In silico identification of novel benzophenone-coumarin derivatives as SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibitors.

In this study, we propose our novel benzophenone-coumarin derivatives (BCDs) as potent inhibitors of the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 virus, one of the key targets that are involved in the viral genome replication. We aim to evaluate the in silico antiviral potential of BCDs against this protein target, which involves molecular docking simulations, druglikeliness and pharmacokinetic evaluations, PASS analysis, molecular dynamics simulations, and computing binding free energy. Out of all the BCDs screened through these parameters, BCD-8 was found to be the most efficient and potent inhibitor of SARS-CoV-2 RdRp. During molecular docking simulation, BCD-8 showed an extensive molecular interaction in comparison with that of the standard control used, remdesivir. The druglikeliness and pharmacokinetic analyses also proved the efficiency of BCD-8 as an effective drug without adverse effects. Further, pharmacological potential analysis through PASS depicted the antiviral property of BCD-8. With these findings, we performed molecular dynamics simulations, where BCD-8 edged out remdesivir with its exemplary stable interaction with SARS-CoV-2 RdRp. Furthermore, binding free energy of both BCD-8 and remdesivir was calculated, where BCD-8 showed a lower binding energy and standard deviations in comparison with that of remdesivir. Moreover, being a non-nucleoside analogue, BCD-8 can be used effectively against SARS-CoV-2, whereas nucleoside analogues like remdesivir may become non-functional or less functional due to exonuclease activity of nsp14 of the virus. Therefore, we propose BCD-8 as a SARS-CoV-2 RdRp inhibitor, showing higher predicted efficiency than remdesivir in all the in silico experiments conducted.Communicated by Ramaswamy H. Sarma.

Design, synthesis, docking, Hirshfeld surface analysis and DFT calculations of 2-methylxanthen-9-with the FtsZ protein from Staphylococcus aureus.

It is of interest to document the design, synthesis, docking, Hirshfeld surface analysis and DFT calculations of 2-methylxanthen-9-with the FtsZ protein (PDB ID: 3VOB) from Staphylococcus aureus for antimicrobial applications. We report the quantitative structure function data in this context.

Synthesis of coumarin analogs appended with quinoline and thiazole moiety and their apoptogenic role against murine ascitic carcinoma.

The synthesis and antiproliferative effect of a series of quinoline and thiazole containing coumarin analogs 12a-d and 13a-f respectively, on mice leukemic cells was performed. The chemical structures of newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and mass spectral analysis. The result indicates that, 7-methoxy-2-oxo-2H-chromene-3-carboxylic acid [4-(4-methoxy-phenyl)-thiazol-2-yl]-amide (13f) showed potent activity against EAC and DLA cells in MTT (15.3 µM), tryphan blue (15.6 µM) and LDH (14.2 µM) leak assay with 5-fluorouracil as a standard. Further, the anti-neoplastic effect of the compound 13f was verified against Ehrlich ascites tumour by BrdU incorporation, TUNEL, FACS and DNA fragmentation assays. Experimental data showed that compound 13f induces the apoptotic cell death by activating apoptotic factors such as caspase-8 &-3, CAD, Cleaved PARP, γ-H2AX and by degrading genomic DNA of cancer cells and thereby decreasing the ascitic tumour development in mice. Besides, compound 13f was also subjected for docking studies to approve the in vitro and in vivo studies. The data revealed that the compound 13f has very good interaction with caspase 3 protein by binding with amino acid Arg 207 through hydrogen bond.

A tumoural angiogenic gateway blocker, Benzophenone-1B represses the HIF-1α nuclear translocation and its target gene activation against neoplastic progression.

Hypoxia is an important module in all solid tumours to promote angiogenesis, invasion and metastasis. Stabilization and subsequent nuclear localization of HIF-1α subunits result in the activation of tumour promoting target genes such as VEGF, MMPs, Flt-1, Ang-1 etc. which plays a pivotal role in adaptation of tumour cells to hypoxia. Increased HIF-α and its nuclear translocation have been correlated with pronounced angiogenesis, aggressive tumour growth and poor patient prognosis leading to current interest in HIF-1α as an anticancer drug target. Benzophenone-1B ([4-(1H-benzimidazol-2-ylmethoxy)-3,5-dimethylphenyl]-(4-methoxyphenyl) methanone, or BP-1B) is a new antineoplastic agent with potential angiopreventive effects. Current investigation reports the cellular biochemical modulation underlying BP-1B cytotoxic/antiangiogenic effects. Experimental evidences postulate that BP-1B exhibits the tumour specific cytotoxic actions against various cancer types with prolonged action. Moreover BP-1B efficiently counteracts endothelial cell capillary formation in in-vitro, in-vivo non-tumour and tumour angiogenic systems. Molecular signaling studies reveal that BP-1B arrests nuclear translocation of HIF-1α devoid of p42/44 pathway under CoCl2 induced hypoxic conditions in various cancer cells thereby leading to abrogated HIF-1α dependent activation of VEGF-A, Flt-1, MMP-2, MMP -9 and Ang-1 angiogenic factors resulting in retarded cell migration and invasions. The in-vitro results were reproducible in the reliable in-vivo solid tumour model. Taken together, we conclude that BP-1B impairs angiogenesis by blocking nuclear localization of HIF-1α which can be translated into a potent HIF-1α inhibitor.

Synthesis of oxadiazole-morpholine derivatives and manifestation of the repressed CD31 Microvessel Density (MVD) as tumoral angiogenic parameters in Dalton's Lymphoma.

A series of oxadiazole derivatives possessing morpholine 6a-l were synthesized by nucleophilic substitution reaction of key intermediates [1,3,4]-oxadiazole-2-thiol derivatives 5a-l with 4-(2-chloroethyl) morpholine. Compounds 6a-l were evaluated for their in vitro and in vivo antitumor potential in Dalton's Lymphoma Ascites (DLA) tumor cells. Among 6a-l series, compound 6a with concentration ∼8.5µM have shown extensive cytotoxicity in vitro and 85% reduction in tumor volume in vivo, attributing an excellent anti-proliferative capability towards the cancer cells. Compound 6a has extensively inhibited the Microvessel Density (MVD) or tumoral neovasculature which was evident from the CD31 immuno staining and peritoneal H&E staining. The major reason for the antiproliferative activity of compound 6a was due to the repression of tumor vasculature.

SYNTHESIS AND BIOLOGICAL EFFICACY OF NOVEL PIPERAZINE ANALOGUES BEARING QUINOLINE AND PYRIDINE MOIETIES.

A series of novel piperazine analogues bearing quinolin-8-yloxy-butan--ones/pyridin-2-yloxy-ethanones were synthesized by a simple and convenient approach based on various substituted piperazine incorporating quinoline and pyridine moieties. The analogues were evaluated for in vitro antioxidant activity against 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and ferrous ion radical scavenging activities and anti-inflammatory activity by inhibition of Vipera russelli venom (PLA2) and gastric K+/H(+)-ATPase activities. Most of the title compounds exhibited promising activity. Best antioxidant and PLA2-inhibiting activities were found for piperazine analogues with phenyl and nitro phenyl groups, whereas methoxy group on phenyl piperazine indicated selectivity for the H+/K(+)-ATPase.

Synthesis, xanthine oxidase inhibition, and antioxidant screening of benzophenone tagged thiazolidinone analogs.

A series of novel 2-(diaryl methanone)-N-(4-oxo-2-phenyl-thiazolidin-3-yl)-acetamides were synthesized by various Schiff bases of (4-benzoyl-phenoxy)-aceto hydrazide with thioglycolic acid. The structures of the newly synthesized compounds were confirmed by IR, (1) H NMR, mass spectra, and C, H, N analysis. Further, all the synthesized compounds 9a-n were evaluated for xanthine oxidase (XO) inhibition and antioxidant properties. Among all the tested compounds, 9f, 9m, and 9n demonstrated potent XO inhibition of 52, 76, and 26%, respectively, compared to the standard drug allopurinol, which is evident from in vitro and in silico analysis. On the other hand, compounds 9c, 9d, and 9k exhibit potent antioxidant properties.

Synthesis, antioxidant, and xanthine oxidase inhibitory activities of 5-[4-[2-(5-ethyl-2-pyridinyl)ethoxy]phenyl]methyl]-2,4-thiazolidinedione derivatives.

Xanthine oxidase (XO) is a complex metalloflavoprotein, the overproduction of which usually leads to a pathological condition called gout. The XO inhibitors may prove to be promising antigout agents. The XO generates superoxide anions and H2O2 for the self-defense system of the organism. Abnormal production of this superoxide (reactive oxygen species) is responsible for a number of complications including inflammation, metabolic disorder, cellular aging, reperfusion damage, atherosclerosis, and carcinogenesis. In this paper, we report the synthesis of N-substituted analogs of thiazolidinedione derivatives as effective and new class of XO inhibitors and also as antioxidant agents. Among all the compounds in the series, compound 2i produced relatively better activity against human milk XO (72% inhibition), which was also supported by docking studies.

Synthesis, angiopreventive activity, and in vivo tumor inhibition of novel benzophenone-benzimidazole analogs.

AIM: The development of anticancer drugs with specific targets is of prime importance in modern biology. This study investigates the angiopreventive and in vivo tumor inhibition activities of novel synthetic benzophenone-benzimidazole analogs. MAIN METHODS: The multistep synthesis of novel benzophenone-benzimidazole analogs (8a-n) allowing substitution with methoxy, methyl and halogen groups at different positions on the identical chemical backbone and the variations in the number of substituents were synthesized and characterized. The newly synthesized compounds were further evaluated for cytotoxic and antiproliferative effects against Ehrlich ascites carcinoma (EAC) cells. The potent lead compounds were further assessed for antiangiogenic effects in a CAM model and a tumor-induced vasculature in vivo model. The effect of angioprevention on tumor growth was verified in a mouse model. KEY FINDINGS: The cytotoxicity studies revealed that compounds 8f and 8n are strongly cytotoxic. Analyzing the structure-activity relationship, we found that an increase in the number of methyl groups in addition to methoxy substitution at the para position of the benzoyl ring in compound 8n resulted in higher potency compared to 8f. Furthermore, neovessel formation in in vivo systems, such as the chorioallantoic membrane (CAM) and tumor-induced mice peritoneum models, was significantly suppressed and reflected the tumor inhibition observed in mice. SIGNIFICANCE: These results suggest the potential clinical application of compound 8n as an antiangiogenic drug for cancer therapy.

Ethyl 2-[4-(2-chloro-benzo-yl)-2,6-di-methyl-phen-oxy]ethano-ate.

The asymmetric unit of the title compound, C(19)H(19)ClO(4), contains two independent mol-ecules. The dihedral angles between the benzene rings are 63.41 (8) and 61.41 (9)°. Adjacent mol-ecules of different types are inter-connected in pairs through π-π inter-actions between their central benzene rings [centroid-centroid separation = 3.801 (2) Å, inter-planar spacing = 3.605 (2) Å, centroid shift = 1.204 (2) Å]. Finally, C-H⋯O hydrogen bonds link these dimers into bilayers parallel to (100).

2-Methylxanthen-9-one.

In the title compound, C(14)H(10)O(2), the tricycle is not planar, being bent with a dihedral angle of 4.7 (1)° between the two benzene rings. In the crystal, π-π inter-actions between the six-membered rings of neighbouring mol-ecules [centroid-centroid distances = 3.580 (3) and 3.605 (3) Å] form stacks propagating along [101].