Compounds 4d Research Articles

Highly Efficient Bimetallic Catalyst for the Synthesis of N-substituted Decahydroacridine-1,8-diones and Xanthene-1,8-diones: Evaluation of their Biological Activity

Background: Bimetallic catalysis plays a major role in boosting the catalytic performance of monometallic counterparts due to the synergetic effect. Method and Materials: In the present study, we have exploited ZrCl4:Mg(ClO4)2 as an efficient bimetallic catalyst for the synthesis of a few biologically relevant N-substituted decahydroacridine-1,8-diones and xanthene-1,8-diones under solvent-free conditions. The complete characterization data (XRD, SEM, BET, pH, TGA, and IR) of the bimetallic catalyst, ZrCl4: Mg(ClO4)2, are provided in the supporting information. Results: Among the compounds screened for anti-oxidant and anti-microbial activities, the acridine derivatives with chloro and fluoro substitutions (compounds 4b, 4c, 4d, and 4j) have exhibited potent activities when compared to other compounds. Among the xanthene derivatives screened for anti-oxidant activity, compounds 5c, 5i, and 5j with chloro and nitro derivatives exhibited potent antioxidant activity, and the rest all showed moderately potent activity. Conclusion: Among the compounds screened for antibacterial activity, compound 5j with chloro substitution showed potent activity, followed by compounds 5c, 5d, 5h, and 5i against Gram +ve bacteria, and compounds 5h, 5f, and 5g with N,N-dimethyl, methoxy and hydroxy substitutions have shown potent activity against Gram -ve bacteria.

Synthesis and Evaluation of Aminothiazole Hybrids as Potential Acetylcholinesterase Inhibitors

This study aimed to synthesize aminothiazole derivatives with 1,3,4-oxadiazole moiety and evaluated their acetylcholinesterase (AChE) and antioxidant activity in order to check their potency against Alzheimer's disease. Inhibition screening against AChE indicated that synthesized derivatives expressed well to moderate AChE inhibitory activity in vitro. Of the examined synthetic compounds (3a-i), compound 3d expressed the best inhibition with IC50-0.35 µM. The antioxidant activity of all the synthesized compounds was also analyzed by the DPPH assay. Finally, in molecular docking analysis, the best docking score was displayed by the most active compound 3d supported the in vitro inhibition results. Compound 3d emerged to be promising lead for the further development of anti- Alzheimer’s drugs.

Synthesis and in silico Assessment of Heteroaryl Semicarbazones: Towards Understanding Antimicrobial Activities and Safety Profiles

Seven semicarbazone derivatives incorporating either substituted furan or thiophene were synthesized by reacting phenylurea with semicarbazide and various heteroaryl aldehydes. The newly synthesized compounds were characterized using IR, NMR, mass spectrometry and elemental analysis. Additionally, their antibacterial and anti-tubercular activities were also evaluated. In silico tools such as Swiss ADME and Pro Tox II were employed to assess molecular targets, medicinal chemistry properties, as well as toxicity and safety profiles. Compounds 3a-g demonstrated significant antibacterial activity at a 100 µg/mL when compared to the standard ciprofloxacin. Notably, compounds 3c, 3d, 3f and 3g exhibited the highest activity against all bacterial strains. Furthermore, compound 3d demonstrated anti-tubercular activity at all tested concentrations.

Synthesis and anticancer activity evaluation of some novel imidazo[1,2-a]pyridine based heterocycles containing S-alkyl/aryl moiety

Here we report the synthesis and anticancer activities of fourteen novel imidazo[1,2-a]pyridine derivatives (6a-6n) containing S-alkyl/aryl moiety. The target compounds were obtained via a six-step synthetic route. 1-(4-Aminophenyl)ethan-1-one was the starting material. In the last step, 2-chloro-N-[4-(imidazo[1,2-a]pyridin-2-yl)phenyl]acetamide (5) was allowed to react with various aliphatic/aromatic thiol derivatives, affording the final compounds 6a-6n. The cytotoxicity of the compounds was evaluated against A549 (human non-small cell lung cancer), C6 (rat glioma), MCF-7 (human breast carcinoma) and HepG2 (human liver carcinoma) tumor cells and NIH/3T3 (mouse embryonic fibroblast cells) healthy cells. First step MTT assay reported that compounds 6a, 6d, 6e and 6i exhibited antiproliferative activity against all tested tumor lines. Second step BrdU cell proliferation assay and flow cytometric analysis revealed that compounds 6d and 6i inhibited DNA synthesis on HepG2 cell line time-dependently by apoptotic pathway. Molecular docking study of compounds 6d and 6i with caspase-3 and caspase-9 revealed their binding interactions with the enzyme’s active site, confirming the experimental findings.

Design, synthesis and systemic acquired resistance of 2-benzothiadiazolylquinoline-4-carboxamides by COI1 based virtual screening.

Coronatine-insensitive 1 (COI1) has been identified as a target receptor of plant elicitor coronatine (COR). To discover novel plant elicitor leads, most of the potential molecules among 129 compounds discovered from the ZINC database by docking based virtual screening targeting COI1 were quinoline amides. On this lead basis, 2-benzothiadiazolylquinoline-4-carboxamides were rationally designed and synthesized for bioassay. All target compounds did not show significantly in vitro antifungal activity, compounds 4d, 4e and 4o displayed good in vivo systemic acquired resistance activity for Arabidopsis thaliana against Hyaloperonospora arabidopsidis isolate Noco2 with over 80% of inhibitory rate at the concentration of 50μM. These results indicate that 2-benzothiadiazolylquinoline-4-carboxamides are promising plant elicitor leads for further study.

Development of novel 9H-carbazole-4H-chromene hybrids as dual cholinesterase inhibitors for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disease affecting mental ability and neurocognitive functions. Cholinesterase enzymes affect concentration of acetylcholine in the brain, leading to dementia. Thus, there is an urgent need to develop novel dual cholinesterase inhibitors as possible anti-AD drugs. Herein, we have designed and synthesized a novel series of 9H-carbazole-4H-chromenes 4(a-l) through a one-pot three-component reaction of salicylaldehydes (1), hydroxycarbazole (2) and N-methyl-1-(methylthio)-2-nitroethenamine (3) using triethylamine as a catalyst in ethanol. Synthetic transformation involves the formation of two C-C bonds and one C-O bond in a single step to obtain desired analogs. The rapid one-pot reaction does not require chromatographic purification, proceeds under mild conditions, and exhibits good tolerance toward various functional groups with high synthetic yields. Synthesized compounds were screened for cytotoxicity using MTT assay in BV-2 microglial cells. These compounds were then in-vitro screened against acetylcholinesterase (AChE) and butyrylcholinestrase (BuChE) enzymes. Most of these ligands have shown dual cholinesterase inhibitory activity compared to the standard drug. In-vitro results showed that the compounds 4a and 4d have promising anticholinesterase response against both cholinesterase enzymes (4a, AChE IC50: 5.76µM, BuChE IC50: 48.98µM; 4d, AChE IC50: 3.58µM, BuChE IC50: 42.73µM). In-vitro results were validated by molecular docking and dynamic simulation at 100ns. Molecular docking and molecular dynamics simulation study strongly supported structural features present in these analogs. Together, these analogs could be exploited to develop dual anti-cholinesterase candidates to treat AD in combination with other drugs.

Design, synthesis and structure-activity relationship of 1,8-naphthalimide derivatives as highly potent hCYP1B1 inhibitors

Human cytochrome P450 1B1 enzyme (hCYP1B1), a member of hCYP1 subfamily, plays a crucial role in multiple diseases by participating in many metabolic pathways. Although a suite of potent hCYP1B1 inhibitors have been previously reported, most of them also act as aryl hydrocarbon receptor (AhR) agonists that can up-regulate the expression of hCYP1B1 and then counteract their inhibitory potential in living systems. This study aimed to develop novel efficacious hCYP1B1 inhibitors that worked well in living cells but without AhR agonist effects. For these purposes, a series of 1,8-naphthalimide derivatives were designed and synthesized, and their structure-activity relationships (SAR) as hCYP1B1 inhibitors were analyzed. Following three rounds SAR studies, several potent hCYP1B1 inhibitors were discovered, among which compound 3n was selected for further investigations owing to its extremely potent anti-hCYP1B1 activity (IC50 = 0.040 nM) and its blocking AhR transcription activity in living cells. Inhibition kinetic analyses showed that 3n potently inhibited hCYP1B1 via a mix inhibition manner, showing a Ki value of 21.71 pM. Docking simulations suggested that introducing a pyrimidine moiety to the hit compound (1d) facilitated 3n to form two strong interactions with hCYP1B1/heme, viz., the C-Br⋯π halogen bond and the N-Fe coordination bond. Further investigations demonstrated that 3n (5 μM) could significantly reverse the paclitaxel (PTX) resistance in H460/PTX cells, evidenced by the dramatically reduced IC50 values, from 632.6 nM (PTX alone) to 100.8 nM (PTX plus 3n). Collectively, this study devised a highly potent hCYP1B1 inhibitor (3n) without AhR agonist effect, which offered a promising drug candidate for overcoming hCYP1B1-associated drug resistance.

Design, synthesis, and biological evaluation of dinaciclib and CAN508 hybrids as CDK inhibitors.

The scaffolds of two known CDK inhibitors (CAN508 and dinaciclib) were the starting point for synthesizing two series of pyarazolo[1,5-a]pyrimidines to obtain potent inhibitors with proper selectivity. The study presented four promising compounds; 10d, 10e, 16a, and 16c based on cytotoxic studies. Compound 16a revealed superior activity in the preliminary anticancer screening with GI % = 79.02-99.13 against 15 cancer cell lines at 10 μM from NCI full panel 60 cancer cell lines and was then selected for further investigation. Furthermore, the four compounds revealed good safety profile toward the normal cell lines WI-38. These four compounds were subjected to CDK inhibitory activity against four different isoforms. All of them showed potent inhibition against CDK5/P25 and CDK9/CYCLINT. Compound 10d revealed the best activity against CDK5/P25 (IC50 = 0.063 µM) with proper selectivity index against CDK1 and CDK2. Compound 16c exhibited the highest inhibitory activity against CDK9/CYCLINT (IC50 = 0.074 µM) with good selectivity index against other isoforms. Finally, docking simulations were performed for compounds 10e and 16c accompanied by molecular dynamic simulations to understand their behavior in the active site of the two CDKs with respect to both CAN508 and dinaciclib.

Synthesis of amide derivatives containing the imidazole moiety and evaluation of their anti-cardiac fibrosis activity.

Three series of N-{[4-([1,2,4]triazolo[1,5-α]pyridin-6-yl)-5-(6-methylpyridin-2-yl)-1H-imidazol-2-yl]methyl}acetamides (14a-d, 15a-n, and 16a-f) were synthesized and evaluated for activin receptor-like kinase 5 (ALK5) inhibitory activities in an enzymatic assay. The target compounds showed high ALK5 inhibitory activity and selectivity. The half maximal inhibitory concentration (IC50) for phosphorylation of ALK5 of 16f (9.1 nM), the most potent compound, was 2.7 times that of the clinical candidate EW-7197 (vactosertib) and 14 times that of the clinical candidate LY-2157299. The selectivity index of 16f against p38α mitogen-activated protein kinase was >109, which was much higher than that of positive controls (EW-7197: >41, and LY-2157299: 4). Furthermore, a molecular docking study provided the interaction modes between the target compounds and ALK5. Compounds 14c, 14d, and 16f effectively inhibited the protein expression of α-smooth muscle actin (α-SMA), collagen I, and tissue inhibitor of metalloproteinase 1 (TIMP-1)/matrix metalloproteinase 13 (MMP-13) in transforming growth factor-β-induced human umbilical vein endothelial cells. Compounds 14c and 16f showed especially high activity at low concentrations, which suggests that these compounds could inhibit myocardial cell fibrosis. Compounds 14c, 14d, and 16f are potential preclinical candidates for the treatment of cardiac fibrosis.

Design, Synthesis, and Herbicidal Evaluation of Pyrrolidinone-Containing 2-Phenylpyridine Derivatives as Novel Protoporphyrinogen Oxidase Inhibitors.

In this work, a series of pyrrolidinone-containing 2-phenylpyridine derivatives were synthesized and evaluated as novel protoporphyrinogen IX oxidase (PPO, EC 1.3.3.4) inhibitors for herbicide development. At 150 g ai/ha, compounds 4d, 4f, and 4l can inhibit the grassy weeds of Echinochloa crus-galli (EC), Digitaria sanguinalis (DS), and Lolium perenne (LP) with a range of 60 to 90%. Remarkably, at 9.375 g ai/ha, these compounds showed 100% inhibition effects against broadleaf weeds of Amaranthus retroflexus (AR) and Abutilon theophrasti (AT), which were comparable to the performance of the commercial herbicides flumioxazin (FLU) and saflufenacil (SAF) and better than that of acifluorfen (ACI). Molecular docking analyses revealed significant hydrogen bonding and π-π stacking interactions between compounds 4d and 4l with Arg98, Asn67, and Phe392, respectively. Additionally, representative compounds were chosen for in vivo assessment of PPO inhibitory activity, with compounds 4d, 4f, and 4l demonstrating excellent inhibitory effects. Notably, compounds 4d and 4l induced the accumulation of reactive oxygen species (ROS) and a reduction in the chlorophyll (Chl) content. Consequently, compounds 4d, 4f, and 4l are promising lead candidates for the development of novel PPO herbicides.

Quinazoline sulfonamide derivatives targeting MicroRNA-34a/MDM4/p53 apoptotic axis with radiosensitizing activity.

Aim: New quinazoline benzenesulfonamide hybrids 4a-n were synthesized to determine their cytotoxicity and effect on the miR-34a/MDM4/p53 apoptotic pathway. Materials & methods: Cytotoxicity against hepatic, breast, lung and colon cancer cell lines was estimated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: Compound 4d was the most potent against HepG2 and MCF-7 cancer cells, with potential apoptotic activity verified by a significant upregulation of miR-34a and p53 gene expressions. The apoptotic effect of 4d was further investigated and showed downregulation of miR-21, VEGF, STAT3 and MDM4 gene expression. Conclusion: The anticancer and apoptotic activities of 4d were enhanced post irradiation by a single dose of 8Gy γ-radiation. Docking analysis demonstrated a valuable affinity of 4d toward VEGFR2 and MDM4 active sites.

Design and synthesis of phenoxy methyl-oxadiazole compounds against Alzheimer's disease.

This study examines the synthesis and evaluation of 11 newly developed compounds as potential anti-Alzheimer's agents that occur via cholinesterase and β-secretase inhibition. The compounds were tested for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using the modified Ellman method. The results showed that several compounds exhibited significant inhibition of AChE, particularly compounds 6d, 7a, and 7e, which demonstrated high inhibitory activity at lower concentrations, with IC50 values of 0.120, 0.039, and 0.063 µM, respectively. However, the compounds showed limited effectiveness against BChE, with only a few compounds exhibiting moderate inhibition. Compound 7e showed an inhibitory effect against BACE-1 close to that of the standard drug. Structural analysis revealed that the compounds with substituted benzothiazole and thiazole moieties exhibited the most promising inhibitory activity. This study provides valuable insights into the potential of these synthesized derivatives as a treatment against Alzheimer's disease. Moreover, the structure, stability, and properties of the active compounds were further investigated using density functional theory calculations. As a final note, the utilization of molecular docking and molecular dynamics simulation studies allowed us to elucidate the action mechanism of the active compounds and gain insights into the structure-activity relationship against AChE and β-secretase proteins. These computational techniques provide valuable information on the binding modes, interactions with target enzymes, dynamic behavior, and conformational changes of the compounds, enabling a comprehensive understanding of their biological activity.

The study on synthesis and vitro hypolipidemic activity of novel berberine derivatives nitric oxide donors

Berberine was used as the lead compound in the present study to design and synthesize novel berberine derivatives by splicing bromine bridges of different berberine carbon chain lengths coupled nitric oxide donors, and their lipid lowering activities were assessed in a variety of ways. This experiment synthesized 17 new berberine nitric oxide donor derivatives. Compared with berberine hydrochloride, most of the compounds exhibited certain glycerate inhibitory activity, and compounds 6a, 6b, 6d, 12b and 12d showed higher inhibitory activity than berberine, with 6a, 6b and 6d having significant inhibitory activity. In addition, compound 6a linked to furazolidone nitric oxide donor showed better NO release in experiments; In further mechanistic studies, we screened and got two proteins, PCSK9 and ACLY, and docked two proteins with 17 compounds, and found that most of the compounds bound better with ATP citrate lyase (ACLY), among which there may be a strong interaction between compound 6a and ACLY, and the interaction force was better than the target drug Bempedoic Acid, which meaning that 6a may exert hypolipidemic effects by inhibiting ACLY; moreover, we also found that 6a may had the better performance in gastrointestinal absorption, blood-brain barrier permeability, Egan, Muegge class drug principle model calculation and bioavailability.

Synthesis and biological evaluation of some novel benzoxazin-4-one and quinazolin-4-one derivatives based on anti-inflammatory commercial drugs

Benzoxazine and quinazoline are nitrogen-containing heterocyclic scaffolds found in various biologically active compounds. Due to their diverse biological actions, these heterocyclic rings serve as crucial frameworks for designing medicinal compounds. This study aimed to synthesize and assess in vivo anti-inflammatory, analgesic, and low ulcerogenic potential of a few novel benz[d][1,3]-oxazin-4-one and quinazolinone derivatives. Benzoxazinones (3a-e) were synthesized by cyclizing the carboxylic group (-COOH) of five nonsteroidal anti-inflammatory drugs viz., aceclofenac, ibuprofen, diclofenac, mefenamic acid and ketoprofen (2a-e) with anthranilic acid (1) using dry phosphorus oxychloride (POCl3) in pyridine. The corresponding quinazolinone derivatives (5a-e) were obtained by reacting 3a-e with isonicotinic acid hydrazide (4). Both sets of compounds were evaluated for their anti-inflammatory, analgesic effects, and ulcerogenicity in animal models. Structural characterization was performed using spectral analysis. Among the benzoxazinone derivatives, compound 2-(2-((2,6-dichlorophenyl) amino) benzyl)-4H-benzo[d][1,3]oxazin-4-one (3d) exhibited significant anti-inflammatory activity (62.61% inhibition of rat paw edema) and analgesic activity (62.36% protection in acetic acid-induced writhings) with tolerable gastrointestinal toxicity (2.67 ulcerogenicity index) compared to quinazolinone derivatives. The results of anti-inflammatory and analgesic activities of both the series are comparable with the respective, positive control. Compound 3d, a benzoxazinone-diclofenac hybrid, emerged as a lead molecule with potent anti-inflammatory, analgesic activities and moderate gastric toxicity showcasing the promising potential for further development.

Synthesis, docking study, and antitumor evaluation of benzamides and oxadiazole derivatives of 3-phenoxybenzoic acid as VEGFR-2 inhibitors.

Current chemotherapeutic agents have several limitations, including lack of selectivity, the development of undesirable side effects, and chemoresistance. As a result, there is an unmet need for the development of novel small molecules with minimal side effects and the ability to specifically target tumor cells. A new series of 3-phenoxybenzoic acid derivatives, including 1,3,4-oxadiazole derivatives (4a-d) and benzamides derivatives (5a-e) were synthesized; their chemical structures were confirmed by Fourier-transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectra; and various physicochemical properties were determined. The antiproliferative activities of the new derivatives were evaluated by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Three compounds (4b, 4c, and 4d) exhibited cytotoxicity against two of the three cell lines tested, five compounds (3, 4a, 5a, 5b, and 5e) were toxic to one cell line, while two compounds (5c and 5d) were not cytotoxic to any of the three cell lines tested in the current study. Based on docking scores, MTT assay findings, and vascular endothelial growth factor receptor 2 (VEGFR-2) kinase activity data, Compound 4d was selected for further biological investigation. Flow cytometry was used to determine the mode of cell death (apoptosis vs. necrosis) and the effect on cell cycle progression. Compound 4d arrested HepG2 hepatocellular carcinoma cells in the G2/M phase and activated both the intrinsic and extrinsic apoptosis pathways. In conclusion, Compound 4d has shown promising results for future research as a potent VEGFR-2 tyrosine kinase inhibitor.

Probing benzenesulfonamide–thiazolidinone hybrids as multitarget directed ligands for efficient control of type 2 diabetes mellitus through targeting the enzymes: α-glucosidase and carbonic anhydrase II

Diabetes mellitus is a chronic metabolic disorder characterized by improper expression/function of a number of key enzymes that can be regarded as targets for anti-diabetic drug design. Herein, we report the design, synthesis, and biological assessment of two series of thiazolidinone-based sulfonamides 4a-l and 5a-c as multitarget directed ligands (MTDLs) with potential anti-diabetic activity through targeting the enzymes: α-glucosidase and human carbonic anhydrase (hCA) II. The synthesized sulfonamides were evaluated for their inhibitory activity against α-glucosidase where most of the compounds showed good to potent activities. Compounds 4d and 4e showed potent inhibitory activities (IC50 = 0.440 and 0.3456 μM), comparable with that of the positive control (acarbose; IC50 = 0.420 μM). All the synthesized derivatives were also tested for their inhibitory activities against hCA I, II, IX, and XII. They exhibited different levels of inhibition against these isoforms. Compound 4d outstood as the most potent one against hCA II with Ki equals to 7.0 nM, more potent than the reference standard (acetazolamide; Ki = 12.0 nM). In silico studies for the most active compounds within the active sites of α-glucosidase and hCA II revealed good binding modes that can explain their biological activities. MM-GBSA refinements and molecular dynamic simulations were performed on the top-ranking docking pose of the most potent compound 4d to confirm the formation of stable complex with both targets. Compound 4d was screened for its in vivo antihyperglycemic efficacy by using the oral glucose tolerance test. Compound 4d decreased blood glucose level to 217 mg/dl, better than the standard acarbose (234 mg/dl). Hence, this revealed its synergistic mode of action on post prandial hyperglycemia and hepatic gluconeogenesis. Thus, these benzenesulfonamide thiazolidinone hybrids could be considered as promising multi-target candidates for the treatment of type II diabetes mellitus.

Synthesis, biofilm formation inhibitory, and inflammation inhibitory activities of new coumarin derivatives.

Coumarins are heterocycles of great interest in the development of valuable active structures in chemistry and biological domains. The ability of coumarins to inhibit biofilm formation of Gram positive bacterium (Staphylococcus aureus), Gram negative bacterium (Escherichia coli) as well as the methicillin-resistant S. aureus (MRSA) has been previously described. In the present work, new hybrid coumarin-heterocycles have been synthesized via the reaction of coumarin-6-sulfonyl chloride and 6-aminocoumarin with different small heterocycle moieties. The biological efficacy of the new compounds was evaluated towards their ability to inhibit biofilm formation and their anti-inflammatory properties. The antimicrobial activities of the newly synthesized compounds were tested against Gram positive bacterium (S. aureus ATCC 6538), Gram negative bacterium (E. coli ATCC 25922), yeast (Candida albicans ATCC 10231) and the fungus (Aspergillus niger NRRL-A326). Compounds 4d, 4e, 4f, 6a and 9 showed significant MIC and MBC values against S. aureus, E. coli, C. albicans, and methicillin-resistant S. aureus (MRSA) with especial incidence on compound 9 which surpasses all the other compounds giving MIC and MBC values of (4.88 and 9.76µg/mL for S. aureus), (78.13 and 312.5µg/mL for E. coli), (9.77 and 78.13µg/mL for C. albicans), and (39.06 and 76.7µg/mL for MRSA), respectively. With reference to the antibiofilm activity, compound 9 exhibited potent antibiofilm activity with IC50 of 60, 133.32, and 19.67µg/mL against S. aureus, E. coli, and MRSA, (respectively) considering the reference drug (neomycin). Out of all studied compounds, the anti-inflammatory results indicated that compound 4d effectively inhibited nitric oxide production in lipopolysaccharide-(LPS-) stimulated RAW264.7 macrophage cells, giving NO% inhibition of 70% compared to Sulindac (55.2%).

Synthesis and anti-HCV activity of novel 5-arylmethylene-1,3-thiazolidin-4-one derivatives via suppression of NS5B polymerase and COX-2

Hepatitis C (HCV) is a viral infection that leads to forms of acute and chronic liver disease, including cirrhosis (scarring of the liver) and liver cancer. The World Health Organization (WHO) estimated in 2019 that approximately 290,000 people died from hepatitis C (mostly from cirrhosis and hepatocellular carcinoma). Direct-acting antiviral drugs (DAAs) can cure more than 95% of individuals with hepatitis C infection, while research on the discovery of new antiviral agents is still ongoing. The Hepatitis C virus (HCV) can cause various biochemical changes in liver cells, and some of these changes are associated with the COX-2 enzyme. The identification of its role in promoting growth in liver cells as well as its involvement in various cancer types, including hepatocellular carcinoma, has made COX-2 an important target in the development of new agents effective against HCV. In this study, thirty-six new 5-arylmethylene-2-imino-1,3-thiazolidin-4-one derivatives (5a-s, 6a-s) were synthesized through Knoevenagel condensation of 2-[(4-substitutedpyridin-2-yl)imino]-1,3-thiazolidin-4-one derivatives with various aldehydes. Structures of the synthesized compounds were elucidated by the use of spectral and chromatographic techniques, besides elemental analyses. Four compounds were selected for further studies as they were found to suppress the NS5B protein with anti-HCV activity using the Western Blotting method. The selected compounds 5o, 6m, 6r, and 6s inhibited HCV with EC50 values of 8.0 ± 0.2 µM, 13.9 ± 0.45, 9.2 ± 0.2 µM, and 12.1 ± 0.1 µM, respectively. It was determined that these compounds reduced HCV-induced COX-2 promoter activity in Ava5 cells compared to Huh7 cells. The antiviral effects of the compounds were also investigated on DENV, closely related to HCV due to sharing certain biological, structural, and mechanical properties throughout their life cycles. However, no significant effect was observed in the preliminary screening study, indicating the compounds' specificity for HCV. Considering the relationship between HCV, DENV, and COX-2, the compounds' COX-1 and COX-2 enzyme inhibition potentials were investigated both in vitro and in silico. Compounds 6d, 6e, 6f, and 6m, which exhibited high selective COX-2 inhibition, were discussed for their interactions with the active site. Our study revealed that our target compounds suppressed COX-2 both at the protein level and through enzyme inhibition, thus providing promising findings for the discovery of new anti-HCV effective COX-2 inhibitors.

Green synthesis, density functional theory (DFT), molecular docking, molecular dynamics simulation and biological activity of 1,2,3,4-tetrahydropyrimidine-5-carbonitrile derivatives as PLA2 and proteinase K inhibitors

In diseases like atherosclerosis, rheumatoid arthritis, and sepsis, phospholipase A2 (PLA2) and proteinase K play a role in inflammation by releasing arachidonic acid (AA). The crucial step in the inflammatory process is believed to be the release of prostaglandins after PLA2 mobilizes AA. Drugs obstructing the COX and LOX pathways in the arachidonic acid cascade, drugs that inhibit these enzymes can treat inflammatory processes. To combat against these inflammatory promoters,the authors herein report an effective method for the synthesis of a series of 1,2,3,4-tetrahydropyrimidine-5-carbonitrile derivatives (4a–h) under the effect of TiO2 as a photocatalyst in ethanolic medium, and their effect against phospholipase A2, as well as proteinase K, was evaluated. The results confirmed that using TiO2 (20 mg) as a photocatalyst exhibits excellent performance in terms of yield and reaction time. The yield of all the synthesized compounds is between 79 and 91 % in just 60 min. After closely evaluating the SAR of the examined compounds against both enzymes, it was discovered that compounds (4b, 4f) with electron-donating substituents have higher PLA2 inhibitory (%) activity than those with electron-removing substituents (4a, 4e). Compounds (4c, 4d) containing heterocyclic rings showed significantly higher proteinase inhibitory (%) activity when compared to other electron-donating or withdrawing compounds. It was further confirmed that studied compounds against both enzymes exhibited dose-dependent behavior. We studied the intermolecular interactions of the compounds by molecular docking with human non-pancreatic secretory phospholipase A2 and proteinase K. We evaluated the dynamical stability of the docked complexes using a 100 ns molecular dynamics simulation, which revealed stable interactions based on root mean square deviation/fluctuation (RMSD/RMSF), radius of gyration, Gibbs free energy landscapes, and principal component analyses (PCA). Moreover, the ADME properties of the compounds align with Lipinski’s rule of five, suggesting their potential as viable candidates for the development of therapies against inflammatory diseases. All compounds tested inhibited PLA2 more than proteinase K. However, compounds 4b and 4f better inhibited phospholipase A2, whereas compounds 4c and 4d showed better activity against proteinase K.

Statine-based peptidomimetic compounds as inhibitors for SARS-CoV-2 main protease (SARS-CoV‑2 Mpro)

COVID-19 is a multisystemic disease caused by the SARS-CoV-2 airborne virus, a member of the Coronaviridae family. It has a positive sense single-stranded RNA genome and encodes two non-structural proteins through viral cysteine-proteases processing. Blocking this step is crucial to control virus replication. In this work, we reported the synthesis of 23 statine-based peptidomimetics to determine their ability to inhibit the main protease (Mpro) activity of SARS-CoV-2. Among the 23 peptidomimetics, 15 compounds effectively inhibited Mpro activity by 50% or more, while three compounds (7d, 8e, and 9g) exhibited maximum inhibition above 70% and IC50 < 1 µM. Compounds 7d, 8e, and 9g inhibited roughly 80% of SARS-CoV-2 replication and proved no cytotoxicity. Molecular docking simulations show putative hydrogen bond and hydrophobic interactions between specific amino acids and these inhibitors. Molecular dynamics simulations further confirmed the stability and persisting interactions in Mpro's subsites, exhibiting favorable free energy binding (ΔGbind) values. These findings suggest the statine-based peptidomimetics as potential therapeutic agents against SARS-CoV-2 by targeting Mpro.