α-glucosidase inhibition with high selectivity over α-amylase as well as low cytotoxicity. Furthermore, inhibition type and detailed ligand/enzyme binding interactions were elucidated by the binding kinetic study and docking simulation, respectively.

Design, synthesis, in vitro, and in silico biological evaluations of coumarin-indole hybrids as new anti-α-glucosidase agents

BACKGROUND

A series of coumarin-indole hybrids was synthesized as the new α-glucosidase inhibitors. The title hybrids were considered as α-glucosidase inhibitors because had two active pharmacophores against α-glucosidase: coumarin and indole.

METHODS

The thirteen various derivatives 4a-m were synthesized, purified, and fully characterized. These compounds were evaluated against α-glucosidase in vitro and in silico. In silico pharmacokinetic studies of the most potent compounds were also performed.

RESULTS

Most of the title compounds exhibited high anti-α-glucosidase activity in comparison to standard drug acarbose. In particular, the phenoxy derivative 4d namely 3-((1H-indol-3-yl)(3-phenoxyphenyl)methyl)-4-hydroxy-2H-chromen-2-one showed promising activity. This compound is a competitive inhibitor against α-glucosidase and showed the lowest binding energy at the α-glucosidase active site in comparison to other potent synthesized compounds and acarbose.

CONCLUSION

Compound 4d can be a lead compound for further structural development to obtain effective and potent α-glucosidase inhibitors.

Bio-Oriented Synthesis of Novel (S)-Flurbiprofen Clubbed Hydrazone Schiff’s Bases for Diabetic Management: In Vitro and In Silico Studies

A new series of (S)-flurbiprofen derivatives 4a–4p and 5a–5n were synthesized with different aromatic or aliphatic aldehydes and ketones to produce Schiff’s bases and their structures were confirmed through HR-ESI-MS, ¹H, and ¹³C-NMR spectroscopy. The α-glucosidase inhibitory activities of the newly synthesized compounds were scrutinized, in which six compounds 5k, 4h, 5h, 4d, 4b, and 5i showed potent inhibition in the range of 0.93 to 10.26 µM, respectively, whereas fifteen compounds 4c, 4g, 4i, 4j, 4l, 4m, 4o, 4p, 5c, 5d, 5j, 5l, 5m, 5n and 1 exhibited significant inhibitory activity with IC₅₀ in range of = 11.42 to 48.39 µM. In addition, compounds 5g, 5f, 4k, 4n, and 4f displayed moderate-to-low activities. The modes of binding of all the active compounds were determined through the molecular docking approach, which revealed that two residues, specifically Glu277 and His351 are important in the stabilization of the active compounds in the active site of α-glucosidase. Furthermore, these compounds block the active site with high binding energies (−7.51 to −3.36 kcal/mol) thereby inhibiting the function of the enzyme.

α-Glucosidase inhibitors from brown rice bound phenolics extracts (BRBPE): Identification and mechanism

Brown rice bound phenolics extracts (BRBPE) have been reported to possess α-glucosidase inhibitory effects, the specific enzyme inhibitors involved in this process were unknown. Here, α-glucosidase inhibitors in BRBPE were screened using bioaffinity ultrafiltration methods, and seven phenolic compounds - three monomers (p-coumaric acid, ferulic acid and methyl ferulate), three dimers (8-5', 5-5' and 8-O-4' diferulic acid) and a trimer (5-5'/8-O-4″ dehydrotriferulic acid) were identified as exact inhibitors, among which 5-5'/8-O-4″ dehydrotriferulic acid and 5-5'diferulic acid exhibited the best inhibitory activity. Enzyme kinetic analysis suggested that the inhibitory mechanism of these seven inhibitors including competitive, noncompetitive, uncompetitive and mixed manner. Molecular docking analysis revealed that the seven inhibitors bind with α-glucosidase mainly by hydrogen bonding interaction, hydrophobic force and ionic bond. Molecular dynamics simulation further explored the structure and molecular property of phenolic-glucosidase complex. This work provided a deep insight into brown rice bound phenolics acting as potent α-glucosidase inhibitors.

Identification of potent α-amylase inhibitors via dynamic combinatorial chemistry

In this study, we report for the first time the discovery of potent α-amylase inhibitors using principle of dynamic combinatorial chemistry. The best compound identified exhibited not only high inhibitory efficiency but also low cytotoxicity. The binding mode and possible mechanism are determined in the subsequent kinetic and molecular docking studies.

Identification of Novel Potential Anti-Diabetic Candidates targeting Human Pancreatic ɑ-Amylase and Human ɑ-Glycosidase: An Exhaustive Structure-based Screening

Diabetes is a major health issue that half a billion people affected worldwide. It is a serious, long-term medical condition majorly impacting the lives and well-being of individuals, families, and societies at large. It is amongst the top 10 diseases responsible for the death amongst adults with an expected rise to 10.2% (578 million) by 2030 and 10.9% (700 million) by 2045. The carbohydrates absorbed into the body are hydrolyzed by pancreatic α-amylase and other enzymes, human α-glucosidase. The α-amylase and α-glucosidase are validated therapeutic targets in the treatment of Type II diabetes (T2DM) as they play a vital role in modulating the blood glucose post meal. Herein, we report novel and diverse molecules as potential candidates, with predicted affinity for α-amylase and α-glucosidase. These molecules have been identified via hierarchical multistep docking of small molecules database with the estimated binding free energies. A Glide XP Score cutoff −8.00 kcal/mol was implemented to filter out non potential molecules. Four molecules viz. amb22034702, amb18105639, amb17153304, and amb9760832 have been identified after an exhaustive computational study involving, evaluation of binding interactions and assessment of the pharmacokinetics and toxicity profiles. The in-depth analysis of protein– ligand interactions was performed using a 100ns molecular dynamics (MD) simulation to establish the dynamic stability. Furthermore MM-GBSA based binding free energies were computed for 1000 trajectory snapshots to ascertain the strong binding affinity of these molecules for α-amylase and αglucosidase. The identified molecules can be considered as promising candidates for further drug development through necessary experimental assessments.

Synthesis of indole derivatives as diabetics II inhibitors and enzymatic kinetics study of α-glucosidase and α-amylase along with their in-silico study

In this study, we have investigated a series of indole-based compounds for their inhibitory study against pancreatic α-amylase and intestinal α-glucosidase activity. Inhibitors of carbohydrate degrading enzymes appear to have an essential role as antidiabetic drugs. All analogous exhibited good to moderate α-amylase (IC₅₀ = 3.80 to 47.50 μM), and α-glucosidase inhibitory interactions (IC₅₀ = 3.10-52.20 μM) in comparison with standard acarbose (IC₅₀ = 12.28 μM and 11.29 μM). The analogues 4, 11, 12, 15, 14 and 17 had good activity potential both for enzymes inhibitory interactions. Structure activity relationships were deliberated to propose the influence of substituents on the inhibitory potential of analogues. Docking studies revealed the interaction of more potential analogues and enzyme active site. Further, we studied their kinetic study of most active compounds showed that compounds 15, 14, 12, 17 and 11 are competitive for α-amylase and non- competitive for α-glucosidase.

Phenolics from Physalis peruviana fruits ameliorate streptozotocin-induced diabetes and diabetic nephropathy in rats via induction of autophagy and apoptosis regression

The objective of our study was to evaluate the effect of Physalis peruviana L. fruits in the management of diabetes and diabetic nephropathy in relation to its metabolic profile. In-vitro α-amylase, β-glucosidase, and lipase inhibition activities were assessed for the ethanolic extract (EtOH) and its subfractions. Ethyl acetate (EtOAc) fraction showed the highest α-amylase, β-glucosidase, and lipase inhibition effect. In vivo antihyperglycemic testing of EtOAc in streptozotocin (STZ)-induced diabetic rats showed that it decreased the blood glucose level, prevented the reduction in body weight, improved serum indicators of kidney injury (urea, uric acid, creatinine), and function (albumin and total protein). EtOAc increased autophagic parameters (LC3B, AMPK) and depressed mTOR contents. Histopathology revealed that EtOAc ameliorated the pathological features and decreased the glycogen content induced by STZ. The immunohistochemical analysis showed that EtOAc reduced P53 expression as compared to the STZ-diabetic group. UPLC-ESI-MS/MS metabolite profiling of EtOAc allowed the identification of several phenolic compounds. Among the isolated compounds, gallic acid, its methylated dimer and the glycosides of quercetin had promising α-amylase and β-glucosidase inhibition activity. The results suggest that the phenolic-rich fraction has a protective effects against diabetic nephropathy presumably via enhancing autophagy (AMPK/mTOR pathway) and prevention of apoptosis (P53 suppression).

A facile approach synthesis of benzoylaryl benzimidazole as potential α-amylase and α-glucosidase inhibitor with antioxidant activity

Synthetic routes to a series of benzoylarylbenzimidazol 3a-h have been derived from 3,4-diaminobenzophenone and an appropriate arylaldehyde in the presence of ammonium chloride or a mixture of ammonium chloride and sodium metabisulfite as catalyst. The antioxidant activity of targeted compounds 3a-h has been measured by four different methods and the overall antioxidant evaluation of the compounds indicated the significant MCA, FRAP, and (DPPH-SA) of the compounds except for the compound 3h. In vitro antidiabetic assay of α-amylase and α-glucosidase suggest a good to excellent activity for most tested compounds. The target benzimidazole 3f containing hydroxyl motif at para-position of phenyl revealed an important activity inhibitor against α- amylase (IC₅₀ = 12.09 ± 0.38 µM) and α-glucosidase (IC₅₀ = 11.02 ± 0.04 µM) comparable to the reference drug acarbose. The results of the anti hyperglycemic activity were supported by means of in silico molecular docking calculations showing strong binding affinity of compounds 3a-h with human pancreatic α-amylase (HPA) and human lysosomal acid-α-glucosidase (HLAG) active sites that confirm a good to excellent activity for most of tested compounds.

Synthesis, Structure, Carbohydrate Enzyme Inhibition, Antioxidant Activity, In Silico Drug-Receptor Interactions and Drug-Like Profiling of the 5-Styryl-2-Aminochalcone Hybrids

The 2-amino-5-(3/4-fluorostyryl)acetophenones were prepared and reacted with benzaldehyde derivatives to afford the corresponding 5-styryl-2-aminochalcone hybrids. The trans geometry of the styryl and α,β-unsaturated carbonyl arms, and the presence of NH…O intramolecular hydrogen bond were validated using 1H-NMR and X-ray data. The 2-amino-5-styrylacetophenones and their 5-styryl-2-aminochalcone derivatives were screened in vitro for their capability to inhibit α-glucosidase and/or α-amylase activities. Their antioxidant properties were evaluated in vitro through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) free radical scavenging assays. Kinetic studies of the most active derivatives from each series against α-glucosidase and/or α-amylase activities have been performed supported by molecular docking studies to determine plausible protein-ligand interactions on a molecular level. The key aspects of the pharmacokinetics of these compounds, i.e., absorption, distribution, metabolism, and excretion have also been simulated at theoretical level. The most active compounds from each series, namely, 2a and 3e, were evaluated for cytotoxicity against the normal monkey kidney cells (Vero cells) and the adenocarcinomic human epithelial (A549) cell line to establish their safety profile at least in vitro.

Synergistic growth inhibition effect of TiO2 nanoparticles and tris(1,3-dichloro-2-propyl) phosphate on earthworms in soil

The co-existence of organic pollutants and nanoparticles in the environment may lead to combined biological effects. The joint toxicity of pollutants and nanoparticles has been receiving increasing attention from researchers, but few studies have focused on soil biota due to the complexity of soil matrices. This study investigated the effects of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) at 0, 5, and 25 mg/kg and nanoparticulate TiO₂ (nTiO₂) at 0, 500, and 2500 mg/kg in a 3 × 3 factorial arrangement of treatments for 28 days (d) on Eisenia fetida (earthworm). Compared with the control group (the 0 mg/kg TDCIPP + 0 mg/kg nTiO₂ treatment), all other single (TDCIPP or nTiO₂) and binary (TDCIPP + nTiO₂) treatments except for the single 500 mg/kg nTiO₂ treatment significantly reduced the weight gain rate of E. fetida. The binary treatments had significantly greater such effect than their corresponding single treatments, exhibiting a synergistic toxicity between TDCIPP and nTiO2 on the growth of E. fetida. Since TDCIPP and nTiO₂ had no significant effect on their concentrations in the soil or in E. fetida during binary exposure, the synergistic toxicity could be a result of the superimposition of the toxicity pathways of TDCIPP and nTiO₂. Transcriptomic analysis of E. fetida intestinal region revealed that exposure to 25 mg/kg TDCIPP or 2500 mg/kg nTiO₂ affected nutrient-related or cell apoptosis and DNA damage related genes, respectively; their co-exposure greatly inhibited genes related to nutrient digestion and absorption, while causing abnormal transcription of genes related to the development and maintenance of E. fetida's muscles, leading to synergistic toxicity. These findings provide new insights into the environmental risks of organophosphorus flame retardants, nanoparticles, and their co-exposure.

Adsorption and desorption characteristics of polyphenols from Eucommia ulmoides Oliv. leaves with macroporous resin and its inhibitory effect on α-amylase and α-glucosidase

Background

Eucommia ulmoides Oliv. (EUO) was a traditional Chinese herb, its leaves were abundant in China, and polyphenol compounds were considered to be an important active ingredient in Eucommia ulmoides Oliv. leaves (EUOL). However, previous research mainly focused on compound identification and extraction process, there were few reported on the efficient enrichment process and biological activity evaluation of polyphenols in EUOL.

Methods

The adsorption and desorption characteristics of twelve different resins (HPD-100, HPD-300, HPD-600, D-3250, X-5, D-140, NKA-9, NKA-II, D-101, AB-8, S-8 and Polyamide) were investigated to develop an efficient method for the enrichment of polyphenol from EUOL, and the static adsorption, kinetics, isotherm and thermodynamics of the polyphenol from EUOL were analyzed. The eluted component was obtained through dynamic elution, and its main polyphenol compounds were detected by high-phase liquid chromatography (HPLC) and the inhibitory effects on the enzyme activity of α-amylase and α-glucosidase was also evaluated for different elution components. Meanwhile, the binding of main polyphenol compounds to enzyme was also evaluated.

Results

The selected resins (HPD-300, HPD-600, D-3250, X-5, D-140, NKA-9, D-101 and AB-8) showed adsorption patterns that fitted well to the pseudo second-order kinetics. The intra-particle diffusion model demonstrated that the diffusion of polyphenol compounds on these resins were divided into three processes. For HPD-300, HPD-600 and NKA-9, the Freundlich model better described the adsorption isotherm behavior than the Langmuir model, and the adsorption of polyphenol was a physical, exothermic, and spontaneous process. Subsequently, dynamic elution was performed yielding a higher polyphenol content in a 60% ethanol-water elution component, and it also exhibited a higher inhibitory effect on α-amylase and α-glucosidase activity. Furthermore, as the main polyphenol compounds, chlorogenic acid, rutin, quercetin and kaempferol were used to simulate the binding to the enzyme protein through molecular docking technology. The results showed that quercetin had a higher docking score for α-amylase, while rutin displayed superior binding to α-glucosidase.

Conclusions

Therefore, polyphenols of EUOL could be enriched through macroporous resins and have the potential to be effective enzyme inhibitor.

Novel cyclic thiourea derivatives of aminoalcohols at the presence of AlCl3 catalyst as potent α-glycosidase and α-amylase inhibitors: Synthesis, characterization, bioactivity investigation and molecular docking studies

The article is devoted to the targeted synthesis and study of cyclic thiourea and their various new derivatives as new organic compounds containing polyfunctional group in the molecule. First time the reaction of the corresponding synthesized pyrimidinethione with 1,2-epoxy-3-chlorpropane at the presence of AlCl₃ catalyst in 75-80% yield alkyl-1-(3-chloro-2-hydroxypropyl)-4-alkyl-6-phenyl-2-thioxo-1,2,5,6- tetrahydropyrimidine-5-carboxylates. In the next stage, new cyclic thiourea derivatives of aminoalcohols were synthesised from the reaction of chlorinated derivatives of pyrimidinethiones with single amines and their structures were investigated by spectroscopic methods. In this study, a series of novel compounds were tested towards some metabolic enzymes including α-glycosidase (α-Gly) and α-amylase (α-Amy) enzymes. Novel compounds showed K_is in ranging of 10.43 ± 0.94-111.37 ± 13.25 µM on α-glycosidase and IC₅₀ values in ranging of 14.38-106.51 µM on α-amylase. The novel cyclic thiourea derivatives of aminoalcohols had effective inhibition profiles against all tested metabolic enzymes. Binding affinity and inhibition mechanism of the most active compounds were detected with in silico studies and have shown that 2-Hydroxypropyl and butan-1-aminium moieties play a key role for inhibition of the enzymes.