Quercetin and Kaempferol as Multi-Targeting Antidiabetic Agents against Mouse Model of Chemically Induced Type 2 Diabetes

Diabetes, a multifactorial metabolic disorder, demands the discovery of multi-targeting drugs with minimal side effects. This study investigated the multi-targeting antidiabetic potential of quercetin and kaempferol. The druggability and binding affinities of both compounds towards multiple antidiabetic targets were explored using pharmacokinetic and docking software (AutoDock Vina 1.1.2). Our findings showed that quercetin and kaempferol obey Lipinski's rule of five and exhibit desirable ADMET (absorption, distribution, metabolism excretion, and toxicity) profiles. Both compounds showed higher binding affinities towards C-reactive protein (CRP), interleukin-1 (IL-1), dipeptidyl peptidase-4 (DPP-IV), peroxisome proliferator-activated receptor gamma (PPARG), protein tyrosine phosphatase (PTP), and sodium-glucose co-transporter-1 (SGLT-1) compared to metformin (the positive control). Both quercetin and kaempferol inhibited α-amylase activity (in vitro) up to 20.30 ± 0.49 and 37.43 ± 0.42%, respectively. Their oral supplementation significantly reduced blood glucose levels (p < 0.001), improved lipid profile (p < 0.001), and enhanced total antioxidant status (p < 0.01) in streptozotocin-nicotinamide (STZ-NA)-induced diabetic mice. Additionally, both compounds significantly inhibited the proliferation of Huh-7 and HepG2 (cancer cells) (p < 0.0001) with no effect on the viability of Vero cell line (non-cancer). In conclusion, quercetin and kaempferol demonstrated higher binding affinities towards multiple targets than metformin. In vitro and in vivo antidiabetic potential along with the anticancer activities of both compounds suggest promise for further development in diabetes management. The combination of both drugs did not show a synergistic effect, possibly due to their same target on the receptors.

Design and Pharmacophore Study of Triazole Analogues as Aromatase Inhibitors

BACKGROUND

In current scenario breast cancer measured as one of the dangerous health issues. An effective therapeutic class of drug known as aromatase inhibitors (AIs) is dominant against estrogen receptorpositive breast cancer. However, there is an urgent need to create target-specific AIs with better anti-breast cancer profiles due to the increased toxicity and adverse effects related to currently existing anti-breast cancer drugs.

OBJECTIVES

In the present study, we have designed of 100 novel tiazole analogues as aromatase inhibitors their pharmacophoric features were explored.

METHOD

Molecular docking was applied to a series of 4-substituted-1, 2, 3-triazoles containing letrozole for their aromatase inhibitory effects. The aromatase inhibitory activity of the compound in a series varies in the range of (IC50 = 0.008-31.26 μM). A hydrogen atom positioned at R1 of the triazole ring in compound (01) was responsible for the most potent compound (IC50 = 0.008 μM) in the series of 28 compounds as compared to letrozole. The self-organizing molecular field study was used to assess the molecular characteristics and biological activities of the compounds. The four models were developed using PLS and MLR methods. The PLS method was good for statistical analysis. The letrozole scaffold-based 100 compounds were designed by selecting an effective pharmacophore responsible for aromatase inhibitory activity. The designed compound was placed on the previous model as a test set, and its IC50 values were calculated.

RESULT

Hydrogen bonds were established between the potent molecule (01) and the essential residues Met 374 and Arg 115, which were responsible for the aromatase-inhibiting action. Cross-validated q2 (0.6349) & noncross- validated r2 (0.7163) were discovered in the statistical findings as having reliable predictive power. Among 100 designed compounds, seven compounds showed good aromatase inhibitory activities.

CONCLUSION

The additional final SOMFA model created for the interactions between the aromatase and the triazole inhibitors may be helpful for future modification and enhancement of the inhibitors of this crucial enzyme.

Polycystic ovary syndrome: Current scenario and future insights

Polycystic ovary syndrome (PCOS) prevails in approximately 33% of females of reproductive age globally. Although the root cause of the disease is unknown, attempts are made to clinically manage the disturbed hormone levels and symptoms arising due to hyperandrogenism, a hallmark of PCOS. This review presents detailed insights on the etiology, risk factors, current treatment strategies, and challenges therein. Medicinal agents currently in clinical trials and those in the development pipeline are emphasized. The significance of the inclusion of herbal supplements in PCOS and the benefits of improved lifestyle are also explained. Last, emerging therapeutic targets for treating PCOS are elaborated. The present review will assist the research fraternity working in the concerned domain to access significant knowledge associated with PCOS.

Dual aromatase-steroid sulfatase inhibitors (DASI's) for the treatment of breast cancer: a structure guided ligand based designing approach

Dual aromatase-steroid sulfatase inhibitors (DASIs) lead to significant deprivation of estrogen levels as compared to a single target inhibition and thereby exhibited an additive or synergistic effect in the treatment of hormone-dependent breast cancer (HDBC). Triazole-bearing DASI's having structural features of clinically available aromatase inhibitors are identified as lead structures for optimization as DASI's. To identify the spatial fingerprints of target-specific triazole as DASI's, we have performed molecular docking assisted Gaussian field-based comparative 3D-QSAR studies on a dataset with dual aromatase-STS inhibitory activities. Separate contours were generated for both aromatase and steroid sulphates showing respective pharmacophoric structural requirements for optimal activity. These developed 3D-QSAR models also showed good statistical measures with the excellent predictive ability with PLS-generated validation constraints. Comparative steric, electrostatic, hydrophobic, HBA, and HBD features were elucidated using respective contour maps for selective target-specific favourable activity. Furthermore, the molecular docking was used for elucidating the mode of binding as DASI's along with the MD simulation of 100 ns revealed that all the protease-ligand docked complexes are overall stable as compared to reference ligand (inhibitor ASD or Irosustat) complex. Further, the MM-GBSA study revealed that compound 24 binds to aromatase as well as STS active site with relatively lower binding energy than reference complex, respectively. A comparative study of these developed multitargeted QSAR models along with molecular docking and dynamics study can be employed for the optimization of drug candidates as DASI's.Communicated by Ramaswamy H. Sarma.

A comprehension on structure guided alignment dependent 3D-QSAR modelling, and molecular dynamics simulation on 2,4-thiazolidinediones as aldose reductase inhibitors for the management of diabetic complications

Aldose reductase is an oxo-reductase enzyme belonging to the aldo-keto reductase class. Compounds having thiazolidine-2,4-dione scaffold are reported as potential aldose reductase inhibitors for diabetic complications. The present work uses structure-guided alignment-dependent Gaussian field- and atom-based 3D-QSAR on a dataset of 84 molecules. 3D-QSAR studies on two sets of dataset alignment have been carried out to understand the favourable and unfavourable structural features influencing the affinity of these inhibitors towards the enzyme. Using common pharmacophore hypotheses, the five-point pharmacophores for aldose reductase favourable features were generated. The molecular dynamics simulations (up to 100 ns) were performed for the potent molecule from each alignment set (compounds 24 and 65) compared to reference standard tolrestat and epalrestat to study target-ligand complexes' binding energy and stability. Compound 65 was most stable with better interactions in the aldose reductase binding pocket than tolrestat. The MM-PBSA study suggests compound 65 possessed better binding energy than reference standard tolrestat, i.e. -87.437 ± 19.728 and -73.424 ± 12.502 kJ/mol, respectively. The generated 3D-QSAR models provide information about structure-activity relationships and ligand-target binding energy. Target-specific stability data from MD simulation would be helpful for rational compound design with better aldose reductase activity.Communicated by Ramaswamy H. Sarma.

Multifaceted 3D-QSAR analysis for the identification of pharmacophoric features of biphenyl analogues as aromatase inhibitors

Aromatase, a cytochrome P450 enzyme, is responsible for the conversion of androgens to estrogens, which fuel the multiplication of cancerous cells. Inhibition of estrogen biosynthesis by aromatase inhibitors (AIs) is one of the highly advanced therapeutic approach available for the treatment of estrogen-positive breast cancer. Biphenyl moiety aids lipophilicity to the conjugated scaffold and enhances the accessibility of the ligand to the target. The present study is focused on the investigation of, the mode of binding of biphenyl with aromatase, prediction of ligand-target binding affinities, and pharmacophoric features essential for favorable for aromatase inhibition. A multifaceted 3D-QSAR (SOMFA, Field and Gaussian) along with molecular docking, molecular dynamic simulations and pharmacophore mapping were performed on a series of biphenyl bearing molecules (1-33) with a wide range of aromatase inhibitory activity (0.15-920 nM). Among the generated 3D-QSAR models, the Force field-based 3D-QSAR model (R² = 0.9151) was best as compared to SOMFA and Gaussian Field (R²=0.7706, 0.9074, respectively). However, all the generated 3D-QSAR models were statistically fit, robust enough, and reliable to explain the variation in biological activity in relation to pharmacophoric features of dataset molecules. A four-point pharmacophoric features with three acceptor sites (A), one aromatic ring (R) features, AAAR_1, were obtained with the site and survival score values 0.890 and 4.613, respectively. The generated 3D-QSAR plots in the study insight into the structure-activity relationship of dataset molecules, which may help in the designing of potent biphenyl derivatives as newer inhibitors of aromatase.Communicated by Ramaswamy H. Sarma.

CADD Studies in the Discovery of Potential ARI (Aldose Reductase Inhibitors) Agents for the Treatment of Diabetic Complications

The lack of currently available drugs for treating diabetes complications has stimulated our interest in finding new Aldose Reductase inhibitors (ARIs) with more beneficial biological properties. One metabolic method uses aldose reductase inhibitors in the first step of the polyol pathway to control excess glucose flux in diabetic tissues. Computer-aided drug discovery (CADD) is key in finding and optimizing potential lead substances. AR inhibitors (ARI) have been widely discussed in the literature. For example, Epalrestat is currently the only ARI used to treat patients with diabetic neuropathy in Japan, India, and China. Inhibiting R in patients with severe to moderate diabetic autonomic neuropathy benefits heart rate variability. AT-001, an AR inhibitor, is now being tested in COVID-19 to see how safe and effective it reduces inflammation and cardiac damage. In summary, these results from animal and human studies strongly indicate that AR can cause cardiovascular complications in diabetes. The current multi-center, large-scale randomized human study of the newly developed powerful ARI may prove its role in diabetic cardiovascular disease to establish therapeutic potential. During the recent coronavirus disease (COVID-19) outbreak in 2019, diabetes and cardiovascular disease were risk factors for severely negative clinical outcomes in patients with COVID19. New data shows that diabetes and obesity are among the strongest predictors of COVID-19 hospitalization. Patients and risk factors for severe morbidity and mortality of COVID- 19.

Molecular Iodine-Catalyzed Synthesis of Imidazo[1,2-a]Pyridines: Screening of Their In Silico Selectivity, Binding Affinity to Biological Targets, and Density Functional Theory Studies Insight

The present paper discloses an ultrasonication strategy assisted by molecular iodine as an environmentally benign catalyst leading to the synthesis of pharmacologically significant imidazo[1,2-a]pyridine scaffolds. The molecular-iodine-catalyzed approach for the synthesis of biologically active synthetic equivalents was achieved through three-component coupling embracing 2-aminopyridine derivatives, pertinent acetophenones, and dimedone in water medium under aerobic conditions. The higher product yield (up to 96%) with a miniature reaction time and modest catalyst loading as demonstrated by higher ecological compatibility and sustainability factors are fascinating features of this protocol. The structures of synthesized compounds were accomplished through FT-IR, ¹H NMR,¹³C NMR, mass, and elemental analysis data. The virtual screening of synthetic moieties was performed to ascertain the in silico selectivity and binding affinities against several biological targets. Lipinski's rules of five, ADMET, and TOPKAT descriptors were used to evaluate the drug-likeness assets. Furthermore, a quantum computational study was computed at the B3LYP/6-311G++(d,p) level of theory to investigate the density functional theory-based chemical reactivity parameters and HOMO-LUMO energy gap of the synthesized derivatives. The present studies open the way for in vitro and in vivo testing of synthesized derivatives as potent inhibitors with an improved pharmacological profile against farnesyl diphosphate synthase, phosphodiesterase III, CXCR4, and GABAa receptor agonists.

Potential Therapeutic Target Protein Tyrosine Phosphatase-1B for Modulation of Insulin Resistance with Polyphenols and Its Quantitative Structure–Activity Relationship

The increase in the number of cases of type 2 diabetes mellitus (T2DM) and the complications associated with the side effects of chemical/synthetic drugs have raised concerns about the safety of the drugs. Hence, there is an urgent need to explore and identify natural bioactive compounds as alternative drugs. Protein tyrosine phosphatase 1B (PTP1B) functions as a negative regulator and is therefore considered as one of the key protein targets modulating insulin signaling and insulin resistance. This article deals with the screening of a database of polyphenols against PTP1B activity for the identification of a potential inhibitor. The research plan had two clear objectives. Under first objective, we conducted a quantitative structure–activity relationship analysis of flavonoids with PTP1B that revealed the strongest correlation (R² = 93.25%) between the number of aromatic bonds (naro) and inhibitory concentrations (IC₅₀) of PTP1B. The second objective emphasized the binding potential of the selected polyphenols against the activity of PTP1B using molecular docking, molecular dynamic (MD) simulation and free energy estimation. Among all the polyphenols, silydianin, a flavonolignan, was identified as a lead compound that possesses drug-likeness properties, has a higher negative binding energy of −7.235 kcal/mol and a pKd value of 5.2. The free energy-based binding affinity (ΔG) was estimated to be −7.02 kcal/mol. MD simulation revealed the stability of interacting residues (Gly183, Arg221, Thr263 and Asp265). The results demonstrated that the identified polyphenol, silydianin, could act as a promising natural PTP1B inhibitor that can modulate the insulin resistance.

Molecular dynamics and 3D-QSAR studies on indazole derivatives as HIF-1α inhibitors

Hypoxia-inducible factor (HIF) is a transcriptional factor which plays a crucial role in tumour metastasis thereby responsible for development of various forms of cancers. Indazole derivatives have been reported in the literature as potent HIF-1α inhibitor via interaction with key residues of the HIF-1α active site. Taking into consideration the role HIF-1α in cancer and potency of indazole derivative against HIF-1α; it was considered of interest to correlate structural features of known indazole derivatives with specified HIF-1α inhibitory activity to map pharmacophoric features through Three-dimensional quantitative structural activity relationship (3D-QSAR) and pharmacophore mapping. Field and Gaussian based 3D-QSAR studies were performed to realize the variables influencing the inhibitory potency of HIF-1α inhibitors. Field and Gaussian- based 3D-QSAR models were validated through various statistical measures generated by partial least square (PLS). The steric and electrostatic maps generated for both 3D-QSAR provide a structural framework for designing new inhibitors. Further; 3D-maps were also helpful in understanding variability in the activity of the compounds. Pharmacophore mapping also generates a common five-point pharmacophore hypothesis (A₁D₂R₃R₄R₅_4) which can be employed in combination with 3D-contour maps to design potent HIF-1α inhibitors. Molecular docking and molecular dynamics (MD) simulation of the most potent compound 39 showed good binding efficiency and was found to be quite stable in the active site of the HIF-1α protein. The developed 3D-QSAR models; pharmacophore modelling; molecular docking studies along with the MD simulation analysis may be employed to design lead molecule as selective HIF-1α inhibitors for the treatment of Cancer.

The assembly of integrated continuous flow platform for on-demand rosiglitazone and pioglitazone synthesis

Manufacturing thiazolidinediones in a batch process is often carried out at different locations, where each successive batch collects a certain amount of intermediate followed by its transportation to another location.

Thiazole Ring-A Biologically Active Scaffold

BACKGROUND

Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs.

OBJECTIVE

To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews.

RESULTS

Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

Isolation, semi-synthesis, docking-based prediction, and bioassay-based activity of Dolichandrone spathacea iridoids: new catalpol derivatives as glucosidase inhibitors

Dolichandrone spathacea iridoids are promising anti-diabetic inhibitors towards α-glucosidase protein (PDB-3W37) and oligo-1,6-glucosidase protein (PDB-3AJ7). Five catalpol iridoids (1, 2, 10, 13, 14) were isolated from mangrove plant D. spathacea, and their derivatives (3, 4, 5, 6, 7, 8, 9, 11, 12, 15) were obtained from reduction, acetylation, O-alkylation, acetonisation, or hydrolysation starting from naturally isolated compounds. They were identified by spectral methods such as IR, MS, and 1D and 2D NMR. Their glucosidase-related (3W37 and 3AJ7) inhibitability and physiological compatibility were predicted by molecular docking simulation and prescreened based on Lipinski's rule of five. Experimental α-glucosidase inhibition of 1-15 was evaluated using enzyme assays. Compounds 3, 4, 5, 6, and 9 are new iridoid derivatives, introduced to the literature for the first time, while all fifteen compounds 1-15 are studied for molecular docking for the first time. Regarding protein 3W37, the five strongest predicted inhibitors assemble in the order 2 > 10 > 1 > 9 > 14. In respect to 3AJ7, the corresponding order is 14 > 2 > 10 > 5 > 1 = 9. Lipinski's criteria suggest 10 as the candidate with the most potential for oral administration. The in vitro bioassay revealed that compound 10 is the most effective inhibitor with a respective IC50 value of 0.05 μM, in the order 10 > 2 > 14 > 13 > 1. The computational and experimental results show good consistency. The study opens an alternative approach for diabetes treatment based on inhibitability of natural and semi-synthesised catalpol iridoid derivatives towards carbohydrate-hydrolases.

Lead Molecules as Novel Aromatase Inhibitors: In Silico De Novo Designing and Binding Affinity Studies

Background:

Aromatase inhibitors emerged as a pivotal moiety to selectively block estrogen production, prevention and treatment of tumour growth in breast cancer. De novo drug design is an alternative approach to blind virtual screening for successful designing of the novel molecule against various therapeutic targets.

Objective:

In the present study, we have explored the de novo approach to design novel aromatase inhibitors.

Method:

The e-LEA3D, a computational-aided drug design web server was used to design novel drug-like candidates against the target aromatase. For drug-likeness ADME parameters (molecular weight, H-bond acceptors, H-bond donors, LogP and number of rotatable bonds) of designed molecules were calculated in TSAR software package, geometry optimization and energy minimization was accomplished using Chem Office. Further, molecular docking study was performed in Molegro Virtual Docker (MVD).

Results:

Among 17 generated molecules using the de novo pathway, 13 molecules passed the Lipinski filter pertaining to their bioavailability characteristics. De novo designed molecules with drug-likeness were further docked into the mapped active site of aromatase to scale up their affinity and binding fitness with the target. Among de novo fabricated drug like candidates (1-13), two molecules (5, 6) exhibited higher affinity with aromatase in terms of MolDock score (-150.650, -172.680 Kcal/mol, respectively) while molecule 8 showed lowest target affinity (-85.588 Kcal/mol).

Conclusion:

The binding patterns of lead molecules (5, 6) could be used as a pharmacophore for medicinal chemists to explore these molecules for their aromatase inhibitory potential.

Quantitative structure-activity relationship (QSAR) and design of novel ligands that demonstrate high potency and target selectivity as protein tyrosine phosphatase 1B (PTP 1B) inhibitors as an effective strategy used to model anti-diabetic agents

Diabetes and obesity have increased dramatically in recent decades worldwide. Diabetes mainly emerged as a major health care burden disease in both the US and other industrialized countries, among which type II diabetes is the most common. Discovering new and effective treatments for diabetes is currently a high international health priority. In the present study a computational technique was used to model 97 compounds with PTP-1B inhibitory activity, in order to demonstrate the Quantitative structure-activity relationship (QSAR) of these compounds a genetic function approximation (GFA) algorithm was applied to pick the best descriptors and multiple linear regression (MLR) was used to establish a relationship between the PTP-1B inhibitory activity of these compounds and the best molecular descriptors. This QSAR study allowed investigating the influence of very simple and easy-to-compute descriptors in determining biological activities, which shed light on the key factors that aid in the design of novel potent molecules using computer-aided drug design tools.

A Comprehension into Target Binding and Spatial Fingerprints of Noscapinoid Analogues as Inhibitors of Tubulin

BACKGROUND

Owing to its potential to interfere in microtubule dynamics in the mitotic phase of cell cycle and selectively induce apoptosis in cancer cells without affecting normal cells, noscapine and its synthetic analogues have been investigated by other research groups in different cell lines for their capability to be used as anti-cancer agents.

OBJECTIVE

The present study is focused on the investigation of the mode of binding of noscapinoids with tubulin, prediction of target binding affinities and mapping of their spatial fingerprints (shape and electrostatic).

METHODS

Molecular docking assisted alignment based 3D-QSAR was used on a dataset (43 molecules) having an inhibitory activity (IC₅₀ = 1.2-250 μM) against human lymphoblast (CEM) cell line.

RESULTS AND CONCLUSION

Key amino acid residues of target tubulin were mapped for the binding of most potent noscapine analogue (Compound 11) and were compared with noscapine. Spatial fingerprints of noscapinoids for favorable tubulin inhibitory activity were generated and are proposed herewith for further pharmacophoric amendments of noscapine analogues to design and develop novel potent noscapine based anti-cancer agents that may enter into drug development pipeline.

Structure Guided Molecular Docking Assisted Alignment Dependent 3DQSAR Study on Steroidal Aromatase Inhibitors (SAIs) as Anti-breast Cancer Agents

Background:

In spite of the availability of various treatment approaches including surgery, radiotherapy, and hormonal therapy, the steroidal aromatase inhibitors (SAIs) play a significant role as chemotherapeutic agents for the treatment of estrogen-dependent breast cancer with the benefit of reduced risk of recurrence. However, due to greater toxicity and side effects associated with currently available anti-breast cancer agents, there is emergent requirement to develop target-specific AIs with safer anti-breast cancer profile.

Methods:

It is challenging task to design target-specific and less toxic SAIs, though the molecular modeling tools viz. molecular docking simulations and QSAR have been continuing for more than two decades for the fast and efficient designing of novel, selective, potent and safe molecules against various biological targets to fight the number of dreaded diseases/disorders. In order to design novel and selective SAIs, structure guided molecular docking assisted alignment dependent 3D-QSAR studies was performed on a data set comprises of 22 molecules bearing steroidal scaffold with wide range of aromatase inhibitory activity.

Results:

3D-QSAR model developed using molecular weighted (MW) extent alignment approach showed good statistical quality and predictive ability when compared to model developed using moments of inertia (MI) alignment approach.

Conclusion:

The explored binding interactions and generated pharmacophoric features (steric and electrostatic) of steroidal molecules could be exploited for further design, direct synthesis and development of new potential safer SAIs, that can be effective to reduce the mortality and morbidity associated with breast cancer.

2,4-Thiazolidinediones as PTP 1B Inhibitors: A Mini Review (2012-2018)

2,4-thiazolidinedione (TZD) scaffold is a synthetic versatile scaffold explored by medicinal chemists for the discovery of novel molecules for the target-specific approach to treat or manage number of deadly ailments. PTP 1B is the negative regulator of insulin signaling cascade, and its diminished activity results in abolishment of insulin resistance associated with T2DM. The present review focused on the seven years journey (2012-2018) of TZDs as PTP 1B inhibitors with the insight into the amendments in the structural framework of TZD scaffold in order to optimize/design potential PTP 1B inhibitors. We have investigated the synthesized molecules based on TZD scaffold with potential activity profile against PTP 1B. Based on the SAR studies, the combined essential pharmacophoric features of selective and potent TZDs have been mapped and presented herewith for further design and synthesis of novel inhibitors of PTP 1B. Compound 46 bearing TZD scaffold with N-methyl benzoic acid and 5-(3-methoxy-4-phenethoxy) benzylidene exhibited the most potent activity (IC50 1.1 µM). Imidazolidine-2,4-dione, isosteric analogue of TZD, substituted with 1-(2,4-dichlorobenzyl)-5-(3-(2,4- dichlorobenzyloxy)benzylidene) (Compound 15) also endowed with very good PTP inhibitory activity profile (IC50 0.57 µM). It is noteworthy that Z-configuration is essential in structural framework around the double bond of arylidene for the designing of bi-dentate ligands with optimum activity.

Combined comparative molecular field analysis, comparative molecular similarity indices analysis, molecular docking and molecular dynamics studies of histone deacetylase 6 inhibitors

Human histone deacetylase isoform 6 (HDAC6) has been shown to have an immense role in cell motility and aggresome formation and is being an attractive selective target for the treatment of multiple tumour types and neurodegenerative conditions. The discovery of selective HDAC6 inhibitors with new chemical functionalities is therefore of utmost interest to researchers. In order to examine the structural requirements for HDAC6-specific inhibitors and to derive predictive model which can be used for designing new selective HDAC6 inhibitors, a three-dimensional quantitative structure-activity relationship study was carried out on a diverse set of ligands using common feature-based pharmacophore alignment followed by employing comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques. The models displayed high correlation of 0.978 and 0.991 for best CoMFA and CoMSIA models, respectively, and a good statistical significance. The model could be used for predicting activities of the test set compounds as well as for deriving useful information regarding steric, electrostatic, hydrophobic properties of the molecules used in this study. Further, the training and test set molecules were docked into the HDAC6 binding site and molecular dynamics was carried out to suggest structural requirements for design of new inhibitors.

Current anti-diabetic agents and their molecular targets: A review

Diabetes mellitus is a medical condition characterized by the body's loss of control over blood sugar. The frequency of diagnosed cases and consequential increases in medical costs makes it a rapidly growing chronic disease that threatens human health worldwide. In addition, its unnerving statistical projections are perilous to both the economy of the nation and man's life expectancy. Type-I and type-II diabetes are the two clinical forms of diabetes mellitus. Type-II diabetes mellitus (T2DM) is illustrated by the abnormality of glucose homeostasis in the body, resulting in hyperglycemia. Although significant research attention has been devoted to the development of diabetes regimens, which demonstrates success in lowering blood glucose levels, their efficacies are unsustainable due to undesirable side effects such as weight gain and hypoglycemia. Over the years, heterocyclic scaffolds have been the basis of anti-diabetic chemotherapies; hence, in this review we consolidate the use of bioactive scaffolds, which have been evaluated for their biological response as inhibitors against their respective anti-diabetic molecular targets over the past five years (2012-2017). Our investigation reveals a diverse target set which includes; protein tyrosine phosphatase 1 B (PTP1B), dipeptidly peptidase-4 (DPP-4), free fatty acid receptors 1 (FFAR1), G protein-coupled receptors (GPCR), peroxisome proliferator activated receptor-γ (PPARγ), sodium glucose co-transporter-2 (SGLT2), α-glucosidase, aldose reductase, glycogen phosphorylase (GP), fructose-1,6-bisphosphatase (FBPase), glucagon receptor (GCGr) and phosphoenolpyruvate carboxykinase (PEPCK). This review offers a medium on which future drug design and development toward diabetes management may be modelled (i.e. optimization via structural derivatization), as many of the drug candidates highlighted show promise as an effective anti-diabetic chemotherapy.

Development of leads targeting ER-α in breast cancer: An in silico exploration from natural domain

The steroid, estrogen has been recognized as being important for stimulating the growth of breast cancers primarily mediated via the steroidal estrogen receptor-α (ER-α). Inhibition of estrogen activity by small molecules with increased target specificity has proven to be an effective treatment for breast cancer. After the success stories of SERMs and fulvestrant, there is a need for the development of new small molecule modulating ER-α is due to developing resistance and side effects to current breast cancer therapy. In this pursuit, we virtually screened 227 chemically diverse bioactive natural products to get the best hits having an ER-α binding affinity. The docking scores and protein-ligand interactions of the obtained hits were emulated with the clinically used selective estrogen modulators and ER-antagonists. The results revealed 18 potential hits, which were putatively classified as hits belonging to ER agonists, modulators, and antagonists. Furthermore, as most of the hits were found to comprise the chromene nucleus, the 2D and 3D QSAR studies were performed using a set of natural products and synthesized compounds containing this scaffold, to understand the structural requirements for improving activity against breast cancer. Additionally, a pharmacophore model was generated to investigate the pharmacophoric features of the explored scaffolds for an optimal anticancer activity. The results signify that these compounds with structural modification could serve as potential leads in the drug discovery process for the treatment of breast cancer.

Evaluation of 4-methyl-2-[(2-methylbenzyl) amino]-1,3-thiazole-5-carboxylic acid against hyperglycemia, insulin sensitivity, and oxidative stress-induced inflammatory responses and β-cell damage in the pancreas of streptozotocin-induced diabetic rats

4-Methyl-2-[(2-methylbenzyl) amino]-1,3-thiazole-5-carboxylic acid (bioactive compound (BAC)), a novel thiazole derivative, is a xanthine oxidase inhibitor and free radical scavenging agent. Effects of BAC on hyperglycemia, insulin sensitivity, oxidative stress, and inflammatory mediators were evaluated in streptozotocin (STZ)-induced neonatal models of non-insulin-dependent diabetes mellitus (NIDDM) rats where NIDDM was induced in neonatal pups with single intraperitoneal injection of STZ (100 mg/kg). The effect of BAC (10 and 20 mg/kg, p.o.) for 3 weeks was evaluated by the determination of blood glucose, oral glucose tolerance test (OGTT), HbA1c level, insulin level, insulin sensitivity, and insulin resistance (IR). Furthermore, inflammatory mediators (tumor necrosis factor-alpha and interleukin-6) and oxidative stress were estimated in serum and pancreatic tissue, respectively. Significant alteration in the level of blood glucose, OGTT, HbA1c, insulin level, insulin sensitivity, in addition variation in the antioxidant status and inflammatory mediators, and alteration in histoarchitecture of pancreatic tissue confirmed the potential of BAC in STZ-induced neonatal models of NIDDM rats. Pretreatment with BAC restored the level of glucose by decreasing the IR and increasing the insulin sensitivity. Furthermore, BAC balanced the antioxidant status and preserved the inflammatory mediators. Histological studies of pancreatic tissues showed normal architecture after BAC administration to diabetic rats. Altogether, our results suggest that BAC successfully reduces the blood glucose level and possesses antioxidant as well as anti-inflammatory activities. This leads to decreased histological damage in diabetic pancreatic tissues, suggesting the possibility of future diabetes treatments.

Structure based comprehensive modelling, spatial fingerprints mapping and ADME screening of curcumin analogues as novel ALR2 inhibitors

Aldose reductase (ALR2) inhibition is the most legitimate approach for the management of diabetic complications. The limited triumph in the drug development against ALR2 is mainly because of its close structural similarity with the other members of aldo-keto reductase (AKR) superfamily viz. ALR1, AKR1B10; and lipophilicity problem i.e. poor diffusion of synthetic aldose reductase inhibitors (ARIs) to target tissues. The literature evidenced that naturally occurring curcumin demonstrates relatively specific and non-competitive inhibition towards human recombinant ALR2 over ALR1 and AKR1B10; however β-diketone moiety of curcumin is a specific substrate for liver AKRs and accountable for it’s rapid in vivo metabolism. In the present study, structure based comprehensive modelling studies were used to map the pharmacophoric features/spatial fingerprints of curcumin analogues responsible for their ALR2 specificity along with potency on a data set of synthetic curcumin analogues and naturally occurring curcuminoids. The data set molecules were also screened for drug-likeness or ADME parameters, and the screening data strongly support that curcumin analogues could be proposed as a good drug candidate for the development of ALR2 inhibitors with improved pharmacokinetic profile compared to curcuminoids due to the absence of β-diketone moiety in their structural framework.

Insight into the structural requirements of pyrimidine-based phosphodiesterase 10A (PDE10A) inhibitors by multiple validated 3D QSAR approaches

Schizophrenia is a complex disorder of thinking and behaviour (0.3-0.7% of the population is affected). The over-expression of phosphodiesterase 10A (PDE10A) enzyme may be a potential target for schizophrenia and Huntington's disease. Because 3D QSAR analysis is one of the most frequently used modelling techniques, in the present study, five different 3D QSAR tools, namely CoMFA, CoMSIA, kNN-MFA, Open3DQSAR and topomer CoMFA methods, were used on a dataset of pyrimidine-based PDE10A inhibitors. All developed models were validated internally and externally. The non-commercial Open3DQSAR produced the best statistical results amongst 3D QSAR tools. The structural interpretations obtained from different methods were thoroughly analysed and were justified on the basis of information obtained from the crystal structure. Information from one method was mostly validated by the results of other methods and vice versa. In the current work, the use of multiple tools in the same analysis revealed more complete information about the structural requirements of these compounds. On the basis of the observations of the 3D QSAR studies, 12 new compounds were designed for better PDE10A inhibitory activity. The current investigation may help in further designing new PDE10A inhibitors with promising activity.

Discovery of novel cinnamylidene-thiazolidinedione derivatives as PTP-1B inhibitors for the management of type 2 diabetes

Synthesis, biological evaluation,in silicobinding affinity prediction and 3D-QSAR studies of cinnamylidene-thiazolidinedione derivatives was performed as inhibitors of PTP-1B.

Fe–SBA-15 catalyzed synthesis of 2-alkoxyimidazo[1,2-a]pyridines and screening of their in silico selectivity and binding affinity to biological targets

Regioselective synthesis of 2-alkoxyimidazopyridines by Fe-SBA-15 and screening of their in silico binding affinity to biological targets.

Study of novel pyrazolo[3,4-d]pyrimidine derivatives as selective TgCDPK1 inhibitors: molecular docking, structure-based 3D-QSAR and molecular dynamics simulation

We explored the structural features that have an impact on TgCDPK1 activity and TgCDPK1/Src selectivity by multi-computational methods with different statistical models.