DNA interaction, enhanced DNA photocleavage, electrochemistry, thermal investigation and biopotencial properties of new mixed-ligand complexes of Cu(II)/VO(IV) based on Schiff bases

Biologically active oxovanadium(IV) Schiff base metal complex: antibacterial, antioxidant, biomolecular interaction and molecular docking studies

The oxovanadium(IV) Schiff base metal complex (ISNPV) have been synthesized as well as characterized by using micro analytical and traditional spectroscopic techniques. The spectral findings were utilized to validate the formation of ISNPV with structure exhibited square pyramidal geometry. The in vitro antibacterial activities of ISNPV were investigated to five different bacterial stains such as S. aureus, S. epidermidis, B. cereus, B. amyloliquefaciens and B. subtilis. The obtained result have suggested that the ISNPV has highest antibacterial activity against S. aureus than the other bacterial stains. The in vitro antioxidant activity like DPPH free radical scavenging assay method was studied by ISNPV in DMSO medium. Because it scavenges all free radicals, the ISNPV possesses higher antioxidant activity than the free ligand. UV-visible absorption and emission spectral techniques were used to investigate the binding of CT-DNA to the ISNPV. Both the spectral data indicate that the ISNPV binds the double helix structure of CT-DNA via an intercalation mode. Additionally, investigate the interactions of ISNPV with the protein molecules like BSA/HAS has been investigated using absorption and emission techniques. The absorption intensity of metal complex increases as well as the emission intensity of protein molecules ability decreases due to the binding nature of ISNPV with BSA/HSA protein molecules. The binding nature of ISNPV with bio molecules such as CT-DNA, BSA and HSA was also validated using molecular docking approach.

Chemometrics in investigation of small molecule-biomacromolecule interactions: A review

Chemometrics is chemical discipline in which mathematical and statistical methods are coupled with chemical data to extract useful information which cannot be extracted by the use of conventional methods. When experimental techniques are assisted by chemometric methods, very interesting studies will be performed which enable us to obtain valuable information about the system under our study. Chemico-biological interactions are very useful studies which are performed to obtain information about binding of small molecules with biological macromolecules. Recently, these studies have been assisted by chemometric methods to perform advanced studies which can help us to have a deep insight to them. Literature survey showed us that multivariate analysis of the chemico-biological interactions is becoming popular and nowadays, chemometricians are using multivariate chemometric methods for resolving chemico-biological interactions. This article focuses on the works published in the literature to provide a background for those who are interested to work in this field and finally, the results will be discussed and concluded.

Synthesis, structural characterization, and biological studies of ATBS-M complexes (M(II) = Cu, Co, Ni, and Mn): Access for promising antibiotics and anticancer agents

A new bidentate Schiff base ligand (ATBS [4-bromo-2-(thiazole-2-yliminomethyl)phenol]) was synthesized via the condensation reaction of 2-aminothiazole with 5-bromosalicylaldehyde in ethanol. The reaction of ATBS with transition metal salts of Cu(II), Co(II), Ni(II), and Mn(II) afforded the corresponding ATBS-M complexes. Results from physicochemical and spectral analyses, such as elemental analysis, infrared, UV-Vis spectroscopy, magnetic susceptibility, and molar conductance, revealed a nonelectrolytic nature with octahedral (O_h ) geometry and a metal/ligand ratio of 1:2 for Cu(II), Co(II), and Ni(II), but 1:1 for the Mn(II) complex. The density functional theory (DFT) calculations are correlated very well with the proposed structure and molecular geometry of the complexes as [M(ATBS)₂ ] (M = Cu, Co, and Ni) and [Mn(ATBS)(H₂ O)₂ ]. Significantly, the prepared compounds showed strong inhibition activity for a wide spectrum of bacteria (Escherichia coli, Bacillus subtilis, and Staphylococcus aureus) and fungi (Candida albicans, Aspergillus flavus, and Trichophyton rubrum), with the ATBS-Ni complex being the most promising antibiotic agent. Molecular docking studies of the binding interaction between the title complexes with the bacterial protein receptor CYP51 revealed clear insights about the inhibition nature against the studied microorganisms, with the following order: ATBS-Cu > ATBS-Mn > ATBS-Ni > ATBS-Co for complex stability. Moreover, the cytotoxicity measurements of all prepared metal complexes against the colon carcinoma (HCT-116) and hepatocellular carcinoma (Hep-G2) cell lines showed exceptional anticancer efficacy of the complexes as compared with the free ATBS Schiff base ligand. Significantly, the results attested that ATBS-Cu is the most effective complex against HCT-116 cells, whereas ATBS-Mn has the highest cytotoxic efficiency against Hep-G2 cells. Furthermore, electronic spectra, viscosity measurements, and gel electrophoresis techniques were employed to probe the interaction of all prepared ATBS-metal complexes with calf thymus (CT)-DNA. Results confirmed that all complexes are strongly bound to CT-DNA via intercalation mode, with the ATBS-Co complex having the highest binding ability.

Exploration of DNA binding mode, chemical nuclease, cytotoxic and apoptotic potentials of diketone based oxovanadium(IV) complexes

Two diketone based oxovanadium complexes, viz., bis(4,4,4-trifluoro-1-phenylbutane-1,3-dionato)oxovanadium(IV) (1) and bis(1,1,1-trifluoropentane-2,4-dionato)oxovanadium(IV) (2), have been synthesized and characterized by spectroscopic and analytical techniques. The DNA binding and the cleaving ability of the complexes is assessed by UV-vis spectroscopy, fluorescence spectroscopy, viscometry and gel electrophoretic studies. The DNA binding constant values (Kb) are found to be 1.95 ± 0.16 × 10(3)M(-1) for complex 1 and 1.064 ± 0.17 × 10(3)M(-1) for complex 2, respectively. Based on the results of the spectral and viscosity studies, it is observed that the complexes, interestingly, have preferred minor groove binding with DNA. Further, the concentration-dependent oxidative cleavage pattern of pBR322 in the presence of the activating reagent, hydrogen peroxide, has also been discussed. In addition, the complexes have shown moderate cytotoxic activity by inducing apoptosis against the cervical cancer cell line, HeLa. The results of in silico analysis and logP predictions are found to be in good agreement with the experimental observations. Thus, synthesized oxovanadium complexes have displayed promising DNA binding behavior and DNA cleavage activity with moderately cytotoxic nature.

Metal based pharmacologically active complexes of Cu(II), Ni(II) and Zn(II): synthesis, spectral, XRD, antimicrobial screening, DNA interaction and cleavage investigation

The present contribution reports a thorough characterization of newly obtained metallointercalators incorporating Schiff bases, formed by the condensation of N-acetoacetyl-o-toluidine with 1-amino-4-nitrobenzene (L(1))/1-amino-4-chlorobenzene (L(2)) as main ligand and 1,10-phenanthroline as co-ligand respectively. The characterization of newly formed metallointercalators has been done by (1)H NMR, UV-Vis, IR, EPR spectroscopy and molar conductivity studies. X-ray powder diffraction illustrates that they are crystalline nature. Binding interaction of these complexes with calf thymus (CT-DNA) has been investigated by emission, absorption, viscosity, cyclic voltammetry and differential pulse voltammetry. DNA binding experiments results reveal that the synthesized complexes interact with DNA through intercalative mode. The in vitro antibacterial and antifungal assay indicate that these complexes are good antimicrobial agents against various pathogens. The DNA cleavage exhibits that they act as efficient cleaving agents.

Spectroscopic and molecular modeling based approaches to study on the binding behavior of DNA with a copper (II) complex

Blocking the division of tumor cells by small-molecules is currently of great interest for the design of new antitumor drugs. The interaction of a new metal complex with DNA was investigated through several techniques. Absorption spectroscopy and gel electrophoresis studies on the interaction of the Cu-complex of (2a-4mpyH)2 [Cu(pyzdc)2 (H2O)2].6 H2O with DNA have shown that this complex can bind to CT-DNA with binding constant 3.99 × 10(5) M(-1). The cyclic voltammetry (CV) responses of the metal complex in the presence of CT-DNA have shown that the metal complex can bind to CT-DNA through partial intercalation mode and this is consistent with molecular docking analysis, quenching process and thermal denaturation experiments. The cytotoxicity of this complex has been evaluated by MTT assay. The results of cell viability assay on DU145 cell line revealed that the metal complex had cytotoxic effects.

Anti-mycobacterial activities of copper(II) salicylaldimine complexes derived from long-chain aliphatic amines

Twelve copper(II) Schiff base complexes derived from lipophilic amines have been prepared using either salicylaldehyde or ortho-vanillin via a microwave-assisted reaction. All complexes have been obtained elementally pure and an X-ray diffraction of an isopentyl derivative has confirmed the structure of these compounds. All complexes showed a promising degree of anti-mycobacterial activity against Mycobacterium tuberculosis, where activity seemed to increase with an increase in the length of the aliphatic chain.

Structure investigation of intramolecular hydrogen bond in some substituted salicylaldehydes and 4-aminoantipyrine derivatives in solution and in the solid state

Seven imine derivatives obtained by condensation of appropriate aldehydes and salicylaldehydes with 4-aminoantipyrine were investigated in terms of intramolecular hydrogen bond structure. On the base of (1)H, (13)C and (15)N NMR measurements in solution and in the solid state we found out that all compounds which can form such structure exist as OH forms with strong H-bonds to nitrogen atom. The structure conclusions taken from NMR study were confirmed by pKa measurements. Surpassingly, the positions of protons in H-bridges only very slightly depend on the substituents in aldehyde used for condensation and on the phase (solution vs. solid state). The influence of antipyrine moiety seems to be the major factor defining H-bond structure.

Synthesis and characterization of unsymmetrical oxidovanadium complexes: DNA-binding, cleavage studies and antitumor activities

Four oxidovanadium(IV) complexes, [VO(hntdtsc)(phen)] (1), [VO(hntdtsc)(bpy)] (2) (hntdtsc=2-hydroxy-1-naphthaldehyde thiosemicarbazone, phen=1,10-phenanthroline), [VO(satsc)(phen)] (3) and [VO(satsc)(bpy)] (4) (satsc=salicylaldehyde thiosemicarbazone, bpy=2,2'-bipyridine) have been synthesized and characterized. The results show that complexes 1, 2, 3 and 4 interact with DNA through intercalative mode and can efficiently cleave the plasmid pBR 322 DNA. It is interesting to note that these four complexes present highly cytotoxic activities against Myeloma cell (Ag8.653) and Gliomas cell (U251) lines. Complex 1 was found to be the most potent antitumor agent among the four complexes.