From triazolophthalazines to triazoloquinazolines: A bioisosterism-guided approach toward the identification of novel PCAF inhibitors with potential anticancer activity

Novel imidazolone derivatives as potential dual inhibitors of checkpoint kinases 1 and 2: Design, synthesis, cytotoxicity evaluation, and mechanistic insights

Applying various drug design strategies including ring variation, substituents variation, and ring fusion, two series of 2-(alkylthio)-5-(arylidene/heteroarylidene)imidazolones and imidazo[1,2-a]thieno[2,3-d]pyrimidines were designed and prepared as dual potential Chk1 and Chk2 inhibitors. The newly synthesized hybrids were screened in NCI 60 cell line panel where the most active derivatives 4b, d-f, and 6a were further estimated for their five dose antiproliferative activity against the most sensitive tumor cells including breast MCF-7 and MDA-MB-468 and non-small cell lung cancer EKVX as well as normal WI-38 cell. Noticeably, increasing the carbon chain attached to thiol moiety at C-2 of imidazolone scaffold elevated the cytotoxic activity. Hence, compounds 4e and 4f, containing S-butyl fragment, exhibited the most antiproliferative activity against the tested cells where 4f showed extremely potent selectivity toward them. As well, compound 6a, containing imidazothienopyrimidine core, exerted significant cytotoxic activity and selectivity toward the examined cells. The mechanistic investigation of the most active cytotoxic analogs was achieved through the evaluation of their inhibitory activity against Chk1 and Chk2. Results revealed that 4f displayed potent dual inhibition of both Chk1 and Chk2 with IC50 equal 0.137 and 0.25 μM, respectively. It also promoted its antiproliferative and Chk suppression activity via EKVX cell cycle arrest at S phase through stimulating the apoptotic approach. The apoptosis induction was also emphasized by elevating the expression of Caspase-3 and Bax, that are accompanied by Bcl-2 diminution. The in silico molecular docking and ADMET profiles of the most active analogs have been carried out to evaluate their potential as significant anticancer drug candidates.

Repurposed organoselenium tethered amidic acids as apoptosis inducers in melanoma cancer via P53, BAX, caspases-3, 6, 8, 9, BCL-2, MMP2, and MMP9 modulations

Organoselenium (OSe) agents hold promise for preventing cancer due to their potential ability to fight cancer development and protect cells from oxidative damage. Herein, OSe-based maleanilic and succinanilic acids were tested to estimate their antitumor activities against fifteen cancer cell lines. Besides, their potential safety and selectivity were further investigated against two normal cell lines, namely, human skin fibroblasts (HSF) and olfactory ensheathing cell line (OEC) using the growth inhibition percentage (GI%) assay. Moreover, the apoptotic potential of the superior anticancer candidates (8, 9, 10, and 11) was evaluated against P53, BAX, Caspase-3, Caspase-6, Caspase-8, Caspase-9, BCL-2, MMP2, and MMP9 apoptotic markers. Additionally, to enhance our understanding and predict the inhibitory potential of the examined compounds as potential anticancer agents, a thorough structure-activity relationship (SAR) analysis was conducted. On the other hand, molecular docking and ADMET studies were performed for the examined candidates as well. Overall, our findings point to significant anticancer activities of the organoselenium tethered amidic acids, suggesting their promising cytotoxic potential as effective anticancer drugs.

Design, synthesis, in-silico studies and apoptotic activity of novel amide enriched 2-(1H)- quinazolinone derivatives

Cancer is a broad classification of diseases that can affect any organ or body tissue due to aberrant cellular proliferation for unknown reasons. Many present chemotherapeutic drugs are highly toxic and have little selectivity. Additionally, they lead to the development of medication resistance. Therefore, developing tailored chemotherapeutic drugs with minimal side effects and good selectivity is crucial for cancer treatment. 2-(1H)-Quinazolinone is one of the vital scaffold and anticancer activity is one of the prominent biological activities of this class. Here we report the novel set of amide-enriched 2-(1H)-quinazolinone derivatives (7a-j) and their apoptotic activity with the help of MTT assay method against four human cancer cell lines: PC3 (prostate cancer), DU-145 (prostate cancer), A549 (lung cancer), and MCF7 (breast cancer). When compared to etoposide, every synthetic test compound (7a-j) exhibited moderate to excellent activity. The IC50 values of the new amide derivatives (7a-j) varied from 0.07 ± 0.0061 μM to 10.8 ± 0.69 μM. While the positive control, etoposide, exhibited 1.97 ± 0.45 μM to 3.08 ± 0.135 μM range. Among the novel amide derivatives (7a-j), in particular, 7i and 7j showed strong apoptotic activity against MCF7; 7h showed against PC3, and 7g showed against DU-145. Molecular docking studies of test compounds (7a-j) with the EGFR tyrosine kinase domain (PDB ID: 1M17) protein provided the significant docking scores for each test compound (7a-j) (-9.00 to -9.67 kcal/mol). Additionally, DFT investigations and MD simulations validated the predictions of molecular docking. According to the findings of the ADME analysis, oral absorption by humans is anticipated to be higher than 85 % for all test compounds.

Multi-target rational design and synthesis of novel diphenyl-tethered pyrazolopyrimidines targeting EGFR and topoisomerase II with potential DNA intercalation and apoptosis induction

Herein, we envisioned the design and synthesis of novel pyrazolopyrimidines (confirmed by elemental analysis, 1H and 13C NMR, and mass spectra) as multitarget-directed drug candidates acting as EGFR/TOPO II inhibitors, DNA intercalators, and apoptosis inducers. The target diphenyl-tethered pyrazolopyrimidines were synthesized starting from the reaction of phenyl hydrazine and ethoxymethylenemalononitrile to give aminopyrazole-carbonitrile 2. The latter hydrolysis with NaOH and subsequent reaction with 4-chlorobenzaldhyde afforded the corresponding pyrazolo[3,4-d]pyrimidin-4-ol 4. Chlorination of 4 with POCl3 and sequential reaction with different amines afforded the target compounds in good yields (up to 73 %). The growth inhibition % of the new derivatives (6a-m) was investigated against different cancer and normal cells and the IC50 values of the most promising candidates were estimated for HNO97, MDA-MB-468, FaDu, and HeLa cancer cells. The frontier derivatives (6a, 6i, 6k, 6l, and 6m) were pursued for their EGFR inhibitory activity. Compound 6l decreased EGFR protein concentration by a 6.10-fold change, compared to imatinib as a reference standard. On the other side, compounds (6a, 6i, 6k, 6l, and 6m) underwent topoisomerase II (TOPO II) inhibitory assay. In particular, compounds 6a and 6l exhibited IC50s of 17.89 and 19.39 μM, respectively, surpassing etoposide with IC50 of 20.82 μM. Besides, the DNA fragmentation images described the great potential of both candidates 6a and 6l in inducing DNA degradation at lower concentrations compared to etoposide and doxorubicin. Moreover, compound 6l, with the most promising EGFR/TOPO II inhibition and DNA intercalation, was selected for further investigation for its apoptosis induction ability by measuring caspases 3, 7, 8, and 9, Bax, p53, MMP2, MMP9, and BCL-2 proteins. Additionally, molecular docking was used to explain the SAR results based on the differences in the molecular features of the investigated congeners and the target receptors' topology.

Computational Design, Synthesis, and Bioevaluation of 2-(Pyrimidin-4-yl)oxazole-4-carboxamide Derivatives: Dual Inhibition of EGFRWT and EGFRT790M with ADMET Profiling

The ongoing research in cancer treatment underscores the significance of dual epidermal growth factor receptor (EGFR) kinase inhibitors targeting both mutant and wild-type variants. In this study, employing in silico fragment-based drug design (FBDD) and computational analysis, we have successfully developed a novel chemical series of 2-(pyrimidin-4-yl)oxazole-4-carboxamide (16a-j) derivatives designed as dual EGFR kinase inhibitors. A comparative in vitro anticancer profile of the newly synthesized compounds (16a-j) was tested against a panel of five human cancer cell lines like prostate cancer (PC3 & DU-145), lung cancer (A549), human liver cancer (HEPG2), and breast cancer (MDA-MB-468) by employing MTT method. In this experiment a well-known anticancer agent, Etoposide was used as positive control. Most of the derivatives demonstrated significant cytotoxicity, ranging from excellent to moderate levels. The IC50 values for the synthesized compounds observed between 0.10 ± 0.052 to 9.83 ± 5.96 µM, while the positive control exhibited a range of 1.97 ± 0.45 µM to 3.08 ± 0.135 µM. These results indicate that the synthesized compounds demonstrate higher cytotoxic potency in comparison to the reference compound. Furthermore, all these compounds underwent screening against normal Vero cell lines to assess their cytotoxicity. In each case, the observed cytotoxicity values (IC50) were higher than 22 µM, affirming the compounds selectivity for cancer cell lines. Among the compounds investigated, three compounds (16a, 16e, and 16i) exhibited notable cytotoxicity, while two compounds (16g and 16h) demonstrated exceptional cytotoxicity. The selectivity index of the tested compounds indicates a pronounced preference for targeting cancer cell lines over normal cells. Furthermore, all the compounds 16a-j underwent assessment for their EGFR kinase inhibitory activity against both EGFRWT and mutated EGFRT790M. The results unveiled the potential eligibility of this new series of compounds as effective EGFR inhibitors. Moreover, compound 16h underwent additional testing for cell cycle analysis, revealing its capability to arrest the cell cycle in the G2/M phase and induce apoptosis at the IC50 concentration.

Design, synthesis, docking, and anticancer evaluations of new thiazolo[3,2-a] pyrimidines as topoisomerase II inhibitors

New thiazolopyrimidine derivatives 2, 3a-d, 4a-c, 5, 6a-c, and 7a,b were synthesised. All prepared compounds were evaluated by MTT cytotoxicity assay against three human tumour cell lines. Compounds 3c, 3d, 4c, 6a, 6b, and 7b exhibited potent to strong anticancer activity that was nearly comparable or superior to Doxorubicin. Compounds exhibiting significant cytotoxicity were further selected to study their inhibitory activity on the Topo II enzyme. Compound 4c was the most potent Topo II inhibitor with an IC₅₀ value of 0.23 ± 0.01 µM, which was 1.4-fold and 3.6-fold higher than the IC₅₀ values of Etoposide and Doxorubicin. Furthermore, compound 4c showed significant cell cycle disruption and apoptosis on A549 cells compared to control cells. Molecular docking of the most active compounds illustrated proper fitting to the Topo II active site, suggesting that our designed compounds are promising candidates for the development of effective anticancer agents acting through Topo II inhibition.

Biological evaluation, docking studies, and in silico ADME prediction of some pyrimidine and pyridine derivatives as potential EGFRWT and EGFRT790M inhibitors

Herein, a set of pyridine and pyrimidine derivatives were assessed for their impact on the cell cycle and apoptosis. Human breast cancer (MCF7), hepatocellular carcinoma (HEPG2), larynx cancer (HEP2), lung cancer (H460), colon cancers (HCT116 and Caco2), and hypopharyngeal cancer (FADU), and normal Vero cell lines were used. Compounds 8 and 14 displayed outstanding effects on the investigated cell lines and were further tested for their antioxidant activity in MCF7, H460, FADU, HEP2, HEPG2, HCT116, Caco2, and Vero cells by measuring superoxide dismutase (SOD), malondialdehyde content (MDA), reduced glutathione (GSH), and nitric oxide (NO) content. Besides, Annexin V-FITC apoptosis detection and cell cycle DNA index using the HEPG-2 cell line were established on both compounds as well. Furthermore, compounds 8 and 14 were assessed for their EGFR kinase (Wild and T790M) inhibitory activities, revealing eligible potential. Additionally, molecular docking, ADME, and SAR studies were carried out for the investigated candidates.

Recent advances in triazoles as tyrosinase inhibitors

The tyrosinase enzyme, which is widely found in microorganisms, animals and plants, has a significant position in melanogenesis, plays an important role in undesirable browning of fruits and vegetables, antibiotic resistance, skin pigment formation, sclerotization of cuticle, neurodegeneration, etc. Therefore, with the wide potential application fields of tyrosinase in food, agriculture, cosmetics and pharmaceutical industries, which has become the target enzyme for the development of therapeutic agents such as antibrowning, anticancer, antibacterial, skin whitening, insecticides, etc., a large number of synthetic tyrosinase inhibitors have been widely reported in recent years. The triazole ring, which has a broad spectrum of biological action, is of increasing interest in the synthesis of new tyrosinase inhibitors. In this review, tyrosinase inhibition effects, structure-activity relationships, enzyme inhibition kinetics and mechanisms of action of 1,2,3- or 1,2,4-triazole derivatives were investigated. The data gathered is anticipated to supply rational guidance and an influential strategy for the development of novel, potent and safe tyrosinase inhibitors for better practical application in the future.

Novel fused imidazotriazines acting as promising top. II inhibitors and apoptotic inducers with greater selectivity against head and neck tumors: Design, synthesis, and biological assessments

Although the great effectiveness of doxorubicin (Dox) in the treatment of many types of tumors, it showed limited effectiveness against the head and neck squamous cell carcinoma (HNSCC) subtype which is attributed to its reported multiple drug resistance (MDR). In the current study, we considered the essential pharmacophoric features of Dox as an effective Top. II inhibitor and sought to develop a novel set of imidazo[1,2-a] [1,3,5]triazin-2-amines (2a-2p) as a suggested anticancer option that could intercalate the DNA base pairs. We evaluated the % inhibition of the newly synthesized compounds on thirteen cancer cell lines and the analysis of structure-activity relationships revealed that the human head and neck cancer cell line (HNO97) was the most sensitive to their growth inhibition effect. Then, the IC50 values were recorded against the most sensitive cancer cell lines (HNO97, MDA-MB-231, and HEPG2), and compared to the normal cell line OEC (human oral epithelial cells). Compounds 2f and 2g showed very strong activities against HNO97 with IC50 values of (4 ± 1 and 3 ± 1.5 μg/mL), respectively, compared to that of Dox (9 ± 1.6 μg/mL). Next, a quantitative determination of human DNA Top. II concentrations in the most sensitive cell line (HNO97) were recorded for the most active anticancer derivatives. Again, compound 2f showed a superior Top. II inhibition with 87.86% compared to that of Dox (86.44%), while compound 2g achieved an inhibition of 81.37% which was close to the effect of Dox. To further investigate their effects on cell cycle progression and apoptosis induction in HNO97 cells, both 2f and 2g were selected for analysis. Both candidates arrested cell cycle progression at both the S and G2-M phases, as well as increased the early and late apoptosis phase ratios. Besides, both 2f and 2g were subjected to protein expression analysis of apoptosis-related genes (p53, BAX, IL-6, and BCL2). Moreover, the antioxidant effect of 2f and 2g was evaluated by measuring GSH, MDA, and NO markers in HNO97 cells. Furthermore, molecular docking for the newly designed tricyclic derivatives against both the Top. II and DNA double helix was carried out.

New Phenylthiazoles: Design, Synthesis, and Biological Evaluation as Antibacterial, Antifungal, and Anti-COVID-19 Candidates

The combination of antibacterial and antiviral agents is becoming a very important aspect of dealing with resistant bacterial and viral infections. The N-phenylthiazole scaffold was found to possess significant anti-MRSA, antifungal, and anti-COVID-19 activities as previously published; hence, a slight refinement was proposed to attach various alkyne lipophilic tails to this promising scaffold, to investigate their effects on the antimicrobial activity of the newly synthesized compounds and to provide a valuable structure-activity relationship. Phenylthiazole 4 m exhibited the most potent anti-MRSA activity with 8 μg/mL MIC value. Compounds 4 k and 4 m demonstrated potent activity against Clostridium difficile with MIC values of 2 μg/mL and moderate activity against Candida albicans with MIC value of 4 μg/mL. When analyzed for their anti-COVID-19 inhibitory effect, compound 4 b emerged with IC50 =1269 nM and the highest selectivity of 138.86 and this was supported by its binding score of -5.21 kcal mol-1 when docked against SARS-CoV-2 M pro . Two H-bonds were formed, one with His164 and the other with Met49 stabilizing phenylthiazole derivative 4 b, inside the binding pocket. Additionally, it created two arene-H bonds with Asn142 and Glu166, through the phenylthiazole scaffold and one arene-H bond with Leu141 via the phenyl ring of the lipophilic tail.

Bromodomain inhibitors and therapeutic applications

The bromodomain acts to recognize acetylated lysine in histones and transcription proteins and plays a fundamental role in chromatin-based cellular processes including gene transcription and chromatin remodeling. Many bromodomain proteins, particularly the bromodomain and extra terminal domain (BET) protein BRD4 have been implicated in cancers and inflammatory disorders and recognized as attractive drug targets. Although clinical studies of many BET bromodomain inhibitors have made substantial progress toward harnessing the therapeutic potential of targeting the bromodomain proteins, the development of this new class of epigenetic drugs is met with challenges, especially on-target dose-limiting toxicity. In this review, we highlight the current development of new-generation small molecule inhibitors for the BET and non-BET bromodomain proteins and discuss the research strategies used to target different bromodomain proteins for a wide array of human diseases including cancers and inflammatory disorders.

Design and Synthesis of 2-(4-Bromophenyl)Quinoline-4-Carbohydrazide Derivatives via Molecular Hybridization as Novel Microbial DNA-Gyrase Inhibitors

Microbial DNA gyrase is regarded as an outstanding microbial target. Hence, 15 new quinoline derivatives (5-14) were designed and synthesized. The antimicrobial activity of the afforded compounds was pursued via in vitro approaches. The investigated compounds displayed eligible MIC values, particularly against G-positive Staphylococcus aureus species. Consequently, an S. aureus DNA gyrase supercoiling assay was performed, using ciprofloxacin as a reference control. Obviously, compounds 6b and 10 unveiled IC₅₀ values of 33.64 and 8.45 μM, respectively. Alongside, ciprofloxacin exhibited an IC₅₀ value of 3.80 μM. Furthermore, a significant docking binding score was encountered by compound 6b (-7.73 kcal/mol), surpassing ciprofloxacin (-7.29 kcal/mol). Additionally, both compounds 6b and 10 revealed high GIT absorption without passing the blood brain barrier. Finally, the conducted structure-activity relationship study assured the usefulness of the hydrazine moiety as a molecular hybrid for activity either in cyclic or opened form.

Exploring the cytotoxic effect and CDK-9 inhibition potential of novel sulfaguanidine-based azopyrazolidine-3,5-diones and 3,5-diaminoazopyrazoles

Regarding the structural analysis of variable effective CDK-9 suppressors, we record the design and synthesis of two new sets of sulfaguanidine-based azopyrazolidine-3,5-diones and 3,5-diaminoazopyrazoles with expected anticancer and CDK-9 inhibiting activity. In the designed molecules, the pyrazole ring and sulphaguanidine fragment were linked together for the first time through diazo linkers as they are expected to enhance the anticancer activity and CDK degrading interaction. All derivatives have been estimated regarding their cytotoxic activity toward three tumor cells where CDK overexpression has been reported (HePG2, HCT-116, and MCF-7). Among these, four derivatives VII, VIII, X, and XIII exerted potent cytotoxicity against the chosen tumor cells presenting IC₅₀ range equal to 2.86-25.89 µM. As well cytotoxicity on non-cancer cells and CDK-9 inhibition assay have been also assessed for these candidates to evaluate their selectivity indices and enzyme inhibition. The 3,5-diaminopyrazole-1-carboxamide derivative XIII showed a superior combined profile as cytotoxic with high selectivity toward cancer cells (HePG2: IC₅₀ = 6.57 µM, SI = 13.31; HCT-116: IC₅₀ = 9.54 µM, SI = 9.16; MCF-7: IC₅₀ = 7.97 µM, SI = 10.97). Accordingly, it has been chosen to evaluate its probable mechanistic effect both in vitro (via enzyme assay, apoptosis induction, and cell cycle study) as well as in silico (through molecular docking). Overall, this work introduces the 3,5-diaminopyrazole-1-carboxamide derivative XIII as a potent CDK-9 inhibitor candidate (IC₅₀ = 0.16 µM) that merits further investigations for the management of breast, colorectal, and hepatic malignancies.

Binding mechanism of anacardic acid, carnosol and garcinol with PCAF: A comprehensive study using molecular docking and molecular dynamics simulations and binding free energy analysis

The p300/CBP associated factor bromodomain (PCAF Brd) is emerged as one of the promising target proteins for different types of cancers. PCAF is one among the histone acetyltransferase enzymes which involved in the regulation of transcriptase process by modifying the chromatin structure. Anacardic acid, carnosol, garcinol are the experimentally reported inhibitors of PCAF Brd; however, their detailed binding mechanism these inhibitors are not yet known. The intermolecular interaction, binding energy, and the stability of these inhibitors with the active site of PCAF Brd are playing the key role in the binding of these inhibitors with PCAF. The in silico study incorporates the molecular docking and dynamics simulations; these molecular level simulations allow to understand the binding mechanism. In the present study, the induced fit molecular docking and molecular dynamics of anacardic acid, carnosol and garcinol molecules against the PCAF Brd have been performed. The docking score values of these molecules are -5.112 (anacardic acid), -5.141 (carnosol), -5.199 (garcinol) and -3.641 (L45) kcal/mol, respectively. Further, the molecular dynamics simulation was carried out for these docked complexes to understand their conformational their stability and binding energy from the roots means square deviation (RMSD) and root means square of fluctuation (RMSF), and molecular mechanics with the generalized born and surface area solvation (MM/GBSA) binding free energy calculations. The intermolecular interactions and binding free energy values confirm that garcinol forms key interactions and has high binding affinity towards PCAF Brd on compare with the other two inhibitors. Therefore, garcinol may be considered as a potential inhibitor of PCAF Brd.

Recent Advances on Small-Molecule Bromodomain-Containing Histone Acetyltransferase Inhibitors

In recent years, substantial research has been conducted on molecular mechanisms and inhibitors targeting bromodomains (BRDs) and extra-terminal (BET) family proteins. On this basis, non-BET BRD is gradually becoming a research hot spot. BRDs are abundant in histone acetyltransferase (HAT)-associated activating transcription factors, and BRD-containing HATs have been linked to cancer, inflammation, and viral replication. Therefore, the development of BRD-containing HATs as chemical probes is useful for understanding the specific biological roles of BRDs in diseases and drug discovery. Several types of BRD-containing HATs, including CBP/P300, PCAF/GCN5, and TAF1, are discussed in this context in terms of their structures, functions, and small-molecule inhibitors. Additionally, progress in BRD inhibitors/chemical probes and proteolysis targeting chimeras in terms of drug design, biological activity, and disease application are summarized. These findings provide insights into the development of BRD inhibitors as potential drug candidates for various diseases.

Synthesis, Molecular Docking, and Dynamic Simulation Targeting Main Protease (Mpro) of New, Thiazole Clubbed Pyridine Scaffolds as Potential COVID-19 Inhibitors

Many biological activities of pyridine and thiazole derivatives have been reported, including antiviral activity and, more recently, as COVID-19 inhibitors. Thus, in this paper, we designed, synthesized, and characterized a novel series of N-aminothiazole-hydrazineethyl-pyridines, beginning with a N'-(1-(pyridine-3-yl)ethylidene)hydrazinecarbothiohydrazide derivative and various hydrazonoyl chlorides and phenacyl bromides. Their Schiff bases were prepared from the condensation of N-aminothiazole derivatives with 4-methoxybenzaldehyde. FTIR, MS, NMR, and elemental studies were used to identify new products. The binding energy for non-bonding interactions between the ligand (studied compounds) and receptor was determined using molecular docking against the SARS-CoV-2 main protease (PDB code: 6LU7). Finally, the best docked pose with highest binding energy (8a = -8.6 kcal/mol) was selected for further molecular dynamics (MD) simulation studies to verify the outcomes and comprehend the thermodynamic properties of the binding. Through additional in vitro and in vivo research on the newly synthesized chemicals, it is envisaged that the achieved results will represent a significant advancement in the fight against COVID-19.

Ligand-Based Design on the Dog-Bone-Shaped BIBR1532 Pharmacophoric Features and Synthesis of Novel Analogues as Promising Telomerase Inhibitors with In Vitro and In Vivo Evaluations

Telomerase is an outstanding biological target for cancer treatment. BIBR1532 is a non-nucleoside selective telomerase inhibitor; however, it experiences ineligible pharmacokinetics. Herein, we aimed to design new BIBR1532-based analogues as promising telomerase inhibitors. Therefore, two novel series of pyridazine-linked to cyclopenta[b]thiophene (8a-f) and tetrahydro-1-benzothiophene (9a-f) were synthesized. A quantitative real-time polymerase chain reaction was utilized to investigate the telomerase inhibitory activity of candidates. Notably, 8e and 9e exhibited the best inhibition profiles. Moreover, 8e showed strong antitumor effects against both MCF-7 and A549 cancer cell lines. The effects of 8e on the cell cycle and apoptosis were measured. Besides, 8e was evaluated for its in vivo antitumor activity using solid Ehrlich carcinoma. The reduction in both the tumor weight and volume was greater than doxorubicin. Also, molecular docking and ADME studies were performed. Finally, a SAR study was conducted to gain further insights into the different telomerase inhibition potentials upon variable structural modifications.

Thieno[2,3-b]thiophene Derivatives as Potential EGFRWT and EGFRT790M Inhibitors with Antioxidant Activities: Microwave-Assisted Synthesis and Quantitative In Vitro and In Silico Studies

Microwave-assisted synthesis and spectral analysis of certain novel derivatives of 3,4-diaminothieno[2,3-b]thiophene-2,5-dicarbonitrile 1-7 were carried out. Compounds 1-7 were examined for cytotoxicity against MCF-7 and A549 cell lines using the quantitative MTT method, and gefitinib and erlotinib were used as reference standards. Compounds 1-7 were shown to be more active than erlotinib against the two cell lines tested. Compound 2 outperformed regular erlotinib by 4.42- and 4.12-fold in MCF-7 and A549 cells, respectively. The most cytotoxic compounds were subsequently studied for their suppression of kinase activity using the homogeneous time-resolved fluorescence assay versus epidermal growth factor receptor (EGFR^WT) and EGFR^790M. With IC₅₀ values of 0.28 ± 0.03 and 5.02 ± 0.19, compound 2 was demonstrated to be the most effective against both forms of EGFR. Furthermore, compound 2 also had the best antioxidant property, decreasing the radical scavenging activity by 78%. Molecular docking research, on the other hand, was carried out for the analyzed candidates (1-7) to study their mechanism of action as EGFR inhibitors. In silico absorption, distribution, metabolism, excretion, and toxicity tests were also performed to explain the physicochemical features of the examined derivatives.

Ligand-based design, synthesis, computational insights, and in vitro studies of novel N-(5-Nitrothiazol-2-yl)-carboxamido derivatives as potent inhibitors of SARS-CoV-2 main protease

The global outbreak of the COVID-19 pandemic provokes scientists to make a prompt development of new effective therapeutic interventions for the battle against SARS-CoV-2. A new series of N-(5-nitrothiazol-2-yl)-carboxamido derivatives were designed and synthesised based on the structural optimisation principle of the SARS-CoV Mpro co-crystallized WR1 inhibitor. Notably, compound 3b achieved the most promising anti-SARS-CoV-2 activity with an IC₅₀ value of 174.7 µg/mL. On the other hand, compounds 3a, 3b, and 3c showed very promising SARS-CoV-2 Mpro inhibitory effects with IC₅₀ values of 4.67, 5.12, and 11.90 µg/mL, respectively. Compound 3b docking score was very promising (-6.94 kcal/mol) and its binding mode was nearly similar to that of WR1. Besides, the molecular dynamics (MD) simulations of compound 3b showed its great stability inside the binding pocket until around 40 ns. Finally, a very promising SAR was concluded to help to design more powerful SARS-CoV-2 Mpro inhibitors shortly.

Investigating the Potential Anti-SARS-CoV-2 and Anti-MERS-CoV Activities of Yellow Necklacepod among Three Selected Medicinal Plants: Extraction, Isolation, Identification, In Vitro, Modes of Action, and Molecular Docking Studies

The anti-MERS-CoV activities of three medicinal plants (Azadirachta indica, Artemisia judaica, and Sophora tomentosa) were evaluated. The highest viral inhibition percentage (96%) was recorded for S. tomentosa. Moreover, the mode of action for both S. tomentosa and A. judaica showed 99.5% and 92% inhibition, respectively, with virucidal as the main mode of action. Furthermore, the anti-MERS-CoV and anti-SARS-CoV-2 activities of S. tomentosa were measured. Notably, the anti-SARS-CoV-2 activity of S. tomentosa was very high (100%) and anti-MERS-CoV inhibition was slightly lower (96%). Therefore, the phytochemical investigation of the very promising S. tomentosa L. led to the isolation and structural identification of nine compounds (1−9). Then, both the CC50 and IC50 values for the isolated compounds against SARS-CoV-2 were measured. Compound 4 (genistein 4’-methyl ether) achieved superior anti-SARS-CoV-2 activity with an IC50 value of 2.13 µm. Interestingly, the mode of action of S. tomentosa against SARS-CoV-2 showed that both virucidal and adsorption mechanisms were very effective. Additionally, the IC50 values of S. tomentosa against SARS-CoV-2 and MERS-CoV were found to be 1.01 and 3.11 µg/mL, respectively. In addition, all the isolated compounds were subjected to two separate molecular docking studies against the spike (S) and main protease (Mpr°) receptors of SARS-CoV-2.

Synthesis, Molecular Docking Study, and Cytotoxicity Evaluation of Some Novel 1,3,4-Thiadiazole as Well as 1,3-Thiazole Derivatives Bearing a Pyridine Moiety

Pyridine, 1,3,4-thiadiazole, and 1,3-thiazole derivatives have various biological activities, such as antimicrobial, analgesic, anticonvulsant, and antitubercular, as well as other anticipated biological properties, including anticancer activity. The starting 1-(3-cyano-4,6-dimethyl-2-oxopyridin-1(2H)-yl)-3-phenylthiourea (2) was prepared and reacted with various hydrazonoyl halides 3a–h, α-haloketones 5a–d, 3-chloropentane-2,4-dione 7a and ethyl 2-chloro-3-oxobutanoate 7b, which afforded the 3-aryl-5-substituted 1,3,4-thiadiazoles 4a–h, 3-phenyl-4-arylthiazoles 6a–d and the 4-methyl-3- phenyl-5-substituted thiazoles 8a,b, respectively. The structures of the synthesized products were confirmed by spectral data. All of the compounds also showed remarkable anticancer activity against the cell line of human colon carcinoma (HTC-116) as well as hepatocellular carcinoma (HepG-2) compared with the Harmine as a reference under in vitro condition. 1,3,4-Thiadiazole 4h was found to be most promising and an excellent performer against both cancer cell lines (IC₅₀ = 2.03 ± 0.72 and 2.17 ± 0.83 µM, respectively), better than the reference drug (IC₅₀ = 2.40 ± 0.12 and 2.54 ± 0.82 µM, respectively). In order to check the binding modes of the above thiadiazole derivatives, molecular docking studies were performed that established a binding site with EGFR TK.

The effect of novel synthetic semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles on the apoptotic markers, VEGFR-2, and cell cycle of myeloid leukemia

Vascular Endothelial Growth Factor II (VEGFR-2) has been proved as a rational target in cancer therapy. Although currently prescribed VEGFR-2 inhibitors are showing potent antitumor activity, they are often causing serious unwanted effects, restricting their extensive use as chemotherapeutics. Herein, after analyzing the structures of the effective VEGFR-2 inhibitor molecules, we report the synthesis of a new set of semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles with expected potency of inhibiting the VEGFR-2 signaling. The design of new compounds considered maintaining the essential pharmacophoric features of sorafenib for effective binding with the receptor target. All compounds have been evaluated for their growth inhibition effect against a panel of sixty cancer cells at the National Cancer Institute. Leukemia cancer cells, especially HL-60 and SR, were shown to be the most sensitive to the cytotoxic effect of new compounds. Thiosemicarbazones 21, 26, and 30 exhibited the best activity against almost all tested cancer cells. Therefore, a set of subsequent in vitro biological evaluations has been performed to understand the mechanistic effect of these compounds further. They inhibited the VEGFR-2 with IC₅₀ values of 0.128, 0.413, and 0.067 µM respectively compared with 0.048 µM of Sorafenib. The probable mechanistic effect of 30 has been further evaluated on a number of apoptotic and antiapoptotic markers including BAX, BCL2, caspase-3, and caspase-9. Results revealed the potential of the thiosemicarbazone-linked triazole 30 to induce both the early and the late apoptosis, elevate BAX/BCL2 ratio, induce caspase-3 & caspase-9, and arrest the HL-60 cell cycle at the G2/M and G0-G1 phases. Molecular docking of new semicarbazones and thiosemicarbazones into the proposed biological target receptor has also been performed. Results of docking studies proved the potential of new semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles to effectively bind with crucial residues of the VEGFR-2 binding pocket.

Synthesis, structural characterization, DFT calculations, molecular docking, and molecular dynamics simulations of a novel ferrocene derivative to unravel its potential antitumor activity

In this article, we describe a set of subsequent five-steps chemical reactions to synthesize a ferrocene derivative named 1-(5-(diphenylphosphaneyl)cyclopenta-1,3-dien-1-yl)ethyl)imino)-1,3-dihydroisobenzofuran-5-yl)methanol (compound 10). Structural characterization of 10 and its intermediate products was also performed and reported to attest to their formation. A molecular docking study was performed to propose the novel synthesized ferrocene derivative (10) as a potential antitumor candidate targeting the mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1. The computed docking score of (10) at -9.50 kcal/mol compared to the native anticancer staurosporine at -8.72 kcal/mol postulated a promising anticancer activity. Also, molecular dynamics (MD) simulations were carried out for 500 ns followed by MM-GBSA-binding free energy calculations for both the docked complexes of ferrocene and staurosporine to give more deep insights into their dynamic behavior in physiological conditions. Furthermore, DFT calculations were performed to unravel some of the physiochemical characteristics of the ferrocene derivative (10). The quantum mechanics calculations shed the light on some of the structural and electrochemical configurations of (10) which would open the horizon for further investigation. HighlightsThe synthesis of a ferrocene derivative named 1-(5-(diphenylphosphaneyl)cyclopenta-1,3-dien-1-yl)ethyl)imino)-1,3-dihydroisobenzofuran-5-yl)methanol (compound 10) was described.Structural characterizations of ferrocene derivative (10) and its intermediate products were also performed.DFT calculations, molecular docking, molecular dynamics, and MM-GBSA calculations were carried out.Computational studies revealed the antitumor potential of ferrocene derivative (10) through targeting and inhibiting mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1.Communicated by Ramaswamy H. Sarma.

A novel role of Nano selenium and sildenafil on streptozotocin-induced diabetic nephropathy in rats by modulation of inflammatory, oxidative, and apoptotic pathways

AIMS

The present study aimed to investigate the effect of nano selenium, sildenafil, and their combination on inflammation, oxidative stress, and apoptosis in streptozotocin-induced diabetic nephropathy in rats. Herein, a new anti-inflammatory pathway for sildenafil as a high-mobility group box (HMGB1) inhibitor was proposed using the molecular docking technique.

MATERIALS AND METHODS

Rats were divided into 7 groups: normal control, control nano selenium, control sildenafil, control diabetic, diabetic+ nano selenium, diabetic+ sildenafil, diabetic+ nano selenium+ sildenafil. The effects of drugs were evaluated by measuring serum urea, creatinine, lactate dehydrogenase (LDH), levels of tumor necrosis factor-alpha (TNF-α), Interleukin 1 beta (IL-1β), HMGB1, receptor advanced glycation end product (RAGE), malondialdehyde (MDA), thioredoxin reductase (TrxR) by biochemical assays, nuclear factor-kappa b (NF-κB), toll-like receptor (TLR4) by immunohistochemistry, gene expressions of caspase 3 and monocyte chemoattractant protein (MCP-1) besides histopathological investigations of renal cells.

KEY FINDINGS

Results showed beneficial effects of 8 weeks of treatment by nano selenium and sildenafil supported by improvement in kidney function, histopathological changes, and reduction in all of these parameters. These results supported molecular docking that indicated sildenafil had a high binding score and interactions with the HMGB1 receptor.

SIGNIFICANCE

The current study demonstrated a renoprotective effect of nano‑selenium and sildenafil by interfering at multiple pathways, especially the HMGB1/NF-κB signaling pathway.

Design, synthesis, and SAR studies of novel 4-methoxyphenyl pyrazole and pyrimidine derivatives as potential dual tyrosine kinase inhibitors targeting both EGFR and VEGFR-2

Guided by the pharmacophoric features of both EGFR and VEGFR-2 antagonists, two novel series of 4-methoxyphenyl pyrazole and pyrimidine derivatives [(4a-c) and (5a-c, 6, 7a-c, 8, 9, 10, 11a,c, 12, 13a-c, 14a-c, and 15a,b)], respectively, were designed and synthesized as dual EGFR/VEGFR-2 inhibitors. Interestingly, compound 12 showed very strong antiproliferative effects towards all the five studied cell lines (HepG-2, MCF-7, MDA-231, HCT-116, and Caco-2) with IC₅₀ values of 3.74, 7.81, 4.85, 2.96, and 9.27 µM, respectively. Also, it achieved the highest inhibitory activities against both EGFR and VEGFR-2 as well (IC₅₀ = 0.071 and 0.098 µM) compared to the two reference drugs, erlotinib (IC₅₀ = 0.063 µM) and sorafenib (IC₅₀ = 0.041 µM), respectively. Moreover, four compounds (4a, 7a, 7c, and 12) were selected for further evaluation through cell cycle analysis and Annexin V-based flow cytometry assay in the HepG-2 cell line. In addition, deep computational studies including molecular docking, physicochemical properties, profiling pharmacokinetics, ADMET studies, and toxicity predictions were performed for the designed compounds to evaluate the prospective drug candidates. Finally, analyzing the structure-activity relationship (SAR) of the new derivatives gives us a lot of interesting promising results which could help medicinal chemists to design more potent drug candidates soon as well.

Potential Valorization of Edible Nuts By-Products: Exploring the Immune-Modulatory and Antioxidants Effects of Selected Nut Shells Extracts in Relation to Their Metabolic Profiles

The immune system is a potent army that defends our body against various infections and diseases through innate and adaptive immunity. Herbal medicine is one of the essential sources for enhancing immunity because of affordability, availability, minor side effects, and consumers’ preferences. Hazelnuts, walnuts, almonds, and peanuts are among the most widespread edible nuts that are rich in phenolics, fats, fibers, vitamins, proteins, and minerals. The potential of nut shells in phytoremediation has attracted increasing attention as a sustainable solution for waste recycling. Here, we determined the in vitro immune-modulatory activity as well as the metabolite profile of the four nut shell extracts. The addition of the extracts to LPS-stimulated macrophages, especially peanut and walnut shells, has downregulated the gene expression of AP-1, TNF-α, IL-8, iNOS, and COX-2 expression levels. Significant antioxidant capabilities and immune-modulatory effects have been traced for peanut shells. UPLC-MS metabolic profiling of the four nut shell extracts allowed the detection of a relatively high level of phenolic compounds in peanut shells. Intriguingly, a significant correlation between the antioxidant capacity and the total phenolic content was found, indicating the contribution of the phenolic compounds to the antioxidant properties and hence the immune-modulatory activity. Furthermore, molecular docking and structure–activity relationship (SAR) studies revealed kaempferol rutinoside and proanthocyanidin A5’ as potential iNOS inhibitors.

Unravelling the antifungal and antiprotozoal activities and LC-MS/MS quantification of steroidal saponins isolated from Panicum turgidum

Bioassay-guided investigation of Panicum turgidum extract resulted in the identification of seven steroidal saponins (Turgidosterones 1–7). They were evaluated for their in vitro antifungal, antileishmanial, and antitrypanosomal activities. Turgidosterone 6 was the most active antifungal against Candida albicans and Candida neoformans (IC₅₀ values of 2.84 and 1.08 μg mL⁻¹, respectively). Turgidosterones 4–7 displayed antileishmanial activity against Leishmania donovani promastigotes with IC₅₀ values ranging from 4.95 to 8.03 μg mL⁻¹ and against Leishmania donovani amastigote/THP with IC₅₀ values range of 4.50–9.29 μg mL⁻¹. Activity against Trypanosoma brucei was also observed for Turgidosterones 4–7 with an IC₅₀ values range of 1.26–3.77 μg mL⁻¹. Turgidosterones 1–3 did not display any activity against the tested pathogens. The study of structure–activity relationships of the isolated saponins indicated that the antifungal, antileishmanial, and antitrypanosomal activities are markedly affected by the presence of spirostane-type saponins and the elongation of the sugar residue at C-3. To quantitatively determine the most abundant active ingredient in Panicum turgidum extract, a single run, sensitive, and highly selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been applied under positive and negative modes. The obtained results showed that compound 5 was the most abundant (95.93 ± 1.10 mg per gram of dry Panicum turgidum extract), followed by 6 (52.51 ± 1.05 mg gm⁻¹), 4 (32.71 ± 0.48 mg gm⁻¹), and 7 (13.19 ± 0.50 mg gm⁻¹). Docking of these saponins against the Candida albicans oxidoreductases and Leishmania infantum trypanothione reductase active sites revealed their potential to effectively bind with a number of key residues in both receptor targets.

Bioassay-guided investigation of Panicum turgidum extract resulted in the identification of seven steroidal saponins (Turgidosterones 1–7).

In Silico and In Vitro Studies for Benzimidazole Anthelmintics Repurposing as VEGFR-2 Antagonists: Novel Mebendazole-Loaded Mixed Micelles with Enhanced Dissolution and Anticancer Activity

Cancer is a leading cause of death worldwide and its incidence is unfortunately anticipated to rise in the next years. On the other hand, vascular endothelial growth factor receptor 2 (VEGFR-2) is highly expressed in tumor-associated endothelial cells, where it affects tumor-promoting angiogenesis. Therefore, VEGFR-2 is considered one of the most promising therapeutic targets for cancer treatment. Furthermore, some FDA-approved benzimidazole anthelmintics have already shown potential anticancer activities. Therefore, repurposing them against VEGFR-2 can provide a rapid and effective alternative that can be implicated safely for cancer treatment. Hence, 13 benzimidazole anthelmintic drugs were subjected to molecular docking against the VEGFR-2 receptor. Among the tested compounds, fenbendazole (FBZ, 1), mebendazole (MBZ, 2), and albendazole (ABZ, 3) were proposed as potential VEGFR-2 antagonists. Furthermore, molecular dynamics simulations were carried out at 200 ns, giving more information on their thermodynamic and dynamic properties. Besides, the anticancer activity of the aforementioned drugs was tested in vitro against three different cancer cell lines, including liver cancer (HUH7), lung cancer (A549), and breast cancer (MCF7) cell lines. The results depicted potential cytotoxic activity especially against both HUH7 and A549 cell lines. Furthermore, to improve the aqueous solubility of MBZ, it was formulated in the form of mixed micelles (MMs) which showed an enhanced drug release with better promising cytotoxicity results compared to the crude MBZ. Finally, an in vitro quantification for VEGFR-2 concentration in treated HUH7 cells has been conducted based on the enzyme-linked immunosorbent assay. The results disclosed that FBZ, MBZ, and ABZ significantly (p < 0.001) reduced the concentration of VEGFR-2, while the lowest inhibition was achieved in MBZ-loaded MMs, which was even much better than the reference drug sorafenib. Collectively, the investigated benzimidazole anthelmintics could be encountered as lead compounds for further structural modifications and thus better anticancer activity, and that was accomplished through studying their structure-activity relationships.

Rationale design, synthesis, cytotoxicity evaluation, and in silico mechanistic studies of novel 1,2,3-triazoles with potential anticancer activity

A new set of 1,2,3-triazoles was designed and synthesized to evaluate their potential to inhibit the growth of cancer cells.

Newly synthesized series of oxoindole–oxadiazole conjugates as potential anti-SARS-CoV-2 agents: in silico and in vitro studies

The pharmacophoric features of the novel series of 1,3,4-oxadiazole–oxoindole conjugates (IVa–g) as potential anti-SARS-CoV-2 agents based on the reported Mpro inhibitor (Ia) are presented.

Quinoxaline Derivatives as a Promising Scaffold for Breast Cancer Treatment

According to Global Cancer Statistics 2021, female breast cancer has exceeded lung cancer as the most frequently diagnosed cancer. As a result of this widespread breast cancer, it was necessary...

Design and synthesis of novel quinazolinone–chalcone hybrids as potential apoptotic candidates targeting caspase-3 and PARP-1: in vitro, molecular docking, and SAR studies

Novel quinazolinone–chalcone hybrids as potential apoptotic candidates targeting caspase-3 and PARP-1.

In vitro and computational investigations of novel synthetic carboxamide-linked pyridopyrrolopyrimidines with potent activity as SARS-CoV-2-MPro inhibitors

An essential target for COVID-19 is the main protease of SARS-CoV-2 (M^pro). With the objective of targeting this receptor, a novel set of pyrido[1,2-a]pyrrolo[2,3-d]pyrimidines with terminal carboxamide fragments was designed, synthesized, and considered as an initial motif for the creation of effective pan-coronavirus inhibitors. Accordingly, nine derivatives (21–29) have been introduced for in vitro assay to evaluate their antiviral activity and cytotoxicity effect against COVID-19 virus using Vero cells. The obtained data revealed that the majority of these derivatives showed potent cellular anti-COVID-19 activity and prevent viral growth by more than 90% at two different concentrations with weak or even no detectable cytotoxic effect on Vero cells. Extensive molecular docking simulations highlighted proper non-covalent interaction of new compounds within the binding pocket of M^pro as a potential target for their antiviral activity. In vitro assay for all the synthesized derivatives against the viral M^pro target indicated that compounds 25 and 29 have promising inhibitory activity with IC₅₀ values at low micromolar concentrations. The molecular dynamic simulation results predicted the stability of compound 29 in the binding cavity of SARS-CoV-2 M^pro and hence supported the high inhibitory activity shown by the In vitro assay. These results suggested that compounds 25 and 29 merit further investigations as promising drug candidates for the management of SARS-CoV-2.

An essential target for COVID-19 is the main protease of SARS-CoV-2 (M^pro).

Design, synthesis, biological evaluation, and SAR studies of novel cyclopentaquinoline derivatives as DNA intercalators, topoisomerase II inhibitors, and apoptotic inducers

Novel cyclopentaquinoline derivatives as promising DNA intercalators, topoisomerase II inhibitors, and apoptotic inducers.

In vitro and computational insights revealing the potential inhibitory effect of Tanshinone IIA against influenza A virus

Seasonal human influenza is a serious respiratory infection caused by influenza viruses that can be found all over the world. Type A influenza is a contagious viral infection that, if left untreated, can lead to life-threatening consequences. Fortunately, the plant kingdom has many potent medicines with broad-spectrum antiviral activity. Herein, six plant constituents, namely Tanshinone IIA 1, Carnosic acid 2, Rosmarinic acid 3, Glycyrrhetinic acid 4, Baicalein 5, and Salvianolic acid B 6, were screened for their antiviral activities against H1N1 virus using in vitro and in silico approaches. Hence, their anti-influenza activities were tested in vitro to determine inhibitory concentration 50 (IC₅₀) values after measuring their CC₅₀ values using MTT assay on MDCK cells. Interestingly, Tanshinone IIA (TAN) 1 was the most promising member with CC₅₀ = 9.678 μg/ml. Moreover, the plaque reduction assay carried on TAN 1 revealed promising viral inhibition percentages of 97.9%, 95.8%, 94.4%, and 91.7% using concentrations 0.05 μg/μl, 0.025 μg/μl, 0.0125 μg/μl, and 0.006 μg/μl, respectively. Furthermore, in silico molecular docking disclosed the superior affinities of Salvianolic acid B (SAL) 6 towards both surface glycoproteins of influenza A virus (namely, hemagglutinin (HA) and neuraminidase (NA)). The docked complexes of both SAL and TAN inside HA and NA receptor pockets were selected for 100 ns MD simulations followed by MM-GBSA binding free energy calculation to confirm the docking results and give more insights regarding the stability of both compounds inside influenza mentioned receptors, respectively. The selection criteria of the previously mentioned complexes were based on the fact that SAL showed the highest docking scores on both viral HA and NA glycoproteins whereas TAN achieved the best inhibitory activity on the other hand. Finally, we urge more advanced preclinical and clinical research, particularly for TAN, which could be used to treat the human influenza A virus effectively.

Topo II inhibition and DNA intercalation by new phthalazine-based derivatives as potent anticancer agents: design, synthesis, anti-proliferative, docking, and in vivo studies

This research presents the design and synthesis of a novel series of phthalazine derivatives as Topo II inhibitors, DNA intercalators, and cytotoxic agents. In vitro testing of the new compounds against HepG-2, MCF-7, and HCT-116 cell lines confirmed their potent cytotoxic activity with low IC₅₀ values. Topo II inhibition and DNA intercalating activities were evaluated for the most cytotoxic members. IC₅₀ values determination demonstrated Topo II inhibitory activities and DNA intercalating affinities of the tested compounds at a micromolar level. Amongst, compound 9d was the most potent member. It inhibited Topo II enzyme at IC₅₀ value of 7.02 ± 0.54 µM with DNA intercalating IC₅₀ of 26.19 ± 1.14 µM. Compound 9d was then subjected to an in vivo antitumor examination. It inhibited tumour proliferation reducing solid tumour volume and mass. Additionally, it restored liver enzymes, proteins, and CBC parameters near-normal, indicating a remarkable amelioration in their functions along with histopathological examinations.

Design, synthesis and molecular docking studies of some 1-(5-(2-fluoro-5-(trifluoromethoxy)phenyl)-1,2,4-oxadiazol-3-yl)piperazine derivatives as potential anti-inflammatory agents

We herein report the facile synthesis of a series of 3,5-substituted-1,2,4-oxadiazole derivatives in good to excellent yields. The anti-inflammatory potential of the newly synthesized compounds was evaluated by anti-denaturation assay using diclofenac sodium as the reference standard. Some of the compounds exhibited profound activity profile when compared to the standard drug. The molecular docking and SAR studies were carried out at the later stage for gaining more insights about the promising activity profile of the synthesized molecules.

Mahmoud S, Shehata M, Shama NMA, GabAllah M, Mostafa-Hedeab G, Marzouk MM. Naturally Available Flavonoid Aglycones as Potential Antiviral Drug Candidates against SARS-CoV-2

Flavonoids are important secondary plant metabolites that have been studied for a long time for their therapeutic potential in inflammatory diseases because of their cytokine-modulatory effects. Five flavonoid aglycones were isolated and identified from the hydrolyzed aqueous methanol extracts of Anastatica hierochuntica L., Citrus reticulata Blanco, and Kickxia aegyptiaca (L.) Nabelek. They were identified as taxifolin (1), pectolinarigenin (2), tangeretin (3), gardenin B (4), and hispidulin (5). These structures were elucidated based on chromatographic and spectral analysis. In this study, molecular docking studies were carried out for the isolated and identified compounds against SARS-CoV-2 main protease (Mpro) compared to the co-crystallized inhibitor of SARS-CoV-2 Mpro (α-ketoamide inhibitor (KI), IC50 = 66.72 µg/mL) as a reference standard. Moreover, in vitro screening against SARS-CoV-2 was evaluated. Compounds 2 and 3 showed the highest virus inhibition with IC50 12.4 and 2.5 µg/mL, respectively. Our findings recommend further advanced in vitro and in vivo studies of the examined isolated flavonoids, especially pectolinarigenin (2), tangeretin (3), and gardenin B (4), either alone or in combination with each other to identify a promising lead to target SARS-CoV-2 effectively. This is the first report of the activity of these compounds against SARS-CoV-2.

Pimenta dioica (L.) Merr. Bioactive Constituents Exert Anti-SARS-CoV-2 and Anti-Inflammatory Activities: Molecular Docking and Dynamics, In Vitro, and In Vivo Studies

In response to the urgent need to control Coronavirus disease 19 (COVID-19), this study aims to explore potential anti-SARS-CoV-2 agents from natural sources. Moreover, cytokine immunological responses to the viral infection could lead to acute respiratory distress which is considered a critical and life-threatening complication associated with the infection. Therefore, the anti-viral and anti-inflammatory agents can be key to the management of patients with COVID-19. Four bioactive compounds, namely ferulic acid 1, rutin 2, gallic acid 3, and chlorogenic acid 4 were isolated from the leaves of Pimenta dioica (L.) Merr (ethyl acetate extract) and identified using spectroscopic evidence. Furthermore, molecular docking and dynamics simulations were performed for the isolated and identified compounds (1-4) against SARS-CoV-2 main protease (Mpro) as a proposed mechanism of action. Furthermore, all compounds were tested for their half-maximal cytotoxicity (CC50) and SARS-CoV-2 inhibitory concentrations (IC50). Additionally, lung toxicity was induced in rats by mercuric chloride and the effects of treatment with P. dioca aqueous extract, ferulic acid 1, rutin 2, gallic acid 3, and chlorogenic acid 4 were recorded through measuring TNF-α, IL-1β, IL-2, IL-10, G-CSF, and genetic expression of miRNA 21-3P and miRNA-155 levels to assess their anti-inflammatory effects essential for COVID-19 patients. Interestingly, rutin 2, gallic acid 3, and chlorogenic acid 4 showed remarkable anti-SARS-CoV-2 activities with IC50 values of 31 µg/mL, 108 μg/mL, and 360 µg/mL, respectively. Moreover, the anti-inflammatory effects were found to be better in ferulic acid 1 and rutin 2 treatments. Our results could be promising for more advanced preclinical and clinical studies especially on rutin 2 either alone or in combination with other isolates for COVID-19 management.

Design and Synthesis of New Quinoxaline Derivatives as Potential Histone Deacetylase Inhibitors Targeting Hepatocellular Carcinoma: In Silico, In Vitro, and SAR Studies

Guided by the structural optimization principle and the promising anticancer effect of the quinoxaline nucleus, a new series of novel HDAC inhibitors were designed and synthesized. The synthesized compounds were designed to bear the reported pharmacophoric features of the HDAC inhibitors in addition to an extra moiety to occupy the non-used vacant deep pocket of the HDAC receptor. The newly prepared compounds were evaluated for their in vitro anti-proliferative activities against HepG-2 and HuH-7 liver cancer cell lines. The tested compounds showed promising anti-proliferative activities against both cell lines. The most active ten candidates (6 c , 6 d , 6 f , 6 g , 6 k , 6 l , 7 b , 8, 10 h , and 12) were further evaluated for their effect on the gene expression levels of Bax as an apoptotic marker and Bcl-2 as an anti-apoptotic one. Moreover, they were evaluated for their ability to inhibit histone deacetylase (HDAC1, HDAC4, and HDAC6) activities. Compound 6 c achieved the best cytotoxic activities on both HepG-2 and HuH-7 cell lines with IC50 values of 1.53 and 3.06 µM, respectively, and also it showed the most inhibitory activities on HDAC1, HDAC4, and HDAC6 with IC50 values of 1.76, 1.39, and 3.46 µM, respectively, compared to suberoylanilide hydroxamic acid (SAHA) as a reference drug (IC50 = 0.86, 0.97, and 0.93 µM, respectively). Furthermore, it achieved a more characteristic arrest in the growth of cell population of HepG-2 at both G0/G1 and S phases with 1.23-, and 1.18-fold, respectively, compared to that of the control, as determined by cell cycle analysis. Also, compound 6 c showed a marked elevation in the AnxV-FITC apoptotic HepG-2 cells percentage in both early and late phases increasing the total apoptosis percentage by 9.98-, and 10.81-fold, respectively, compared to the control. Furthermore, docking studies were carried out to identify the proposed binding mode of the synthesized compounds towards the prospective target (HDAC4). In silico ADMET and toxicity studies revealed that most of the synthesized compounds have accepted profiles of drug-likeness with low toxicity. Finally, an interesting SAR analysis was concluded to help the future design of more potent HDACIs in the future by medicinal chemists.

Investigating the structure-activity relationship of marine natural polyketides as promising SARS-CoV-2 main protease inhibitors

Since its first report in December 2019, the novel coronavirus virus, SARS-CoV-2, has caused an unprecedented global health crisis and economic loss imposing a tremendous burden on the worldwide finance, healthcare system, and even daily life. Even with the introduction of different preventive vaccines, there is still a dire need for effective antiviral therapeutics. Nature has been considered as the historical trove of drug discovery and development, particularly in cases of worldwide crises. Herein, a comprehensive in silico investigation of a highly focused chemical library of 34 pederin-structurally related marine compounds, belonging to four polyketides families, was initiated against the SARS-CoV-2 main protease, Mpro, being the key replicating element of the virus and main target in many drugs development programs. Two of the most potent SARS-CoV-2 Mpro co-crystallized inhibitors, O6K and N3, were added to the tested database as reference standards. Through molecular docking simulation, promising compounds including Pederin (1), Dihydro-onnamide A (11), Onnamide C (14), Pseudo-onnamide A (17), and Theopederin G (29) have been identified from different families based on their superior ligand–protein energies and relevant binding profiles with the key Mpro pocket residues. Thermodynamic behaviors of the identified compounds were investigated through 200 ns all-atom molecular dynamics simulation illustrating their significant stability and pocket accommodation. Furthermore, structural activity preferentiality was identified for the pederin-based marine compounds highlighting the importance of the terminal guanidine and cyclic hemiacetal linker, and the length of the sidechain. Our findings highlight the challenges of targeting SARS-CoV-2 Mpro as well as recommending further in vitro and in vivo studies regarding the examined marine products either alone or in combination paving the way for promising lead molecules.

Marine natural polyketides showed promising SARS-CoV-2 main protease inhibitory activities.

Anti-SARS-CoV-2 activities of tanshinone IIA, carnosic acid, rosmarinic acid, salvianolic acid, baicalein, and glycyrrhetinic acid between computational and in vitro insights

Six compounds namely, tanshinone IIA (1), carnosic acid (2), rosmarinic acid (3), salvianolic acid B (4), baicalein (5), and glycyrrhetinic acid (6) were screened for their anti-SARS-CoV-2 activities against both the spike (S) and main protease (Mpro) receptors using molecular docking studies. Molecular docking recommended the superior affinities of both salvianolic acid B (4) and glycyrrhetinic acid (6) as the common results from the previously published computational articles. On the other hand, their actual anti-SARS-CoV-2 activities were tested in vitro using plaque reduction assay to calculate their IC₅₀ values after measuring their CC₅₀ values using MTT assay on Vero E6 cells. Surprisingly, tanshinone IIA (1) was the most promising member with IC₅₀ equals 4.08 ng μl^-1. Also, both carnosic acid (2) and rosmarinic acid (3) showed promising IC₅₀ values of 15.37 and 25.47 ng μl^-1, respectively. However, salvianolic acid (4) showed a weak anti-SARS-CoV-2 activity with an IC₅₀ value equals 58.29 ng μl^-1. Furthermore, molecular dynamics simulations for 100 ns were performed for the most active compound from the computational point of view (salvianolic acid 4), besides, the most active one biologically (tanshinone IIA 1) on both the S and Mpro complexes of them (four different molecular dynamics processes) to confirm the docking results and give more insights regarding the stability of both compounds inside the SARS-CoV-2 mentioned receptors, respectively. Also, to understand the mechanism of action for the tested compounds towards SARS-CoV-2 inhibition it was necessary to examine the mode of action for the most two promising compounds, tanshinone IIA (1) and carnosic acid (2). Both compounds (1 and 2) showed very promising virucidal activity with a most prominent inhibitory effect on viral adsorption rather than its replication. This recommended the predicted activity of the two compounds against the S protein of SARS-CoV-2 rather than its Mpro protein. Our results could be very promising to rearrange the previously mentioned compounds based on their actual inhibitory activities towards SARS-CoV-2 and to search for the reasons behind the great differences between their in silico and in vitro results against SARS-CoV-2. Finally, we recommend further advanced preclinical and clinical studies especially for tanshinone IIA (1) to be rapidly applied in COVID-19 management either alone or in combination with carnosic acid (2), rosmarinic acid (3), and/or salvianolic acid (4).

Pharmacophore-linked pyrazolo[3,4-d]pyrimidines as EGFR-TK inhibitors: Synthesis, anticancer evaluation, pharmacokinetics, and in silico mechanistic studies

Targeting the epidermal growth factor receptors (EGFRs) with small inhibitor molecules has been validated as a potential therapeutic strategy in cancer therapy. Pyrazolo[3,4-d]pyrimidine is a versatile scaffold that has been exploited for developing potential anticancer agents. On the basis of fragment-based drug discovery, considering the essential pharmacophoric features of potent EGFR tyrosine kinase (TK) inhibitors, herein, we report the design and synthesis of new hybrid molecules of the pyrazolo[3,4-d]pyrimidine scaffold linked with diverse pharmacophoric fragments with reported anticancer potential. These fragments include hydrazone, indoline-2-one, phthalimide, thiourea, oxadiazole, pyrazole, and dihydropyrazole. The synthesized molecules were evaluated for their anticancer activity against the human breast cancer cell line, MCF-7. The obtained results revealed comparable antitumor activity with that of the reference drugs doxorubicin and toceranib. Docking studies were performed along with EGFR-TK and ADMET profiling studies. The results of the docking studies showed the ability of the designed compounds to interact with key residues of the EGFR-TK through a number of covalent and noncovalent interactions. The obtained activity of compound 25 (IC50  = 2.89 µM) suggested that it may serve as a lead for further optimization and drug development.