Design, Synthesis, In Vitro Biological Evaluation and In Silico Molecular Docking Study of Benzimidazole-Based Oxazole Analogues: A Promising Acetylcholinesterase and Butyrylcholinesterase Inhibitors.

Alzheimer's disease (AD) is a degenerative neurological condition that severely affects the elderly and is clinically recognised by a decrease in cognition and memory. The treatment of this disease has drawn considerable attention and sparked increased interest among the researchers in this field as a result of a number of factors, including an increase in the population of patients over time, a significant decline in patient quality of life, and the high cost of treatment and care. The current work was carried out for the synthesis of benzimidazole-oxazole hybrid derivatives as efficient Alzheimer's inhibitors and as a springboard for investigating novel anti-chemical Alzheimer's prototypes. The inhibition profiles of each synthesised analogue against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes were assessed. All the synthesized benzimidazole-based oxazole analogues displayed a diverse spectrum of inhibitory potentials against targeted AChE and BuChE enzymes when compared to the reference drug donepezil (IC50 = 2.16 ± 0.12 M and 4.50 ± 0.11 µM, respectively). The most active AChE and BuChE analogues were discovered to be analogues 9 and 14, with IC50 values of 0.10 ± 0.050 and 0.20 ± 0.050 µM (against AChE) and 0.20 ± 0.050 and 0.30 ± 0.050 µM (against BuChE), respectively. The nature, number, position, and electron-donating and -withdrawing effects on the phenyl ring were taken into consideration when analysing the structure-activity relationship (SAR). Molecular docking studies were also carried out on the active analogues to find out how amino acids bind to the active sites of the AChE and BuChE enzymes that were being studied.

Synthesis, DFT Studies, Molecular Docking and Biological Activity Evaluation of Thiazole-Sulfonamide Derivatives as Potent Alzheimer's Inhibitors.

Alzheimer's disease is a major public brain condition that has resulted in many deaths, as revealed by the World Health Organization (WHO). Conventional Alzheimer's treatments such as chemotherapy, surgery, and radiotherapy are not very effective and are usually associated with several adverse effects. Therefore, it is necessary to find a new therapeutic approach that completely treats Alzheimer's disease without many side effects. In this research project, we report the synthesis and biological activities of some new thiazole-bearing sulfonamide analogs (1-21) as potent anti-Alzheimer's agents. Suitable characterization techniques were employed, and the density functional theory (DFT) computational approach, as well as in-silico molecular modeling, has been employed to assess the electronic properties and anti-Alzheimer's potency of the analogs. All analogs exhibited a varied degree of inhibitory potential, but analog 1 was found to have excellent potency (IC50 = 0.10 ± 0.05 µM for AChE) and (IC50 = 0.20 ± 0.050 µM for BuChE) as compared to the reference drug donepezil (IC50 = 2.16 ± 0.12 µM and 4.5 ± 0.11 µM). The structure-activity relationship was established, and it mainly depends upon the nature, position, number, and electron-donating/-withdrawing effects of the substituent/s on the phenyl rings.

Synthesis, In Vitro Biological Evaluation and In Silico Molecular Docking Studies of Indole Based Thiadiazole Derivatives as Dual Inhibitor of Acetylcholinesterase and Butyrylchloinesterase.

The current study was conducted to obtain hybrid analogues of indole-based thiadiazole derivatives (1-16) in which a number of reaction steps were involved. To examine their biological activity in the presence of the reference drug Donepezil (0.21 ± 0.12 and 0.30 ± 0.32 M, respectively), the inhibitory potentials of AChE and BuChE were determined for these compounds. Different substituted derivatives showing a varied range of inhibitory profiles, when compared to the reference drug, analogue 8 was shown to have potent activity, with IC50 values for AchE 0.15 ± 0.050 M and BuChE 0.20 ± 0.10, respectively, while other substituted compounds displayed good to moderate potentials. Varied spectroscopic techniques including 1H, 13CNMR and HREI-MS were used to identify the basic skeleton of these compounds. Furthermore, all analogues have a known structure-activity relationship (SAR), and molecular docking investigations have verified the binding interactions of molecule to the active site of enzymes.

Multipotent Cholinesterase Inhibitors for the Treatment of Alzheimer's Disease: Synthesis, Biological Analysis and Molecular Docking Study of Benzimidazole-Based Thiazole Derivatives.

Twenty-four analogues of benzimidazole-based thiazoles (1-24) were synthesized and assessed for their in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory potential. All analogues were found to exhibit good inhibitory potential against cholinesterase enzymes, having IC50 values in the ranges of 0.10 ± 0.05 to 11.10 ± 0.30 µM (for AChE) and 0.20 ± 0.050 µM to 14.20 ± 0.10 µM (for BuChE) as compared to the standard drug Donepezil (IC50 = 2.16 ± 0.12 and 4.5 ± 0.11 µM, respectively). Among the series, analogues 16 and 21 were found to be the most potent inhibitors of AChE and BuChE enzymes. The number (s), types, electron-donating or -withdrawing effects and position of the substituent(s) on the both phenyl rings B & C were the primary determinants of the structure-activity relationship (SAR). In order to understand how the most active derivatives interact with the amino acids in the active site of the enzyme, molecular docking studies were conducted. The results obtained supported the experimental data. Additionally, the structures of all newly synthesized compounds were elucidated by using several spectroscopic methods like 13C-NMR, 1H-NMR and HR EIMS.

Synthesis of New Triazole-Based Thiosemicarbazone Derivatives as Anti-Alzheimer's Disease Candidates: Evidence-Based In Vitro Study.

Triazole-based thiosemicarbazone derivatives (6a-u) were synthesized then characterized by spectroscopic techniques, such as 1HNMR and 13CNMR and HRMS (ESI). Newly synthesized derivatives were screened in vitro for inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. All derivatives (except 6c and 6d, which were found to be completely inactive) demonstrated moderate to good inhibitory effects ranging from 0.10 ± 0.050 to 12.20 ± 0.30 µM (for AChE) and 0.20 ± 0.10 to 14.10 ± 0.40 µM (for BuChE). The analogue 6i (IC50 = 0.10 ± 0.050 for AChE and IC50 = 0.20 ± 0.050 µM for BuChE), which had di-substitutions (2-nitro, 3-hydroxy groups) at ring B and tri-substitutions (2-nitro, 4,5-dichloro groups) at ring C, and analogue 6b (IC50 = 0.20 ± 0.10 µM for AChE and IC50 = 0.30 ± 0.10 µM for BuChE), which had di-Cl at 4,5, -NO2 groups at 2-position of phenyl ring B and hydroxy group at ortho-position of phenyl ring C, emerged as the most potent inhibitors of both targeted enzymes (AChE and BuChE) among the current series. A structure-activity relationship (SAR) was developed based on nature, position, number, electron donating/withdrawing effects of substitution/s on phenyl rings. Molecular docking studies were used to describe binding interactions of the most active inhibitors with active sites of AChE and BuChE.

Benzimidazole Bearing Thiosemicarbazone Derivatives Act as Potent α-Amylase and α-Glucosidase Inhibitors; Synthesis, Bioactivity Screening and Molecular Docking Study.

Diabetes mellitus is one of the most chronic metabolic diseases. In the past few years, our research group has synthesized and evaluated libraries of heterocyclic analogs against α-glucosidase and α-amylase enzymes and found encouraging results. The current study comprises the evaluation of benzimidazole-bearing thiosemicarbazone as antidiabetic agents. A library of fifteen derivatives (7-21) was synthesized, characterized via different spectroscopic techniques such as HREI-MS, NMR, and screened against α-glucosidase and α-amylase enzymes. All derivatives exhibited excellent to good biological inhibitory potentials. Derivatives 19 (IC50 = 1.30 ± 0.20 µM and 1.20 ± 0.20 µM) and 20 (IC50 = 1.60 ± 0.20 µM and 1.10 ± 0.01 µM) were found to be the most potent among the series when compared with standard drug acarbose (IC50 = 11.29 ± 0.07 and 11.12 ± 0.15 µM, respectively). These derivatives may potentially serve as the lead candidates for the development of new therapeutic representatives. The structure-activity relationship was carried out for all molecules which are mainly based upon the pattern of substituent/s on phenyl rings. Moreover, in silico docking studies were carried out to investigate the active binding mode of selected derivatives with the target enzymes.

Synthesis, in vitro alpha-glucosidase inhibitory potential of benzimidazole bearing bis-Schiff bases and their molecular docking study.

Voglibose and acarbose are distinguished α-glucosidase inhibitors used for controlling of diabetes mellitus. Unfortunately, these distinguished and clinically used inhibitors have also numerous side effects. Subsequently, there is still needed to develop safer therapy. Despite of a broad spectrum of biological importance of benzimidazole, it is occasionally evaluated for α-glucosidase activity. Current study deals with the synthesis and biological screening of benzimidazole bearing bis-Schiff bases (1-19) for their α-glucosidase inhibitory activity. All analogues exhibited excellent to good inhibitory potential (IC50 = 2.20 ±â€¯0.1to 88.60 ±â€¯1.70 µM) when compared with standard drug acarbose (IC50 = 38.45 ±â€¯0.80 µM). A structure activity relationship has been established on the basis of electronic effects and position of different substituents present on phenyl ring. In order to rationalize the binding interactions of most active analogues with the active site of α-glucosidase enzyme, molecular docking study was conducted.

DLNR-SIQA: Deep Learning-Based No-Reference Stitched Image Quality Assessment.

Due to recent advancements in virtual reality (VR) and augmented reality (AR), the demand for high quality immersive contents is a primary concern for production companies and consumers. Similarly, the topical record-breaking performance of deep learning in various domains of artificial intelligence has extended the attention of researchers to contribute to different fields of computer vision. To ensure the quality of immersive media contents using these advanced deep learning technologies, several learning based Stitched Image Quality Assessment methods have been proposed with reasonable performances. However, these methods are unable to localize, segment, and extract the stitching errors in panoramic images. Further, these methods used computationally complex procedures for quality assessment of panoramic images. With these motivations, in this paper, we propose a novel three-fold Deep Learning based No-Reference Stitched Image Quality Assessment (DLNR-SIQA) approach to evaluate the quality of immersive contents. In the first fold, we fined-tuned the state-of-the-art Mask R-CNN (Regional Convolutional Neural Network) on manually annotated various stitching error-based cropped images from the two publicly available datasets. In the second fold, we segment and localize various stitching errors present in the immersive contents. Finally, based on the distorted regions present in the immersive contents, we measured the overall quality of the stitched images. Unlike existing methods that only measure the quality of the images using deep features, our proposed method can efficiently segment and localize stitching errors and estimate the image quality by investigating segmented regions. We also carried out extensive qualitative and quantitative comparison with full reference image quality assessment (FR-IQA) and no reference image quality assessment (NR-IQA) on two publicly available datasets, where the proposed system outperformed the existing state-of-the-art techniques.

Automatic 360° Mono-Stereo Panorama Generation Using a Cost-Effective Multi-Camera System.

In recent years, 360° videos have gained the attention of researchers due to their versatility and applications in real-world problems. Also, easy access to different visual sensor kits and easily deployable image acquisition devices have played a vital role in the growth of interest in this area by the research community. Recently, several 360° panorama generation systems have demonstrated reasonable quality generated panoramas. However, these systems are equipped with expensive image sensor networks where multiple cameras are mounted in a circular rig with specific overlapping gaps. In this paper, we propose an economical 360° panorama generation system that generates both mono and stereo panoramas. For mono panorama generation, we present a drone-mounted image acquisition sensor kit that consists of six cameras placed in a circular fashion with optimal overlapping gap. The hardware of our proposed image acquisition system is configured in such way that no user input is required to stitch multiple images. For stereo panorama generation, we propose a lightweight, cost-effective visual sensor kit that uses only three cameras to cover 360° of the surroundings. We also developed stitching software that generates both mono and stereo panoramas using a single image stitching pipeline where the panorama generated by our proposed system is automatically straightened without visible seams. Furthermore, we compared our proposed system with existing mono and stereo contents generation systems in both qualitative and quantitative perspectives, and the comparative measurements obtained verified the effectiveness of our system compared to existing mono and stereo generation systems.

New triazinoindole bearing thiazole/oxazole analogues: Synthesis, α-amylase inhibitory potential and molecular docking study.

New triazinoindole bearing thiazole/oxazole analogues (1-21) were synthesized and characterized through spectroscopic techniques such as HREI-MS, 1H and 13C NMR. The configuration of compound 2i and 2k was confirmed through NOESY. All analogues were evaluated against α-amylase inhibitory potential. Among the synthesized analogues, compound 1h, 1i, 1j, 2a and 2f having IC50 values 1.80 ±â€¯0.20, 1.90 ±â€¯0.30, 1.2 ±â€¯0.30, 1.2 ±â€¯0.01 and 1.30 ±â€¯0.20 µM respectively, showed excellent α-amylase inhibitory potential when compared with acarbose as standard (IC50 = 0.91 ±â€¯0.20 µM). All other analogues showed good to moderate inhibitory potential. Structural activity relationship (SAR) has been established and binding interactions were confirmed through docking studies.

Synthesis of new arylhydrazide bearing Schiff bases/thiazolidinone: α-Amylase, urease activities and their molecular docking studies.

Alpha-amylase and urease enzyme over expression endorses various complications like rheumatoid arthritis, urinary tract infection, colon cancer, metabolic disorder, cardiovascular risk, and chronic kidney disease. To overcome these complications, we have synthesized new arylhydrazide bearing Schiff bases/thiazolidinone analogues as α-amylase and urease inhibitors. The analogues 1a-r were evaluated for α-amylase inhibitory potential. All analogues were found active and show IC50 value ranging between 0.8 ±â€¯0.05 and 12.50 ±â€¯0.5 µM as compare to standard acarbose (IC50 = 1.70 ±â€¯0.10 µM). Among the synthesized analogs, compound 1j, 1r, 1k, 1e, 1b and 1f having IC50 values 0.8 ±â€¯0.05, 0.9 ±â€¯0.05, 1.00 ±â€¯0.05, 1.10 ±â€¯0.10, 1.20 ±â€¯0.10 and 1.30 ±â€¯0.10 µM respectively showed an excellent inhibitory potential. Analogs 2a-o were evaluated against urease activity. All analogues were found active and show IC50 value ranging between 4.10 ±â€¯0.02 and 38.20 ±â€¯1.10 µM as compare to standard thiourea (IC50 = 21.40 ±â€¯0.21 µM). Among the synthesized analogs, compound 2k, 2a, 2h, 2j, 2f, 2e, 2g, 2b and 2l having IC50 values 4.10 ±â€¯0.02, 4.60 ±â€¯0.02, 4.70 ±â€¯0.03, 5.40 ±â€¯0.02, 6.70 ±â€¯0.05, 8.30 ±â€¯0.3, 11.20 ±â€¯0.04, 16.90 ±â€¯0.8 and 19.80 ±â€¯0.60 µM respectively showed an excellent inhibitory potential. All compounds were characterized through 1H, 13C NMR and HR-EIMS analysis. Structure activity relationship of the synthesized analogs were recognized and confirmed through molecular docking studies.

Synthesis, in vitro urease inhibitory potential and molecular docking study of Benzimidazole analogues.

Despite of many diverse biological activities exhibited by benzimidazole scaffold, it is rarely explored for the urease inhibitory potential. For that purpose, benzimidazole analogues 1-19 were synthesized and screened for in vitro urease inhibitory potential. Structures of all synthetic analogues were deduced by different spectroscopic techniques. All analogues revealed inhibition potential with IC50 values of 0.90 ±â€¯0.01 to 35.20 ±â€¯1.10 µM, when compared with the standard thiourea (IC50 = 21.40 ±â€¯0.21 µM). Limited SAR suggested that the variations in the inhibitory potentials of the analogues are the result of different substitutions on phenyl ring. In order to rationalize the binding interactions of most active compounds with the active site of urease enzyme, molecular docking study was conducted.

Synthesis of Novel Triazinoindole-Based Thiourea Hybrid: A Study on α-Glucosidase Inhibitors and Their Molecular Docking.

A new class of triazinoindole-bearing thiosemicarbazides (1-25) was synthesized and evaluated for α-glucosidase inhibitory potential. All synthesized analogs exhibited excellent inhibitory potential, with IC50 values ranging from 1.30 ± 0.01 to 35.80 ± 0.80 µM when compared to standard acarbose (an IC50 value of 38.60 ± 0.20 µM). Among the series, analogs 1 and 23 were found to be the most potent, with IC50 values of 1.30 ± 0.05 and 1.30 ± 0.01 µM, respectively. The structure-activity relationship (SAR) was mainly based upon bringing about different substituents on the phenyl rings. To confirm the binding interactions, a molecular docking study was performed.

Bisindolylmethane thiosemicarbazides as potential inhibitors of urease: Synthesis and molecular modeling studies.

Bisindolylmethane thiosemicarbazides 1-18 were synthesized, characterized by 1H NMR and ESI MS and evaluated for urease inhibitory potential. All analogs showed outstanding urease inhibitory potentials with IC50 values ranging between 0.14 ±â€¯0.01 to 18.50 ±â€¯0.90 µM when compared with the standard inhibitor thiourea having IC50 value 21.25 ±â€¯0.90 µM. Among the series, analog 9 (0.14 ±â€¯0.01 µM) with di-chloro substitution on phenyl ring was identified as the most potent inhibitor of urease. The structure activity relationship has been also established on the basis of binding interactions of the active analogs. These binding interactions were identified by molecular docking studies.

Synthesis, molecular docking study and in vitro thymidine phosphorylase inhibitory potential of oxadiazole derivatives.

We have synthesized oxadiazole derivatives (1-16), characterized by 1H NMR, 13C NMR and HREI-MS and screened for thymidine phosphorylase inhibitory potential. All derivatives display varied degree of thymidine phosphorylase inhibition in the range of 1.10 ±â€¯0.05 to 49.60 ±â€¯1.30 µM when compared with the standard inhibitor 7-Deazaxanthine having an IC50 value 38.68 ±â€¯1.12 µM. Structure activity relationships (SAR) has been established for all compounds to explore the role of substitution and nature of functional group attached to the phenyl ring which applies imperious effect on thymidine phosphorylase activity. Molecular docking study was performed to understand the binding interaction of the most active derivatives with enzyme active site.

Synthesis of Bis-indolylmethane sulfonohydrazides derivatives as potent α-Glucosidase inhibitors.

In search of better α-glucosidase inhibitors, a series of bis-indolylmethane sulfonohydrazides derivatives (1-14) were synthesized and evaluated for their α-glucosidase inhibitory potential. All derivatives exhibited outstanding α-glucosidase inhibition with IC50 values ranging between 0.10 ±â€¯0.05 to 5.1 ±â€¯0.05 µM when compared with standard drug acarbose having IC50 value 856.28 ±â€¯3.15 µM. Among the series, analog 7 (0.10 ±â€¯0.05 µM) with tri-chloro substitution on phenyl ring was identified as the most potent inhibitor of α-glucosidase (∼ 8500 times). The structure activity relationship has been also established. Molecular docking studies were also performed to help understand the binding interaction of the most active analogs with receptors. From the docking studies, it was observed that all the active bis-indolylmethane sulfonohydrazides derivatives showed considerable binding interactions within the active site (acarbose inhibition site) of α-glucosidase. We also evaluated toxicity of all derivatives and found none of them are toxic.

Synthesis and study of the α-amylase inhibitory potential of thiadiazole quinoline derivatives.

α-Amylase is a target for type-2 diabetes mellitus treatment. However, small molecule inhibitors of α-amylase are currently scarce. In the course of developing small molecule α-amylase inhibitors, we designed and synthesized thiadiazole quinoline analogs (1-30), characterized by different spectroscopic techniques such as 1HNMR and EI-MS and screened for α-amylase inhibitory potential. Thirteen analogs 1, 2, 3, 4, 5, 6, 22, 23, 25, 26, 27, 28 and 30 showed outstanding α-amylase inhibitory potential with IC50 values ranges between 0.002±0.60 and 42.31±0.17µM which is many folds better than standard acarbose having IC50 value 53.02±0.12µM. Eleven analogs 7, 9, 10, 11, 12, 14, 15, 17, 18, 19 and 24 showed good to moderate inhibitory potential while seven analogs 8, 13, 16, 20, 21 and 29 were found inactive. Our study identifies novel series of potent α-amylase inhibitors for further investigation. Structure activity relationship has been established.

Synthesis and in vitro study of benzofuran hydrazone derivatives as novel alpha-amylase inhibitor.

The α-amylase acts as attractive target to treat type-2 diabetes mellitus. Therefore in discovering a small molecule as α-amylase inhibitor, we have synthesized benzofuran carbohydrazide analogs (1-25), characterized through different spectroscopic techniques such as 1HNMR and EI-MS. All screened analog shows good α-amylase inhibitory potentials with IC50 value ranging between 1.078±0.19 and 2.926±0.05µM when compared with acarbose having IC50=0.62±0.22µM. Only nine analogs among the series such as analogs 3, 5, 7, 8, 10, 12, 21, 23 and 24 exhibit good inhibitory potential with IC50 values 1.644±0.128, 1.078±0.19, 1.245±0.25, 1.843±0.19, 1.350±0.24, 1.629±0.015, 1.353±0.232, 1.359±0.119 and 1.488±0.07µM when compare with standard drug acarbose. All other analogs showed good to moderate α-amylase inhibitory potentials. The SAR study was conducted on the basis of substituent difference at the phenyl ring. The binding interaction between analogs and active site of enzyme was confirmed by docking studies.

Synthesis, α-glucosidase inhibitory activity and in silico study of tris-indole hybrid scaffold with oxadiazole ring: As potential leads for the management of type-II diabetes mellitus.

Discovery of α-glucosidase inhibitors has been actively pursued with the aim to develop therapeutics for the treatment of type-II diabetes mellitus and the other carbohydrate mediated disease. In continuation of our drug discovery research on potential antidiabetic agents, we synthesized novel tris-indole-oxadiazole hybrid analogs (1-21), structurally characterized by various spectroscopic techniques such as 1H NMR, EI-MS, and 13C NMR. Elemental analysis was found in agreement with the calculated values. All compounds were evaluated for α-glucosidase inhibiting potential and showed potent inhibitory activity in the range of IC50=2.00±0.01-292.40±3.16µM as compared to standard acarbose (IC50=895.09±2.04µM). The pharmacokinetic predictions of tris-indole series using descriptor properties showed that almost all compounds in this series indicate the drug aptness. Detailed binding mode analyses with docking simulation was also carried out which showed that the inhibitors can be stabilized by the formation of hydrogen bonds with catalytic residues and the establishment of hydrophobic contacts at the opposite side of the active site.

Synthesis of alpha amylase inhibitors based on privileged indole scaffold.

Twenty five derivatives of indole carbohydrazide (1-25) had been synthesized. These compounds were characterized using 1H NMR and EI-MS, and further evaluated for their α-amylase inhibitory potential. The analogs (1-25) showed varying degree of α-amylase inhibitory potential. ranging between 9.28 and 599.0µM when compared with standard acarbose having IC50 value 8.78±0.16µM. Six analogs, 25 (IC50=9.28±0.153µM), 22 (IC50=9.79±0.43µM), 4 (IC50=11.08±0.357µM), 1 (IC50=12.65±0.169µM), 8 (IC50=21.37±0.07µM) and 14 (IC50=43.21±0.14µM) showed potent α-amylase inhibition as compared to the standard acarbose (IC50=8.78±0.16µM). All other analogs displayed good to moderate inhibitory potential. Structure-activity relationship was established through the interaction of the active compounds with enzyme active site with the help of docking studies.