Novel Thiosemicarbazone Derivatives: In Vitro and In Silico Evaluation as Potential MAO-B Inhibitors

MAO-B inhibitors are frequently used in the treatment of neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Due to the limited number of compounds available in this field, there is a need to develop new compounds. In the recent works, it was shown that various thiosemicarbazone derivatives show hMAO inhibitory activity in the range of micromolar concentration. It is thought that benzofuran and benzothiophene structures may mimic structures such as indane and indanone, which are frequently found in the structures of such inhibitors. Based on this view, new benzofuran/benzothiophene and thiosemicarbazone hybrid compounds were synthesized, characterized and screened for their hMAO-A and hMAO-B inhibitory activity by an in vitro fluorometric method. The compounds including methoxyethyl substituent (2b and 2h) were found to be the most effective agents in the series against MAO-B enzyme with the IC₅₀ value of 0.042 ± 0.002 µM and 0.056 ± 0.002 µM, respectively. The mechanism of hMAO-B inhibition of compounds 2b and 2h was investigated by Lineweaver–Burk graphics. Compounds 2b and 2h were reversible and non-competitive inhibitors with similar inhibition features as the substrates. The K_i values of compounds 2b and 2h were calculated as 0.035 µM and 0.046 µM, respectively, with the help of secondary plots. The docking study of compound 2b and 2h revealed that there is a strong interaction between the active sites of hMAO-B and analyzed compound.     

On the Inhibitability of Natural Products Isolated from Tetradium ruticarpum towards Tyrosine Phosphatase 1B (PTP1B) and α-Glucosidase (3W37): An In Vitro and In Silico Study

Folk experiences suggest natural products in Tetradium ruticarpum can be effective inhibitors towards diabetes-related enzymes. The compounds were experimentally isolated, structurally elucidated, and tested in vitro for their inhibition effects on tyrosine phosphatase 1B (PTP1B) and α-glucosidase (3W37). Density functional theory and molecular docking techniques were utilized as computational methods to predict the stability of the ligands and simulate interaction between the studied inhibitory agents and the targeted proteins. Structural elucidation identifies two natural products: 2-heptyl-1-methylquinolin-4-one (1) and 3-[4-(4-methylhydroxy-2-butenyloxy)-phenyl]-2-propenol (2). In vitro study shows that the compounds (1 and 2) possess high potentiality for the inhibition of PTP1B (IC₅₀ values of 24.3 ± 0.8, and 47.7 ± 1.1 μM) and α-glucosidase (IC₅₀ values of 92.1 ± 0.8, and 167.4 ± 0.4 μM). DS values and the number of interactions obtained from docking simulation highly correlate with the experimental results yielded. Furthermore, in-depth analyses of the structure–activity relationship suggest significant contributions of amino acids Arg254 and Arg676 to the conformational distortion of PTP1B and 3W37 structures overall, thus leading to the deterioration of their enzymatic activity observed in assay-based experiments. This study encourages further investigations either to develop appropriate alternatives for diabetes treatment or to verify the role of amino acids Arg254 and Arg676.     

1,2-萘醌类化合物抑制PTP1B的三维定量构效关系研究

蛋白酪氨酸磷酸酶1B (protein tyrosine phosphatase 1B, PTP-1B)是近年来发现的治疗II型糖尿病的新靶点, 1,2-萘醌类化合物对PTP-1B有较好的抑制活性, 具有良好的药用前景. 为了设计出本类化合物抑制效果更好的分子构型, 用比较分子力场分析(CoMFA)和比较分子相似性指数分析(CoMSIA)对该类化合物进行了三维定量构效关系(3D-QSAR)的研究, 并建立了相关的预测模型. 其中, CoMFA模型的交叉验证相关系数(q²)为0.555, 非交叉验证相关系数(r²)为0.991, 标准偏差(SEE)为0.049, F值为564.910. CoMSIA模型的q²为0.558, r²为0.991, SEE为0.050, F值为542.773. 计算结果表明, 获得的CoMFA和CoMSIA模型具有良好的预测能力, 可以应用于指导该类化合物的设计.     

酪氨酸蛋白磷酸酯酶1B抑制剂的分子对接和三维定量构效关系研究

用一种柔性分子对接方法(FlexX)将12个2-草酰胺苯甲酸类抑制剂和酪氨酸蛋白磷酸酯酶(PTP1B)活性口袋进行分子对接,对接程序预测的抑制剂和酶之间的相互作用能与抑制活性之间有很好的相关性(非线性相关系数R²达0.859),这说明对接结果可以比较准确地预测抑制剂和PTP1B之间的结合模式.然后,将33个同类抑制剂的骨架叠合在分子对接预测的结合构象上,用比较分子力场分析方法(CoMFA)对其进行三维定量活性构效关系研究,得到的CoMFA模型具有很好的统计相关性(交互验证回归系数q²为0.650),并可以准确地预测测试集6个化合物的活性(平均标准偏差为0.177).同时,由CoMFA模型得出的抑制剂改造信息与用FlexX预测的结合模式是一致的,进一步证明我们预测的结合模式是正确的.为研究这类抑制剂和PTP1B的结合模式及对抑制剂进行结构改造提供了信息.     

1,5-Benzothiazepine Derivatives: Green Synthesis,In Silico and In Vitro Evaluation as Anticancer Agents

Considering the importance of benzothiazepine pharmacophore, an attempt was carried out to synthesize novel 1,5-benzothiazepine derivatives using polyethylene glycol-400 (PEG-400)-mediated pathways. Initially, different chalcones were synthesized and then subjected to a cyclization step with benzothiazepine in the presence of bleaching clay and PEG-400. PEG-400-mediated synthesis resulted in a yield of more than 95% in less than an hour of reaction time. Synthesized compounds 2a–2j were investigated for their in vitro cytotoxic activity. Moreover, the same compounds were subjected to systematic in silico screening for the identification of target proteins such as human adenosine kinase, glycogen synthase kinase-3β, and human mitogen-activated protein kinase 1. The compounds showed promising results in cytotoxicity assays; among the tested compounds, 2c showed the most potent cytotoxic activity in the liver cancer cell line Hep G-2, with an IC₅₀ of 3.29 ± 0.15 µM, whereas the standard drug IC₅₀ was 4.68 ± 0.17 µM. In the prostate cancer cell line DU-145, the compounds displayed IC₅₀ ranges of 15.42 ± 0.16 to 41.34 ± 0.12 µM, while the standard drug had an IC₅₀ of 21.96 ± 0.15 µM. In terms of structural insights, the halogenated phenyl substitution on the second position of benzothiazepine was found to significantly improve the biological activity. This characteristic feature is supported by the binding patterns on the selected target proteins in docking simulations. In this study, 1,5-benzothiazepines have been identified as potential anticancer agents which can be further exploited for the development of more potent derivatives.     

Synthesis,In Silico Studies,and Evaluation of Syn and Anti Isomers of N-Substituted Indole-3-carbaldehyde Oxime Derivatives as Urease Inhibitors against Helicobacter pylori

Gastrointestinal tract infection caused by Helicobacter pylori is a common virulent disease found worldwide, and the infection rate is much higher in developing countries than in developed ones. In the pathogenesis of H. pylori in the gastrointestinal tract, the secretion of the urease enzyme plays a major role. Therefore, inhibition of urease is a better approach against H. pylori infection. In the present study, a series of syn and anti isomers of N-substituted indole-3-carbaldehyde oxime derivatives was synthesized via Schiff base reaction of appropriate carbaldehyde derivatives with hydroxylamine hydrochloride. The in vitro urease inhibitory activities of those derivatives were evaluated against that of Macrotyloma uniflorum urease using the modified Berthelot reaction. Out of the tested compounds, compound 8 (IC₅₀ = 0.0516 ± 0.0035 mM) and compound 9 (IC₅₀ = 0.0345 ± 0.0008 mM) were identified as the derivatives with potent urease inhibitory activity with compared to thiourea (IC₅₀ = 0.2387 ± 0.0048 mM). Additionally, in silico studies for all oxime compounds were performed to investigate the binding interactions with the active site of the urease enzyme compared to thiourea. Furthermore, the drug-likeness of the synthesized oxime compounds was also predicted.     

Chromenol Derivatives as Novel Antifungal Agents: Synthesis,In Silico and In Vitro Evaluation

Herein we report the synthesis of some new 1H-1,2,4-triazole functionalized chromenols (3a–3n) via tandem reactions of 1-(alkyl/aryl)-2-(1H-1,2,4-triazole-1-yl) with salicylic aldehydes and the evaluation of their antifungal activity. In silico prediction of biological activity with computer program PASS indicate that the compounds have a high novelty compared to the known antifungal agents. We did not find any close analog among the over 580,000 pharmaceutical agents in the Cortellis Drug Discovery Intelligence database at the similarity cutoff of 70%. The evaluation of antifungal activity in vitro revealed that the highest activity was exhibited by compound 3k, followed by 3n. Their MIC values for different fungi were 22.1–184.2 and 71.3–199.8 µM, respectively. Twelve from fourteen tested compounds were more active than the reference drugs ketoconazole and bifonazole. The most sensitive fungus appeared to be Trichoderma viride, while Aspergillus fumigatus was the most resistant one. It was found that the presence of the 2-(tert-butyl)-2H-chromen-2-ol substituent on the 4th position of the triazole ring is very beneficial for antifungal activity. Molecular docking studies on C. albicans sterol 14α-demethylase (CYP51) and DNA topoisomerase IV were used to predict the mechanism of antifungal activities. According to the docking results, the inhibition of CYP51 is a putative mechanism of antifungal activity of the novel chromenol derivatives. We also showed that most active compounds have a low cytotoxicity, which allows us to consider them promising antifungal agents for the subsequent testing activity in in vivo assays.     

Identification of Vinyl Sulfone Derivatives as EGFR Tyrosine Kinase Inhibitor: In Vitro and In Silico Studies

Epidermal growth factor receptor (EGFR), overexpressed in many types of cancer, has been proved as a high potential target for targeted cancer therapy due to its role in regulating proliferation and survival of cancer cells. In the present study, a series of designed vinyl sulfone derivatives was screened against EGFR tyrosine kinase (EGFR-TK) using in silico and in vitro studies. The molecular docking results suggested that, among 78 vinyl sulfones, there were eight compounds that could interact well with the EGFR-TK at the ATP-binding site. Afterwards, these screened compounds were tested for the inhibitory activity towards EGFR-TK using ADP-Glo™ kinase assay, and we found that only VF16 compound exhibited promising inhibitory activity against EGFR-TK with the IC₅₀ value of 7.85 ± 0.88 nM. In addition, VF16 showed a high cytotoxicity with IC₅₀ values of 33.52 ± 2.57, 54.63 ± 0.09, and 30.38 ± 1.37 µM against the A431, A549, and H1975 cancer cell lines, respectively. From 500-ns MD simulation, the structural stability of VF16 in complex with EGFR-TK was quite stable, suggesting that this compound could be a novel small molecule inhibitor targeting EGFR-TK.     

Solvent-Free Synthesis,In Vitro and In Silico Studies of Novel Potential 1,3,4-Thiadiazole-Based Molecules against Microbial Pathogens

A new series of 1,3,4-thiadiazoles was synthesized by the reaction of methyl 2-(4-hydroxy-3-methoxybenzylidene) hydrazine-1-carbodithioate (2) with selected derivatives of hydrazonoyl halide by grinding method at room temperature. The chemical structures of the newly synthesized derivatives were resolved from correct spectral and microanalytical data. Moreover, all synthesized compounds were screened for their antimicrobial activities using Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Staphylococcus aureus, and Candida albicans. However, compounds 3 and 5 showed significant antimicrobial activity against all tested microorganisms. The other prepared compounds exhibited either only antimicrobial activity against Gram-positive bacteria like compounds 4 and 6, or only antifungal activity like compound 7. A molecular docking study of the compounds was performed against two important microbial enzymes: tyrosyl-tRNA synthetase (TyrRS) and N-myristoyl transferase (Nmt). The tested compounds showed variety in binding poses and interactions. However, compound 3 showed the best interactions in terms of number of hydrogen bonds, and the lowest affinity binding energy (−8.4 and −9.1 kcal/mol, respectively). From the in vitro and in silico studies, compound 3 is a good candidate for the next steps of the drug development process as an antimicrobial drug.     

Thiazolidinedione Derivatives: In Silico,In Vitro,In Vivo,Antioxidant and Anti-Diabetic Evaluation

This work aimed to synthesize a new antihyperglycemic thiazolidinedione based on the spectral data. The DFT\B3LYP\6-311G** level of theory was used to investigate the frontier molecular orbitals (FMOs), chemical reactivity and map the molecular electrostatic potentials (MEPs) to explain how the synthesized compounds interacted with the receptor. The molecular docking simulations into the active sites of PPAR-γ and α-amylase were performed. The in vitro potency of these compounds via α-amylase and radical scavenging were evaluated. The data revealed that compounds (4–6) have higher potency than the reference drugs. The anti-diabetic and anti-hyperlipidemic activities for thiazolidine-2,4-dione have been investigated in vivo using the alloxan-induced diabetic rat model along with the 30 days of treatment protocol. The investigated compounds didn’t show obvious reduction of blood glucose during pre-treatments compared to diabetic control, while after 30 days of treatments, the blood glucose level was lower than that of the diabetic control. Compounds (4–7) were able to regulate hyperlipidemia levels (cholesterol, triglyceride, high-density lipoproteins and low- and very-low-density lipoproteins) to nearly normal value at the 30th day.     

In Search for Multi-Target Ligands as Potential Agents for Diabetes Mellitus and Its Complications—A Structure-Activity Relationship Study on Inhibitors of Aldose Reductase and Protein Tyrosine Phosphatase 1B

Diabetes mellitus (DM) is a complex disease which currently affects more than 460 million people and is one of the leading cause of death worldwide. Its development implies numerous metabolic dysfunctions and the onset of hyperglycaemia-induced chronic complications. Multiple ligands can be rationally designed for the treatment of multifactorial diseases, such as DM, with the precise aim of simultaneously controlling multiple pathogenic mechanisms related to the disease and providing a more effective and safer therapeutic treatment compared to combinations of selective drugs. Starting from our previous findings that highlighted the possibility to target both aldose reductase (AR) and protein tyrosine phosphatase 1B (PTP1B), two enzymes strictly implicated in the development of DM and its complications, we synthesised 3-(5-arylidene-4-oxothiazolidin-3-yl)propanoic acids and analogous 2-butenoic acid derivatives, with the aim of balancing the effectiveness of dual AR/PTP1B inhibitors which we had identified as designed multiple ligands (DMLs). Out of the tested compounds, 4f exhibited well-balanced AR/PTP1B inhibitory effects at low micromolar concentrations, along with interesting insulin-sensitizing activity in murine C2C12 cell cultures. The SARs here highlighted along with their rationalization by in silico docking experiments into both target enzymes provide further insights into this class of inhibitors for their development as potential DML antidiabetic candidates.     

Synthesis of mangiferin derivates and study their potent PTP1B inhibitory activity

Protein tyrosine phosphatase 1B (PTP1B) has received considerable attention from the drug industry as a potential treatment for diabetes mellitus.Mangiferin has been reported to possess significant antidiabetic activity.Based on the previous study,eight new mangiferin derivates were synthesized and evaluated for their PTP1B inhibitory activity.Some of them displayed good inhibitory activity on PTP1B.     

Design,Synthesis, Bioactivity Evaluation,Crystal Structures,and In Silico Studies of New α-Amino Amide Derivatives as Potential Histone Deacetylase 6 Inhibitors

Hydroxamate, as a zinc-binding group (ZBG), prevails in the design of histone deacetylase 6(HDAC6) inhibitors due to its remarkable zinc-chelating capability. However, hydroxamate-associated genotoxicity and mutagenicity have limited the widespread application of corresponding HDAC6 inhibitors in the treatment of human diseases. To avoid such side effects, researchers are searching for novel ZBGs that may be used for the synthesis of HDAC6 inhibitors. In this study, a series of stereoisomeric compounds were designed and synthesized to discover non-hydroxamate HDAC6 inhibitors using α-amino amide as zinc-ion-chelating groups, along with a pair of enantiomeric isomers with inverted L-shaped vertical structure as cap structures. The anti-proliferative activities were determined against HL-60, Hela, and RPMI 8226 cells, and 7a and its stereoisomer 13a exhibited excellent activities against Hela cells with IC₅₀ = 0.31 µM and IC₅₀ = 5.19 µM, respectively. Interestingly, there is a significant difference between the two stereoisomers. Moreover, an evaluation of cytotoxicity toward human normal liver cells HL-7702 indicated its safety for normal cells. X-ray single crystal diffraction was employed to increase insights into molecule structure and activities. It was found that the carbonyl of the amide bond is on the different side from the amino and pyridine nitrogen atoms. To identify possible protein targets to clarify the mechanism of action and biological activity of 7a, a small-scale virtual screen using reverse docking for HDAC isoforms (1–10) was performed and the results showed that HDAC6 was the best receptor for 7a, suggesting that HDAC6 may be a potential target for 7a. The interaction pattern analysis showed that the α-amino amide moiety of 7a coordinated with the zinc ion of HDAC6 in a bidentate chelate manner, which is similar to the chelation pattern of hydroxamic acid. Finally, the molecular dynamics simulation approaches were used to assess the docked complex’s conformational stability. In this work, we identified 7a as a potential HDAC6 inhibitor and provide some references for the discovery of non-hydroxamic acid HDAC6 inhibitors.     

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.     

Synthesis,Characterization, In Vitro Anticancer Potentiality,and Antimicrobial Activities of Novel Peptide–Glycyrrhetinic-Acid-Based Derivatives

Glycyrrhetinic acid (GA) is one of many interesting pentacyclic triterpenoids showing significant anticancer activity by triggering apoptosis in tumor cell lines. This study deals with the design and synthesis of new glycyrrhetinic acid (GA)–amino acid peptides and peptide ester derivatives. The structures of the new derivatives were established through various spectral and microanalytical data. The novel compounds were screened for their in vitro cytotoxic activity. The evaluation results showed that the new peptides produced promising cytotoxic activity against the human breast MCF-7 cancer cell line while comparing to doxorubicin. On the other hand, only compounds 3, 5, and 7 produced potent activity against human colon HCT-116 cancer cell line. The human liver cancer (HepG-2) cell line represented a higher sensitivity to peptide 7 (IC₅₀; 3.30 μg/mL), while it appeared insensitive to the rest of the tested peptides. Furthermore, compounds 1, 3, and 5 exhibited a promising safety profile against human normal skin fibroblasts cell line BJ-1. In order to investigate the mode of action, compound 5 was selected as a representative example to study its in vitro effect against the apoptotic parameters and Bax/BCL-2/p53/caspase-7/caspase-3/tubulin, and DNA fragmentation to investigate beta (TUBb). Additionally, all the new analogues were subjected to antimicrobial assay against a panel of Gram-positive and Gram-negative bacteria and the yeast candida Albicans. All the tested GA analogues 1–8 exhibited more antibacterial effect against Micrococcus Luteus than gentamicin, but they exhibited moderate antimicrobial activity against the tested bacterial and yeast strains. Molecular docking studies were also simulated for compound 5 to give better rationalization and put insight to the features of its structure.     

基于咔唑的新型碳酰腙衍生物的合成及蛋白酪氨酸磷酸酶1B(PTP1B)抑制活性评价

合成出了一系列新型基于咔唑的单-/双-碳酰腙衍生物3和4.利用1H NMR、13C NMR、IR和元素分析对其进行了结构表征.评价了目标化合物对蛋白酪氨酸磷酸酶1B(PTP1B)的抑制活性,讨论了结构与活性的关系.实验结果显示,大部分化合物对PTP1B具有良好的抑制活性,其中1,5-双[(9-丁基-3-咔唑基)亚甲基]碳酰腙(4c)的抑制活性最高,IC50=(4.81±0.41)mmol/L,且活性高于对照药物齐墩果酸.对目标化合物1-[(9-庚基-3-咔唑基)亚甲基]碳酰腙(3f)和4c进行分子对接研究和密度泛函理论(DFT)计算.分子对接结果表明,化合物3f和4c结合到PTP1B酶由螺旋α3和α6形成的活性位点,与PTP1B酶通过氢键、极性、疏水和p-p等相互作用形成了稳定的复合物.     

Synthesis of mangiferin derivatives as protein tyrosine phosphatase 1B inhibitors

Protein tyrosine phosphatase 1B (PTP1B) has received much attention due to its pivotal role in type 2 diabetes and obesity as a negative regulator of the insulin signaling pathway. Mangiferin, a xanthone glucoside, has been reported to possess significant antidiabetic activity. In the present study, a series of mangiferin derivatives was synthesized and evaluated for their PTP1B inhibitory activity. Some of the screened compounds displayed good PTP1B inhibitory activity. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 549–551, November–December, 2007.     

Design,Synthesis, Crystal Structure,In Vitro and In Silico Evaluation of New N′-Benzylidene-4-tert-butylbenzohydrazide Derivatives as Potent Urease Inhibitors

Background: Hydrazides play a vital role in making biologically active compounds in various fields of chemistry. These determine antioxidant, antidepressant, antimalarial, anti-inflammatory, antiglycating, and antimicrobial activity. In the present study, twenty-three new N′ benzylidene-4-(tert-butyl)benzohydrazide derivatives (4–26) were synthesized by the condensation of aromatic aldehydes and commercially available 4-(tert-butyl)benzoic acid. All the target compounds were successfully synthesized from good to excellent yield; all synthesized derivatives were characterized via spectroscopic techniques such as HREI-MS and ¹H-NMR. Synthesized compounds were evaluated for in vitro urease inhibition. All synthesized derivatives demonstrated good inhibitory activities in the range of IC₅₀ = 13.33 ± 0.58–251.74 ± 6.82 µM as compared with standard thiourea having IC₅₀ = 21.14 ± 0.425 µM. Two compounds, 6 and 25, were found to be more active than standard. SAR revealed that electron donating groups in phenyl ring have more influence on enzyme inhibition. However, to gain insight into the participation of different substituents in synthesized derivatives on the binding interactions with urease enzyme, in silico (computer simulation) molecular modeling analysis was carried out.     

基于咔唑的单-/双-硫代碳酰腙衍生物的合成及Cdc25B/PTP1B抑制活性评价

合成了一系列新型的基于咔唑的单-/双-硫代碳酰腙衍生物.利用IR、1H NMR、13C NMR和元素分析对其进行了结构表征.评价了目标化合物对Cdc25B和PTP1B的抑制活性,讨论了其结构与活性的关系.实验结果显示,大部分目标化合物对Cdc25B和PTP1B表现出良好的抑制活性.其中,1,5-双[(9-戊基-3-咔唑基)亚甲基]硫代碳酰腙(4d)对Cdc25B的抑制活性最高,IC50为(0.23±0.02)μg/m L.1,5-双[(9-乙基-3-咔唑基)亚甲基]硫代碳酰腙(4a)对PTP1B的抑制活性最高, IC50为(1.00±0.16)μg/m L.对目标化合物4a和4d进行分子对接研究和密度泛函理论(DFT)计算,结果表明,目标化合物4d和4a分别进入到了Cdc25B和PTP1B酶的活性位点区域,有活性作用的主要是硫代碳酰腙和咔唑基团.