Disturbance of suprachiasmatic nucleus function improves cardiac repair after myocardial infarction by IGF2-mediated macrophage transition.

Suprachiasmatic nucleus (SCN) in mammals functions as the master circadian pacemaker that coordinates temporal organization of physiological processes with the environmental light/dark cycles. But the causative links between SCN and cardiovascular diseases, specifically the reparative responses after myocardial infarction (MI), remain largely unknown. In this study we disrupted mouse SCN function to investigate the role of SCN in cardiac dysfunction post-MI. Bilateral ablation of the SCN (SCNx) was generated in mice by electrical lesion; myocardial infarction was induced via ligation of the mid-left anterior descending artery (LAD); cardiac function was assessed using echocardiography. We showed that SCN ablation significantly alleviated MI-induced cardiac dysfunction and cardiac fibrosis, and promoted angiogenesis. RNA sequencing revealed differentially expressed genes in the heart of SCNx mice from D0 to D3 post-MI, which were functionally associated with the inflammatory response and cytokine-cytokine receptor interaction. Notably, the expression levels of insulin-like growth factor 2 (Igf2) in the heart and serum IGF2 concentration were significantly elevated in SCNx mice on D3 post-MI. Stimulation of murine peritoneal macrophages in vitro with serum isolated from SCNx mice on D3 post-MI accelerated the transition of anti-inflammatory macrophages, while antibody-mediated neutralization of IGF2 receptor blocked the macrophage transition toward the anti-inflammatory phenotype in vitro as well as the corresponding cardioprotective effects observed in SCNx mice post-MI. In addition, disruption of mouse SCN function by exposure to a desynchronizing condition (constant light) caused similar protective effects accompanied by elevated IGF2 expression on D3 post-MI. Finally, mice deficient in the circadian core clock genes (Ckm-cre; Bmal1f/f mice or Per1/2 double knockout) did not lead to increased serum IGF2 concentration and showed no protective roles in post-MI, suggesting that the cardioprotective effect observed in this study was mediated particularly by the SCN itself, but not by self-sustained molecular clock. Together, we demonstrate that inhibition of SCN function promotes Igf2 expression, which leads to macrophage transition and improves cardiac repair post-MI.

Dicyanamide Bridged Cu(II)36-Metallacrown-6 Complex with 1,4,7-Triisopropyl-1,4,7-Triazacyclononane and Binding Properties with DNA.

A novel 36-metallacrown-6 complex [CuL(N(CN)2)(PF6)]6∙0.5H2O 1 was achieved using a tridendate ligand, 1,4,7-triisopropyl-1,4,7-triazacyclononane (L), and a flexible ligand, dicyanamide in MeOH. The µ1,5 bridging models of the dicyanamide ligand linked the macrocycle to form in a specific size with the chair conformation. The anion was important to form this 36-metallacrown-6 complex, as change was obtained with the larger anion BPh4-, binuclear copper compound 2. The magnetic property indicates that slightly ferromagnetic interactions resulted from a superexchange mechanism. DNA binding properties were also studied. UV and fluorescence spectra showed that complex 1 could bind with DNA.

Synthesis, magnetism and spectral studies of six defective dicubane tetranuclear {M4O6} (M = Ni(II), Co(II), Zn(II)) and three trinuclear Cd(II) complexes with polydentate Schiff base ligands.

A series of Ni(II), Co(II), Zn(II) and Cd(II) complexes with polytopic Schiff base ligands have been synthesized. The single-crystal X-ray crystallography results show that tetranuclear complexes have common face-shared defective dicubane cores, whereas trinuclear Cd(II) complexes are almost linear entities. Synthesis methods (solvent evaporation and hydrothermal synthesis), reaction conditions (pH, solvents and dosage) and coligands (azide, methanol, chloride and acetate) play vital roles in determining the final structure of the complexes and therefore their magnetic properties. In complexes , the terminal and central M(2+) ions are connected through mixed bridges, µ-phenoxido/µ1,1,1-X and µ-Oalphatic/µ1,1,1-X, while central two M(2+) ions are linked by double bridges, µ1,1,1-X (X = azido and methoxido groups for and respectively). For complex , two central Ni(II) ions are connected through two µ1,1,1-N3(-) which is relatively less reported. For complexes , there are two kinds of Cd(II), the centre Cd(II) ions are eight-coordinated with triangle dodecahedral geometries, while the two side Cd(II) ions are six-coordinated with trigonal prism geometries using chlorides or acetates as terminal ligands. Magnetic susceptibility measurements (χM) for compounds have been performed, and they reveal predominant ferromagnetic exchange interactions in Co(II) and Ni(II) tetramers. The photoluminescence studies show that the Zn(II) complex and three Cd(II) complexes have strong fluorescence, and the lifetimes are measured to be in the 10(2) nanosecond timescale.

Copper complexes based on chiral Schiff-base ligands: DNA/BSA binding ability, DNA cleavage activity, cytotoxicity and mechanism of apoptosis.

Four copper(II) complexes with chiral Schiff-base ligands, [Cu(R-L(1))2]·EtOAc (1) and [Cu(S-L(1))2]·EtOAc (2), [Cu(R-L(2))2]·EtOAc (3) and [Cu(S-L(2))2]·EtOAc (4), (R/S-HL(1) = (R/S)-(1-naththyl)-salicylaldimine, R/S-HL(2) = (R/S)-(1-naththyl)-3-methoxysalicylaldimine, EtOAc = ethyl acetate) were synthesized to serve as artificial nucleases and anticancer drugs. All complexes and R/S-HL(1) ligands were structurally characterized by X-ray crystallography. The interaction of these complexes with CT-DNA was researched via several spectroscopy methods, which indicates that complexes bind to CT-DNA by moderate intercalation binding mode. Moreover, DNA cleavage experiments revealed that the complexes exhibited remarkable DNA cleavage activities in the presence of H2O2via the generation of hydroxyl radical. Particularly, complex 4 also could nick DNA with the production of (1)O2. And all complexes exhibited excellent cytotoxicity to MDA-MB-231, A549 and Hela human cancer cells in micromole magnitude. Furthermore, complex 4 exhibited comparable cytotoxic effect to cisplatin against the proliferation of MDA-MB-231 and A549 cancer cells, as well as showed better anticancer ability to the three cancer cells than the other complexes. The results of cell cycle analysis indicated that complexes 3-4 could induce G2/M phase cell cycle arrest. Furthermore, MDA-MB-231 cells treated with 3 and 4 were subjected to apoptosis and death by generation of ROS and the activation of caspase-3. Interestingly, the chiral complexes 3 and 4 may induce cell apoptosis through extrinsic and mitochondrial intrinsic pathway, respectively.

Efficacy and safety of anticoagulation therapy with different doses of enoxaparin for portal vein thrombosis in cirrhotic patients with hepatitis B.

BACKGROUND: Patients with cirrhosis have a high incidence of portal vein thrombosis (PVT), and optimal management of PVT in cirrhotic patients remains unclear. Currently, there is no paper on optimal doses of enoxaparin for the management of PVT with cirrhosis. AIMS: To evaluate the efficacy and safety of anticoagulation therapy with different doses of enoxaparin for PVT in cirrhotic patients with hepatitis B. MATERIALS AND METHODS: Sixty-five patients with hepatitis B-related cirrhosis and acute PVT were treated by different doses of enoxaparin. All the patients were assigned randomly to two groups: one group received enoxaparin 1 mg/kg subcutaneously every 12 h and the other group received enoxaparin 1.5 mg/kg subcutaneously every 24 h. Clinical, biochemical evaluation, Doppler ultrasound, and contrast-enhanced computed tomography were performed during the anticoagulation treatment. RESULTS: Of the 65 patients, 51 patients (78.5%) achieved complete/partial recanalization of PVT after 6 months of anticoagulation therapy. Child-Pugh scores were lower in the 51 patients who achieved complete/partial recanalization than those of the 14 nonresponders (P<0.01). No patients showed variceal bleeding during anticoagulation therapy in the two groups. The rates of nonvariceal bleeding with the use of 1.5 mg/kg every 24 h (23.5%) were higher than those with the use of 1 mg/kg every 12 h (6.4%). CONCLUSION: Anticoagulation therapy with different doses of enoxaparin for PVT in hepatitis B patients with cirrhosis is efficient and safe, and 1 mg/kg enoxaparin subcutaneously every 12 h is a better anticoagulation regimen in the treatment of PVT in cirrhotic patients.

Synthesis, characterization, DNA/BSA interactions and anticancer activity of achiral and chiral copper complexes.

Six novel copper(ii) complexes of [CuCl]ClO4 (), [Cu(acac)]PF6 (), [CuCl]2(PF6)2 (), [CuCl]2(PF6)2 (), [Cu(acac)]PF6 () and [Cu(acac)]PF6 (), ( = 1-naphthyl-N,N-[bis(2-pyridyl)methyl]amine, = R/S-1-naphthyl-N,N-[bis(2-pyridyl)methyl]ethanamine, acac = diacetone) were synthesized to serve as artificial nucleases. All complexes were structurally characterized using X-ray crystallography. The crystal structures showed the presence of distorted square-planar CuLCl (, and ) and distorted tetragonal-pyramidal CuL(acac) (, and ) geometry. The interaction of these complexes with calf thymus DNA (CT-DNA) was researched by means of several spectroscopy methods, which indicated that the complexes were bound to CT-DNA by an intercalation binding mode. DNA cleavage experiments revealed that the complexes exhibited remarkable DNA cleavage activities in the presence of H2O2, and single oxygen ((1)O2) or hydroxyl radicals may serve as the major cleavage active species. In particular, the in vitro cytotoxicity of the complexes on four human cancer cell lines (HeLa, MCF-7, Bel-7404 and HepG-2) demonstrated that the six compounds had broad-spectrum anti-cancer activity with low IC50 values. The stronger cytotoxicity and DNA cleavage activity of the chiral enantiomers compared with chiral analogues verified the influence of chirality on the antitumor activity of complexes. Meanwhile, the protein binding ability was revealed by quenching of tryptophan emission with the addition of complexes using BSA as a model protein. The results indicated that the quenching mechanism of BSA by the complexes was a static process.

Solvent effects on the structures and magnetic properties of two doubly interpenetrated metal-organic frameworks.

Two doubly interpenetrated coordination polymers [Co2(BDC)2(bpt)2]·nSolvent based on dimeric secondary building units and crystallizing with distinct solvent molecules (-H2O and -MeOH for nSolvent = 2H2O and MeOH·H2O, respectively) were obtained by employing 1,4-benzenedicarboxylate (BDC) and 1H-3,5-bis(4-pyridyl)-1,2,4-triazole) (bpt) as linkers. The structures consist of a square grid of dimers bridged by BDC and pillared by bpt. Thermogravimetry and PXRD indicate that the frameworks are stable and are retained up to 400 °C, but the structures are modified irreversibly. -H2O, high-symmetry Pna21, exhibits antiferromagnetic coupling within the dimer, while -MeOH, low-symmetry P21/n, exhibits ferromagnetic coupling. Upon desolvation, the -de and -de couplings are antiferromagnetic but reduced. Subsequent resolvation to -H2O and -MeOH resulted in a slight increase of the antiferromagnetic coupling without attaining the virgin states. The interesting difference of magnetic properties between -H2O and -MeOH, the solvated/desolvated phases, particularly at low temperature, indicates that there is a prominent solvent effect.

A new model combining the liver/spleen volume ratio and classification of varices predicts HVPG in hepatitis B patients with cirrhosis.

BACKGROUND: Although the therapy of varices in liver cirrhosis has improved, the mortality during a variceal hemorrhage episode remains high. Patients with hepatic venous pressure gradient (HVPG) greater than 12 mmHg have been identified as being at a higher risk for the first hemorrhage episode. AIMS: The aim of this study was to find an accurate method to predict HVPG greater than 12 mmHg. METHODS: A total of 150 hepatitis B patients with liver cirrhosis were enrolled and analyzed retrospectively. The patients were randomly divided into the experiment group and the validation group. The experiment group was used to construct a model to predict HVPG greater than 12 mmHg. The validation group was used to verify the predictive equation. RESULTS: The predictive model combined with the liver/spleen volume ratio and classification of varices was constructed to predict HVPG greater than 12 mmHg. The area under the curve of this predictive equation was 0.919. The values of sensitivity, specificity, positive predictive value, and negative predictive value were 92.9, 87.0, 89.7, and 90.9%, respectively. The following equation was used to calculate the HVPG score: HVPG score = 13.651 - 6.187×ln (liver/spleen volume)+2.755×[classification of varices score (classification of varices : small, 1; large; 2]. CONCLUSION: The new model combining the liver/spleen volume ratio and classification of varices can accurately predict HVPG in hepatitis B patients with cirrhosis.

Bio-relevant cobalt(II) complexes with compartmental polyquinoline ligand: synthesis, crystal structures and biological activities.

Three new Co(II) complexes, [Co4(L)2(µ3-CrO4)2](ClO4)2·2CH3CN (1), [Co2(L)(µ2-na)(H2O)](ClO4)2 (2) and [Co2(L)(µ2-ba)](ClO4)2·0.5CH3CN (3) (Hna=nicotinic acid, Hba=benzoic acid, HL=N,N,N',N'-tetrakis (2-quinolylmethyl)-1,3-diaminopropan-2-ol), have been synthesized and characterized by various physicochemical techniques. The Co(II) centers are connected by endogenous alkoxy bridge from L(-) and various extrinsic auxiliary linkers, some of which display coordination number asymmetry (5, 6-coordinated for 1 and 2; 5, 5-coordinated for 3). It is worth mentioning that complex 1 contains two rare reported µ3-η(1), η(1), η(1)-CrO4(2-) moieties. Susceptibility data of three complexes indicated intramolecular antiferromagnetic coupling of high-spin Co(II) atoms with exchange integral values (J) -14.94 cm(-1), -11.26 cm(-1) and -13.66 cm(-1) for 1, 2 and 3, respectively. Interaction of compounds with calf thymus DNA (CT-DNA) have been investigated by absorption spectral titration, ethidium bromide (EB) displacement assay and viscosity measurement, which revealed that compounds bound to CT-DNA with a moderate intercalative mode, accompanied the affinities order: 1>2≈3. Three complexes exhibit oxidative cleavage of pBR322 plasmid DNA including a reliance on H2O2 as the activator. Compound 1 demonstrates an increased DNA cleavage activity as compared with 2 and 3, which could degrade super coiled DNA (SC DNA) into nicked coiled DNA (NC DNA) in lower concentration (5 µM). Moreover, all compounds could quench the intrinsic fluorescence of bovine serum albumin (BSA) in a static quenching process. Complex 1 also shows higher anticancer activity than cisplatin with lower IC50 value of incubation for both 24 h and 48 h.

A novel inflammatory regulator TIPE2 inhibits TLR4-mediated development of colon cancer via caspase-8.

AIMS: TIPE2 is a novel inflammation regulator, and the role of TIPE2 in colitis-induced colon cancer is not clear. The aim of this study was to test whether TIPE2 inhibits TLR4 pathway in colon cancer patients and to explore potential mechanism of TIPE2 in colon cancer by caspase-8. METHODS: Expression of TIPE2 and TLR4 in human colon cancer tissues and cell line HT-29 was detected by immunohistochemistry or real-time PCR. TIPE2 mRNA was suppressed by siRNA transfection and the transfection efficiency was proved by fluorescence microscopy and real-time PCR. TLR4 pathway was activated by treating the cells with 1 µg/ml LPS for 4 h. Caspase-8 activities were tested by colorimetric assay in four HT-29 cell groups. RESULTS: TIPE2 was expressed in the cytoplasm of colon cancer tissues and HT-29 cells. TIPE2 expression was more pronounced in colon cancer tissues compared to normal controls and it was related with lymph node metastasis and Dukes stage of colon cancer. TIPE2 expression was positively correlated with that of TLR4 in colon cancer (r=0.7354). TIPE2 expression was knocked down successfully by siRNA transfection. Caspase-8 activity was elevated both in TIPE2 knockdown cells and in TLR4 activated cells compared to wild-type cells (P< 0.05). And the caspase-8 activity was further increased in TIPE2 knockdown cells after TLR4 was activated (P < 0.05). CONCLUSION: TIPE2 can inhibit caspase-8 activity in colon cancer cells. TIPE2 can regulate TLR4 inflammatory effect and inhibit further amplification of cascade reaction via caspase-8, which provides one new therapeutic target for clinical treatment schedule.

Synthesis, characterization, and biological activities of two Cu(II) and Zn(II) complexes with one polyquinoline ligand.

Two new complexes, [CuLCl]ClO4 (1) and [Zn2L2SO4(H2O)2](ClO4)2 (2) [L=N,N-bis(quinolin-2-ylmethyl)quinolin-8-amine], have been synthesized and structurally characterized. The interactions of two complexes with CT-DNA have been investigated by UV absorption, fluorescence spectroscopy, viscosity measurements and gel electrophoresis under physiological conditions. Results show that the complexes bind to CT-DNA with a moderate intercalative mode and exhibit efficient DNA cleavage activity on UV-A light of 365 nm. Furthermore, two complexes could quench the intrinsic fluorescence of BSA in a static quenching process based on BSA binding experiments. Notably, in vitro cytotoxicity study of two complexes on four human tumor cells lines (7404, HeLa, MCF-7, and HepG-2) indicate that both of them have the potential to act as effective anticancer drugs with low IC50 values.

Two water-soluble copper(II) complexes: synthesis, characterization, DNA cleavage, protein binding activities and in vitro anticancer activity studies.

Two water-soluble ternary copper(II) complexes of [Cu(L)Cl](ClO4) (1) and [Cu(L)Br2] (2) (L=(2-((quinolin-8-ylimino)methyl)pyridine)) were prepared and characterized by various physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square-pyramidal CuN3Cl2 (1) or CuN3Br2 (2) geometry in which Schiff-base L acts as a neutral tridentate ligand. Both complexes present intermolecular π-π stacking interactions between quinoline and pyridine rings. The interaction of two complexes with CT-DNA (calf thymus-DNA) and BSA (bovine serum albumin) was studied by means of various spectroscopy methods, which revealed that 1 and 2 could interact with CT-DNA through intercalation mode, and could quench the intrinsic fluorescence of BSA in a static quenching process. Furthermore, the competition experiment using Hoechst 33258 indicated that two complexes may bind to CT-DNA by a minor groove. DNA cleavage experiments indicate that the complexes exhibit efficient DNA cleavage activities without any external agents, and hydroxyl radical (HO) and singlet oxygen ((1)O2) may serve as the major cleavage active species. Notably, the in vitro cytotoxicity of the complexes on three human tumor cells lines (HeLa, MCF-7, and A549) demonstrates that two compounds have broad-spectrum antitumor activity with quite low IC50 ranges of 0.43-1.85µM. Based on the cell cycle experiments, 1 and 2 could delay or inhibit cell cycle progression through the S phase.

Synthesis, DNA binding, photo-induced DNA cleavage, cytotoxicity studies of a family of heavy rare earth complexes.

As a continuing investigation of our previous studies about the influence of the different rare earth metal ions on the bioactivity, a family of heavy rare earth metal complexes, [RE(acac)3(dpq)] (RE=Tb (1), Dy (2), Ho (3), Er (4), Tm (5), Yb (6), Lu (7)) and [RE(acac)3(dppz)]·CH3OH (RE=Tb (8), Dy (9), Ho (10), Er (11), Tm (12), Yb (13), Lu (14) viz. acetylacetonate (acac), dipyrido[3,2-d:20,30-f]quinoxaline (dpq), dipyrido[3,2-a:20,30-c] phenazine (dppz)), has been synthesized and their biological activities were also investigated. On the irradiation with UV-A light of 365nm or ambient light, all complexes exhibit efficient DNA cleavage activity via the mechanistic pathway involving the formation of singlet oxygen and hydroxyl radical as the reactive species. In addition, the in vitro cytotoxicity of these complexes on HeLa cells has been examined by MTT assay, which indicate that these compounds have the potential to act as effective anticancer drugs. The results of the above biological experiments also reveal that the choice of different rare earth metal ions has little influence on the DNA binding, DNA cleavage and cytotoxicity.

Impact of metal on the DNA photo-induced cleavage activity of a family of Phterpy complexes.

A family of Phterpy complexes, [Mn(Phterpy)2][N(CN)2]2·0.5H2O (1), [Fe(Phterpy)2](NO3)2 (2), [Ni(Phterpy)2](NO3)2 (3), [Ni(Phterpy)2]Cl2·10H2O (4), [Cd(Phterpy)2](NO3)2·2H2O (5) and [Zn(Phterpy)Cl2] (6) (Phterpy=4'-phenyl-2,2':6',2″-terpyridine), have been synthesized and structurally characterized, and their DNA binding and photo-induced DNA cleavage activities have been investigated. These complexes display binding propensity to the CT-DNA giving a relative order: 1>4>3, 5, 2, 6. Under dark or ambient lighting conditions, all complexes show no efficient DNA cleavage activity to pBR322 DNA. While on irradiation with UV-A light of 365nm, complexes of 1, 3 and 4 exhibit significant cleavage activities. In the presence of H2O2 as a revulsant or an activator, the cleavage ability of complex 2 is obviously enhanced. Complexes 5 and 6 do not exhibit any apparent chemical nuclease activities under irradiation conditions or with the addition of H2O2. The DNA photo-induced cleavage activities are consistent with the number of single-electron in the central metal ion of complexes and singlet oxygen and hydroxyl radical are found as the reactive oxygen species.

Two new dicopper(II) complexes with oxamido-bridged ligand: synthesis, crystal structures, DNA binding/cleavage and BSA binding activity.

New oxamido-bridged copper(II) complexes, [Cu(2)(oxbp)(H(2)O)(2)(NCS)(2)] (1) and [Cu(2)(oxbp)(µ-DMSO)(2)(NCS)(2)][Cu(2)(oxbp)(DMSO)(2)(NCS)(2)] (2) (H(2)oxbp=N,N'-bis(2-(diethylamino)ethyl)oxalamide), were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR, and electronic spectra. X-ray analysis revealed that complex 1 consists of neutral binuclear [Cu(2)(oxbp)(H(2)O)(2)(NCS)(2)] units which forms a two-dimensional network through intermolecular hydrogen bonds and complex 2 is constructed by neutral [Cu(2)(oxbp)(µ-DMSO)(2)(NCS)(2)] (2a) and [Cu(2)(oxbp)(DMSO)(2)(NCS)(2)] (2b) entities which alternately distribute to form a two-dimensional network by means of quasi µ-DMSO bridge and intermolecular hydrogen bonds. In both 1 and 2, bicopper centers are linked by the "trans-form" oxamido bridges with the distances of 5.272 Å for 1 and av. 5.296 Å for 2, respectively. The interaction of Cu(II) complexes with DNA was investigated by UV-visible, fluorescence emission spectrometry and agarose gel electrophoresis. The apparent binding constant (K(app)) values of 3.16×10(5) M(-1) for 1 and 4.9×10(5) M(-1) for 2 suggest moderate intercalative binding modes between the complexes and DNA. Complex 1 displayed efficient oxidative cleavage of supercoiled DNA, which might indicate that the underlying mechanism involves singlet oxygen (((1))O(2)) as reactive oxygen species. Complex 2 is characteristic of the involvement of a singlet oxygen-like entity and hydrogen peroxide in the cleavage process. In addition, our present work showed, by fluorescence spectrometry of BSA with complexes, both 1 and 2 bind to BSA with a medium affinity through a static mode which is tentatively assigned binding to Trp134 in BSA.

Synthesis, characterization, DNA binding and cleavage, BSA interaction and anticancer activity of dinuclear zinc complexes.

Three new zinc(II) complexes: [Zn(2)(L(1))(2)Cl(2)](ClO(4))(2)·C(2)H(5)OH (1) and [ZnL(2)X(4)]·2CH(3)CN (X = Br for 2, Cl for 3), utilizing two new and interrelated di-nucleating polypyridyl ligands (L(1), L(2)), have been synthesized and characterized by using various physico-chemical techniques. The interactions of three complexes with CT-DNA have been explored by using absorption, emission and CD spectral methods, which reveal that three complexes bind to CT-DNA by partial intercalation binding modes. Notably, in the presence of H(2)O(2) as a revulsant or an activator, the cleavage abilities of all complexes are obviously enhanced. The hydrolytic mechanism was demonstrated by adding standard radical scavengers and anaerobic reaction. Further, the protein binding ability has been monitored by quenching of tryptophan emission in the presence of complexes using BSA as a model protein. The quenching mechanisms of BSA by the complexes are static procedures. In addition, the in vitro cytotoxicity of the complexes on three human tumor cells lines (HeLa, MCF-7 and RL952) and the apoptosis-inducing activity of were assessed by MTT, Clonogenic assay, Hoechst 33342 staining, Cell cycle and Annexin V binding experiments.

Synthesis, DNA binding, photo-induced DNA cleavage and cell cytotoxicity studies of a family of light rare earth complexes.

A family of light rare earth complexes, [RE(acac)(3)(dpq)] (RE=La (1), Ce (2), Pr (3), Nd (4), Sm (5)) and [RE(acac)(3)(dppz)].CH(3)OH (RE=La (6), Ce (7), Pr (8), Nd (9), Sm (10) viz. acetylacetonate (acac), dipyrido[3,2-d:20,30-f]quinoxaline (dpq), dipyrido[3,2-a:20,30-c] phenazine (dppz)), have been synthesized and structurally characterized. Binding interactions of these complexes with CT-DNA and their photo-induced DNA cleavage activity with pBR 322 DNA are also investigated. These complexes have strong DNA binding interaction (K(b)≈10(5)M(-1) and K(app)≈10(5)M(-1))and the binding propensity to CT-DNA decrease with the order: dppz complexes>dpq complexes. Furthermore, DNA photocleavage experiments indicate that these complexes are efficient DNA cleaving agents in UV-A (365 nm) and ambient light in the absence of any external reagents. Hydroxyl radical (HO(•)) and singlet oxygen ((1)O(2)) are the major cleavage active species from the machanistic studies. Moreover, cell cytotoxicity studies of these complexes on HeLa, K562 and MDA-MB-231 cells indicate that they have the potential to act as effective metal-based anti-cancer drugs.

A new enneanuclear nickel(II) cluster with a rectangular face-centered trigonal prism structure and cluster glass behavior.

An enneanuclear nickel(II) complex with a rectangular face-centered trigonal prism structure bridged by µ(2)-pyrazolate, µ(6)-CO(3)(2-) and µ(3)-OH(-) groups was synthesized. It displays cluster glass-like magnetic behavior assigned to the single molecule magnet properties of {Ni(9)} clusters and weak intercluster interaction.

Cyano-bridged terbium(III)-chromium(III) bimetallic quasi-one-dimensional assembly exhibiting long-range magnetic ordering.

A new cyano-bridged Tb(III)-Cr(III) heterometallic complex [Tb(H(2)O)(2)(DMF)(4){Cr(CN)(6)}]·H(2)O (DMF = dimethylformamide) (1), assembled from paramagnetic hexacyanochromium(III) [Cr(CN)(6)](3-) building block and highly anisotropic terbium(III) ion has been prepared and structurally and magnetically characterized. Complex 1 shows one-dimensional (1D) zig-zag chain-like structural motif which is further extended into three-dimensional network through hydrogen-bonding interactions. The long-range magnetic ordering observed in complex 1, which is possibly due to interchain magnetic dipolar interactions, illuminates that this complex is a molecule-based magnet with critical temperature of about 5 K. This higher critical temperature among those of Ln(III)-Cr(III) heterometallic complexes exhibiting long-range magnetic ordering is probably due to the introduction of highly anisotropic terbium(III) ion.