DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes

An Insight into the Effect of Schiff Base and their d and f Block Metal Complexes on Various Cancer Cell Lines as Anticancer Agents: A Review

Over the last few decades, an alarming rise in the percentage of individuals with cancer and those with multi-resistant illnesses has forced researchers to explore possibilities for novel therapeutic approaches. Numerous medications currently exist to treat various disorders, and the development of small molecules as anticancer agents has considerable potential. However, the widespread prevalence of resistance to multiple drugs in cancer indicates that it is necessary to discover novel and promising compounds with ideal characteristics that could overcome the multidrug resistance issue. The utilisation of metallo-drugs has served as a productive anticancer chemotherapeutic method, and this approach may be implemented for combating multi-resistant tumours more successfully. Schiff bases have been receiving a lot of attention as a group of compounds due to their adaptable metal chelating abilities, innate biologic properties, and versatility to tweak the structure to optimise it for a specific biological purpose. The biological relevance of Schiff base and related complexes, notably their anticancer effects, has increased in their popularity as bio-inorganic chemistry has progressed. As a result of learning about Schiff bases antitumor efficacy against multiple cancer cell lines and their complexes, researchers are motivated to develop novel, side-effect-free anticancer treatments. According to study reports from the past ten years, we are still seeking a powerful anticancer contender. This study highlights the potential of Schiff bases, a broad class of chemical molecules, as potent anticancer agents. In combination with other anticancer strategies, they enhance the efficacy of treatment by elevating the cytotoxicity of chemotherapy, surmounting drug resistance, and promoting targeted therapy. Schiff bases also cause cancer cell DNA repair, improve immunotherapy, prevent angiogenesis, cause apoptosis, and lessen the side effects of chemotherapy. The present review explores the development of potential Schiff base and their d and f block metal complexes as anticancer agents against various cancer cell lines.

Synthesis, Spectral Characterization and Biological Activities of Co(II) and Ni(II) Mixed Ligand Complexes

2,4-Dinitrophynylhydrazine and two thiocyanate ions in a (M:L1:L2) 1:2:2 molar ratio was synthesized in the complexes of Co(II) and Ni(II). The prepared compounds were identified through a C.H.N.S. analysis, conductivity measurements, powder X-ray diffraction (PXRD), the infrared spectrum, and a UV-visible spectrum analysis, in addition to the magnetic properties being measured. The measurements of the molar conductance implieda nonelectrolytic nature of compounds Co(II) and Ni(II). The magnetic susceptibility, as well as electronic spectra, represented all the metal complexesthroughoctahedral geometry, respectively. The PXRD patterns suggested that all the complexes were an orthorhombic system with unit cell parameters. The in-vitro biological activity of the ligand and the metal complexes were screened against the Gram-positive and negative pathogenic bacteria Staphylococcus aureus, Bacillus subtilis, Pseudomonas, aeruginosa and Escherichia coli, as well as the fungal species of Aspergillusniger and Candida albicans.Thus, the metal complexes showeda high efficiency of antimicrobial activity compared with the ligand. Furthermore, applications of the ligand, as well as the metal complexes, were tested for in-vitro antioxidant potential in aDPPH assay. The results showed that the activity of the metal complexes with the in-vitro antioxidant was more active than that of 2,4-dinitrophenylhydrazine(DNPH).

Anticancer Activity Assessment and DNA Binding Properties of Two Binuclear Platinum (II) Complexes using Spectroscopic and Molecular Simulation Approaches

BACKGROUND

Nowadays, the biological properties and anticancer activities of platinum-based drugs and metal coordination complexes have been receiving particular attention. These compounds have revealed clinical potential in cancer chemotherapy.

OBJECTIVE

In this research, two binuclear platinum complexes including [Pt2Cl2(bhq)2(μ-dppm)] (1) and [(p- MeC6H4)(bhq) Pt(μ-dppm)Pt(bhq)(CF3CO2)] (2) with bhq: benzo[h] quinolone and dppm: bis(diphenylphosphino) methane have been synthesized and evaluated for their anticancer activity against A2780 and A2780/RCIS cancer cell lines.

METHODS

The DNA binding and interaction of AMP/GMP nucleotide with these complexes were explored by several experimental and theoretical methods, including UV-Visible, fluorescence spectroscopic techniques and docking analysis. These complexes have demonstrated significant anticancer properties against cisplatinsensitive (A2780) and cisplatin-resistant (A2780/RCIS) human ovarian cancer cell lines.

RESULTS

The obtained results indicated that these complexes interact with DNA. Additionally, the fluorescence emission measurements indicated that the platinum complexes binding with DNA structure occurs through nonintercalative interaction. The molecular docking assessments have also revealed the binding of these platinum complexes through DNA grooves. Moreover, the results have indicated that complex 1 exhibited more anticancer activity than complex 2.

CONCLUSION

The results of the DNA binding with these platinum complexes confirmed their potential antitumor properties. The substitution of -C6H4CH3 and -CO2CF3 groups in complex 2 with two chlorine atoms in complex 1 acquired the significant improvement of the anticancer activity against the cancer cell.

Biological and molecular modeling studies on some transition metal(II) complexes of a quinoxaline based ONO donor bishydrazone ligand

In this report, synthesis, characterization, biological and molecular modeling studies of an ONO donor tridentate bishydrazone ligand, 3-[N'-(2-Hydroxy-3-methoxy-benzylidene)-hydrazino]-1H-quinoxalin-2-one (HHQ) and its 1:1 mononuclear Co(II) (HHQ-1), Ni(II) (HHQ-2), Cu(II) (HHQ-3) and Zn(II) (HHQ-4) complexes have been conferred. Octahedral geometry was assigned to HHQ-1, HHQ-2 and HHQ-4 and distorted octahedral geometry for HHQ-3. The lattice parameters, morphology and electrochemical behaviors of the compounds were studied by powder XRD, SEM and cyclic voltammetry analyses respectively. The antimicrobial assays were carried out against the bacterial (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and fungal (Aspergillus flavus, Aspergillus niger and Candida albicans) strains. Furthermore, the DNA binding, cleaving and superoxide dismutase (SOD) activities of HHQ and its metal(II) complexes were discussed. The structures of HHQ and its derivatives were optimized by DFT techniques. Using molecular docking the molecular interaction dynamics amongst the DNA and SOD with HHQ and its metal(II) complexes were recognized.Communicated by Ramaswamy H. Sarma.

Copper complexes bearing 2-aminobenzothiazole derivatives as potential antioxidant: Synthesis, characterization

Novel copper complexes of Schiff base ligands of 2-aminobenzothiazole derivatives were synthesized by the condensation of Knoevenagel condensate of acetoacetanilide (obtained from substituted benzaldehydes and acetoacetanilide) and 2-aminobenzothiazole. They were characterized by elemental analysis, IR, (1)H NMR, UV-Vis., molar conductance, magnetic susceptibility measurements and electrochemical studies. Based on the magnetic moment and electronic spectral data, square planar geometry has been suggested for all the complexes. Antibacterial and antifungal screening of the ligands and their complexes reveal that all the complexes show higher activities than the ligands. The binding behaviour of the complexes with calf thymus DNA has been investigated by electronic absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through intercalation binding mode. Superoxide dismutase and antioxidant activities of the copper complexes have also been studied. The antioxidant activities of the complexes showed higher activities. Thermal denaturation studies suggested the nature binding affinity of copper complexes with CT-DNA. All complexes exhibit suitable Cu(II)/Cu(I) redox potential to act as antioxidant enzymes mimic. Further, the copper complexes also showed catalase activity. It is hope that copper complexes were capable of decrease ROS levels or reduce oxidative stress in Alzheimer's patients.

Synthesis, spectral characterization, DNA interaction, anticancer and molecular docking studies on some transition metal complexes with bidentate ligand

The ligand, N(2),N(3)-bis(3-nitrophenyl)quinoxaline-2.3-diamine was prepared by the condensation of quinoxaline-2.3(1,4H)-dione with 3-nitroaniline. It was treated with Co(II), Ni(II), Cu(II) and Zn(II) acetates to form the metal complexes. These were characterized by elemental analysis, molar conductance, magnetic moment, UV-Vis., IR, (1)H NMR, ESR and mass spectral data. Octahedral geometry has been assigned to Co(II), Ni(II) and Zn(II) complexes, whereas Cu(II) complex has distorted octahedral geometry. From the powder XRD data, crystallite size and unit cell parameters were calculated. The surface morphology of the synthesized compounds were determined using SEM analysis. The antimicrobial activity of the compounds against some bacterial species viz. Escherichiacoli, Klebsiella pneumoniae, Pseudomonas aeuruginosa and Staphylococcus aureus; also the fungal species, Aspergillus niger, and Candida albicans were done by disc diffusion method. DNA binding, cleavage and super oxide anion scavenging activities were also evaluated. The DNA binding activity of the compounds were identified using electronic absorption titrations and DNA cleavage was determined using gel electrophoresis. The anticancer activities of the compounds against HeLa cell line were determined using MTT assay. The highly potent compound among the five against HeLa cell line is subjected to molecular docking study against human papilloma virus receptor molecule and ATP binding site of telomerase.

A novel one-pot synthesis of heterocyclic compound (4-benzoyl-5-phenyl-2-(pyridin-2-yl)-3,3a-dihydropyrazolo[1,5-c]pyrimidin-7(6H)-one): structural (X-ray and DFT) and spectroscopic (FT-IR, NMR, UV-Vis and Mass) characterization studies

In this study, the title compound named as 4-benzoyl-5-phenyl-2-(pyridin-2-yl)-3,3a-dihydropyrazolo[1,5-c]pyrimidin-7(6H)-one (C24H18N4O2) was both experimentally and theoretically investigated. The compound was synthesized and characterized by FT-IR, NMR ((1)H NMR, (13)C NMR and HETCOR-NMR), Mass spectroscopies and single-crystal X-ray diffraction methods. The compound crystallizes in the monoclinic space group P2(1)/n with a=6.1402 (3) Å, b=21.4470 (15) Å, c=15.0049 (8) Å and β=97.407 (4)°. The molecular geometry was obtained from the X-ray structure determination optimized using density functional theory (DFT/B3LYP) method with the 6-31+G(d, p) basis set in ground state. From the optimized structure, geometric parameters, vibrational wavenumbers and chemical shifts of molecule were obtained. Experimental measurements were compared with its corresponding the calculated data. An excellent harmony between the two data was ascertained. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs) and non-linear optical (NLO) properties of the title molecule were investigated by theoretical calculations at the B3LYP/6-31+G(d, p) level.

Synthesis, characterization, electrochemical and biological studies on some metal(II) Schiff base complexes containing quinoxaline moiety

Novel Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff base derived from quinoxaline-2,3-(1,4H)-dione and 4-aminoantipyrine (QDAAP) were synthesized. The ligand and its complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, FTIR, UV-Vis., mass and (1)H NMR spectral studies. The X band ESR spectrum of the Cu(II) complex at 300 and 77K were also recorded. Thermal studies of the ligand and its complexes show the presence of coordinated water in the Ni(II) and Zn(II) complexes. The coordination behavior of QDAAP is also discussed. All the complexes are mono nuclear and tetrahedral geometry was found for Co(II) complex. For the Ni(II) and Zn(II) complexes, octahedral geometry was assigned and for the Cu(II) complex, square planar geometry has been suggested. The grain size of the complexes was estimated using powder XRD. The surface morphology of the compounds was studied using SEM analysis. Electrochemical behavior of the synthesized complexes in DMF at room temperature was investigated by cyclic voltammetry. The in vitro biological screening of QDAAP and its metal complexes were tested against bacterial species Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The fungal species include Aspergillus niger, Aspergillus flavus and Candida albicans. The DNA cleavage activity of QDAAP and its complexes were also discussed.

Interaction study of ciprofloxacin with human telomeric DNA by spectroscopy and molecular docking

The interaction of ciprofloxacin (CIP) with human telomeric DNA was studied in vitro using multi-spectroscopy and molecular modeling methods. The hypochromic effect with a red shift in ultraviolet (UV) absorption indicated the occurrence of the interaction between CIP and DNA. The fluorescence quenching of CIP was observed with the addition of DNA and was proved to be the static quenching. The binding constant was found to be 9.62×10(4) L mol(-1). Electrospray ionization mass spectrometry (ESI-MS) result further confirmed the formation of 1:1 non-covalent complex between DNA and CIP. Combined with the UV melting results, circular dichroism (CD) results confirmed the existence of groove binding mode, as well as conformational changes of DNA. Molecular docking studies illustrated the visual display of the CIP binding to the GC region in the minor groove of DNA. Specific hydrogen bonds and van der Waals forces were demonstrated as main acting forces between CIP and guanine bases of DNA.