Antiproliferative and proapoptotic activities of methanolic extracts from Ligustrum vulgare L. as an individual treatment and in combination with palladium complex

The aim of this study is to examine the growth inhibitory effects of methanolic leaf and fruit extracts of L. vulgare on HCT-116 cells over different time periods and their synergistic effect with a Pd(apox) complex. The antiproliferative activity of plant extracts alone or in combination with the Pd(apox) complex was determined using MTT cell viability assay, where the IC(50) value was used as a parameter of cytotoxicity. Results show that antiproliferative effects of L. vulgare extracts increase with extension of exposure time, with decreasing IC(50) values, except for 72 h where the IC(50) values for methanolic leaf extract were lower than for the fruit extract. The Pd(apox) complex alone had a weak antiproliferative effect, but combination with L. vulgare extracts caused stronger effects with lower IC(50) values than with L. vulgare extracts alone. The type of cell death was explored by fluorescence microscopy using the acridin orange/ethidium bromide method. Treatments with plant extracts caused typical apoptotic morphological changes in HCT-116 cells and co-treatments with Pd(apox) complex caused higher levels of apoptotic cells than treatment with plant extracts alone. The results indicate that L. vulgare is a considerable source of natural bioactive substances with antiproliferative activity on HCT-116 cells and which have a substantial synergistic effect with the Pd(apox) complex.

Nucleic acid interaction and antibacterial behaviours of a ternary palladium(II) complexes

The bidentate ligands and Pd(II) complexes have been synthesized and characterized using elemental analysis (C, H, N), (1)H NMR, (13)C NMR, electronic spectra, FT-IR and FAB mass spectroscopy. The binding of palladium complexes with calf thymus DNA (CT DNA) has been explored using absorption titration, DNA melting temperature and viscosity measurements. The cleavage reaction on pUC19 DNA has been monitored by agarose gel electrophoresis. The results suggest that complexes can bind to DNA by intercalative modes and exhibit nuclease activities in which supercoil form is converted to open circular form. The antibacterial activity of ligands and complexes has been performed against three Gram(-ve) and two Gram(+ve) microorganisms and the study indicates that all the complexes show better microbial inhibition activity than ligands and palladium salt.

Palladium-α-lipoic acid complex attenuates alloxan-induced hyperglycemia and enhances the declined blood antioxidant status in diabetic rats

BACKGROUND

Palladium α-lipoic acid (Pd-LA) complex has unique electronic and redox properties that appear to be the key to its physiological effectiveness. A proprietary liquid blend containing Pd-LA as the major component was demonstrated to be effective in improving the activities of mitochondrial enzymes in aged rats.

METHODS

The Pd-LA complex was evaluated for its hypoglycemic effect against the alloxan-induced diabetic model, as well as in the oral glucose tolerance test in rats. The in vitro free radical scavenging activity of Pd-LA was also determined.

RESULTS

Administration of Pd-LA (0.5 mL/kg; equivalent to 3.8 mg complexed α-lipoic acid/kg, p.o.) daily for 5 days to alloxan-induced diabetic animals significantly reduced the blood glucose level (P < 0.05). The blood antioxidant status in the diabetic animals was significantly improved by the treatment of Pd-LA (P < 0.05). Similarly, Pd-LA showed significant in vitro antioxidant activity in a concentration-dependent manner.

CONCLUSIONS

Results of the study conclude that the Pd-LA complex is effective in lowering the blood glucose level and enhancing the declined antioxidant status in diabetic animals. Significant finding(s) of the study include: (i) Pd-LA significantly increased the tolerance of glucose and was also effective in ameliorating hyperglycemia induced by alloxan; (ii) Pd-LA significantly enhanced the activities of blood superoxide dismutase, catalase, glutathione peroxidase and level of glutathione in diabetic animals; and (iii) Pd-LA showed significant in vitro antioxidant activity. This study adds: The therapeutic efficiency of Pd-LA is demonstrated against declined antioxidant status as well as hyperglycemia associated with diabetes.

C7a, a biphosphinic cyclopalladated compound, efficiently controls the development of a patient-derived xenograft model of adult T cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is a highly aggressive disease that occurs in individuals infected with the human T lymphotropic virus type 1 (HTLV-1). Patients with aggressive ATLL have a poor prognosis because the leukemic cells are resistant to conventional chemotherapy. We have investigated the therapeutic efficacy of a biphosphinic cyclopalladated complex {Pd₂ [S₍₋₎C², N-dmpa]₂ (μ-dppe)Cl₂}, termed C7a, in a patient-derived xenograft model of ATLL, and investigated the mechanism of C7a action in HTLV-1-positive and negative transformed T cell lines in vitro. In vivo survival studies in immunocompromised mice inoculated with human RV-ATL cells and intraperitoneally treated with C7a led to significantly increased survival of the treated mice. We investigated the mechanism of C7a activity in vitro and found that it induced mitochondrial release of cytochrome c, caspase activation, nuclear condensation and DNA degradation. These results suggest that C7a triggers apoptotic cell death in both HTLV-1 infected and uninfected human transformed T-cell lines. Significantly, C7a was not cytotoxic to peripheral blood mononuclear cells (PBMC) from healthy donors and HTLV-1-infected individuals. C7a inhibited more than 60% of the ex vivo spontaneous proliferation of PBMC from HTLV-1-infected individuals. These results support a potential therapeutic role for C7a in both ATLL and HTLV-1-negative T-cell lymphomas.

Synthesis, structural, spectral, thermal and antimicrobial studies of palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes derived from N,N,N,N-tetradentate macrocyclic ligand

Palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes of general stoichiometry [PdL]Cl(2), [PtL]Cl(2), [Ru(L)Cl(2)]Cl and [Ir(L)Cl(2)]Cl are synthesized with a tetradentate macrocyclic ligand, derived from 2,6-diaminopyridine with 3-ethyl 2,4-pentanedione. Ligand was characterized on the basis of elemental analyses, IR, mass, and (1)H NMR and (13)C NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, electronic spectral techniques and thermal studies. The value of magnetic moments indicates that all the complexes are diamagnetic except Ru(III) complex which shows magnetic moments corresponding its one unpaired electron. The macrocyclic ligand and all its metal complexes were also evaluated in vitro against some plant pathogenic fungi and bacteria to assess their biocidal properties.

Palladium(II) complex with S-allyl-L-cysteine: new solid-state NMR spectroscopic measurements, molecular modeling and antibacterial assays

Nuclear magnetic resonance studies, molecular modeling and antibacterial assays of the palladium(II) complex with S-allyl-L-cysteine (deoxyalliin) are presented. Studies based on solid and solution 13C and 15N nuclear magnetic resonance (NMR) spectroscopy confirmed that the palladium(II) complex preserved the same structural arrangement in both states, with no modifications on coordination sphere when dissolved in water. Density functional theory (DFT) studies stated that the trans isomer is the most stable one. Antibacterial activities of S-allyl-L-cysteine and its palladium(II) complex were evaluated by antibiogram assays using the disc diffusion method. The palladium(II) complex showed an effective antibacterial activity against Staphylococcus aureus (Gram-positive), Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacterial cells.

Palladium(II) and platinum(II) derivatives of benzothiazoline ligands: Synthesis, characterization, antimicrobial and antispermatogenic activity

A series of Pd(II) and Pt(II) complexes with two N(∩)S donor ligands, 5-chloro-3-(indolin-2-one)benzothiazoline and 6-nitro-3-(indolin-2-one)benzothiazoline, have been synthesized by the reaction of metal chlorides (PdCl2 and PtCl2) with ligands in 1:2 molar ratios. All the synthesized compounds were characterized by elemental analyses, melting point determinations and a combination of electronic, IR, 1H NMR and 13C NMR spectroscopic techniques for structure elucidation. In order to evaluate the effect of metal ions upon chelation, both the ligands and their complexes have been screened for their antimicrobial activity against the various pathogenic bacterial and fungal strains. The metal complexes have shown to be more antimicrobial against the microbial species as compared to free ligands. One of the ligands, 5-chloro-3-(indolin-2-one)benzothiazoline and its corresponding palladium and platinum complexes have been tested for their antifertility activity in male albino rats. The marked reduction in sperm motility and density resulted in infertility by 62-90%. Significant alterations were found in biochemical parameters of reproductive organs in treated animals as compared to control group. It is concluded that all these effects may finally impair the fertility of male rats.

Evaluation of cytotoxicity of new trans-palladium(II) complex in human cells in vitro

Studies of cytotoxicity allow to elucidate the mechanisms by which chemical compounds influence cells and tissues. On the basis of the structural analogy between platinum(II) and palladium(II) complexes, a variety of studies on palladium(II) compounds as potential anticancer drugs have been carried out (1, 2). The cytotoxicity was evaluated by MTT assay. Abilities of trans-palladium(II) complex containing diethyl (pyridin-2-ylmethyl)phosphates as non-leaving ligands (trans-[PdCl2(2-pmOpe 2)]) to induce apoptosis and necrosis in normal lymphocytes, A549 cells and HT29 cell lines were performed by use of fluorochrome staining. The obtained results revealed, that the new trans-palladium(II) complex was more cytotoxic against A549 and HT29 tumor cells than on the normal lymphocytes in vitro. The novel complex induces apoptosis in all tested cells, but in lymphocytes to a lesser degree. The compound tested also induced significant amounts of necrotic cells, which exceeded the level of apoptotic cell fractions. The results demonstrate that the trans-Pd(II) complex showed substantial cytotoxic activity against A549 and HT29 tumor cells and indicate that the new trans-palladium(II) complex effectively inhibited cancer cells growth.

Noble metal targeting of thioredoxin reductase--covalent complexes with thioredoxin and thioredoxin-related protein of 14 kDa triggered by cisplatin

Palladium (Pd), platinum (Pt), and gold (Au) are noble metals, two of which have established medical use. Pt has anticancer efficacy, predominantly as cisplatin, whereas the gold compound auranofin is used against arthritis. Both compounds inhibit the selenoprotein thioredoxin reductase (TrxR), but Pd has not been studied in this regard. Using salts of Pd, Pt, and Au as well as cisplatin and auranofin we found that Pd and Au were strikingly more potent inhibitors of recombinant TrxR1 than Pt. The TrxR-related nonselenoprotein glutathione reductase in pure form (but less so in a cellular context), as well as cellular thioredoxin (Trx) activities, were inhibited by the gold salt KAuCl(4) but were little affected by auranofin or the other compounds. In an analysis of three cancer cell lines, the extent of inhibition of TrxR activity and decrease in cell viability depended upon the choice of both noble metal and ligand and also seemed independent of p53 status. During treatment of cells with cisplatin, covalent complexes of TrxR1 with either Trx1 or TRP14 (Trx-related protein of 14kDa) were formed, as verified by Western blot analyses and mass spectrometry. These results reveal that Au and Pd are strong inhibitors of TrxR, but Pt and cisplatin trigger highly specific cellular effects on the Trx system, including covalent cross-linking of TrxR1 with Trx1 and TRP14.

Synthesis, characterization and cytotoxicity studies of palladium(II)-proflavine complexes

An investigation of the reaction of Pd(II) complexes with proflavine (3,6-diaminoacridine) resulted in the isolation of the compounds [Pd(terpy)(proflavine)](NO(3))(HSO(4))*3H(2)O, 1, (terpy = 2,2':6',2″-terpyridine), [Pd(en)(proflavineH))](NO(3))(SO(4)), 2, (en = ethylenediamine), and [Pd(proflavineH)Cl(2)](SO(4))(0.5)*H(2)O, 3. They have been isolated and characterized by NMR, IR, and electro-spray ionization mass spectrometry techniques and by elemental analyses. The proflavine was bonded to the Pd(II) through the endocyclic nitrogen in 1, but through the proflavine NH(2) in 2. Compound 3 appeared to be polymeric in the solid state with a 1:1 mole ratio of Pd(II):proflavine. Upon solution of 3 in DMSO, two unique species were formed. In one species the Pd(II) was bonded to two proflavines through the endocyclic nitrogen (1:2 mole ratio) and in the other species, a Pd(II) was bonded to each NH(2) group of a single proflavine (2:1 mole ratio). Molecular modeling of the equilibrium geometry by Spartan 8 produced structures which were consistent with the experimental data on the solutions of the three compounds. In vitro cytotoxicity testing against two breast cancer cell lines and one ovarian cancer cell line showed that compounds 1 and 3 had significant activity.

Interaction studies between a 1,10-phenanthroline adduct of palladium(II) dithiocarbamate anti-tumor complex and calf thymus DNA. A synthesis spectral and in-vitro study

The interaction of calf thymus DNA (CT-DNA) with a novel synthesized and characterized Palladium (II) complex with the formula of [Pd (Et-dtc) (phen)] NO(3) (where phen is 1,10-phenanthroline and Et-dtc is ethyldithiocarbamate) was extensively studied by various spectroscopic techniques. UV-vis studies imply that there is a set of 6 binding sites for the complex on DNA with positive cooperativity in the binding process. This complex unexpectedly denatures the DNA at very low concentration (approximately 9.8 microM). Gel filtration studies indicate that the binding of metal complex with DNA is strong enough not to readily break. Fluorescence studies show that the palladium complex intercalates in DNA through the planar 1,10-phenanthroline ligand presented in its structure. Several binding and thermodynamic parameters are also described. Furthermore, anti-tumor studies of this water soluble complex against human cell tumor lines (K562) have been done. It shows 50% cytotoxic concentration (Ic(50)) value much lower than that of cisplatin.

In vitro and in vivo trypanocidal effects of the cyclopalladated compound 7a, a drug candidate for treatment of Chagas' disease

Chagas' disease, a neglected tropical infection, affects about 18 million people, and 100 million are at risk. The only drug available, benznidazole, is effective in the acute form and in the early chronic form, but its efficacy and tolerance are inversely related to the age of the patients. Side effects are frequent in elderly patients. The search for new drugs is thus warranted. In the present study we evaluated the in vitro and in vivo effect of a cyclopalladated compound (7a) against Trypanosoma cruzi, the agent of Chagas' disease. The 7a compound inhibits trypomastigote cell invasion, decreases intracellular amastigote proliferation, and is very effective as a trypanocidal drug in vivo, even at very low dosages. It was 340-fold more cytotoxic to parasites than to mammalian cells and was more effective than benznidazole in all in vitro and in vivo experiments. The 7a cyclopalladate complex exerts an apoptosis-like death in T. cruzi trypomastigote forms and causes mitochondrion disruption seen by electron microscopy.

Effects of palladium nanoparticles on the cytokine release from peripheral blood mononuclear cells of non-atopic women

The object of this study is to determine the cytokine release from PBMCs exposed to Pd model nanoparticles emitted from catalytic converters. PBMCs of 8 healthy non-atopic women were incubated in the presence of Pd nanoparticles (5-10 nm) or salt (potassium hexa-chloropalladate) 10-5 and 10-6 M. Release of cytokines in supernatant of PBMCs was then determined. In cultures without LPS, IL-10 and IL-17 release from PBMCs was inhibited by Pd salt, while Pd nanoparticles inhibited TNF-alpha and IL-17 release. In LPS-stimulated cultures, release of IFN-gamma, TNF-alpha, IL-10 and IL-17 was inhibited by Pd salt, whereas IFN-gamma release was enhanced and TNF-alpha and IL-17 release was inhibited by Pd nanoparticles. In conclusion, Pd salt inhibits cytokine release, whereas Pd nanoparticles exert modulatory effects enhancing the release of IFN-gamma, a Th1 cytokine typical of delayed allergic reactions. This result is interesting considering the increase of allergic contact dermatitis to Pd in people exposed to Pd nanoparticles in urban environments.

Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines

Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C(9)H(13)N(3)OS(2) or L(1)H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C(9)H(13)N(3)OS or L(2)H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, (1)H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

Recent advancements and challenges of palladium(II)-catalyzed oxidation reactions with molecular oxygen as the sole oxidant

During the past 10 years there have been significant advances in Pd(II)-catalyzed oxidation reactions where the use of ligands has led to the development of catalytic systems capable of achieving high turnover numbers, which employ molecular oxygen as the sole stoichiometric oxidant. This Feature article will highlight some of the recent developments in direct molecular oxygen-coupled Pd(II)-catalyzed oxidation reactions with an emphasis on enhanced catalytic systems and new reactions. Additionally, limitations of current catalytic systems, such as ligand oxidation, are presented and their implications for the development of new reactions are discussed.

Structural and biological studies of mononuclear palladium(II) complexes containing N-substituted thiosemicarbazones

New complexes of Pd(II) with N-substituted thiosemicarbazone (1)-(3) have been synthesised and characterised by elemental analyses, IR, electronic, (1)H NMR spectroscopies. The electrochemical behaviour of the complexes has been tested by using cyclic voltammetry. The crystal structures of the complexes have been determined by single crystal X-ray diffraction technique. In all the complexes the thiosemicarbazone ligand is coordinated to palladium through ONS mode. The complex 1 crystallises in the monoclinic space group P2(1)/c with two molecules per unit cell, has the dimensions of a=9.4390(19)A, b=10.645(2)A, c=13.668(3)A, alpha=90 degrees , beta=91.43 degrees and gamma=90 degrees . The complex 3 crystallises in the monoclinic space group P2(1)/c with four molecules per unit cell, has the dimensions of a=14.119(3)A, b=11.155(2)A, c=18.503(4)A, alpha=90 degrees , beta=112.02 degrees and gamma=90 degrees . The new complexes have been tested for their antibacterial activity against various pathogenic bacteria. From this study, it was found out that the activity of the complex 2 almost reaches the effectiveness of the conventional bacteriocide Streptomycin.

Palladium alters cigarette smoke toxicological profile, but accumulates in the lungs of rats during inhalation exposure

The use of a palladium (Pd) catalyst has been proposed to promote combustion of tobacco, thereby reducing concentrations of certain toxic components of smoke, including polyaromatic hydrocarbons (PAHs). In the present work, toxicological comparisons were made using experimental cigarettes containing no added Pd, against otherwise similar cigarettes containing three different amounts of Pd as potassium tetrachloropalladate added to the tobacco. A full analysis of smoke chemistry was made, along with a subchronic 90-day inhalation study with mainstream smoke (rats exposed to 150 mg/m(3) of total particulate matter, 6 h/day for 90 consecutive days) and in vitro evaluations of Salmonella mutagenicity, cytotoxicity, and in vivo clastogenicity (micronucleus). Addition of Pd to the tobacco resulted in 20-30% reductions in the concentrations of 6 PAHs and 2 aromatic amines, but it also resulted in transfer of Pd to smoke and in 10-50% increases in concentrations of several tobacco-specific nitrosamines. Mutagenicity was reduced by about 50% in 2 of 5 strains of Salmonella (with S9 only), while the cytotoxicity and micronucleus assays showed no changes. Histopathology responses were similar across the four smoke inhalation groups. Smoke Cd was reduced by 40-70% in the smoke, leading to lower lung concentrations; however, the presence of Pd in smoke led to accumulation of Pd in the lungs increasing in both a dose-and an exposure-related manner. While catalysts such as Pd addition may alter the typical chemical/toxicological profile of smoke, a concern arises regarding the "risk-benefit" of the addition of such chemically active materials as Pd to cigarette tobacco, leading to potential pulmonary accumulation with unknown consequences.

Comparison of sensitizers by detecting reactive oxygen species after photodynamic reaction in vitro

The production of reactive oxygen species (ROS) has a crucial effect on the result of photodynamic therapy (PDT). Because of this fact, we examined the ROS formation by means of three porphyrin sensitizers (TPPS(4), ZnTPPS(4) and PdTPPS(4)) and compared their effectivity for induction of cell death in the G361 (human melanoma) cell line. The porphyrins used are very efficient water-soluble aromatic dyes with a potential application in photomedicine and have a high tendency to accumulate in the membranes of intracellular organelles such as lysosomes and mitochondria. Interaction between the triplet excited state of the sensitizer and molecular oxygen leads to the production singlet oxygen and other reactive oxygen species to induce cell death. Production of ROS was investigated by molecular probe CM-H(2)DCFDA. Our results demonstrated that ZnTPPS(4) induces the highest ROS production in the cell line compared to TPPS(4) and PdTPPS(4) at concentrations of 1, 10, and 100 microM and light dose of 1 J cm(-2). We also observed a consequence between ROS production and cell survival. In conclusion, these results demonstrate that photodynamic effect depends on sensitizer type, its concentration and light dose.

Novel cyclopalladated and coordination palladium and platinum complexes derived from α-diphenyl ethanedione bis(thiosemicarbazones): Structural studies and cytotoxic activity against human A2780 and A2780cisR carcinoma cell lines

The preparation of new palladium(II) and platinum(II) complexes derived from alpha-diphenyl ethanedione bis(thiosemicarbazone), 1, and alpha-diphenyl ethanedione bis(4-ethylthiosemicarbazone), 2, is described. The palladium complexes 3 and 4 and platinum complexes 5 and 6 have been characterized by elemental analyses, fast atom bombardment mass spectrometry (FAB(+)) and spectroscopic studies (IR, (1)HNMR). The crystal and molecular structures of the dimeric cyclopalladated compound 4 and the mononuclear platinum complex 6 have been determined by single crystal X-ray diffraction. The cytotoxic activity of the free ligands and palladium and platinum complexes against human A2780 and A2780cisR (acquired resistance to cisplatin) epithelial ovarian carcinoma cells lines is also reported. The IC(50) values for compounds 1, 5 and 6 were found to be higher than that of cisplatin but the maximum antiproliferative activity was similar. Furthermore, the compounds largely retain their activity in the A2780cisR cell line, having a much better resistance factor than cisplatin in the pair of cell lines tested.

103Pd-induced apoptosis of proliferative smooth muscle cells in bile ducts of dogs: significance and effects on related genes

BACKGROUND

With the objective of developing a locally-produced radioactive stent, the present study used in vivo animal experiments to explore apoptosis of proliferative smooth muscle cells resulting from facilitation of the expression of genes caused by gamma-radiation in order to prevent bile duct restenosis. We therefore explored the effects and significance of gamma-radiation on the activity of caspase-3, Fas and Bcl-2 genes in apoptosis of proliferative smooth muscle cells in the bile duct walls of dogs.

METHODS

Twelve dogs were randomly divided into 2 groups (6 in each group). A postinjury bile duct stenosis model was established and radioactive (103)Pd ((103)palladium) or ordinary bile duct stents were implanted into the bile ducts. HE staining, RT-PCR and immunohistochemistry were used to detect the proliferation and apoptosis of bile duct smooth muscle cells in proliferative endomembrane and the expression of related caspase-3, Bcl-2 and Fas genes.

RESULTS

The expression of caspase-3 and Fas genes in the bile duct tissues of dogs with radioactive stents was higher than that of dogs with ordinary stents. There was significant apoptosis of proliferative smooth muscle cells in the bile ducts. The expression of the Bcl-2 gene in the bile duct tissues of dogs with radioactive stents was lower than that in those with ordinary stents. There was significant apoptosis of proliferative smooth muscle cells in the dogs with low Bcl-2 gene expression.

CONCLUSIONS

Radiation increases the activity of caspase-3 and Fas genes and is associated with apoptosis. The radioactive (103)Pd stent may facilitate apoptosis of proliferative smooth muscle cells in the bile ducts of dogs by activating these genes. The Bcl-2 gene expression level is correlated with the occurrence of apoptosis and the radiosusceptibility of cells.

Cytotoxic effect, differentiation, inhibition of growth and theoretical calculations of an N,N-donor ligands and its platinum(II), palladium(II) and copper(II) complexes

The new pyrazole ligand 5-(2-hydroxyphenyl)-3-methyl-1-(2-pyridylo)-1H-pyrazole-4-carboxylic acid methyl ester (2) and the corresponding Pt(II), Pd(II) and Cu(II) complexes 3-5 have been synthesized as potential anticancer compounds, and characterized using IR, and (1)H NMR as well as mass spectrometry. The 3-D structures of the Cu(II) complexes were determined by quantum mechanic calculation DFT methodology (density functional theory). The cytotoxicity assay of the ligand and complexes has been performed on leukemia cell lines. In general, the complexes showed lower cytotoxicity than cisplatin, and the Pt(II) and Cu(II) complexes were found to be more efficient in the induction of leukemia cell death than the Pd(II) complex. Our investigations indicate that the antiproliferating activity of the Pt(II) and Cu(II) complexes was partly due to the modulation of cellular differentiation.

Raman, FT-IR, NMR spectroscopic data and antimicrobial activity of bis[μ2-(benzimidazol-2-yl)-2-ethanethiolato-N,S,S-chloro-palladium(II)] dimer, [(μ2-CH2CH2NHNCC6H4)PdCl]2·C2H5OH complex

The 1,6-bis(benzimidazol-2-yl)-3,4-dithiahexane (1) ligand and its palladium(II) chloride complex [(micro(2)-SCH(2)CH(2)NHNCC(6)H(4))PdCl](2)xC(2)H(5)OH (2) have been synthesised and characterised by spectroscopical methods. The crystal structure of the triclinic title compound (P-1 (no. 2), a=879.6(1) pm, b=984.4(1) pm, c=1471.8(2) pm; alpha=94.330(6) degrees , beta=98.546(6) degrees , gamma=99.258(7) degrees , Z=2) was solved from X-ray single crystal diffraction data. In the binuclear complex, each palladium atom is coordinated in a slightly distorted square-planar arrangement by one nitrogen, two bridging sulphurs and one terminal chlorine atom. Molar conductivity, FT-Raman, FT-IR (mid-i.r., far-i.r.), (1)H and (13)C NMR spectra of the complex (2) have been recorded and show a good accordance with the square-planar geometry. The antimicrobial and antifungal activities of palladium(II) chloride, free ligand, its hydrochloride salt and the complex were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) the dilution method, against 10 bacteria and five yeast cultures. The results for the antibacterial from the disk diffusion method were assessed in side-by-side comparison with those for penicillin-g, ampicillin, cefotaxime, vancomycin, ofloxacin and tetracycline. Antifungal activities were referenced with nystatin, ketaconazole, and clotrimazole, commercial antifungal agents. The data from the dilution procedure were compared with gentamycin as antibacterial and nystatin as antifungal agent, respectively. In most cases, the compounds tested showed broad-spectrum (Gram positive and Gram negative) activities that were comparatively more active, or as potent as referenced pharmaceutical agents. The palladium complex has the potential to generate new kind of metabolites by displaying high affinities for most of the receptors compared with palladium chloride, free ligand and its hydrochloride salt.

Synthesis, spectroscopic characterization and biological analysis of a new palladium(II) complex with methionine sulfoxide

A new palladium(II) complex with methionine sulfoxide was synthesized and characterized by a set of chemical and spectroscopic techniques. Elemental and mass spectrometry analyses of the solid complex fit to the composition [Pd(C5H10NO3S)2].H2O. 13C NMR, [1H-15N] NMR and infrared spectra indicate coordination of the amino acid to Pd(II) through the carboxylate and amino groups in a square planar geometry. The complex is soluble in water. Biological activity was evaluated by cytotoxic analysis using HeLa cells. Determination of cell death was assessed using a tetrazolium salt colorimetric assay, which reflects the cells viability. After incubation for 48 h, 20% of cell death was achieved at a concentration of 200 micromol L-1 of the complex.