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A series of tetrahydrobenzo[b]thiophene derivatives was designed and synthesized as dual topoisomerase (Topo) I/II inhibitors implicating potential DNA intercalation. Ethyl-2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene-4-carboxylate (1) was prepared by modification of the Gewald reaction procedure using a Fe 2 O 3 nanocatalyst and then it was used as a building block for the synthesis of tetrahydrobenzo[b]thiophene candidates (2-14). Interestingly, compound 14 showed the best cytotoxic potential against hepatocellular, colorectal, and breast cancer cell lines (IC 50  = 7.79, 8.10, and 3.53 µM), respectively, surpassing doxorubicin at breast cancer (IC 50  = 4.17 µM). Meanwhile, the Topo I and II inhibition assay displayed that compound 3 could exhibit the best inhibitory potential among the investigated candidates (IC 50  = 25.26 and 10.01 nM), respectively, in comparison to camptothecin (IC 50  = 28.34 nM) and doxorubicin (IC 50  = 11.01 nM), as reference standards. In addition, the DNA intercalation assay showed that compound 14 could display the best binding affinity with an IC 50 value of 77.82 µM in comparison to doxorubicin (IC 50  = 58.03 µM). Furthermore, cell cycle and apoptosis analyses described that compound 3 prompts the G1 phase arrest in michigan cancer foundation-7 cancer cells and increases the apoptosis ratio by 29.31% with respect to untreated cells (2.25%). Additionally, the conducted molecular docking assured the promising binding of the investigated members toward Topo I and II with potential DNA intercalation. Accordingly, the synthesized compounds could be treated as promising anticancer candidates for future optimization., (© 2024 Deutsche Pharmazeutische Gesellschaft.)

The zinc-naproxen complex as a nano-drug (NanoD) was synthesized successfully via effective ultrasound-assisted processes. The chemicophysical properties of the NanoD were determined using FT-IR, XRD, SEM, DLS, and EDX mapping analyses. The results confirmed the formation of the 55 nm NanoD laminates. The interaction of the obtained NanoD with calf thymus deoxyribonucleic acid (CT-DNA) was studied as well. Structural and topography changes of DNA in interaction with the NanoD were investigated by atomic force microscopy (AFM). The results of electronic absorption spectroscopy, the DNA-viscosity studies, and competition fluorescence spectroscopy showed that CT-DNA binds to the NanoD through the intercalative binding mode. The data of AFM analysis indicated swollen CT-DNA upon interaction with the NanoD. The in vitro investigation of cytotoxicity of the NanoD on HT-29, Hep G2, and B16-F10 cancer cells as well as normal HFF-1 cells. The obtained results demonstrated high cytotoxicity activity of the NanoD than that of cisplatin in the HT-29 cell line, especially at lower concentrations. On the B16-F10 cell line at lower concentrations (up to 8 μg mL -1 ), it is comparable to cisplatin and on the Hep G2 cell line and normal HFF-1 cell line at all concentrations, cytotoxicity of cisplatin is more than NanoD., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Major efforts have been devoted to the development of constructs that enable sequence-specific recognition of double-stranded (ds) DNA, fueled by the promise for enabling tools for applications in molecular biology, diagnostics, and medicine. Towards this end, we have previously introduced Invader probes, i.e. , short DNA duplexes with +1 interstrand zipper arrangements of intercalator-functionalized nucleotides. The individual strands of these labile probes display high affinity towards complementary DNA (cDNA), which drives sequence-unrestricted dsDNA-recognition. However, recognition of long targets is challenging due to the high stability of the corresponding probes. To address this, we recently introduced toehold Invader probes, i.e. , Invader probes with 5'-single-stranded overhangs. The toehold architecture allows for shorter double-stranded segments to be used, which facilitates probe dissociation and dsDNA-recognition. As an extension thereof, we here report the biophysical and dsDNA-targeting properties of nicked Invader probes. In this probe architecture, the single-stranded overhangs of toehold Invader probes are hybridized to short intercalator-modified auxiliary strands, leading to formation of additional labile segments. The extra binding potential from the auxiliary strands imparts nicked Invader probes with greater dsDNA-affinity than the corresponding toehold or blunt-ended probes. Recognition of chromosomal DNA targets, refractory to recognition by conventional Invader probes, is demonstrated for nicked Invader probes in the context of non-denaturing FISH experiments, which highlights their utility as dsDNA-targeting tools.

Natural berberine-derived azolyl ethanols as new structural antibacterial agents were designed and synthesized for fighting with dreadful bacterial resistance. Partial target molecules exhibited potent activity against the tested strains, particularly, nitroimidazole derivative 4d and benzothiazole-2-thoil compound 18b , with low cytotoxicity both exerted strong antibacterial activities against multidrug-resistant Escherichia coli at low concentrations as 0.007 and 0.006 mM, respectively. Meanwhile, the active compounds 4d and 18b possessed the ability to rapidly kill bacteria and observably eradicate the E. coli biofilm by reducing exopolysaccharide content to prevent bacterial adhesion, which was conducive to alleviating the development of E. coli resistance. Preliminary mechanistic explorations suggested that the excellent antibacterial potential of molecules 4d and 18b might be attributed to their ability to disintegrate membrane, accelerate ROS accumulation, reduce bacterial metabolism, and intercalate into DNA groove. These results provided powerful information for the further exploitation of natural berberine derivatives against bacterial pathogens.

A series of 6-amidinobenzothiazoles, linked via phenoxymethylene or directly to the 1,2,3-triazole ring with a p -substituted phenyl or benzyl moiety, were synthesised and evaluated in vitro against four human tumour cell lines and the protozoan parasite Trypanosoma brucei . The influence of the type of amidino substituent and phenoxymethylene linker on antiproliferative and antitrypanosomal activities was observed, showing that the imidazoline moiety had a major impact on both activities. Benzothiazole imidazoline 14a , which was directly connected to N -1-phenyl-1,2,3-triazole, had the most potent growth-inhibitory effect (IC 50 = 0.25 µM) on colorectal adenocarcinoma (SW620), while benzothiazole imidazoline 11b , containing a phenoxymethylene linker, exhibited the best antitrypanosomal potency (IC 90 = 0.12 µM). DNA binding assays showed a non-covalent interaction of 6-amidinobenzothiazole ligands, indicating both minor groove binding and intercalation modes of DNA interaction. Our findings encourage further development of novel structurally related 6-amidino-2-arylbenzothiazoles to obtain more selective anticancer and anti-HAT agents.

The novel 1,2,3-triazolyl-appended N - and O -heterocycles containing amidine 4 - 11 and amidoxime 12 - 22 moiety were prepared and evaluated for their antiproliferative activities in vitro. Among the series of amidine-substituted heterocycles, aromatic diamidine 5 and coumarine amidine 11 had the most potent growth-inhibitory effect on cervical carcinoma (HeLa), hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (SW620), with IC 50 values in the nM range. Although compound 5 was toxic to non-tumor HFF cells, compound 11 showed certain selectivity. From the amidoxime series, quinoline amidoximes 18 and 20 showed antiproliferative effects on lung adenocarcinoma (A549), HeLa and SW620 cells emphasizing compound 20 that exhibited no cytostatic effect on normal HFF fibroblasts. Results of CD titrations and thermal melting experiments indicated that compounds 5 and 10 most likely bind inside the minor groove of AT-DNA and intercalate into AU-RNA. Compounds 6 , 9 and 11 bind to AT-DNA with mixed binding mode, most probably minor groove binding accompanied with aggregate binding along the DNA backbone.

Three novel 2-aminopyrazine Schiff bases derived from salicylaldehyde derivatives and their uranyl complexes were synthesized and characterized by elemental analysis, UV-vis, FTIR, molar conductance, and thermal gravimetric analysis (TGA). The proposed structures were optimized using density functional theory (DFT/B3LYP) and 6-311G ∗(d,p) basis sets. All uranyl complexes are soluble in DMSO and have low molar conductance, which indicates that all the complexes are nonelectrolytes. The DNA binding of those Schiff bases and their uranyl complexes was studied using UV-vis spectroscopy, and screening of their ability to bind to calf thymus DNA (CT-DNA) showed that the complexes interact with CT-DNA through an intercalation mode, for which the K b values ranged from 1 × 10 6 to 3.33 × 10 5 M -1 . The anticancer activities of the Schiff base ligands and their uranyl complexes against two ovarian (Ovcar-3) and melanoma cell lines (M14) were investigated, and the results indicated that uranyl complexes exhibit better results than the Schiff base ligands. Molecular docking identified the distance, energy account, type, and position of links contributing to the interactions between these complexes and two different cancer proteins (3W2S and 2OPZ).

Several complexes of general formula [Ru(halide)(η 6 -p-cymene)(α-diimine)] + , in the form of nitrate, triflate and hexafluorophosphate salts, including a newly synthesized iodide compound, were investigated as potential anticancer drugs and bactericides. NMR and UV-Vis studies evidenced remarkable stability of the complexes in water and cell culture medium. In general, the complexes displayed strong cytotoxicity against A2780 and A549 cancer cell lines with IC 50 values in the low micromolar range, and one complex (RUCYN) emerged as the most promising one, with a significant selectivity compared to the non-cancerous HEK293 cell line. A variable affinity of the complexes for BSA and DNA binding was ascertained by spectrophotometry/fluorimetry, circular dichroism, electrophoresis and viscometry. The performance of RUCYN appears associated to enhanced cell internalization, favored by two cyclohexyl substituents, rather than to specific interaction with the evaluated biomolecules. The chloride/iodide replacement, in one case, led to increased cellular uptake and cytotoxicity at the expense of selectivity, and tuned DNA binding towards intercalation. Complexes with iodide or a valproate bioactive fragment exhibited the best antimicrobial profiles., (Copyright © 2021 Elsevier B.V. All rights reserved.)

New analogs of the commercial asymmetric monomethine cyanine dyes thiazole orange (TO) and thiazole orange homodimer (TOTO) with hydroxypropyl functionality were synthesized and their properties in the presence of different nucleic acids were studied. The novel compounds showed strong, micromolar and submicromolar affinities to all examined DNA ds-polynucleotides and poly rA-poly rU. The compounds studied showed selectivity towards GC-DNA base pairs over AT-DNA, which included both binding affinity and a strong fluorescence response. CD titrations showed aggregation along the polynucleotide with well-defined supramolecular chirality. The single dipyridinium-bridged dimer showed intercalation at low dye-DNA/RNA ratios. All new cyanine dyes showed potent micromolar antiproliferative activity against cancer cell lines, making them promising theranostic agents.

Nitrogen mustards are a widely used class of antitumor agents that exert their cytotoxic effects through the formation of DNA interstrand cross-links (ICLs). Despite being among the first antitumor agents used, the biological responses to NM ICLs remain only partially understood. We have previously reported the generation of NM ICL mimics by incorporation of ICL precursors into DNA using solid-phase synthesis at defined positions, followed by a double reductive amination reaction. However, the structure of these mimics deviated from the native NM ICLs. Using further development of our approach, we report a new class of NM ICL mimics that only differ from their native counterpart by substitution of dG with 7-deaza-dG at the ICL. Importantly, this approach allows for the synthesis of diverse NM ICLs, illustrated here with a mimic of the adduct formed by chlorambucil. We used the newly generated ICLs in reactions with replicative and translesion synthesis DNA polymerase to demonstrate their stability and utility for functional studies. These new NM ICLs will allow for the further characterization of the biological responses to this important class of antitumor agents.

A new series of triazolophthalazine derivatives was designed and synthesized as topoisomerase II (Topo II) inhibitors and DNA intercalators. The synthesized derivatives were evaluated in vitro for their cytotoxic activities against three human cancer cell lines: HepG2, MCF-7, and HCT-116 cells. Compound IX b was the most potent counterpart with IC 50 values of 5.39 ± 0.4, 3.81 ± 0.2, and 4.38 ± 0.3 µM, as it was about 1.47, 1.77, and 1.19 times more active than doxorubicin (IC 50  = 7.94 ± 0.6, 6.75 ± 0.4, and 5.23 ± 0.3 µM) against HepG2, MCF-7, and HCT-116 cells, respectively. Additionally, the binding affinity of the synthesized compounds toward the DNA molecule was assessed using the DNA/methyl green assay. Compound IX b showed an excellent DNA binding affinity with an IC 50 value of 27.16 ± 1.2 µM, which was better than that of the reference drug doxorubicin (IC 50  = 31.02 ± 1.80 µM). Moreover, compound IX b was the most potent member among the tested compounds when investigated for their Topo II inhibitory activity. Furthermore, compound IX b induced apoptosis in HepG2 cells and arrested the cell cycle at the G2/M phase. Additionally, compound IX b showed Topo II poisoning effects at 2.5 μM and Topo II catalytic inhibitory effects at 5 and 10 μM. Finally, molecular docking studies were carried out against the DNA-Topo II complex and DNA, to investigate the binding patterns of the designed compounds., (© 2021 Deutsche Pharmazeutische Gesellschaft.)

The interaction of copper(II) with the non-steroidal anti-inflammatory drug sodium meclofenamate (Na-mclf) in the presence or absence of the nitrogen-donor co-ligands pyridine (py) or 2,2'-bipyridylamine (bipyam), yielded the novel Cu(II) complexes [Cu 2 (mclf-O,O') 4 (MeOH) 2 ]·2MeOH (1·2MeOH), [Cu(mclf-O) 2 (py) 3 ]·H 2 O·0.5MeOH (2·H 2 O·0.5MeOH) and [Cu(mclf-O,O') 2 (bipyam)] (3). The characterization of the complexes was achieved by various techniques, including single-crystal X-ray crystallography. In order to study the binding mode and strength of the complexes to calf-thymus (CT) DNA, various techniques were employed which suggested intercalation between the DNA-bases as the most possible interaction mode. Competitive studies with ethidium bromide (EB) revealed the ability of the complexes to displace the EB from the EB-DNA adduct, verifying the intercalative binding mode. The affinity of the complexes to bovine and human serum albumin proteins (SAs) was investigated by fluorescence emission spectroscopy and the corresponding binding constants bear relatively high values, showing that the complexes bind tightly and possibly reversibly to SAs. The antioxidant activity of the complexes against 1,1-diphenyl-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and the ability to reduce H 2 O 2 proved to be of significant magnitude. The in vitro inhibitory activity against the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was evaluated, in order to assess the anticholinergic ability of the complexes, which appeared promising., (Copyright © 2021 Elsevier Inc. All rights reserved.)

We synthesized a series of novel 3-carboranyl-1,8-naphthalimide derivatives, mitonafide and pinafide analogs, using click chemistry, reductive amination and amidation reactions and investigated their in vitro effects on cytotoxicity, cell death, cell cycle, and the production of reactive oxygen species in a HepG2 cancer cell line. The analyses showed that modified naphthalic anhydrides and naphthalimides bearing ortho - or meta -carboranes exhibited diversified activity. Naphthalimides were more cytotoxic than naphthalic anhydrides, with the highest IC 50 value determined for compound 9 (3.10 µM). These compounds were capable of inducing cell cycle arrest at G0/G1 or G2M phase and promoting apoptosis, autophagy or ferroptosis. The most promising conjugate 35 caused strong apoptosis and induced ROS production, which was proven by the increased level of 2'-deoxy-8-oxoguanosine in DNA. The tested conjugates were found to be weak topoisomerase II inhibitors and classical DNA intercalators. Compounds 33 , 34 , and 36 fluorescently stained lysosomes in HepG2 cells. Additionally, we performed a similarity-based assessment of the property profile of the conjugates using the principal component analysis. The creation of an inhibitory profile and descriptor-based plane allowed forming a structure-activity landscape. Finally, a ligand-based comparative molecular field analysis was carried out to specify the (un)favorable structural modifications (pharmacophoric pattern) that are potentially important for the quantitative structure-activity relationship modeling of the carborane-naphthalimide conjugates.

Metal complexes have numerous applications in the current era, particularly in the field of pharmaceutical chemistry and catalysis. A novel synthetic approach for the same is always a beneficial addition to the literature. Henceforth, for the first time, we report the formation of three new Pd(II) complexes through the Michael addition pathway. Three chromone-based thiosemicarbazone ligands (SVSL1-SVSL3) and Pd(II) complexes ( 1 - 3 ) were synthesized and characterized by analytical and spectroscopic tools. The Michael addition pathway for the formation of complexes was confirmed by spectroscopic studies. Distorted square planar structure of complex 2 was confirmed by single-crystal X-ray diffraction. Complexes 1 - 3 were subjected to DNA- and BSA-binding studies. The complex with cyclohexyl substituent on the terminal N of thiosemicarbazone ( 3 ) showed the highest binding efficacy toward these biomolecules, which was further understood through molecular docking studies. The anticancer potential of these complexes was studied preliminarily by using MTT assay in cancer and normal cell lines along with the benchmark drugs (cisplatin, carboplatin, and gemcitabine). It was found that complex 3 was highly toxic toward MDA-MB-231 and AsPC-1 cancer cells with IC 50 values of 0.5 and 0.9 μM, respectively, and was more efficient than the standard drugs. The programmed cell death mechanism of the complexes in MDA-MB-231 cancer cells was confirmed. Furthermore, the complexes induced apoptosis via ROS-mediated mitochondrial signaling pathway. Conveniently, all the complexes showed less toxicity (≥50 μM) against MCF-10a normal cell line. Molecular docking studies were performed with VEGFR2, EGFR, and SARS-CoV-2 main protease to illustrate the binding efficiency of the complexes with these receptors. To our surprise, binding potential of the complexes with SARS-CoV-2 main protease was higher than that with chloroquine and hydroxychloroquine.

In view of their DNA intercalation activities as anticancer agents, novel twenty four [1,2,4]triazolo[4,3-a]quinoxaline derivatives have been designed, synthesized and evaluated against HepG2, HCT-116 and MCF-7 as DNA intercalators and Top II enzyme inhibitors. The data obtained from molecular modeling studies revealed that, our small aromatic molecules were concluded to act through two ways firstly, through non-covalent interaction with the directly bound proteins to DNA hence inhibit topoisomerase-II enzyme. The second is through non-covalently binding to double helical structures of DNA either by intercalating binder as in compounds 10 a and 11 d or by minor groove binding as in compounds 8 e and 8 c . Cytotoxic activity indicated that MCF-7 and HepG2 were the most sensitive cell lines to the influence of the new derivatives respectively. In particular, compounds 10 a , 11 d and 8 e were found to be the most potent derivatives overall the tested compounds against the three HepG2, HCT116 and MCF-7 cancer cell lines with IC 50 = (4.55 ± 0.3, 6.18 ± 0.8 and 3.93 ± 0.6 µM), (5.61 ± 0.5, 6.49 ± 0.5and 3.71 ± 0.3 µM) and (4.66 ± 0.3, 8.08 ± 0.8 and 5.11 ± 0.7 µM) respectively. The three derivatives exhibited higher activities than doxorubicin, (IC 50  = 7.94 ± 0.6, 8.07 ± 0.8 and 6.75 ± 0.4 µM respectively), against HepG2 and MCF-7 but 8 e exhibited nearly the same activity against HCT116 cancer cell lines respectively. The most active derivatives 8 a-e , 10 a , b , 11 b-e , 13 a and 14 b,c were evaluated for their DNA binding activities. The tested compounds displayed very good to moderate DNA-binding affinities. Compounds 10 a 11 d , 8 e , 8 c , 8 a and 8 b displayed the highest binding affinities. These compounds potently intercalate DNA at decreased IC 50 values of 25.27 ± 1.2, 27.47 ± 2.1, 27.54 ± 3.2, 27.78 ± 1.3, 29.15 ± 1.8 and 30.23 ± 3.7 µM respectively, which were less than that of doxorubicin (31.27 ± 1.8). Furthermore, the most active cytotoxic compounds 8 a , 8 b , 8 c , 8 e , 10 a and 11 d were selected to evaluate their inhibitory activities against Topo II enzyme. All the tested compounds could interfere with the Topo II activity. They exhibited very good inhibitory activities with IC 50 values ranging from 0.379 ± 0.07 to 0.813 ± 0.14 µM that were lower than that of doxorubicin (IC 50  = 0.94 ± 0.4 µM). For a great extent, the reported results were in agreement with that of in vitro cytotoxicity activity, DNA binding and molecular modeling studies., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Herein we report the design and synthesis of a new series of phthalazine derivatives as Topo II inhibitors and DNA intercalators. The synthesized compounds were in vitro evaluated for their cytotoxic activities against HepG-2, MCF-7 and HCT-116 cell lines. Additionally, Topo II inhibitory activity and DNA intercalating affinity were investigated for the most active compounds as a potential mechanism for the anticancer activity. Compounds 15h, 23c, 32a, 32b, and 33 exhibited the highest activities against Topo II with IC 50 ranging from 5.44 to 8.90 µM, while compounds 27 and 32a were found to be the most potent DNA binders at IC 50 values of 36.02 and 48.30 µM, respectively. Moreover, compound 32a induced apoptosis in HepG-2 cells and arrested the cell cycle at the G2/M phase. Besides, compound 32a showed Topo II poisoning effect at concentrations of 2.5 and 5 μM, and Topo II catalytic inhibitory effect at a concentration of10 μM. In addition, compound 32b showed in vivo a significant tumor growth inhibition effect. Furthermore, molecular docking studies were carried out against DNA-Topo II complex and DNA to investigate the binding patterns of the designed compounds., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A series of CdCl 2 complexes (1a-1f and 2a-2c) with 4'-(substituted-phenyl)-2,2':6',2″-terpyridine compounds bearing hydrogen (L 1a ), p-methyl (L 1b ), p-phenyl (L 1c ), p-tolyl (L 1d ), p-carboxyl (L 1e ), p-fluoro (L 1f ), p-hydroxyl (L 2a ), m-hydroxyl (L 2b ) or o-hydroxyl (L 2c ), were prepared and characterized by 1 H NMR, IR, elemental analysis and single crystal X-ray diffraction. All the compounds display interesting photoluminescent properties and different maximal emission peaks due to the difference of the substituent groups. The in vitro antiproliferative activities against four human carcinoma cell lines, A549, Bel-7402, Eca-109 and MCF-7, were investigated and cell viability studies indicate that the compounds have excellent results with the lowest IC 50 values of 0.372 (1c), 1.003 (1c), 1.161 (1b) and 0.231 (1c) μM, respectively. The DNA interaction was studied by fluorescence titration, circular dichroism spectroscopy and molecular modeling methods. Spectrophotometric results reveal that the compounds have strong affinity binding with DNA as intercalators and molecular docking studies indicate that the binding is contributed by the π…π stacking and hydrogen bonds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Inc.)

Herein we report on the synthesis and molecular structures of six silver(I) mixed-ligand complexes containing a heterocyclic thioamide [4-phenyl-imidazole-2-thione (phimtH) or 2,2,5,5-tetramethyl-imidazolidine-4-thione (tmimdtH)] and a tertiary arylphosphane [triphenylphosphine (PPh 3 ), tri-o-tolylphosphane (totp)] or diphosphane [(1,2-bis(diphenylphosphano)ethane (dppe), bis(2-diphenylphosphano-phenyl)ether (DPEphos) or 4,5-bis(diphenylphosphano)-9,9-dimethylxanthene) (xantphos)]. The interaction of the compounds with calf-thymus DNA (CT DNA), as monitored directly via UV-vis spectroscopy and DNA-viscosity measurements and indirectly via its competition with ethidium bromide for DNA-intercalation sites, is suggested to take place via an intercalative mode. The new complexes show selective significant in vitro antibacterial activity against four bacterial strains. The antiproliferative effects and cytostatic efficacies of the complexes against four human cancer cell lines were evaluated. The best cytostatic and cytotoxic activity was appeared for the complexes bearing the phimtH moiety. In order to explain the described in vitro activity of the complexes, and to approach a possible mechanism of action, molecular docking studies were adopted on the crystal structure of CT DNA, DNA-gyrase, human estrogen receptor alpha and a cell-cycle specific target protein, human cyclin-dependent kinase 6., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Reactions of 2,6-bis(benzimidazol-2-yl)pyridine (L 1 ), 2,6-bis(benzoxazol-2-yl)pyridine (L 2 ), and 2,6-bis(benzothiazol-2-yl)pyridine (L 3 ) with [Pd(NCMe) 2 Cl 2 ] in the presence of NaBF 4 afforded the corresponding Pd(II) complexes, [Pd(L 1 )Cl]BF 4 , PdL 1 ; [Pd(L 2 )Cl]BF 4 , PdL 2 ; [Pd(L 3 )Cl]BF 4 , PdL 3 ; respectively, while reaction of bis[(1H-benzimidazol-2-yl)methyl]amine (L 4 ) with [Pd(NCMe) 2 Cl 2 ] afforded complex [Pd(L 4 )Cl]Cl, PdL 4 . Characterisation of the complexes was accomplished using NMR, IR, MS, elemental analyses and single crystal X-ray crystallography. Ligand substitution kinetics of these complexes by biological nucleophiles thiourea (Tu), L-methionine (L-Met) and guanosine 5'-diphosphate disodium salt (5-GMP) were examined under pseudo-first order conditions. The reactivity of the complexes decreased in the order: PdL 1  > PdL 2  > PdL 3  > PdL 4 , ascribed to electronic effects. Density functional theory (DFT) supported this trend. Studies of interaction of the Pd(II) complexes with calf thymus DNA (CT-DNA) revealed strong binding affinities via intercalative binding mode. Molecular docking studies established associative non-covalent interactions between the Pd complexes and DNA. The in vitro cytotoxic activities of PdL 1 -PdL 4 were assessed in cancer cell lines HeLa and MRC5-SV2 and a normal cell line MRC-5, using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. PdL 1 exhibited cytotoxic potency and selectivity against HeLa cell that was comparable to cisplatin's. Complex PdL 1 , unlike cisplatin, did not significantly induce caspase-dependent apoptosis., Competing Interests: Declaration of competing interest The authors declare no conflicts of interests with any third party., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The interaction of Cu(NO 3 ) 2 ·3H 2 O with the sulfonyl o-pyridine carboxamidoxime N'-(4-nitrophenylsulfonyloxy)picolinimidamide (L) resulted in the mononuclear complex [Cu(L 1 ) 2 ](L 2 ) 2 (1), where L 1  = pyridine-2-carboxamidine ligand and (L 2 ) - = 4-nitrobenzenesulfonate anion derived from the homolytic cleavage of the NO bond of L. The complex was characterized by diverse techniques including single-crystal X-ray crystallography. From the antimicrobial tests performed, complex 1 seems to be active against gram-negative bacterial strains. The complex binds tightly and reversibly to serum albumins and tightly to calf-thymus DNA via an intercalative mode and also via electrostatic interactions (as expected due to its cationic nature). Additionally, it interacts with (pBluescriptSK(+)) plasmid DNA in a concentration-dependent manner. The results from the present in silico molecular modeling simulations provide useful complementary insights for the elucidation of the mechanism of action of the studied complex at a molecular level. Molecular modeling calculations provide a molecular basis for the understanding of both the impairment of DNA by its binding with the studied complex and the ability of this compound to act as an antibacterial agent, most probably by its activity against DNA-gyrase, as well as for transportation through serum albumins and possible interaction with other protein targets involved in various diseases., Competing Interests: Declaration of competing interest There are no conflicts to declare., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Terpyridine complexes are known for their broad biological activities, of which their anticancer potency is the most extensively studied. Strikingly, free ligand activity has rarely been described in the literature. In this study, a lipophilic derivative of terpyridine 4'-(1-decyl-2,3-triazol-4-yl)phenyl-2,2':6',2″-terpyridine (L) and its complexes were investigated to determine their mechanism of anticancer activity. Our results show that a free ligand expresses the same level of activity on a panel of cancer cells with a low toxicity towards normal fibroblasts as complexes with Cd, Zn or Cu. Breast cancer (MCF-7 cell line) was the most vulnerable for the tested compounds with the IC 50 values in the nanomolar range (IC 50  = 40 nM for L.) The addition of Cu(II) ions increased its activity even further, thus suggesting that ligand exchange and ROS production are the main components of its activity. A cell cycle analysis indicated its inhibition at the G0/G1 phase and the subsequent apoptosis as the cell death mode. A detailed analysis of the protein level that was involved in the aforementioned processes confirmed previous results. Furthermore, the reactive oxygen species generation and DNA intercalation confirmed its cleaving activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Two novel ruthenium(II) polypyridyl complexes, namely, [Ru(dmp) 2 (CAPIP)](ClO 4 ) 2 (Ru(II)-1) and [Ru(dmp) 2 (CFPIP)](ClO 4 ) 2 (Ru(II)-2), which respectively contain (E)-2-(2-(furan-2-yl)vinyl)-1H-imidazo[4,5-f][1,10]phen-anthroline (CAPIP) and (E)-2-(4-fluorostyryl)-1H-imidazo[4,5-f][1,10]phenanthroline. (CFPIP), were first designed and characterized (dmp = 2,9-dimethyl-1,10-phenanthroline). DNA binding experiments indicated that Ru(II) complexes interact with CT DNA through intercalative mode. In addition, the complexes Ru(II)-1 and Ru(II)-2, showed remarkable cell cytotoxicity, giving the respective IC 50 values of 4.1 ± 1.4 μM and 6.1 ± 1.4 μM on the A549 cancer cells. These values indicated higher activity than CAPIP, CFPIP, cisplatin (8.2 ± 1.4 μM) and other corresponding Ru(II) polypyridyl complexes. Furthermore, the Ru(II) complexes could arrive the cytoplasm through the cell membrane and accumulate in the mitochondria. Significantly, complexes Ru(II)-1 and Ru(II)-2 induced A549 cells apoptosis was mediated by increase of ROS levels and dysfunction of mitochondria, and resulted in cell cycle arrest and increased anti-migration activity on A549 cells. Overall, these results indicated that complexes Ru(II)-1 and Ru(II)-2 could be suitable candidates for further investigation as a chemotherapeutic agent in the treatment of tumors., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this work, three aroylhydrazone ligands ((E)-2-hydroxy-N'-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL1; (E)-3-hydroxy-N'-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL2; and (E)-4-hydroxy-N'-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL3) and their complexes with nickel (Ni(L1) 2 , NiL1; Ni(L2) 2 ∙2DMF, NiL2; Ni(L3) 2 ∙2DMF, NiL3) were prepared. The single crystal X-ray structures analysis of three compounds showed that they were neutral. The ligand adopts tridentate chelating mode. The nickel ion is six-coordinate with two O atoms and four N atoms from two ligands, and forms an octahedral arrangement. The investigation of DNA binding ability by ultraviolet and fluorescence titrations showed that NiL2 and NiL3 exhibit moderate binding affinity toward calf Thymus DNA. Spectroscopy, molecular docking, and molecular dynamics simulation indicated that NiL2 and NiL3 bind at the minor groove of DNA through intercalation., Competing Interests: Declaration of competing interest There are no conflicts to declare., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Acridine is a well-known DNA intercalator and thereby gets easily inserted within DNA. As uncontrolled rapid cell division is one of the primary characteristics of the tumors, it is expected that acridine or its suitable derivatives will have preferential accumulation in the tumorous lesions. Therefore, an attempt was made to radiolabel an acridine derivative with 68Ga and study the potential of the 68Ga-acridine complex as a PET agent for tumor imaging., Methods: 9-aminoacridine was coupled with p-NCS-benzyl-DOTA to render it suitable for labeling with 68Ga. The purified acridine-DOTA conjugate was radiolabeled with 68Ga, eluted from a 68Ge/68Ga radionuclide generator. Various radiolabeling parameters were optimized and the stability of the radiolabeled preparation was studied. The biological behavior of the 68Ga-acridine complex was studied both in vitro and in vivo using Raji cell line and fibrosarcoma tumor bearing Swiss mice, respectively., Results: 68Ga-acridine complex was obtained with ~100% radiochemical purity under the optimized reaction conditions involving incubation of 2mg/mL of ligand at 100°C for 30 minutes. The complex maintained a radiochemical purity of >95% in normal saline and >65% in human blood serum at 3h post-incubation. In vitro cellular study showed (3.2±0.1)% uptake of the radiotracer in the Raji cells. Biodistribution study revealed significant tumor accumulation [(11.41±0.41)% injected activity in per gram] of the radiotracer within 1h postadministration along with uptake in other non-target organs such as, blood, liver, GIT kidney etc. Conclusion: The present study indicates the potential of 68Ga-acridine as a PET agent for imaging of tumorous lesions. However, further detailed evaluation of the agent is warranted to explore its actual potential., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Showing anti-proliferation activity against MCF7 cells better than cisplatin, a platinum(ii) complex, [PtL(DMSO)Cl], was found to potently and selectively inhibit protein tyrosine phosphatase 1B (PTP1B), a putative target for anticancer agents, suggesting a new possible anticancer strategy based on platinum drugs.

In the present paper, we synthesized and characterized four N-donor polypyridyl copper(II) complexes (C1-C4); [Cu(mono-CN-PIP) 2 ] 2+ (C1), [Cu(tri-OMe-PIP) 2 ] 2+ (C2), [Cu(di-CF 3 -PIP) 2 ] 2+ (C3) and [Cu(DPPZ) 2 ] 2+ (C4). The (Calf-Thymus) CT-DNA binding studies depicted that the complexes could interact with DNA via intercalative mode. All the complexes, particularly C3 and C4 attenuated the proliferation as well as migration of various cancer cells, indicating their anti-cancer and anti-metastatic activity. Additionally, chick embryo angiogenesis (CEA) assay exhibited the inhibition of vascular sprouting in presence of C3 and C4, suggesting their potential in inhibiting the blood vessel growth. Mechanistic studies revealed that the complexes induced the excessive production of cellular reactive oxygen species (ROS) leading to apoptosis through up regulation of p53 and downregulation of Bcl-xL, which might be the plausible mechanisms underlying their anti-cancer properties. To understand the feasibility of practical application of anti-cancer copper complexes C3 and C4, in vivo sub-chronic toxicity study (4 weeks) was performed in C57BL6 mice and the results exhibited almost non-toxic effects induced by these complexes in terms of haematology and serum biochemical analyses, suggesting their biocompatible nature. The current study provides the basis for future advancement of other novel biocompatible metal complexes that could be employed for the therapy of different cancers., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Herein we report on the synthesis, molecular structures, DNA-binding properties and antibacterial activity of four new copper(I) mixed-ligand complexes obtained by reacting copper(I) halides or [Cu(CH 3 CN) 4 ](BF 4 ) with 1,2-bis(diphenylphosphano)ethane (dppe) and 2,2,5,5-tetramethylimidazolidine-4-thione (tmimdtH). Depending on the nature of the halide, the resulting compounds adopt two different structural motifs. Thus, using CuCl or CuBr, doubly dppe-bridged symmetrical dimmers of type [(κ-S-tmimdtH)XCu(μ-dppe) 2 CuX(κ-S-tmimdtH)] are formed, while in the case of CuI, a rare example of a trinuclear complex was isolated, in which the Cu atom of a CuI(tmimdtH) moiety is linked by two bridging dppe units with the two Cu atoms of a cluster-type Cu 2 I 2 (dppe) core. On the other hand, [Cu(CH 3 CN) 4 ](BF 4 ) reacts with the anion of tmimdtH in the presence of dppe to form a binuclear complex consisting of two (dppe)Cu(tmimdt) units linked together by the P atoms of a dppe bridging ligand. The complexes show significant in vitro antibacterial activity against certain bacterial strains. An intercalative mode is suggested as the most probable interaction fashion of the compounds with calf-thymus (CT) DNA, monitored directly via UV-vis spectroscopy, DNA-viscosity measurements and indirectly via their competition with ethidium bromide for DNA as studied by fluorescence emission spectroscopy. The binding of the complexes to human (HSA) and bovine serum albumin (BSA) is tight. In order to explain the described in vitro activity of the compounds, we adopted molecular docking studies on the crystal structure of HSA, BSA, CT DNA and DNA-gyrase., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A new set of differently hydrated barium and strontium squarates, namely poly[[triaqua(μ-1,2-dioxocyclobut-3-ene-1,2-diolato)barium] monohydrate], {[Ba(C 4 O 4 )(H 2 O) 3 ]·H 2 O} n (1), poly[[diaqua(μ-1,2-dioxocyclobut-3-ene-1,2-diolato)strontium] monohydrate], {[Sr(C 4 O 4 )(H 2 O) 2 ]·H 2 O} n (2), and poly[[triaqua(μ-1,2-dioxocyclobut-3-ene-1,2-diolato)barium/strontium(0.85/0.15)] monohydrate], {[Ba 0.85 Sr 0.15 (C 4 O 4 )(H 2 O) 3 ]·H 2 O} n (3), is reported. The study of their crystal structures indicates that all the complexes crystallize in the triclinic space group P-1. Complexes 1 and 3 have a rare combination of squarate units coordinated through monodentate O atoms to two different metal atoms and through two bidentate O atoms to three different metal atoms. Furthermore, they have three coordinated water molecules to give a coordination number of nine. The squarate ligands in complex 2 exhibit two different coordination modes: (i) monodentate O atoms coordinated to four different Sr atoms and (ii) two monodentate O atoms coordinated to two different metal atoms with the other two O atoms bidentate to four different Sr atoms. All the compounds decompose to give the respective carbonates when heated to 800 °C, as evidenced by thermogravimetry/differential thermal analysis (TG-DTA), which are clusters of nanoparticles. Complexes 1 and 3 show additional endothermic peaks at 811 and 820 °C, respectively, indicating the phase transition of BaCO 3 from an orthorhombic (α-Pmcn) to a trigonal phase (β-R3m). All three complexes have significant DNA-binding constants, ranging from 2.45 × 10 4 to 9.41 × 10 4  M -1 against EB-CT (ethidium bromide-calf thymus) DNA and protein binding constants ranging from 1.1 × 10 5 to 8.6 × 10 5 with bovine serum albumin. The in vitro cytotoxicity of the complexes is indicated by the IC 50 values, which range from 128.8 to 261.3 µg ml -1 . Complex 3 shows better BSA binding, antioxidant activity against the DPPH radical and cytotoxicity than complexes 1 and 2.

Four novel zinc complexes, namely [Zn(oxa) 2 (MeOH) 4 ] (1), [Zn(oxa) 2 (H 2 O)(bipy)]·MeOH·2.5H 2 O (2·MeOH·2.5H 2 O), [Zn(oxa) 2 (bipyam)]·1.25MeOH (3·1.25MeOH) and [Zn(oxa) 2 (phen)] (4), with the non-steroidal anti-inflammatory drug oxaprozin (Hoxa) and a N,N'-donor heterocyclic ligand, such as 2,2'‑bipyridylamine (bipyam), 1,10‑phenanthroline (phen) or 2,2'‑bipyridine (bipy), were characterized with physicochemical techniques, various spectroscopies and single-crystal X-ray crystallography. In these coordination compounds, the oxaprozin ligands are coordinated to zinc ion in a monodentate or a bidentate chelating binding mode. The antioxidant activity of the complexes was evaluated via their ability to scavenge in vitro 1,1‑diphenyl‑2‑picrylhydrazyl, hydroxyl and 2,2'‑azinobis‑(3‑ethylbenzothiazoline‑6‑sulfonic acid) radicals. The complexes bind to calf-thymus DNA via intercalation as suggested via a series of studies employing UV-vis spectroscopy, DNA-viscosity measurements and competition with ethidium bromide. The complexes may bind to serum albumins tightly and reversibly in order to get transferred through the bloodstream., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In this paper, four new ruthenium complexes, [Ru(N-S)(dppm)2]PF6 (1), [Ru(N-S)(dppe)2]PF6 (2), [Ru(N-S)2(dppp)] (3) and [Ru(N-S)2(PPh3)2] (4) [dppm = 1,1-bis(diphenylphosphino)methane, dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, PPh3 = triphenylphosphine and N-S = 2-mercaptopyrimidine anion] were synthesized and characterized using spectroscopy techniques, molar conductance, elemental analysis, electrochemical techniques and X-ray diffraction. The DNA binding studies were investigated using voltammetry and spectroscopy techniques. The results show that all complexes exhibit a weak interaction with DNA. HSA interaction with the complexes was studied using fluorescence emission spectroscopy, where the results indicate a spontaneous interaction between the species by a static quenching mechanism. The cytotoxicity of the complexes was evaluated against A549, MDA-MB-231 and HaCat cells by MTT assay. Complexes (1) and (2), which are very active against triple negative MDA-MB-231, were subjected to further biological tests with this cell line. The cytotoxic activity triggered by the complexes was confirmed by clonogenic assay. Cell cycle analyses demonstrated marked anti-proliferative effects, especially at the G0/G1 and S phases. The morphological detection of apoptosis and necrosis - HO/PI and Annexin V-FITC/PI assay, elucidated that the type of cell death triggered by these complexes was probably by apoptosis. The in vivo toxicological assessment performed on zebrafish embryos revealed that complexes (1) and (2) did not present embryotoxic or toxic effects during embryonic and larval development showing that they are promising new prototypes of safer and more effective drugs for triple negative breast cancer treatment.

The synthesis and characterization of four palladium(II) complexes with substituted salicylaldehydes (X-saloH) having the general formula [Pd(X-salo) 2 ] was undertaken. The complexes are formulated as [Pd(3-OCH 3 -salo) 2 ] 1, [Pd(5-NO 2 -salo) 2 ] 2, [Pd(5-Cl-salo) 2 ] 3, and [Pd(5-Br-salo) 2 ] 4. The structure of complex 1 was verified by single-crystal X-ray crystallography. Spectroscopic (UV-vis), and physicochemical (viscosity measurements) techniques were employed in order to study the binding of the complexes with calf-thymus (CT) DNA, while ethidium bromide (EB) displacement studies, performed by fluorescence emission spectroscopy, revealed the ability of the complexes to displace the DNA-bound EB. Intercalation is the most possible mode of interaction of the complexes with CT DNA. The interaction of the complexes with bovine (BSA) and human (HSA) serum albumin proteins was studied by fluorescence emission spectroscopy and the relatively high binding constants revealed the reversible binding of the complexes to the albumins. Molecular docking simulations on the crystal structure of HSA, BSA and CT DNA were employed in order to study in silico the ability of the studied complexes 1-4 to bind to these target macromolecules., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Organometallic Ru(II)-arene complexes have emerged as potential alternatives to platinum appended agents due to their wide range of interesting features such as stability in solution and solid, significant activity, less toxicity and hydrophobic property of arene moiety, etc. Hence, a series of Ru(II)-p-cymene complexes, [(η 6 -p-cymene)Ru(η 2 -N,N-L1)Cl]Cl (1), [(η 6 -p-cymene)Ru(η 1 -N-L2)Cl 2 ] (2) and [(η 6 -p-cymene)Ru(η 1 -N-L3)Cl 2 ] (3) were prepared from pyrazole based ligands [2-(1H-pyrazol-3-yl)pyridine (L1), 3-(furan-2-yl)-1H-pyrazole (L2) and 3-(thiophen-2-yl)-1H-pyrazole (L3)], and [RuCl 2 -(η 6 -p-cymene)] dimer. The new Ru(II)-p-cymene complexes were well characterized by elemental analysis, and spectroscopic (FT-IR, UV-Visible, 1 H NMR, 13 C NMR and mass) and crystallographic methods. The Ru(II)-p-cymene complexes (1-3) were found to adopt their characteristic piano stool geometry around Ru(II) ion. The calf thymus DNA (CT-DNA) binding ability of the new complexes was investigated by electronic absorption spectroscopic titration and viscosity methods. The molecular docking study results showed that complex 1 strongly bound with targeted biomolecules than 2 and 3. Docked poses of bidentate pyrazole based Ru(II)-p-cymene complex 1 revealed that the complex formed a crucial guanine N 7 position hydrogen bond with DNA receptor. Complexes 1-3 might hydrolyze under physiological conditions and form aqua complexes 4-8, and docking calculations showed that the aqua complexes bound strongly with the receptors than original complexes. The in vitro cytotoxicity of the Ru(II)-p-cymene complexes and cisplatin was evaluated against triple negative breast cancer (TNBC) MDA-MB-231 cells. Our results showed that the inhibitory effect of bidentate pyrazole based Ru(II)-p-cymene complex 1 on the growth of breast cancer cells was superior to other tested complexes., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Copper(II) complexes containing non-steroidal anti-inflammatory drugs (NSAIDs) have been the subject of many research papers and reviews. Here we report the synthesis, spectroscopic study and biological activity of novel mixed copper(II) complexes with NSAIDs: tolfenamic (tolf), mefenamic (mef) and flufenamic (fluf) acids and phenanthroline (phen): [Cu(tolf-O,O') 2 (phen)] (1), [Cu(mef-O,O') 2 (phen)] (2), [Cu(fluf-O,O') 2 (phen)] (3). Complexes were characterized by X-ray analysis and EPR spectroscopy. Complexes 1-3 are monomeric, six-coordinate and crystallize in a monoclinic space group. Interaction of Cu(II) complexes with DNA was studied by means of absorption titrations, viscosity measurements and gel electrophoresis. The relative ability of the complexes to cleave DNA even in the absence of hydrogen peroxide is in the order 3 > 2 > 1. Application of the reactive oxygen species (ROS) scavengers, L-histidine, DMSO and SOD confirmed that singlet oxygen, hydroxyl radicals (Fenton reaction) and superoxide radical were formed, respectively. Thus, in addition to mechanism of intercalation, redox-cycling mechanism which in turn lead to the formation of ROS contribute to DNA damage. Cu(II) complexes exhibit excellent SOD-mimetic activity in the order 3~1 > 2. The fluorescence spectroscopy revealed that albumin may act as a targeted drug delivery vehicle for Cu(II) complexes (K~10 6 ). The anticancer activities of complexes 1-3 were investigated using an MTS assay (reduction of the tetrazolium compound) against three cancer cell lines (HT-29 human colon adenocarcinoma, HeLa and T-47D breast cancer cells) and mesenchymal stromal cells (MSC). The most promising compound, from the viewpoint of its NSAID biological activity is 3, due to the presence of the three fluorine atoms participating in the formation of weak hydrogen-bonds at the DNA surface., (Copyright © 2019 Elsevier Inc. All rights reserved.)

We report the synthesis, crystal structures and biological activities of two dinuclear Cu(II) complexes [Cu(o-phen)LCu(OAc)] (1) and [Cu(o-phen)LCu(o-phen)](OAc) (2), where o-phen = 1,10-phenanthroline, H 3 L = o-HOC 6 H 4 C(H)=N-NH-C(OH)=N-N=C(H)-C 6 H 4 OH-o, and OAc=CH 3 COO - . Both compounds display strong and broad X-band EPR spectra at RT in their powder state confirming that these are paramagnetic. The intercalative DNA binding of the compounds as revealed from spectrophotometric studies was found to be consistent with the results of fluorescence spectroscopic studies for ethidium bromide displacement assay as well as enhanced viscosity of DNA in the presence of these compounds. The compounds effectively catalyze hydrolytic cleavage of supercoiled pUC19 DNA and show remarkable cytotoxicity toward human lung cancer A549 cell line (IC 50 values are 4.34 and 8.46 µM for 1 and 2, respectively) and breast cancer MCF7 cell line (IC 50 values are 6.50 and 8.68 µM for 1 and 2, respectively) and are found to be relatively less toxic toward keratinocyte HaCaT normal cell line (IC 50 values are 11.19 and 16.01 µM for 1 and 2, respectively). Annexin-V/PI dual staining results analyzed by flow cytometry strongly suggest the induction of apoptotic pathway for the anticancer activity of these complexes. Flow cytometry experiment for cell cycle analysis showed considerable increase in the G2/M phase in both A549 and MCF7 cell lines by these two compounds. On the other hand, compounds 1 and 2 activate reactive oxygen species (ROS) level in A549 cells, but act as scavengers or inhibitors of ROS in MCF7 cell line as analyzed by DCFDA staining using flow cytometry. Two dinuclear Cu(II) complexes exhibit efficient hydrolytic cleavage of DNA and display remarkable cytotoxicity against human lung cancer A549 and breast cancer MCF7cells. The ROS level in A549 cells is activated, but the ROS level in MCF7 cells is decreased in the presence of these complexes. Cell cycle analysis by flow cytometry shows G2/M phase arrest in both these cell lines.

One iron(III) and two manganese(III) complexes based on thiosemicarbazone were synthesized and characterized using analytical and spectroscopic data. The crystallographic analysis showed the square pyramid structures of the complexes. Electronic spectra analysis was performed to determine the nature of the interaction between the complexes and calf thymus DNA (CT-DNA). DNA cleavage activities of the complexes were examined by gel electrophoresis (pBR322 DNA). The cytotoxicity of the complexes was determined against human cervical carcinoma (HeLa) and human colorectal adenocarcinoma (HT-29) cell lines by MTT assay. The results indicated that complex Fe1 is bound to CT-DNA via the intercalation mode, while complexes Mn1 and Mn2 are bound to CT-DNA via groove binding and/or electrostatic interactions rather than the intercalation mode. In addition, they showed good binding activity, which followed the order of Fe1 > Mn2 > Mn1. Complexes were found to promote the cleavage of DNA from supercoiled form (SC, Form I) to nicked circular form (NC, Form II) without concurrent formation of Form III, revealing the single-strand DNA cleavage. No significant cleavage was found in the presence of Mn1 and Mn2; however, it was observed at 2000 and 3000 µM concentrations of Fe1. The ability of Fe1 to cleave DNA was greater than that of other complexes and these results are in conformity with their DNA-binding affinities. Cytotoxicity determination tests revealed that the complex Fe1 on HeLa and HT-29 cells exhibited a higher anti-proliferative effect than Mn1 and Mn2 (Fe1 > Mn2 > Mn1). These studies suggested that the complex Fe1 could be a good candidate as a chemotherapeutic drug targeting DNA.

Thermoresponsive polymeric materials are important building blocks for smart materials. In this work, the transformation of dsDNA into a thermoresponsive polymer is reported by intercalation of short, oligoethylene-glycol-modified proflavine intercalators. The thermoresponsiveness of the dsDNA-intercalator complex originates from the heating-induced dehydration of the ethylene glycol side chains, which leads to aggregation of the intercalated dsDNA. This work demonstrates the possibility of designing small-molecule intercalators to prepare thermoresponsive dsDNA complexes with tunable lower critical solution temperature behavior., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This study describes a series of newly synthesized phosphine/diimine ruthenium complexes containing the lawsone as bioligand with enhanced cytotoxicity against different cancer cells, and apoptosis induction in prostatic cancer cells DU-145. The complexes [Ru(law)(N-N) 2 ]PF 6 where N-N is 2,2'-bipyridine (1) or 1,10-phenanthroline (2) and [Ru(law)(dppm)(N-N)]PF 6 , where dppm means bis(diphenylphosphino)methane, N-N is 2,2'-bipyridine (3) or 1,10-phenanthroline (4), and law is lawsone, were synthesized and fully characterized by elemental analysis, molar conductivity, NMR, UV-vis, IR spectroscopies and cyclic voltammetry. The interaction of the complexes (1-4) with DNA was evaluated by circular dichroism, gel electrophoresis, and fluorescence, and the complexes presented interactions by the minor grooves DNA. The phosphinic series of complexes exhibited a remarkably broad spectrum of anticancer activity with approximately 34-fold higher than cisplatin and 5-fold higher than doxorubicin, inhibiting the growth of 3D tumor spheroids and the ability to retain the colony survival of DU-145 cells. Also, the complex (4) inhibits DU-145 cell adhesion and migration potential indicating antimetastatic properties. The mechanism of its anticancer activity was found to be related to increased reactive oxygen species (ROS) generation, increased the BAX/BCL-2 ratio and subsequent apoptosis induction. Overall, these findings suggested that the complex (4) could be a promising candidate for further evaluation as a chemotherapeutic agent in the prostate cancer treatment., (Copyright © 2019 Elsevier Inc. All rights reserved.)

New dithiocarbamate chalcone-based derivatives were synthesized, their structures were elucidated using different spectroscopic techniques. They were subjected to antimicrobial screening against selected Gram negative bacteria focusing on microbial resistance. Bacterial resistance was targeted via phosphoethanolamine transferase enzyme. Most of the synthesized compounds showed equal or higher activity to colistin standard. Compound 24 proved to be the most active candidate with MIC of 8 µg/ml against both Ps12 and K4 and MBC of 32 µg/ml against Ps12 and 16 µg/ml against K4 Molecular docking study showed that 20, 22, 24 and 25 had good binding affinity with active site residues via Thr280. DNA macromolecule was further targeted. Compounds 28 and 34 were recorded to have better DNA binding than doxurubucin with IC 50 of 27.48 and 30.97 µg/ml respectively, suggesting that it could have a role in their higher antibacterial effect. Their docking into DNA has shown a clear intercalation matching with antibacterial data. Pharmacokinetics parameters of active compounds showed that they have better absorption through GIT., (Copyright © 2019. Published by Elsevier Inc.)

Nine novel cobalt(III) ternary complexes bearing 4N donor ligands (tris(2-aminoethyl)amine (tren) or tris(2-methylpyridyl)amine (tpa)) and (fluoro)quinolones (quinH) with antibacterial and potential antitumor activity have been synthesized, characterized and screened in various biological assays. The molecular structures of [Co(tpa)(nal)](PF 6 ) 2 (3) and [Co(tpa)(nor)(Co(tpa)(norH)](PF 6 ) 3 (Cl) 2 ∙5MeOH (8) (nal = deprotonated form of nalidixic acid, norH = norfloxacin) with the expected octahedral geometry and (O,O) coordination of the quinolone ligands are also reported. Cyclic voltammetric studies revealed that the 4N donor ligands have much higher effect on the reduction potential of these ternary complexes than the quinolones. Due to the π-back-bonding interaction of the metal ion with the pyridyl-N atoms, the tpa containing compounds demonstrated lower stability and were easier to get reduced in a reversible manner. This character makes them unlikely candidates for development of effective, highly selective hypoxia-activated pro-drug complexes, but this goal might be achieved by substitution of tpa by tren. [Co(tren)(cip)](PF 6 ) 2 (4) and [Co(tpa)(cip)](PF 6 ) 2 (5) (cip = deprotonated form of ciprofloxacin) showed slightly less antibacterial activity against Escherichia coli than free ciprofloxacin (cipH) and they found to have very low toxicity towards both selected cancer (HeLa, MCF 7, MDA-MB-239) and noncancerous (MRC5 pd30) cells. Interaction of 4 and 5 with calf thymus DNA studied by UV-Vis, flow linear dichroism, viscometry and DNA melting indicated the complexes to bind to DNA as intercalators. DNA electrophoresis revealed that, unlike Co(II) complexes, 4 and 5 are not capable of cleaving DNA, but they can inhibit bacterial DNA gyrase 5 being slightly more active than 4., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Staining compounds containing heavy elements (electron dyes) can facilitate the visualization of DNA and related biomolecules by using TEM. However, research into the synthesis and utilization of alternative electron dyes has been limited. Here, we report the synthesis of a novel DNA intercalator molecule, bis-acridine uranyl (BAU). NMR spectroscopy and MS confirmed the validity of the synthetic strategy and gel electrophoresis verified the binding of BAU to DNA. For TEM imaging of DNA, two-dimensional DNA origami nanostructures were used as a robust microscopy test object. By using scanning transmission electron microscopy (STEM) imaging, which is favored over conventional wide-field TEM for improved contrast, and therefore, quantitative image analysis, it is found that the synthesized BAU intercalator can render DNA visible, even at the single-molecule scale. For comparison, other staining compounds with a purported affinity towards DNA, such as dichloroplatinum, cisplatin, osmium tetroxide, and uranyl acetate, have been evaluated. The STEM contrast is discussed in terms of the DNA-dye association constants, number of dye molecules bound per base pair, and the electron-scattering capacity of the metal-containing ligands. These findings pave the way for the future development of electron dyes with specific DNA-binding motifs for high-resolution TEM imaging., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most widely used drugs in the world but some NSAIDs such as diclofenac and tolfenamic acid display levels of cytotoxicity, an effect which has been attributed to the presence of diphenylamine contained in their structures. A novel series of diphenylamine derivatives were synthetised and evaluated for their cytotoxic activities and proliferation inhibition. The most active compounds in the cytotoxicity tests were derivative 6g with an IC 50 value of 2.5 ± 1.1 × 10 -6  M and derivative 6f with an IC 50 value of 6.0 ± 3.0 × 10 -6  M (L1210 cell line) after 48 h incubation. The results demonstrate that leukemic L1210 cells were much more sensitive to compounds 6f and 6g than the HEK293T cells (IC 50  = 35 × 10 -6  M for 6f and IC 50  > 50 × 10 -6  M for 6g) and NIH-3T3 (IC 50  > 50 × 10 -6  M for both derivatives). The IC 50 values show that these substances may selectively kill leukemic cells over non-cancer cells. Cell cycle analysis revealed that a primary trend of the diphenylamine derivatives was to arrest the cells in the G 1 -phase of the cell cycle within the first 24 h. UV-visible, fluorescence spectroscopy and circular dichroism were used in order to study the binding mode of the novel compounds with DNA. The binding constants determined by UV-visible spectroscopy were found to be in the range of 2.1-8.7 × 10 4  M -1 . We suggest that the observed trend for binding constant K is likely to be a result of different binding thermodynamics accompanying the formation of the complexes., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A series of new pyrazole linked benzothiazole-β-naphthol derivatives were designed and synthesized using a simple, efficient and ecofriendly route under catalyst-free conditions in good to excellent yields. These derivatives were evaluated for their cytotoxicity on selected human cancer cell lines. Among those, the derivatives 4j, 4k and 4l exhibited considerable cytotoxicity with IC 50 values ranging between 4.63 and 5.54 µM against human cervical cancer cells (HeLa). Structure activity relationship was elucidated by varying different substituents on benzothiazoles and pyrazoles. Further, flow cytometric analysis revealed that these derivatives induced cell cycle arrest in G2/M phase and spectroscopic studies such as UV-visible, fluorescence and circular dichroism studies showed that these derivatives exhibited good DNA binding affinity. Additionally, these derivatives can effectively inhibit the topoisomerase I activity. Viscosity studies and molecular docking studies demonstrated that the derivatives bind with the minor groove of the DNA., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Drug resistance to platinum chemotherapeutics targeting DNA often involves abrogation of apoptosis and has emerged as a significant challenge in modern, non-targeted chemotherapy. Consequently, there is great interest in the anti-cancer properties of metal complexes-particularly those that interact with DNA-and mechanisms of consequent cell death. Herein we compare a parent cytotoxic complex, [Ru(phen) 2 (tpphz)] 2+ [phen = 1,10-phenanthroline, tpphz = tetrapyridyl[3,2- a:2',3'- c:3″,2″- h:2‴,3‴- j]phenazine], with a mononuclear analogue with a modified intercalating ligand, [Ru(phen) 2 (taptp)] 2+ [taptp = 4,5,9,18-tetraazaphenanthreno[9,10- b] triphenylene], and two structurally related dinuclear, tpphz-bridged, heterometallic complexes, RuRe and RuPt. All three of these structural changes result in a switch from intercalation to groove-binding DNA interaction and concomitant reduction in cytotoxic potency, but no significant change in relative cytotoxicity toward platinum-resistant A2780CIS cancer cells, indicating that the DNA interaction mode is not critical for the mechanism of platinum resistance. All variants exhibited a light-switch effect, which for the first time was exploited to investigate timing of cell death by live-cell microscopy. Surprisingly, cell death occurred rapidly as a consequence of oncosis, characterized by loss of cytoplasmic volume control, absence of significant mitochondrial membrane potential loss, and lack of activation of apoptotic cell death markers. Importantly, a novel, quantitative proteomic analysis of the A2780 cell genome following exposure of the cells to either mononuclear complex reveals changes in protein expression associated with global cell responses to oxidative stress and DNA replication/repair cellular pathways. This combination of multiple targeting modalities and induction of a non-apoptotic death mechanism makes these complexes highly promising chemotherapeutic cytotoxicity leads.

We report a high-affinity photoswitchable DNA binder, which displays different nucleosome-binding capacities upon visible-light irradiation. Both photochemical and DNA-recognition properties were examined by UV-Vis, HPLC, CD spectroscopy, NMR, FID assays, EMSA and DLS. Our probe sets the basis for developing new optoepigenetic tools for conditional modulation of nucleosomal DNA accessibility.

Nucleus imaging is of great importance for understanding cellular processes of genetic expression, proliferation and growth, etc. Although many nucleic-acid selective dyes for nucleus staining are available, few of them meet multiple standards. Herein, we report a cationic fluorescence dye FTI that possesses visible light excitation (436 nm), orange emission (571 nm) and a large Stokes shift (~135 nm) for nucleic-acid staining. FTI displays an obvious and sensitive fluorescent response to DNA in vitro with a 6.4-fold quantum yield increasing. Co-staining and nucleic acid digest experiments in live cells demonstrate that FTI exhibits an unexpected selectivity for the nucleolus of the cells due to the stronger affinity to RNA than DNA. Because of good photostability and low cytotoxicity, FTI can accomplish a promising stain for DNA recognition in vitro and nucleolus-specific imaging in cancer cells., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Two novel rhodium(III) complexes, namely, [Rh III (X)Cl 3 ] (X = 2 2,6-bis((4 S,7 R)-7,8,8-trimethyl-4,5,6,7-tetrahydro-1 H-4,7-methanoindazol-3-yl)pyridine or 2,6-bis((4 S,7 R)-1,7,8,8-tetramethyl-4,5,6,7-tetrahydro-1 H-4,7-methanoindazol-3-yl)pyridine), were synthesized from camphor derivatives of a bis(pyrazolylpyridine), tridentate nitrogen-donor chelate system, giving [Rh III (H 2 L*)Cl 3 ] (1a) and [Rh III (Me 2 L*)Cl 3 ] (1b). A rhodium(III) terpyridine (terpy) ligand complex, [Rh III (terpy)Cl 3 ] (1c), was also synthesized. By single-crystal X-ray analysis, 1b crystallizes in an orthorhombic P2 1 2 1 2 1 system, with two molecules in the asymmetric unit. Tridentate coordination by the N,N,N-donor localizes the central nitrogen atom close to the rhodium(III) center. Compounds 1a and 1b were reactive toward l-methionine (l-Met), guanosine-5'-monophosphate (5'-GMP), and glutathione (GSH), with an order of reactivity of 5'-GMP > GSH > l-Met. The order of reactivity of the Rh III complexes was: 1b> 1a > 1c. The Rh III complexes showed affinity for calf thymus DNA and bovine serum albumin by UV-vis and emission spectral studies. Furthermore, 1b showed significant in vitro cytotoxicity against human epithelial colorectal carcinoma cells. Since the Rh III complexes have similar coordination modes, stability differences were evaluated by density functional theory (DFT) calculations (B3LYP(CPCM)/LANL2DZp). With (H 2 L*) and (terpy) as model ligands, DFT calculations suggest that both tridentate ligand systems have similar stability. In addition, molecular docking suggests that all test compounds have affinity for the minor groove of DNA, while 1b and 1c have potential for DNA intercalation.

A novel ligand BOPIP (BOPIP = {2-(4-(benzyloxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline}) and its mononuclear Ru(II) polypyridyl complexes [Ru(phen) 2 BOPIP] 2+ (1) (phen = 1,10-Phenanthrolene), [Ru(bpy) 2 BOPIP] 2+ (2) (bpy = 2,2' bipyridyl), [Ru(dmb) 2 BOPIP] 2+ (3) (dmb = 4, 4' -dimethyl 2, 2' -bipyridine), [Ru(Hdpa) 2 BOPIP] 2+ (4) (Hdpa = 2,2'dipyridylamine) have been synthesized successfully and characterized by elemental analysis, UV-vis, IR, 1 H, 13 C-NMR, and ESI-MS Spectroscopy. The interaction of these complexes with CT-DNA was studied using absorption, emission techniques, viscosity measurements and molecular docking studies. The docking study also supports the binding ability of complexes obtained through the absorption and emission techniques. These studies reveal that the Four Ru(II) polypyridyl complexes bind to DNA predominantly by intercalation. The Antimicrobial activity and cytotoxicity of these complexes are also reported.

We report the biological activity of three Cu(II) complexes [Cu(pabt)Cl] (1), [Cu(pma)Cl] (2), and [Cu(pdta)Cl]Cl (3) (pabt = N-(2-mercaptophenyl)-2'-pyridylmethylenimine, pma = N-(2-pyridylmethyl)-2-mercaptoaniline, pdta = 2,2'-di(pyridyl-2-methyleneimine)diphenyl disulfide). 1-3 display four-line EPR multiplet in solution at RT suggesting that these are mononuclear. DNA-binding studies using spectrophotometric titration of these complexes with calf thymus DNA showed binding through intercalation mode which was found to be consistent with the observation of increased viscosity of DNA and quenching of fluorescence of ethidium bromide bound DNA in the presence of these complexes. All three complexes were found to be efficient in bringing about oxidative and hydrolytic cleavage of DNA. The proposed mechanism of hydrolytic DNA cleavage has been discussed. MTT assay showed remarkable cytotoxicity on cervical cancer HeLa cell line and the IC 50 values were 1.27, 4.13, and 3.92 μM for 1, 2 and 3, respectively, as compared to the IC 50 value (13 μM) reported for cisplatin in HeLa cells. AO/PI and Annexin-V/PI assay suggest the induction of cell death primarily via apoptotic pathway. Nuclear staining using DAPI was used to assess changes in nuclear morphology during apoptotic cell death. The role of reactive oxygen species (ROS) for induction of apoptotic cell death was studied using H 2 DCF-DA assay and the result suggests that the generation of ROS by the complexes may be a possible cause for their antiproliferative activity. TUNEL assay showed DNA fragmentation in apoptotic cells. Cell cycle analysis using flow cytometry showed significant increase in the G2/M phase in HeLa cells by the compounds 1-3. Mononuclear Cu(II) complexes display remarkable cytotoxicity against cervical cancer HeLa cell line. The generation of ROS by the complexes may be a cause of their antiproliferative activity. Fluorescent images from DAPI staining assay revealed that the cells undergoing apoptosis displayed typical features like cell shrinkage, membrane blebbing, chromatin condensation and nuclear fragmentation. TUNEL assay showed DNA fragmentation in apoptotic cells.

It is now well established that ruthenium complexes are attractive alternatives to platinum-based anticancer agents. Most of the ruthenium compounds currently under investigation contain a single metal center. The synthesis of multinuclear analogues may provide access to novel complexes with enhanced biological activity. In this work, we have synthesized a set of three trinuclear complexes containing organometallic ruthenium fragments-(arene)RuCl-coordinated to a 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine core [(Arene = benzene (2), p-cymene (1), or hexamethylbenzene (3)]. The interaction of the complexes with DNA was extensively studied using a variety of biophysical probes as well as by molecular docking. The complexes bind strongly to DNA with apparent binding constants ranging from 2.20 to 4.79 × 10 4  M -1 . The binding constants from electronic absorption titrations were an order of magnitude greater. The mode of binding to the nucleic acid was not definitively determined, but the evidence pointed to some kind of non-specific electrostatic interaction. None of the complexes displayed any significant antimicrobial activity against the organisms that were studied and exhibited anticancer activity only at high (> 100 μM) concentration.

Early and accurate assessment of therapeutic response to anticancer therapy plays an important role in determining treatment planning and patient management in clinic. Magnetic rseonance imaging (MRI) of necrosis that occurs after cancer therapies provides chances for that. Here, we reported three novel MRI contrast agents, GdL 1 , GdL 2 , and GdL 3 , by conjugating rhein with gadolinium 2-[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid (Gd-DOTA) through different linkers. The T1 relaxivities of three probes (7.28, 7.35, and 8.03 mM -1 s -1 ) were found to be higher than that of Gd-DOTA (4.28 mM -1 s -1 ). Necrosis avidity of GdL 1 was evaluated on the rat models of reperfused liver infarction (RLI) by MRI, which showed an increase of T1-weighted contrast between necrotic and normal liver during 0.5-12 h. Besides, L 1 was also labeled with 64 Cu to assess its necrosis avidity on rat models of RLI and muscle necrosis (MN) by a γ-counter. The uptakes of 64 CuL 1 in necrotic liver and muscle were higher than those in normal liver and muscle ( P < 0.05). Then, the ability of GdL 1 to assess therapeutic response was tested on rats bearing Walker 256 breast carcinoma injected with a vascular disrupting agent CA4P by MR imaging. The signal intensity of tumoral necrosis was strongly enhanced, and the contrast ratio between necrotic and viable tumor was 1.63 ± 0.11 at 3 h after administration of GdL 1 . Besides, exposed DNA in necrosis cells may be an important mechanism of three probes targeting to necrosis cells. In summary, GdL 1 may serve as a promising MRI contrast agent for accurate assessment of treatment response.