Copper(II) and iron(III) complexes of chiral dehydroabietic acid derived from natural rosin: metal effect on structure and cytotoxicity.

A novel optically pure dinuclear copper(II) complex of a rosin derivative dehydroabietic acid (DHA, HL) was synthesized and fully characterized. The in vitro antitumor activities of the copper(II) complex Cu2(µ2-O)(L)4(DMF)2 (1) were explored and compared with those of a trinuclear iron(III) complex [Fe3(µ3-O)(L)6(CH3OH)2(CH3O)]·H2O (2). 1 was more cytotoxic than 2, and the in vitro cytotoxicity of 1 was comparable to that of cisplatin and oxaliplatin. The metal coordination improved the cytotoxicity of DHA. 1 could arrest cycle in G1 phase and induce apoptosis in MCF-7 cell. 1 increased reactive oxygen species level, GSSG/GSH ratio, and Ca2+ production, and caused the loss of mitochondrial membrane potential (Δψm) in MCF-7 cells. The up-regulated Bax and down-regulated Bcl-2 expression levels, caspase-9/caspase-3 activation, and the release of Cyt c demonstrate that 1 triggered mitochondria-mediated intrinsic apoptosis in MCF-7 cells. Caspase-8/caspase-4 activation and up-regulated Fas expression indicate that death receptor-mediated extrinsic apoptosis was included. Comet assay and up-regulated γ-H2AX and p53 expressions confirmed that 1 caused DNA damage in MCF-7 cells. Moreover, 1 led to enhancement of the biomarker of lipid peroxidation and the indicator of protein carbonylation in MCF-7 cells. All the results suggest that 1 could kill MCF-7 cells by generating oxidative stress, impairing DNA, promoting lipid peroxidation and protein carbonylation, and inducing apoptosis and autophagy. Furthermore, 1 also displayed antimetastatic activities with inhibition of cell invasion and migration, together with antiangiogenesis properties. On the whole, copper complex based on rosin derivatives is worth developing as metal-based antitumor drugs.

Discovery of novel dehydroabietic acid derivatives as DNA/BSA binding and anticancer agents.

To explore the biological properties of rosin derivatives, two dehydroabietic acid derivatives N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2-carboxamide (DTPC) and di-N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2,6-carboxamide (DDTPC) with 1,3,4-thiadiazole, pyridine and amide moieties were designed and synthesized according to superposition principle of activity group. They interact with calf thymus DNA (CT DNA) via intercalation based on the results of circular dichroism (CD) and fluorescence spectroscopy, DNA denaturation and viscosity studies. Fluorescence and CD spectral experiments indicate that they might be transported and stored by protein like bovine serum albumin (BSA). MTT assay was further carried out to examine their cytotoxicity, they both showed selective cytotoxicity and DTPC exhibited better cytotoxicity. The antiproliferative effect of DTPC toward A431 cell line was stronger than that of clinically used cisplatin and oxaliplatin. In addition, the cytotoxicity of DTPC and DDTPC was closely related with their DNA binding ability.

Biological evaluation of optically pure chiral binuclear copper(ii) complexes based on a rosin derivative as highly potential anticancer agents.

Two optically pure chiral binuclear copper(ii) complexes [Cu2(µ-Cl)2L2]·CH2Cl2 (1) and Cu2L4 (2) based on the natural product rosin derivative N-(5-dehydroabietyl-1,3,4-thiadiazole)-2-substituted pyridinecarboxamide (HL) were prepared, fully characterized and their biological activities were evaluated. The circular dichroism (CD), fluorescence spectroscopy, and DNA melting studies indicate that 1 and 2 interact with calf thymus DNA (CT DNA) via intercalation. It can be concluded that 1 and 2 have a strong affinity to bovine serum albumin (BSA) based on the fluorescence and CD spectral evidence. The MTT assay illustrates that the selective cytotoxic activity of 1 is better than that of HL, 2, cisplatin and oxaliplatin. The exposure of 1 to MCF-7 cells resulted in cell cycle arrest in the G1 phase, apoptosis, mitochondrial dysfunction and an elevated ROS level. The western blot analysis results indicate that 1 might induce apoptosis through intrinsic and extrinsic pathways, autophagy and DNA damage in MCF-7 cells. Furthermore, the down-regulated VEGFR2, MMP-2 and MMP-9 expression levels indicate that 1 should have the ability to resist metastasis and angiogenesis. Thus, based on the above described results 1 has high potential value for anticancer applications.

Optically pure chiral copper(II) complexes of rosin derivative as attractive anticancer agents with potential anti-metastatic and anti-angiogenic activities.

The development of optically pure drugs is the trend of new drugs research. Searching for optically pure metallodrugs against cancer has not been taken seriously. [CuL4Cl]Cl·2CH2Cl2·H2O (1) and [CuL4Br]Br·2CH2Cl2 (2) (L = 2-amino-5-dehydroabietyl-1,3,4-thiadiazole), two rosin-derivative based optically pure chiral copper(II) complexes, are rationally synthesized as potential anticancer agents. 1 exhibits effective in vitro and in vivo anticancer activities and tolerable toxicities. 1 promotes MCF-7 cell death by combination of cell arrest at G1 phase, apoptosis (both extrinsic and intrinsic apoptotic pathways), anti-metastasis, anti-angiogenesis, damage of DNA, protein and lipid, and autophagy mediated by the oxidative stress which is confirmed by ROS generation and intracellular glutathione depletion assays. 1 can be identified as a lead anticancer molecule of therapeutic importance. This work may offer insights into the design and mechanism study of multifunctional optically pure metal-based anticancer candidates derived from natural products.

A novel 3D heteropoly blue type photo-Fenton-like catalyst and its ability to remove dye pollution.

A environment-friendly 3D inorganic heteropoly blue (HPB) Ba2Na2 [HPWV4WVI8O40]·26H2O was directly synthesized by hydrothermal method and characterized by means of ICP, IR, XPS, X-ray single crystal and X-ray powder diffraction. It was an efficient heterogeneous photo-Fenton-like catalyst to degrade anionic dye methyl orange under visible light irradiation. It removed cationic dyes methylene blue in neutral environment and rhodamine B in acidic condition via flocculation. The removal efficiency of methylene blue and rhodamine B by flocculation was more than 95%. Moreover, it could degrade methyl orange and flocculate rhodamine B at the same time. For MO and MO-RhB solutions, the degradation rates of MO in 60 min were 85.5% and 49.1%, respectively. Furthermore, the possible pathways for the production of active species in the MO degradation reaction were discussed. This is the first HPB constructed with 4e-reduced phosphotungstate, Ba and Na ions, having the properties of photo-Fenton-like catalyst and flocculant.

A heteropoly blue as environmental friendly material: An excellent heterogeneous Fenton-like catalyst and flocculent.

The first 3D heteropoly blue Ba2Na4[SiW4VW8VIO40]·19H2O (1) as heterogeneous Fenton-like catalyst and flocculent was hydrothermally synthesized and fully characterized by various methods 1 was an efficient Fenton-like catalyst for degradation of phenol with degradation rate of 92.1% (visible light irradiation), and 89.0% (no light) in 90min, respectively. The degradation efficiency of anionic dye methyl orange was 97.0% in 5min, when 1 was used as photo-Fenton-like catalyst under visible light. And 1 was a nice flocculent for cationic dyes methylene blue and rhodamine B, the removal rates were both above 95%. Moreover, 1 could degrade methyl orange and flocculate rhodamine B at the same time, but the degradation rate decreased from 100% to 77.5% in 60min, while the flocculation of RhB in 10min was not affected.

Enantiopure copper(II) complex of natural product rosin derivative: DNA binding, DNA cleavage and cytotoxicity.

To develop chiral anticancer drug candidates for molecular target DNA, the synthesis and characterization of a novel enantiomerically pure copper(II) complex [Cu 1 Cl 2 ] (2) of an optically pure ligand N-(pyridin-2-ylmethylene) dehydroabietylamine (1) was carried out. The coordination geometry of the copper center is a distorted square-planar arrangement. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. All the results reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a higher DNA binding ability. Further, 1 and 2 could cleave supercoiled pBR322 DNA by single strand and 2 displayed stronger cleavage ability in the presence of ascorbic acid. In vitro cytotoxicity of 1 and 2 against HeLa, SiHa, HepG-2 and A431 cancer cell lines was studied using CCK-8 assay. The results indicate that 2 had a superior cytotoxicity than 1 and the widely used drug cisplatin under identical conditions. Flow cytometry analysis demonstrates 2 produced death of HeLa cancer cells through an apoptotic pathway. Cell cycle analysis shows that 2 mainly arrested HeLa cells at the S phase. A novel enantiomerically pure copper(II) complex [Cu 1 Cl 2 ] (2) of an optically pure ligand N-(pyridin-2-ylmethylene) dehydroabietylamine (1), based on natural product rosin has been synthesized. 2 has the potential to act as effective anticancer drug.

Chiral copper(II) complex based on natural product rosin derivative as promising antitumour agent.

To evaluate the biological preference of chiral drug candidates for molecular target DNA, the synthesis and characterization of a chiral copper(II) complex (2) of a chiral ligand N,N'-(pyridin-2-ylmethylene) dehydroabietylamine (1) was carried out. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral, emission spectral and viscosity analysis reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a higher DNA binding ability. In the absence/presence of ascorbic acid, 1 and 2 cleaved supercoiled pBR322 DNA by single-strand and 2 displayed stronger DNA cleavage ability. In addition, in vitro cytotoxicity of 1 and 2 against HeLa, SiHa, HepG-2 and A431 cancer cell lines study show that they exhibited effective cytotoxicity against the tested cell lines, notably, 2 showed a superior cytotoxicity than the widely used drug cisplatin under identical conditions, indicating it has the potential to act as effective anticancer drug. Flow cytometry analysis indicates 2 produced death of HeLa cancer cells through an apoptotic pathway. Cell cycle analysis demonstrates that 2 mainly arrested HeLa cells at the S phase. The study represents the first step towards understanding the mode of the promising chiral rosin-derivative based copper complexes as chemotherapeutics.

DNA binding and cytotoxicity activity of a chiral iron(III) triangle complex based on a natural rosin product.

The first chiral trinuclear iron(III) complex [Fe3(µ3-O)(L)6(CH3OH)2(CH3O)]⋅H2O (2) of a natural rosin product dehydroabietic acid (HL, 1) was synthesized and fully characterized. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=1.30×10(5)M(-1) (1), 1.40×10(5)M(-1)(2)), emission spectral (KSV=1.19×10(4)M(-1) (1), 1.79×10(4)M(-1) (2)) and viscosity measurements reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a slight higher DNA binding ability. The Stern-Volmer quenching constant (KSV) and corresponding thermodynamic parameters (ΔG, ΔH and ΔS) of the binding processes were determined. The negative ΔH and ΔG values indicate that the binding reactions were exothermic and spontaneous. 1 and 2 were also screened for their cytotoxic ability and 1 demonstrated higher growth inhibition of the selected cancer cells at concentrations of 25µM and 50µM, this result was not identical with their DNA binding ability order. Thus, the involvement of Fe(III) centers had positive effect on DNA binding ability and negative effect on cytotoxicity.

A novel 3D inorganic heteropoly blue as visible light responsive photocatalyst.

A new 3D extended heteropoly blue Ba4[SiW(V)4W(VI)8O40]·H2O (1) composed of twelve-coordinated α-Keggin anions [SiW(V)4W(VI)8O40](8-) and eight-coordinated Ba sites {BaO8} has been hydrothermally synthesized and fully characterized by elemental analysis, IR spectroscopy, XPS, single crystal X-ray and X-ray powder (XRPD) diffraction. 1 represents the first inorganic 3D framework constructed from four-electron reduced α-Keggin anions linked by alkaline earth metals. The photocatalytic activity of 1 has been evaluated for rhodamine B (RhB) degradation. 1 exhibits excellent catalytic activity for the degradation of RhB in the presence of H2O2and the involvement of visible light makes a more complete degradation. The results of the current study suggest that multi-electron reduced polyoxometalates can catalyze efficient degradation of an organic dye with H2O2.

Effects of copper ions on DNA binding and cytotoxic activity of a chiral salicylidene Schiff base.

A chiral Schiff base HL N-(5-bromo-salicylaldehyde)dehydroabietylamine (1) and its chiral dinuclear copper complex [Cu2L4]·4DMF (2) have been synthesized and fully characterized. The interactions of 1 and 2 with salmon sperm DNA have been investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=3.30 × 10(5)M(-)(1) (1), 6.63 × 10(5)M(-)(1)(2)), emission spectral (Ksv=7.58 × 10(3)M(-)(1) (1), 1.52 × 10(4)M(-)(1) (2)), and viscosity measurements reveal that 1 and 2 interact with DNA through intercalation and 2 exhibits a higher DNA binding ability. In addition, CD study indicates 2 cause a more evident perturbation on the base stacking and helicity of B-DNA upon binding to it. In fluorimetric studies, the enthalpy (ΔH>0) and entropy (ΔS>0) changes of the reactions between the compounds with DNA demonstrate hydrophobic interactions. 1 and 2 were also screened for their cytotoxic ability and 2 demonstrates higher growth inhibition of the selected cancer cells at concentration of 50 µM, this result is identical with their DNA binding ability order. All the experimental results show that the involvement of Cu (II) centers has some interesting effect on DNA binding ability and cytotoxicity of the chiral Schiff base.

Two novel copper complexes of 2,2'-bipyridine: evaluation of the DNA binding and cytotoxic activity.

Two novel copper-2,2'-bipyridine complexes [Cu(SAL)(2,2'-bipy)ClO4]2 (1) and [Cu(µ2-O)(2,2'-bipy)NO3]2 (2) (HSAL=salicylaldehyde) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis and IR spectra. The interactions of the complexes with salmon sperm DNA were investigated by viscosity analysis, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=3.00×10(5)M(-1) (1), 3.49×10(5)M(-1)(2)), emission spectral ((Ksv) 3.33×10(4)M(-1) (1), 3.40×10(4)M(-1) (2)), and viscosity measurements reveal that 1 and 2 interact with DNA through intercalation. In fluorimetric studies, the enthalpy (ΔH>0) and entropy (ΔS>0) changes of the reactions between the Cu (II) complexes with DNA demonstrate hydrophobic interactions. In addition, CD study indicates the Cu (II) complexes cause a more B-like to a more A-like conformational change upon binding DNA. All the experimental results show that the interaction mode of the two complexes was greatly affected by the coordination environments of Cu (II) centers. Their in vitro cytotoxicity towards five selected tumor cell lines HepG-2, HeLa, NCI-H460, MCF-7 and HL-60 has been evaluated by MTT method, and 2 exhibits higher growth inhibition of the selected cell lines at concentration of 50 µM, this result is identical with their DNA binding ability order.

Crystal structure and magnetic properties of a pseudo-cubic close-packed array of oxalate linked {FeII6(mu3-OH)6}6+ clusters.

The ionic hexanuclear cluster aggregate [FeII6(mu3-OH)6]6+ has been synthesised using hydrothermal conditions starting from ferrous oxalate in the presence of barium and bromide or iodide ions. A single crystal X-ray structure on the compound Ba4[FeII6(mu3-OH)6(C2O4)6]Br2.6H2O shows that the [FeII6(mu3-OH)6]6+ units are held together by bridging oxalates in a pseudo-cubic close-packed array. The barium ions in conjunction with oxalate groups provide a barrel-shaped cage between the FeII6 aggregates containing the bromide counterions and lattice waters and corresponding to an 'octahedral hole' in the pseudo-cubic close-packed structure. A magnetic susceptibility study shows that the FeII centres are antiferromagnetically coupled. Below 10 K the system displays a long range antiferromagnetic ordering mediated by the oxalate bridges and a molecular-based description of the magnetism is no longer valid.