Interaction Of Calf Thymus DNA Research Articles

Selenium nanoparticles: Synthesis, in-vitro cytotoxicity, antioxidant activity and interaction studies with ct-DNA and HSA, HHb and Cyt c serum proteins

The aim of this study was the synthesis of selenium nanoparticles (SeNPs) employing vitamin C as a biocompatible and low toxic reducing agent. The synthesized selenium nanoparticles were characterized by using UV–vis, FT-IR, SEM-EDX, TEM, DLS, and zeta potential measurements. The results of the DPPH free radical scavenging assay demonstrate that this synthesized nano-selenium has strong potentials to scavenge the free radicals and cytotoxicity against MCF-7 and Raji Burkitt's lymphoma cancer cell lines. The interaction of calf thymus DNA (ct-DNA) with SeNPs indicated that the anticancer activity might be associated with the DNA-binding properties of nano-selenium. Finally, it was found that the synthesized nano-selenium can bind to the most important blood proteins such as human serum albumin (HSA), human hemoglobin (HHb), and Cytochrome c (Cyt c). The results showed that the secondary structure of these proteins remains unchanged, suggesting that the synthesized nano-selenium could be employed as a carrier in the drug delivery system without any cytotoxicity effect.

Probing the interaction of ciprofloxacin with dsDNA: Electrochemical, spectro-electrochemical and AFM investigation

Abstract The interaction of double strand calf thymus DNA (dsDNA) with the antibiotic, Ciprofloxacin (Cf) has been investigated using differential pulse voltammetry, impedance spectroscopy, UV–Vis spectroscopy, spectroelectrochemistry and atomic force microscopy (AFM) measurements. Investigation revealed good interaction between Cf and dsDNA, with formation constant of 2.65 × 104 M−1. Electrochemical measurements established the mechanism of interaction to be the intercalative in nature, which has been supported by the spectroscopic findings. The zeta potential analysis reveals that the Cf-dsDNA complex is stable enough to remain in the solution and is stabilized through electrostatic interaction as well as the intercalative binding. The AFM images of dsDNA (at 47 µM concentration) with various concentrations of Cf (0.1, 0.2, 0.5, 1, 5, 10 mM) reveal the condensation of DNA in the presence of the antibiotic drug. The mechanism of the dsDNA condensation by the presence of Cf is ascertained to be through the electrostatic interaction between the –NH– group of Cf and the phosphate group of DNA and also through the carboxylic acid group of Cf with the amine groups of the nucleotides present in the DNA strands.

Multi-stage screening to predict the specific anticancer activity of Ni(II) mixed-ligand complex on gastric cancer cells; biological activity, FTIR spectrum, DNA binding behavior and simulation studies

The anticancer activity of a transition metal complex with [Ni(L1)2L2]H2O (where L1 and L2 were acetylacetonato (acac) and 2-aminopyridine (2-ampy), respectively) was evaluated in MKN45 cell line. Methyl thiazolyl tetrazolium (MTT) assay was performed to assess the antitumor capacity of the Ni(II) complex against gastric cancer cell line MKN45. The complexexhibited high in vitro antitumor activity against MKN45 cells with IC50values of 1.99 μM in 48 hrs.The alterations in the structure of cellular biomolecules (proteins, lipids, carbohydrates, and especially DNA) by the Ni(II) complex were confirmed by bio spectroscopic studies. Fourier Transformed Infrared (FTIR) spectroscopy analysis revealed significant differences between untreated and treated MKN45 cell line in the region of glycogen, nucleic acid, amide I and amide II bands (1000, 1100, ~1650, and ~1577 cm−1). The absorption bands 1150 cm−1 and 1020–1025 cm−1 can be assigned to the CO bond of glycogen and other carbohydrates and are significantly overlapped by DNA. The interaction of calf thymus (CT) DNA with Ni(II) complex was explored using absorption spectral method. The UV–visible studies demonstrated that this complex was able to bind with DNA via groove, non-covalent, and electrostatic interactions, and binding constant (Kb) was found to be 3 * 104. Docking simulation and Non Covalent Interaction (NCI) topological analysis were conducted to provide insights into the nature of DNA/complex interactions. The binding affinity and binding stability of complex was validated by 400-ns MD simulations.

Controlling the reactivity of [Pd(II)(N^N^N)Cl]+ complexes using 2,6-bis(pyrazol-2-yl)pyridine ligands for biological application: Substitution reactivity, CT-DNA interactions and in vitro cytotoxicity study

Four [(N^N^N)Pd(II)Cl]+ complexes [chloride-(2,2′:6′,2′′-terpyridine)Pd(II)]Cl (PdL1), [chlorido(2,6-bis(N-pyrazol-2-yl)pyridine)Pd(II)]Cl (PdL2), [chlorido(2,6-bis(3,5-dimethyl-N-pyrazol-2-yl)pyridine)Pd(II)]Cl (PdL3) and [chlorido(2,6-bis(3,5-dimethyl-N-pyrazol-2-ylmethyl)pyridine)Pd(II)]BF4 (PdL4) were synthesized and characterized. The rates of substitution of these Pd(II) complexes with thiourea nucleophiles viz; thiourea (Tu), N,N′-dimethylthiourea (Dmtu) and N,N,N′,N′-tetramethylthiourea (Tmtu) was investigated under pseudo first-order conditions as a function of nucleophile concentration [Nu] and temperature using the stopped-flow technique. The observed rate constants vary linearly with [Nu]; kobs = k2[Nu] and decreased in the order: PdL1 > PdL2 > PdL3 ≫ PdL4. The lower π-acceptability of the cis-coordinated N-pyrazol-2-yl groups (which coordinates via pyrazollic-N π-donor atoms) of the PdL2–4 significantly decelerates the reactivity relative to PdL1. Furthermore, the six-membered chelates having methylene bridge in PdL4 do not allow π-extension in the ligand and introduces steric hindrance further lowering the reactivity. Trends in DFT calculated data supported the observed reactivity trend. Spectrophotometric titration data of complexes with calf thymus DNA (CT-DNA) and viscosity measurements of the resultant mixtures suggested that associative interactions occur between the complexes and CT-DNA, likely through groove binding with high binding constants (Kb = 104 M−1). In vitro MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cytotoxic activity data showed that PdL1 was the most potent complex against MCF7 breast cancer cells; its IC50 value is lower than that of cisplatin. The results demonstrate how modification of a spectator ligand can be used to slow down the reactivity of Pd(II) complexes. This is of special importance in controlling drug toxicity in both pharmaceutical and biomedical applications.

In vitro biological evaluation and consideration about structure-activity relationship of silver(I) aminoacidate complexes

Two silver(I) aminoacidate complexes {[Ag4(L-HAla)4(NO3)3]NO3}n (AgAla, complex 1, Ala = alanine) and {[Ag(L-Phe)]}n (AgPhe, complex 2, Phe = phenylalanine) were prepared and characterized by elemental, spectral analysis (FT-IR, NMR techniques) and single crystal X-ray analysis in solid state and their solution stability was measured in biological testing time-scale by 1H NMR. The bridging coordination modes of the zwitterionic Ala and deprotonated Phe ligands led to the formation of 1D polymeric chains of the complexes. The significant argentophilic interactions are presented in the structure of AgAla. Antimicrobial testing of prepared Ag(I) complexes was evaluated by IC50 and MIC values and were compared with AgGly, silver(I) sulfadiazine and AgNO3 samples. Moreover, MTS test was used to the testing of broad range antiproliferative activity of studied compounds against different cancer cell lines and also to the investigation of calf thymus DNA interactions by absorption spectroscopy, fluorescence spectroscopy, Ethidium bromide/Hoechst 33258 displacement experiments and circular dichroism spectroscopy. To evaluate the pUC19 DNA fragmentation by silver(I) complexes, the agarose gel electrophoresis was used. In addition to biological evaluation we used lipophilicity measurement results in the discussion about structure-activity relationship (SAR).

Synthesis, characterization, DNA binding and cytotoxicity studies of two novel Cu(II)-2-(2′-pyridyl) quinoxaline complexes

Two novel copper (II) complexes, namely [Cu(2,2′-pq)(NO3)](NO3) (1) and [Cu(2,2′-pq)2(NO3)](NO3)·6H2O(2) where 2,2′-pq is 2-(2′-pyridyl quinoxaline) were synthesized and characterized by various spectral methods. Complex 2 characterized by single crystal X-ray diffraction showed a distorted trigonal bipyramidal geometry and crystallized together with an hexamer, (H2O)6 cluster, with R66(12) topology and chair conformation. The interaction of Calf Thymus DNA (CT-DNA) with 1 and 2 was investigated by UV–Visible absorption spectra, Viscosity, Cyclic Voltammetry, Fluorescence and Circular Dichroism (CD), indicating that both complexes can bind to DNA both by means of intercalation and groove binding. Their DNA interaction mode depends on their concentrations and the differences between their structures. Cleavage experiments were performed by agarose gel electrophoresis using pBR322 DNA both in dark and after illumination. Furthermore, the cytotoxicity of both complexes was evaluated against MCF-7 and healthy cells (HEK-293) by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays; moreover their cell uptake against MCF-7 tumor cells and HEK-293 normal cells was revealed by using confocal laser scanning. Both complexes have the potential to act as effective anticancer drugs with 2 to present an IC50 smaller than that of cis-platin and also to be useful for optically probing tumor cells since it fluoresces at blue and green when is treated with MCF-7 cells.

Novel azomethine Pd (II)‐ and VO (II)‐based metallo‐pharmaceuticals as anticancer, antimicrobial, and antioxidant agents: Design, structural inspection, DFT investigation, and DNA interaction

AbstractThe new NO bidentate imine ligand, namely, (2‐[(3‐nitro‐benzylidene)‐amino]‐benzoic acid) (NBA) imine ligand (L), and its Pd (II) and VO (II) complexes have been synthesized and characterized by utilizing different physiochemical methods including elemental analyses, Fourier transform infrared (FT‐IR), nuclear magnetic resonance (NMR), molar conductance, and magnetic susceptibility measurements. The stability constant of these complexes has also been determined. In studies of these complexes, they were found to have [M(L)] composition where the ligand acts as a bidentate and coordinates with the various metal ions through azomethine and one oxygen atom. Moreover, the suggested geometrical structure of Pd (II) and VO (II) complexes is square planar and a distorted square pyramid, respectively. Density functional theory (DFT) calculations for the different metal complexes were studied and show a good agreement with the experiment data. The minimum inhibitory concentration method has been applied to evaluate the in vitro antimicrobial activity. Furthermore, the interaction of calf thymus DNA with the metal‐imine chelates has been assessed, and Pd (II) complex showed the strongest interaction with DNA for a binding constant value of (9.72 × 104 kcal mol−1). The cytotoxic activity of the new metal chelates has been evaluated against three human cancer cell lines (hepatic carcinoma HepG2 cells, breast carcinoma cells MCF‐7, and colon carcinoma cells HCT‐116). It has found that NBAPd complex exhibited a significant decrease in the time and dose of the cell viability than did the reference drug vinblastine. The antioxidant activity of the tested compounds was determined and compared with that of vitamin C as a standard drug. It has been found that the metal complexes exhibit higher activity than the free ligand. The finding from this investigation revealed that the new compounds are considered to be prospective antibiotic and anticancer agents.

Coordination of Zn(II), Pd(II) and Pt(II) with ligands derived from diformylpyridine and thiosemicarbazide: Synthesis, structural characterization, DNA/BSA binding properties and molecular docking analysis

Synthesis of three novel inorganic complexes (Zn(II), Pd(II), and Pt(II) – [Zn(H2L)](NO3)2, [Pd(L)], and [Pt(L)], respectively) based on 2,6-diformylpyridine-bis-(4-phenyl) thiosemicarbazone (H2L) was obtained under reflux medium, yielded in the range of 67% and 86%. Characterization of each compound was done via X-ray diffraction and spectroscopic methods. Structural analysis revealed the formation of complexes with pentagonal and quadratic bipyramidal geometry. Electronic absorption spectra for the ligand and inorganic complexes exhibited π → π* and n → π* transitions in the UV region, however, [Pd(L)] and [Pt(L)] showed other less energetic bands attributed to ligand-to-metal charge transfer (LMCT). The interaction between each compound and two macromolecules: calf-thymus DNA (CT-DNA) and bovine serum albumin (BSA) was conducted by spectroscopic techniques combined to molecular docking calculation. For CT-DNA interaction, [Zn(H2L)](NO3)2 is the weakest intercalate compound and the increasing order of Kb values follows [Zn(H2L)](NO3)2 < H2L < [Pd(L)] ≈ [Pt(L)]. Molecular docking results suggested van der Waals interactions as the main intermolecular force involved in the interaction process between DNA and each derivative. For BSA, experimental results indicated weak (H2L and [Zn(H2L)](NO3)2) and moderate ([Pd(L)] and [Pt(L)]) interaction in the ground-state, in the proportion 1:1 (n ~ 1.0). Molecular docking results suggested Trp-212 containing binding site as the main protein pocket for H2L, [Zn(H2L)](NO3)2, [Pd(L)], and [Pt(L)].

Ruthenium(II) carbonyl complexes containing thiourea ligand: Enhancing the biological assets through biomolecules interaction and enzyme mimetic activities

The ligand H2L (N-(N,N-diethylaminothiocarbonyl)benzimidoylchloride-2-aminoacetophenone-N-methylthiosemicarbazone) reacts with ruthenium(II) building blocks [RuHCl(CO)(EPh3)3] (E = P or As) to form new complexes [Ru(1,1-DT)(Cl2)(CO)-(EPh3)2] (E = P or As; 1,1-DT = 1,1-diethylthiourea). The ligand H2L in these reactions undergoes C=N bond break and coordinates through sulfur atom of C=S group. Analytical and spectral (IR, UV–Vis, NMR, ESI-MS) methods were used to characterize the compounds. A distorted octahedral geometry for complexes has been furnished by X-ray crystallography, which confirmed the coordination mode of the ligand with metal precursor. The binding affinity and mode of binding of the complex towards some important biomolecules such as calf thymus DNA and bovine serum albumin protein were determined using absorption and emission spectra and found intercalative binding with calf thymus DNA and static interaction with bovine serum albumin. The in vitro cytotoxic activity of complex was assessed using human cervical cancer (HeLa), human hepatocellular carcinoma (HepG2), and normal Vero cells. Furthermore, the complex was found to possess significant enzyme mimic catalytic activity in oxidation and hydrolysis reactions.Graphical abstract

Synthesis, Characterization, in vitro Antifungal Activities and Calf Thymus DNA Interactions of Two Different Hydroxy Benzaldehyde Derivative Schiff Bases from Sulfamethizole: Electrochemical, Spectroscopic and Biological Study

In the present work, the Schiff bases were synthesized by reacting sulfamethizole (SMTZ) with two different hydroxy benzaldehydes (2,3-dihydroxy benzaldehyde (DHBA) and 2,4,6-trihydroxy benzaldehyde (THBA)) and characterized by elemental analysis, 1H-NMR and IR spectroscopies. From the obtained data, it was suggested that 4,6-dihydroxy salicylaldehyde reacted with both primary and secondary amine groups of SMTZ. The binding properties between the synthesized Schiff bases and calf thymus DNA (CT-DNA) at the physiological pH (7.4) was investigated by using cyclic voltammetry and UV-Vis spectroscopy techniques. The experimental results verify that the Schiff bases can bind to CT-DNA by electrostatic mode in 1 : 1 stoichiometry. Antifungal activities of the synthesized Schiff bases against Candida albicans ATCC 10231 were studied and their minimum inhibitory concentrations (MIC) were also determined. The MIC value of the Schiff base 1 synthesized from DHBA is smaller than that of the Schiff base 2 obtained from THBA. Although Schiff base 2 binds to CT-DNA with a higher affinity than Schiff base 1, it is less effective than Schiff base 1 against Candida albicans.

Physicochemical investigations of zinc oxide nanoparticles synthesized from Azadirachta Indica (Neem) leaf extract and their interaction with Calf-Thymus DNA

Abstract Zinc oxide nanoparticles (ZnONps) have been extensively explored for various biological applications because of their characteristic biocompatibility, antimicrobial activity and wound healing. Green synthesis is an environment friendly alternate as compared to chemical synthesis, hence ZnONps using Azadirachta Indica (Neem) leaf extract have been synthesized in this study. ZnONps were then characterized using different analytical techniques including UV–Visible spectroscopy, FTIR, XRD, SEM, FESEM and EDAX. Interaction studies of ZnONps with Calf-Thymus DNA (CT-DNA) have further been investigated utilizing UV–Visible, UV-thermal, Fluorescence, Circular Dichroism spectroscopy and agarose gel electrophoresis. ZnONps exhibited a sharp peak around 368 nm in absorption spectra, confirming their synthesis. The surface morphology of ZnONps was examined by SEM & FESEM and the size was found in range 20–40 nm. After correlating all data, interaction of CT-DNA with ZnONps suggested the stabilization of DNA. These physicochemical investigations could further give insights for biosensing and biomedical applications.

In vitro investigating of anticancer activity of new 7-MEOTA-tacrine heterodimers

A combination of biochemical, biophysical and biological techniques was used to study calf thymus DNA interaction with newly synthesized 7-MEOTA-tacrine thiourea 12–17 and urea heterodimers 18–22, and to measure interference with type I and II topoisomerases. Their biological profile was also inspected in vitro on the HL-60 cell line using different flow cytometric techniques (cell cycle distribution, detection of mitochondrial membrane potential dissipation, and analysis of metabolic activity/viability). The compounds exhibited a profound inhibitory effect on topoisomerase activity (e.g. compound 22 inhibited type I topoisomerase at 1 µM concentration). The treatment of HL-60 cells with the studied compounds showed inhibition of cell growth especially with hybrids containing thiourea (14–17) and urea moieties (21 and 22). Moreover, treatment of human dermal fibroblasts with the studied compounds did not indicate significant cytotoxicity. The observed results suggest beneficial selectivity of the heterodimers as potential drugs to target cancer cells.

The interaction between a zinc(II) phthalocyanine compound bearing octakis phenoxyacetamide substituents and calf thymus DNA

In this study, a zinc(II) phthalocyanine compound ( PcZn ) substituted with octakis phenoxyacetamide was synthesized and characterized. Calf thymus DNA (CT-DNA) was used to determine the DNA binding properties of the zinc(II) phthalocyanine compound. This interaction of CT-DNA with PcZn was investigated using electronic absorption spectra, emission spectroscopy, a thermal melting temperature study, cyclic voltammetry, and viscosity measurements in a Tris-HCl buffer solution at a pH of 7.2. The findings showed that zinc(II) phthalocyanine interacts with calf thymus DNA via partial intercalative binding mechanisms. In addition to the techniques above, a gel electrophoresis study was also carried out to verify the interaction of CT-DNA with the PcZn complex. The results demonstrated that the octakis phenoxyacetamide-substituted zinc(II) phthalocyanine complex binds to CT-DNA via a partial intercalative binding mode.

Quantitative studies of DNA binding with trans complexes of PtII and PdII featuring tetrazolylacetic acids and their derivatives as ligands

The interaction of calf thymus DNA (CT DNA) with trans-[PtCl2L2] and trans-[PdCl2L2] complexes (L–5-methyl-1H-tetrazol-1-ylacetic acid and its ethyl, butyl, and isobutyl esters; ethyl esters of 2-R-2H-tetrazol-5-ylacetic acids, R = But, CH2CH2OH) have been quantitatively studied by a spectrophotometric method. The binding constants (Kb) of the tetrazolecontaining coordination compounds with CT DNA at pH 7.2 and 298 K are in the range of (3.67–5.93)•105 mol L–1 for the PdII complexes and (7.82–13.30)•105 mol L–1 for and the PtII complexes, respectively. The Kb values, as well as negative values of ΔGb (–(31.7–34.9) kJ mol–1) indicate the effective binding between the studied complexes and CT DNA.

New 3D Supramolecular Ag(I) Coordination Polymer Crystal Containing 2‐Quinaldic Acid Radical Biological Ligand: Crystal Structure and Anticancer Activity

AbstractA new coordination polymer of {[Ag(Qina)(Bpp)]·(H2O)2}n (Qina = 2‐quinolinecarboxylic‐carboxylate, Bpp = 4,4'‐trimethylenedipyridine) is successfully synthesized and the structure is determined using single crystal X‐ray diffraction. The complex is crystallized in the monoclinic system with P21/c space group: Each atom of Ag(I) is chelated by one Qina group, with each Bpp ligand bridging two Ag(I) atoms to form the 1D polymer chains. Furthermore, the 3D supramolecular architecture is a costructure directed via weak stacking interactions of C–H···π and hydrogen bond. The complex shows competitive binding affinities in calf thymus DNA (ct‐DNA) interaction by fluorescence spectroscopy. In addition, the complexes’ cytotoxic activity is explored for two kinds of cancer cell lines (Hela, MCF‐7), indicating an anticancer activity and cytotoxicity. CCDC: 1553426

Epirubicin-calf thymus DNA interaction: a comprehensive investigation using molecular docking, spectroscopy and fluorescent quantum dots

Reviewing the mode of interaction between this kind of active pharmaceutical ingredients and DNA has received much more attention in current years. Anthracycline drugs such as Epirubicin are frequently used in cancer treatment for breast cancer treatment. In the present study, the Epirubicin -calf thymus DNA interaction was investigated by using spectroscopic, fluorimetric and molecular docking methods. Water-soluble quantum dots (QDs) with nanometric particle size fabricated and characterized by transmission electron microscope and photon correlation spectroscopy. The binding constant value and the free energy change for this interaction were obtained to be 3.00×106 M-1 and -42.26 kJ mol-1, using the spectroscopic method and docking investigations, respectively. Additionally, fluorescent thioglycolic acid-capped CdTe QDs were used for investigation of EPI and DNA interaction. Epirubicin as a quencher quenched the fluorescence of CdTe QDs after electrostatic adsorption on the surface of QDs. With the addition of DNA, EPI will be desorbed from the surface of CdTe QDs, inserted into the DNA. Subsequently, fluorescence changes of QDs were used for calculation of binding constant value, which was in good agreement with that obtained by the spectroscopic method. By the comparison of the achieved results, the intercalation mode of interaction between Epirubicin and DNA proved.

Zinc(II)‐N2O2 ligation complex‐based DNA/protein binder and cleaver having enhanced cytotoxic and phosphatase activity

The alkyne arms containing zinc(II) N2O2 ligation complexes (1) and (2) were prepared from 2,2′‐{cyclohexane‐1,2‐diylbis[nitrilo(E)methylylidene]}bis[5‐(prop‐2‐yn‐1‐yloxy)phenol] (L1) and 2,2′‐{1,2‐phenylenebis[nitrilo(E)methylylidene]}bis[5‐(prop‐2‐yn‐1‐yloxy)phenol] (L2) and characterized by analytical and various spectral techniques. The molecular geometry of 1 and 2 was optimized by Density Functional Theory (DFT) at B3LYP/6‐311G(d,p) level and compared with literature. The complexes are stable in solution, and their solution structure was assessed using NMR and ESI‐MS spectroscopy. Topological analysis of the electron density and nature of the bonding in the complexes has been determined by using Bader's AIM method. The interaction and binding modes of calf thymus DNA (CT‐DNA) with complexes (1 and 2) were investigated by using absorption and emission spectral and viscometric studies. The nuclease activity investigated through gel electrophoresis reveals that 1 and 2 exhibits a significant DNA cleavage activity via a hydrolytic pathway and is further confirmed by an experiment performed in the presence of T4 ligase. The protein binding ability of 1 and 2 with bovine serum albumin (BSA) protein evaluated show good protein binding propensity. In‐vitro cytotoxicity of the complexes has shown significant activity against human brain tumor (U87 MG) and breast carcinoma (BT20) cancer cell lines. The comet assay has been used to determine the extent of DNA fragmentation in cancer cells. The phosphatase activity investigated through kinetic measurements establishes that the zinc complexes possess significant hydrolytic efficiency and follow the order 2 &gt; 1. The DFT calculations have also been carried out to support the proposed mechanistic pathway of catalytic activity.

Synthesis of a new Pt(II) complex containing valganciclovir drug and calf-thymus DNA interaction study using multispectroscopic methods

A new complex, [Pt(valcyte)(DMSO)Cl]Cl, in which valcyte (trade name) served as valganciclovir hydrochloride drug ([2-[(2-amino-6-oxo-3H-purin-9-yl)methoxy]-3-hydroxypropyl](2S)-2-amino-3-methylbutanoate), was synthesized and characterized by different physicochemical methods. Binding interaction of this complex with calf-thymus DNA (ct-DNA) has been investigated by multispectroscopic techniques. The complex displays significant binding properties with ct-DNA. The results of fluorescence and UV–vis absorption spectroscopy indicated that this complex interacted with ct-DNA in a groove-binding mode, and the binding constant was 3.8 × 104 M−1. Furthermore, the complex induced detectable changes in the CD spectrum of ct-DNA and slightly changed its viscosity which verified the groove-binding mode. Finally, all results indicated that Pt(II) complex interact with DNA via groove-binding mode.

Ru(II)‐η6‐benzene Complexes of Dibenzosuberenyl Appended Aroyl/Acylthiourea Ligands: In vitro Biomolecular Interaction Studies and Catalytic Transfer Hydrogenation

AbstractA series of novel N‐dibenzosuberene appended aroyl/acylthiourea ligands (L1‐L4) and their Ru(II)‐benzene complexes (1‐4), [RuCl2(η6‐benzene)L] (L=monodentate aroyl/acylthiourea ligand) was synthesized and well characterized. The coordination mode of aroyl/acylthiourea ligand with Ru ion through S (neutral monodentate) donor atom was determined by single crystal X‐ray diffraction analysis. In vitro Calf thymus DNA (CT‐DNA) and Bovine serum albumin (BSA) interaction of the complexes were investigated by UV‐Visible, fluorescence spectroscopic and hydrodynamic methods. The results showed the intercalative mode of binding (in the order of 1 &gt; 4 &gt; 3 &gt; 2) of the Ru(II)‐benzene complexes with CT‐DNA. The DNA (pUC19) cleavage study showed that the complexes cleaved DNA through a hydrolytic pathway. All the complexes have been thoroughly screened for their cytotoxicity against human liver carcinoma (HepG‐2) and lung cancer (A549) cells under in vitro conditions. Complex 1 exhibited significant cytotoxic activity (IC50=46.1 μM) towards HepG‐2 cancer cell line. In addition to this, the prepared complexes have been utilized as catalyst precursors for transfer hydrogenation (TH) of ketones, aldehydes and nitro compounds using 2‐propanol as a hydrogen source. The TH reactions proceeded with exceptional conversions (up to 99%) and the present catalytic system was extended to substituted aromatic/heterocyclic carbonyl and nitro compounds.

Spectroscopic investigation on the interaction of DNA with superparamagnetic iron oxide nanoparticles doped with chromene via dopamine as cross linker

Objective(s): The interaction of DNA with iron oxide nanoparticles (SPIONs) was studied to find out the interaction mechanism and design new drug delivery systems. Materials and Methods: The interaction of calf thymus DNA (ctDNA) with SPIONs doped with 2H-chromene via dopamine as cross linker (SPIONs@DA-Chr) was studied using the UV absorption spectroscopy, viscosity measurement, circular dichroism, fluorescence and FT-IR spectroscopic techniques. Results: UV absorption study showed hyperchromic effect in the spectra of DNA. Few changes were observed in the viscosity of ctDNA in the presence of different concentration of SPIONs@DA-Chr. The result of circular dichroism (CD) suggested that SPIONs@DA-Chr can change the secondary structure of DNA. Further, fluorescence quenching reaction of ctDNA with SPIONs@DA-Chr and competitive fluorescence spectroscopy studied by using methylene blue, have shown that the SPIONs@DA-Chr can bind to ctDNA through non-intercalative mode. FT-IR spectroscopy confirmed the binding of SPIONs@DA-Chr and ctDNA. Conclusion: These results suggested that SPIONs@DA-Chr binds to DNA via groove binding mode.