Synthesis, characterization, X-ray structure and in vitro antimycobacterial and antitumoral activities of Ru(II) phosphine/diimine complexes containing the “SpymMe2” ligand, SpymMe2=4,6-dimethyl-2-mercaptopyrimidine

Ruthenium(II)-diphosphine complexes containing acylthiourea ligands are effective against lung and breast cancers

We have synthesized and characterized three new ruthenium(II) diphosphine complexes containing an acylthiourea ligand, with the general formula [Ru(DPEPhos)(O,S)(bipy)]PF₆, where DPEPhos = bis(2-(diphenylphosphino)phenyl)ether, bipy = 2,2'-bipyridine, and O,S = N,N-dimethyl-N'-(benzoyl)thiourea (1), N,N-dimethyl-N'-(furoyl)thiourea (2), and N,N-dimethyl-N'-(thiophenyl)thiourea (3), by several physicochemical techniques. We evaluated the ruthenium complexes for their cytotoxicity against two human cancer cell lines, A549 (lung) and MDA-MB-231 (breast), and two corresponding lines of non-cancer cells, MRC-5 (lung) and MCF-10A (breast). All the complexes are cytotoxic against the cancer cell lines; the IC₅₀ values lie in the micromolar range (0.07-0.70 μM). Ruthenium complex 1 is more selective (7 times more active) toward lung cancer cells (A549) than toward non-cancer cells (MRC-5) and is 160 times more cytotoxic than cisplatin against A549 cells. Investigations of the mechanism of action of complex 1 in A549 cells demonstrated that it inhibits colony formation and promotes cell cycle arrest in the G1 phase and apoptotic cell death. DNA binding studies revealed that complexes 1-3 interact with the biomolecule via minor grooves. These complexes also interact with human serum albumin (HSA) and have affinity for site I by hydrophobic forces. Therefore, this new class of ruthenium complexes can act as cytotoxic agents, mainly for lung cancer treatment.

A bioinorganic chemistry perspective on the roles of metals as drugs and targets against Mycobacterium tuberculosis - a journey of opportunities

Medicinal inorganic chemists have provided many strategies to tackle a myriad of diseases, pushing forward the frontiers of pharmacology. As an example, the fight against tuberculosis (TB), an infectious bacterial disease, has led to the development of metal-based compounds as potential drugs. This disease remains a current health issue causing over 1.4 million of deaths per year. The emergence of multi- (MDR) and extensively-drug resistant (XDR) Mycobacterium tuberculosis (Mtb) strains along with a long dormancy process, place major challenges in developing new therapeutic compounds. Isoniazid is a front-line prodrug used against TB with appealing features for coordination chemists, which have been explored in a series of cases reported here. An isoniazid iron-based compound, called IQG-607, has caught our attention, whose in vitro and in vivo studies are advanced and thoroughly discussed, along with other metal complexes. Isoniazid is inactive against dormant Mtb, a hard to eliminate state of this bacillus, found in one-fourth of the world's population and directly implicated in the lengthy treatment of TB (ca. 6 months). Thus, our understanding of this phenomenon may lead to a rational design of new drugs. Along these lines, we describe how metals as targets can cross paths with metals used as selective therapeutics, where we mainly review heme-based sensors, DevS and DosT, as a key system in the Mtb dormancy process and a current drug target. Overall, we report new opportunities for bioinorganic chemists to tackle this longstanding and current threat.

In vitro cytotoxicity and in vivo zebrafish toxicity evaluation of Ru(ii)/2-mercaptopyrimidine complexes

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.

Ruthenium (II) complexes with N, O-chelating proline and threonine ligands cause selective cytotoxicity by the induction of genomic instability, cell cycle arrest and apoptosis in breast and prostate tumor cells

Ruthenium complexes are being considered as novel chemotherapeutic alternatives for cancer treatment. In our study, we assessed the antitumoral activities of novel ruthenium complexes coupled to the amino acids proline (RuPro) and threonine (RuThr) in prostate tumor cell lines (DU145) and breast (MCF7), and normal cell lines of the lung fibroblast (GM07492A). Our results revealed that the EC₅₀ of the complexes for DU145 and MCF7 was two times lower than that GM07492A. Moreover, RuPro and RuThr were not able to induce significant genomic instability, cell cycle arrest or cell death in GM07492A, but could induce DNA damage, arrest in G2/M and apoptosis in DU145 and MCF7. Furthermore, BAX, TP53 and ATM were found to be upregulated in DU145 and MCF7 treated with RuPro and RuThr, in which, a higher ASCT2 gene expression was also observed. Using molecular docking, RuPro and RuThr interact with ASCT2, suggesting that this transporter might have a pivotal role in the execution of their activities. Hence, our results with RuPro and RuThr are capable of selectively inducing genetic damage, cell cycle arrest and apoptosis in DU145 and MCF7. We suggest that the selective action of the RuPro and RuThr complexes is related to the higher expression of ASCT2 in the tumor cells.

A Nanostructured Lipid System to Improve the Oral Bioavailability of Ruthenium(II) Complexes for the Treatment of Infections Caused by Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious, airborne disease caused by the bacterium Mycobacterium tuberculosis that mainly affects the lungs. Fortunately, tuberculosis is a curable disease, and in recent years, death rates for this disease have decreased. However, the existence of antibiotic-resistant strains and the occurrence of co-infections with human immunodeficiency virus (HIV), have led to increased mortality in recent years. Another area of concern is that one-third of the world's population is currently infected with M. tuberculosis in its latent state, serving as a potential reservoir for active TB. In an effort to address the failure of current TB drugs, greater attention is being given to the importance of bioinorganic chemistry as an ally in new research into the development of anti-TB drugs. Ruthenium (Ru) is a chemical element that can mimic iron (Fe) in the body. In previous studies involving the following heteroleptic Ru complexes, [Ru(pic)(dppb)(bipy)]PF₆ (SCAR1), [Ru(pic)(dppb)(Me-bipy)]PF₆ (SCAR2), [Ru(pic)(dppb)(phen)]PF₆ (SCAR4), cis-[Ru(pic)(dppe)₂]PF₆ (SCAR5), and [Ru(pic)(dppe)(phen)]PF₆ (SCAR7), we observed excellent anti-TB activity, moderate cell-toxicity, and a lack of oral bioavailability in an in vivo model of these complexes. Therefore, the objective of this study was to evaluate the toxicity and oral bioavailability of these complexes by loading them into a nanostructured lipid system. The nanostructured lipid system was generated using different ratios of surfactant (soybean phosphatidylcholine, Eumulgin^®, and sodium oleate), aqueous phase (phosphate buffer with a concentration of 1X and pH 7.4), and oil (cholesterol) to generate a system for the incorporation of Ru(II) compounds. The anti-TB activity of the compounds was determined using a microdilution assay with Resazurin (REMA) against strains of M. tuberculosis H₃₇Rv and clinical isolates resistant. Cytotoxicity assay using J774.A1 cells (ATCC TIB-67) and intra-macrophage activity were performed. The oral bioavailability assay was used to analyze blood collected from female BALB/C mice. Plasma collected from the same mice was analyzed via inductively coupled plasma mass spectrometry (ICP-MS) to quantify the number of Ru ions. The complexes loaded into the nanostructured lipid system maintained in vitro activity and toxicity was found to be reduced compared with the compounds that were not loaded. The complexes showed intra-macrophagic activity and were orally bioavailable.

Cytotoxic activity and structural features of Ru(II)/phosphine/amino acid complexes

Thirteen new ruthenium amino acid complexes were synthesized and characterized. They were obtained by the reaction of α-amino acids (AA) with [RuCl₂(P-P)(N-N)], where P-P=1,4-bis(diphenylphosphino)butane (dppb) or 1,3-bis(diphenylphosphino)propane (dppp) and N-N=4,4'-dimethyl-2,2'-bipyridine (4'-Mebipy), 5,5'-dimethyl-2,2'-bipyridine (5'-Mebipy) or 4,4'-Methoxy-2-2'-bipyridine (4'-MeObipy). This afforded a family of complexes formulated as [Ru(AA-H)(P-P)(N-N)]PF₆, where AA=glycine (Gly), L-alanine (Ala), L-valine (Val), L-tyrosine (Tyr), L-tryptophan (Trp), L-histidine (His) and L-methionine (Met). All compounds were characterized by elemental analysis, spectroscopic and electrochemical techniques. The [Ru(AA-H)(P-P)(N-N)]PF₆ complexes are octahedral (the AA-H ligand binding involves N-amine and O-carboxylate), diamagnetic (low-spin d⁶, S=0) and present bands due to electronic transitions in the visible region. ¹H, ¹³C{¹H} and ³¹P{¹H} NMR spectra of the complexes indicate the presence of C₂ symmetry, and the identification of diastereoisomers. In vitro cytotoxicity assays of the compounds and cisplatin were carried out using MDA-MB-231 (human breast) tumor cell line and a non-tumor breast cell line (MCF-10A). Most complexes present promising results with IC₅₀ values comparable with the reference drug cisplatin and high selectivity indexes were found for the complexes containing L-Trp. The binding of two Ru-precursors of the type [RuCl₂(dppb)(NN)] (N-N=4'-MeObipy or 4'-Mebipy) to the blood transporter protein human serum albumin (HSA) was evaluated by fluorescence and circular dichroism spectroscopy. Both complexes bind HSA, probably in the hydrophobic pocket near Trp214, and the Ru-complex containing 4'-MeObipy shows higher affinity for HSA than the 4'-Mebipy one.

Synthesis, structures, and ESI-mass studies of silver(I) derivatives of imidazolidine-2-thiones: Antimicrobial potential and biosafety evaluation

The basic objective of this investigation is to explore potential metallo-organic antimicrobial agents based on silver-heterocyclic-2-thiones. In this respect, a series of silver(I) halide complexes with imidazolidine-2-thiones (L-NR, R=H, Me, Et, Prⁿ, Buⁿ, Ph), namely, mononuclear [AgX(L-NR)(PPh₃)₂] (X, R: Cl, Bu, 1; Br, Ph, 7); [AgX(L-NR)₃] (Br, Bu, 5; Br, Prⁿ, 8) and halogen bridged dinuclear [Ag₂(μ-X)₂(L-NR)₂(PPh₃)₂] (Cl, Buⁿ, 2; Cl, Ph, 3; Cl, Prⁿ, 4; Br, Ph, 6) have been synthesized and characterized using modern techniques. The thio-ligands are terminally S-bonded in all the complexes. The in vitro antimicrobial potential and biosafety evaluation of the above complexes as well as that of previously reported analogous silver complexes has been studied against Gram positive bacteria, namely, Staphylococcus aureus (MTCC 740) and Methicillin resistant Staphylococcus aureus (MRSA), Gram negative bacteria Klebsiella pneumoniae (MTCC 109), Salmonella typhimurium (MTCC 98) and a yeast Candida albicans (MTCC 227). Most of the complexes tested have shown significant antimicrobial activity with low values of minimum inhibitory concentration (MIC). Significantly, the activity against MRSA is an important outcome of this investigation. Among complexes tested for their cytotoxicity using MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay, some complexes showed low cellular toxicity with high percent cell viability. A dinuclear complex [Ag₂(μ-Cl)₂(L-NPh)₂(PPh₃)₂] 3 with 93.3% cell viability emerges the most important candidate for further investigations.

Variable coordination and C–S bond cleavage activity of N-substituted imidazolidine-2-thiones towards copper: synthesis, spectroscopy, structures, ESI-mass and antimicrobial studies

N-substituted imidazoldine-2-thiones with copper(i) halides have shown variable nuclearity, C–S bond cleavage, antimicrobial activity and non-toxicity in some cases to living cells.

In Vivo Enzymes Activities of Some Ru(II) Compounds with N-Alkylphenothiazines

The purpose of the present study was to investigate and compare the effects of two ruthenium complexes with trifluoperazine on acethylcholinesterase enzyme activity and lactate dehydrogenase levels in vivo under physiological conditions in rats blood. Complexes 1 and 2 showed positive effects on acethylcholinesterase at all doses and did not disturb its normal activity. Total LDH activity was inhibited in the presence of both complexes, but Ru(II) complexes showed different effects on the activity of LDH isoenzymes. The activities of LDH1 and LDH2 isoenzymes were decreased in all applied doses of the complex 2, while the activity of LDH2 reduced using complex 1 in the same doses. Results of the present study suggest the neuro- and cardio protective potential of oral administration of complexes 1 and 2, as non-toxic compounds under physiological conditions. These protective effects are the result of their potent antioxidant activity.

Inhibition of human DNA topoisomerase IB by nonmutagenic ruthenium(II)-based compounds with antitumoral activity

Herein we synthesized two new ruthenium(II) compounds [Ru(pySH)(bipy)(dppb)]PF6 (1) and [Ru(HSpym)(bipy)(dppb)]PF6 (2) that are analogs to an antitumor agent recently described, [Ru(SpymMe2)(bipy)(dppb)]PF6 (3), where [(Spy) = 2-mercaptopyridine anion; (Spym) = 2-mercaptopyrimidine anion and (SpymMe2) = 4,6-dimethyl-2-mercaptopyrimidine anion]. In vitro cell culture experiments revealed significant anti-proliferative activity for 1-3 against HepG2 and MDA-MB-231 tumor cells, higher than the standard anti-cancer drugs doxorubicin and cisplatin. No mutagenicity is detected when compounds are evaluated by cytokinesis-blocked micronucleus cytome and Ames test in the presence and absence of S9 metabolic activation from rat liver. Interaction studies show that compounds 1-3 can bind to DNA through electrostatic interactions and to albumin through hydrophobic interactions. The three compounds are able to inhibit the DNA supercoiled relaxation mediated by human topoisomerase IB (Top1). Compound 3 is the most efficient Top1 inhibitor and the inhibitory effect is enhanced upon pre-incubation with the enzyme. Analysis of different steps of Top1 catalytic cycle indicates that 3 inhibits the cleavage reaction impeding the binding of the enzyme to DNA and slows down the religation reaction. Molecular docking shows that 3 preferentially binds closer to the residues of the active site when Top1 is free and lies on the DNA groove downstream of the cleavage site in the Top1-DNA complex. Thus, 3 can be considered in further studies for a possible use as an anticancer agent.

Ru(II)/clotrimazole/diphenylphosphine/bipyridine complexes: Interaction with DNA, BSA and biological potential against tumor cell lines and Mycobacterium tuberculosis

Three ruthenium complexes [RuCl(CTZ)(bipy)(P-P)]PF₆ [P-P=1,2-bis(diphenylphosphino)ethane (dppe-1), 1,4-bis(diphenylphosphino)butane (dppb-2) and 1,1'-bis(diphenylphosphino)ferrocene (dppf-3), bipy=2,2'-bipiridine and clotrimazole (CTZ) 1-[(2-chlorophenyl)diphenylmethyl]-1H-imidazole] were synthesized. These complexes were characterized by a combination of elemental analysis, molar conductivity, infrared and UV-vis spectroscopy, ¹H, ¹³C{¹H} and ³¹P{¹H} nuclear magnetic resonance techniques, cyclic voltammetry and mass spectroscopy. Bovine serum albumin binding constants, which were in the range of 1.30-36.00×10⁴M^-1, and thermodynamic parameters suggest spontaneous interactions with this protein by electrostatic forces due to the positive charge of the complexes. DNA interactions studied by spectroscopic titration, viscosity measurements, gel electrophoresis, circular dichroism, ethidium bromide displacement and reactions with guanosine and guanosine monophosphate indicated the DNA binding affinity primarily through non-covalent interactions. All complexes 1-3 were tested against the human carcinoma cell lines MCF-7 (breast), A549 (lung) and DU-145 (prostate) presenting promising IC₅₀ values, between 0.50 and 14.00μM, in some cases lower than the IC₅₀ for the reference drug (cisplatin). The antimicrobial activity assays of the complexes provided evidence that they are potential agents against mycobacterial infections, specifically against Mycobacterium tuberculosis H37Rv.

Novel Zinc(II) Complexes [Zn(atc-Et)₂] and [Zn(atc-Ph)₂]: In Vitro and in Vivo Antiproliferative Studies

Cisplatin and its derivatives are the main metallodrugs used in cancer therapy. However, low selectivity, toxicity and drug resistance are associated with their use. The zinc(II) (Zn(II)) thiosemicarbazone complexes [Zn(atc-Et)₂] (1) and [Zn(atc-Ph)₂] (2) (atc-R: monovalent anion of 2-acetylpyridine N4-R-thiosemicarbazone) were synthesized and fully characterized in the solid state and in solution via elemental analysis, Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) and proton nuclear magnetic resonance (¹H NMR) spectroscopy, conductometry and single-crystal X-ray diffraction. The cytotoxicity of these complexes was evaluated in the HepG2, HeLa, MDA-MB-231, K-562, DU 145 and MRC-5 cancer cell lines. The strongest antiproliferative results were observed in MDA-MB-231 and HepG2 cells, in which these complexes displayed significant selective toxicity (3.1 and 3.6, respectively) compared with their effects on normal MRC-5 cells. In vivo studies were performed using an alternative model (Artemia salina L.) to assure the safety of these complexes, and the results were confirmed using a conventional model (BALB/c mice). Finally, tests of oral bioavailability showed maximum plasma concentrations of 3029.50 µg/L and 1191.95 µg/L for complexes 1 and 2, respectively. According to all obtained results, both compounds could be considered as prospective antiproliferative agents that warrant further research.

Ruthenium(II) complexes of 1,3-thiazolidine-2-thione: Cytotoxicity against tumor cells and anti-Trypanosoma cruzi activity enhanced upon combination with benznidazole

Three new mixed and mononuclear Ru(II) complexes containing 1,3-thiazolidine-2-thione (tzdtH) were synthesized and characterized by spectroscopic analysis, molar conductivity, cyclic voltammetry, high-resolution electrospray ionization mass spectra and X-ray diffraction. The complexes presented unique stereochemistry and the proposed formulae are: [Ru(tzdt)(bipy)(dppb)]PF6 (1), cis-[Ru(tzdt)2(PPh3)2] (2) and trans-[Ru(tzdt)(PPh3)2(bipy)]PF6 (3), where dppb=1,4-bis(diphenylphosphino)butane and bipy=2,2'-bipyridine. These complexes demonstrated strong cytotoxicity against cancer cell lines when compared to cisplatin. Specifically, complex 2 was the most potent cytotoxic agent against MCF-7 breast cells, while complexes 1 and 3 were more active in DU-145 prostate cells. Binding of complexes to ctDNA was determined by UV-vis titration and viscosity measurements and revealed binding constant (Kb) values in range of 1.0-4.9×10(3)M(-1), which are characteristic of compounds possessing weak affinity to ctDNA. In addition, these complexes presented antiparasitic activity against Trypanosoma cruzi. Specifically, complex 3 demonstrated strong potency, moderate selectivity index and acted in synergism with the approved antiparasitic drug, benznidazole. Additionally, complex 3 caused parasite cell death through a necrotic process. In conclusion, we demonstrated that Ru(II) complexes have powerful pharmacological activity, while the metal-free tzdtH does not provoke the same outcome.

Cis-[RuCl(BzCN)(N-N)(P-P)]PF6 complexes: Synthesis and in vitro antitumor activity: (BzCN=benzonitrile; N-N=2,2'-bipyridine; 1,10-phenanthroline; P-P=1,4-bis(diphenylphosphino) butane, 1,2-bis(diphenylphosphino)ethane, or 1,1'-(diphenylphosphino)ferrocene)

The motivation to use ruthenium complexes in cancer treatment has led our research group to synthesize complexes with this metal and test them against several types of tumor cells, yielding promising results. In this paper the results of biological tests, assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, were carried out on the complexes cis-[RuCl(BzCN)(bipy)(dppe)]PF6 (1), cis-[RuCl(BzCN)(bipy)(dppb)]PF6 (2), cis-[RuCl(BzCN)(bipy)(dppf)]PF6 (3) and cis-[RuCl(BzCN)(phen)(dppb)]PF6 (4) which are described [BzCN = b enzonitrile; bipy = 2,2'-bipyridine; phen = 1,10-phenanthroline; dppe = 1,2-bis(diphenylphosphino) ethane; dppb = 1,4-bis-(diphenylphosphino)butane; dppf = 1,1'-bis(diphenylphosphino)ferrocene]. The present study is focused on the cytotoxic activity of complexes (1)-(4) against four tumor cell lines and on the apoptosis and changes in the cell cycle and gene expression observed in the sarcoma 180 (S180) tumor cell line treated with complex (1). The results demonstrated that this complex inhibits S180 cell growth, with an IC50 of 17.02 ± 8.21 μM, while exhibiting lower cytotoxicity (IC50 = 53.73 ± 5.71 μM) towards lymphocytes (normal cells). Flow cytometry revealed that the complex inhibits the growth of tumor cells by inducing apoptosis as evidenced by an increase in the proportion of cells positive for annexin V staining and G0/G1 phase cell-cycle arrest. Further investigation showed that complex (1) induces a drop in the mitochondrial membrane potential and provokes a decrease in Bcl-2 protein expression and increase in caspase 3 activation, while the increased activation of caspase 8 caused a decrease in the gene expression in caspases 3 and 9. Increases in Tp53 and Bax expressions were also observed.

Syntheses, crystal structures and antimicrobial activities of Cu(ii), Ru(ii), and Pt(ii) compounds with an anthracene-containing tripodal ligand

Three new Cu(ii), Ru(ii), and Pt(ii) compounds of an anthracene-containing tripodal ligand were synthesized. Their crystal structures was determined by a single-crystal X-ray diffraction method and their antimicrobial activities were investigated.

Hydroxyquinoline derived vanadium(IV and V) and copper(II) complexes as potential anti-tuberculosis and anti-tumor agents

Several mixed ligand vanadium and copper complexes were synthesized containing 8-hydroxyquinoline (8HQ) and a ligand such as picolinato (pic(-)), dipicolinato (dipic(2-)) or a Schiff base. The complexes were characterized by spectroscopic techniques and by single-crystal X-ray diffraction in the case of [V(V)O(L-pheolnaph-im)(5-Cl-8HQ)] and [V(V)O(OMe)(8HQ)2], which evidenced the distorted octahedral geometry of the complexes. The electronic absorption data showed the presence of strong ligand to metal charge transfer bands, significant solvent effects, and methoxido species in methanol, which was further confirmed by (51)V-NMR spectroscopy. The structures of [Cu(II)(dipic)(8HQ)]Na and [V(IV)O(pic)(8HQ)] were confirmed by EPR spectroscopy, showing only one species in solution. The biological activity of the compounds was assessed through the minimal inhibitory concentration (MIC) of the compounds against Mycobacterium tuberculosis (Mtb) and the cytotoxic activity against the cisplatin sensitive/resistant ovarian cells A2780/A2780cisR and the non-tumorigenic HEK cells (IC50 values). Almost all tested vanadium complexes were very active against Mtb and the MICs were comparable to, or better than, the MICs of drugs, such as streptomycin. The activity of the complexes against the A2780 cell line was dependent on incubation time presenting IC50 values in the 3-14 μM (at 48 h) range. In these conditions, the complexes were significantly (*P<0.05-**P<0.001) more active than cisplatin (22 μM), in the A2780 cells and even surpassing its activity in the cisplatin-resistant cells A2780cisR (2.4-8 μM vs. 75.4; **P<0.001). In the non-tumorigenic HEK cells poor selectivity toward cancer cells for most of the complexes was observed, as well as for cisplatin.

Selective anticancer copper(ii)-mixed ligand complexes: targeting of ROS and proteasomes

The ternary copper(ii) complexes 1–4 exhibited anticancer selectivity, as evidenced by MTT assay, % apoptosis, cell cycle arrest, ROS induction and DNA DSBs. Proteasome of cancer cells are also inhibited.

In vitro and in vivo activities of ruthenium(II) phosphine/diimine/picolinate complexes (SCAR) against Mycobacterium tuberculosis

Rifampicin, discovered more than 50 years ago, represents the last novel class of antibiotics introduced for the first-line treatment of tuberculosis. Drugs in this class form part of a 6-month regimen that is ineffective against MDR and XDR TB, and incompatible with many antiretroviral drugs. Investments in R&D strategies have increased substantially in the last decades. However, the number of new drugs approved by drug regulatory agencies worldwide does not increase correspondingly. Ruthenium complexes (SCAR) have been tested in our laboratory and showed promising activity against Mycobacterium tuberculosis. These complexes showed up to 150 times higher activity against MTB than its organic molecule without the metal (free ligand), with low cytotoxicity and high selectivity. In this study, promising results inspired us to seek a better understanding of the biological activity of these complexes. The in vitro biological results obtained with the SCAR compounds were extremely promising, comparable to or better than those for first-line drugs and drugs in development. Moreover, SCAR 1 and 4, which presented low acute toxicity, were assessed by Ames test, and results demonstrated absence of mutagenicity.

Antitumor and antimycobacterial activities of cyclopalladated complexes: X-ray structure of [Pd(C2,N-dmba)(Br)(tu)] (dmba=N,N-dimethylbenzylamine, tu=thiourea)

The reactions between [Pd(C(2),N-dmba)(micro-X)](2) (dmba=N,N-dimethylbenzylamine; X=Cl, Br) and thiourea (tu) in the 1:2 molar ratio at room temperature resulted in the mononuclear compounds [Pd(C(2),N-dmba)(Cl)(tu)] (1) and [Pd(C(2),N-dmba)(Br)(tu)] (2), which were characterized by elemental analyses and infrared (IR), (1)H- and (13)C{(1)H} NMR spectroscopies. The crystal and molecular structures of 2 were determined by single-crystal X-ray diffraction. In vitro cytotoxicity assays of the compounds 1, 2, tu, dmba and cisplatin were carried out using two murine tumor cell lines, namely mammary adenocarcinoma (LM3) and lung adenocarcinoma (LP07). The compounds 1, 2, tu and dmba were also tested against Mycobacterium tuberculosis and their MIC values were determined.