Design, synthesis and DNA interaction studies of new fluorescent platinum complex containing anti-HIV drug didanosine

Biological and computational investigation of transition metal(II) complexes of 2-phenoxyaniline-based ligands

Aim: In the 21st century, we are witness of continuous onslaughts of various pathogen deformities which are a major cause of morbidity and mortality worldwide. Therefore, to investigate the grave for these deformities, antioxidant, anti-inflammatory and antimicrobial biological activities were carried out against newly synthesized Schiff base ligands and their transition metal complexes, which are based on newly synthesized 2-phenoxyaniline and salicylaldehyde derivatives. Materials & methods: The synthesized compounds were characterized by various physiochemical studies, demonstrating the octahedral stereochemistry of the complexes. Results: The biological assessments revealed that complex 6 (3.01 ± 0.01 μM) was found to be highly active for oxidant ailments whereas complex 14 (7.14 ± 0.05 μM, 0.0041-0.0082 μmol/ml) was observed as highly potent for inflammation and microbial diseases. Conclusion: Overall, the biological and computational studies demonstrate that the nickel(II) complex 14 can act as an excellent candidate for pathogen deformities.

Ternary Cobalt (II)-Metformin-Glycine/Histidine/Proline Complexes: Multispectroscopic DNA, HSA, and BSA Interaction and Cytotoxicity Studies

The synthesized water-soluble ternary complexes [Co(met)(gly)(Cl)2] (1), [Co(met)(hist)(Cl)2] (2), and [Co(met)(pro)(Cl)2] (3), (met = metformin, gly = glycine, hist = histidine, and pro = proline) were evaluated using spectro-analytical techniques, and the stereochemistry of the complexes was determined to be octahedral. UV-Vis absorption, competitive DNA-binding experiments using ethidium bromide (EB) by fluorescence, fluorescence emission studies, viscosity studies, and gel electrophoresis techniques were all employed to explore the binding characteristics of the cobalt (II) complexes with CT-DNA and groove-binding mechanism established. The salt-dependent association of the complexes to CT-DNA was investigated using UV-Vis spectrophotometric analysis. The association of the cobalt (II) complexes with BSA and HSA was explored by utilizing UV-Vis absorption and fluorescence spectroscopy approaches. The findings show that the complexes exhibit adequate capacity to quench BSA and HSA fluorescence and that the binding response is mostly a static quenching mechanism. The cytotoxicity of the complexes has also been appraised with the human breast adenocarcinoma cell lines (MCF-7) and (MDA-MB-231) by utilizing the MTT assay. For each cell line, the IC50 values were computed. In both cell lines, all the complexes were active.

Platinum-Nucleos(t)ide Compounds as Possible Antimetabolites for Antitumor/Antiviral Therapy: Properties and Perspectives

Nucleoside analogues (NAs) are a family of compounds which include a variety of purine and pyrimidine derivatives, widely used as anticancer and antiviral agents. For their ability to compete with physiological nucleosides, NAs act as antimetabolites exerting their activity by interfering with the synthesis of nucleic acids. Much progress in the comprehension of their molecular mechanisms has been made, including providing new strategies for potentiating anticancer/antiviral activity. Among these strategies, new platinum-NAs showing a good potential to improve the therapeutic indices of NAs have been synthesized and studied. This short review aims to describe the properties and future perspectives of platinum-NAs, proposing these complexes as a new class of antimetabolites.

State of art in the chemistry of nucleoside-based Pt(II) complexes

After the fortuitous discovery of the anticancer properties of cisplatin, many Pt(II) complexes have been synthesized, to obtain less toxic leads which could overcome the resistance phenomena. Given the importance of nucleosides and nucleotides as antimetabolites, studying their coordinating properties towards Pt(II) ions is challenging for bioorganic and medicinal chemistry. This review aims to describe the results achieved so far in the aforementioned field, paying particular attention to the synthetic aspects, the chemical-physical characterization, and the biological activities of the nucleoside-based Pt(II) complexes.

Inhibition of mycobacteria proliferation in macrophages by low cisplatin concentration through phosphorylated p53-related apoptosis pathway

BACKGROUND

Drug resistance is a prominent problem in the treatment of tuberculosis, so it is urgent to develop new anti- tuberculosis drugs. Here, we investigated the effects and mechanisms of cisplatin (DDP) on intracellular Mycobacterium smegmatis to tap the therapeutic potential of DDP in mycobacterial infection.

RESULTS

Macrophages infected with Mycobacterium smegmatis were treated with DDP alone or combined with isoniazid or rifampicin. The results showed that the bacterial count in macrophages decreased significantly after DDP (≤ 6 μg/mL) treatment. When isoniazid or rifampicin was combined with DDP, the number of intracellular mycobacteria was also significantly lower than that of isoniazid or rifampicin alone. Apoptosis of infected cells increased after 24 h of DDP treatment, as shown by flow cytometry and transmission electron microscopy detection. Transcriptome sequencing showed that there were 1161 upregulated and 645 downregulated differentially expressed genes (DEGs) between the control group and DDP treatment group. A Trp53-centered protein interaction network was found based on the top 100 significant DEGs through STRING and Cytoscape software. The expression of phosphorylated p53, Bax, JAK, p38 MAPK and PI3K increased after DDP treatment, as shown by Western blot analysis. Inhibitors of JAK, PI3K or p38 MAPK inhibited the increase in cell apoptosis and the reduction in the intracellular bacterial count induced by DDP. The p53 promoter Kevetrin hydrochloride scavenges intracellular mycobacteria. If combined with DDP, Kevetrin hydrochloride could increase the effect of DDP on the elimination of intracellular mycobacteria. In conclusion, DDP at low concentrations could activate the JAK, p38 MAPK and PI3K pathways in infected macrophages, promote the phosphorylation of p53 protein, and increase the ratio of Bax to Bcl-2, leading to cell apoptosis, thus eliminating intracellular bacteria and reducing the spread of mycobacteria.

CONCLUSION

DDP may be a new host-directed therapy for tuberculosis treatment, as well as the p53 promoter Kevetrin hydrochloride.

Nickel-Metformin Ternary Complexes: Geometrical, Thermal, DNA Binding, and Molecular Docking Studies

Novel three nickel(II) complexes of type [Ni(metf)(o-phen)₂]Cl₂ (1), [Ni(metf)(opda)₂]Cl₂ (2), [Ni(metf)(2-2'bipy)₂]Cl₂ (3), (Metf = metformin, o-phen = ortho-phenanthroline, opda = ortho-phenylenediamine, 2-2' bipy = 2-2' bipyridyl) were synthesized and characterized by various analytical and spectral techniques. Based on these studies, octahedral geometry is assigned to these complexes. The DNA binding properties of these complexes were investigated by absorption, emission, and viscosity studies. From the spectral data, it was concluded that the complexes bind to DNA through groove mode of binding. The intrinsic binding constants (K_b) from absorption spectroscopy were 1.60 × 10⁴, 3.57 × 10⁴, and 5.70 × 10⁴ M^-1 for 1, 2, and 3, respectively, and Stern-Volmer quenching constants (K_sv) from emission spectroscopy were 0.11, 0.87, and 0.24, respectively. Thermal degradation pattern of the compounds was studied and Coats-Redfern method is used to determine kinetic parameters for complexes 1, 2, and 3 from thermal studies. The software Discovery Studio 2.1 was used to assess the binding affinity and interaction pattern of complexes with the B-DNA receptor protein and complex 1 has the highest dock score.

Experimental and Molecular Docking Studies on the Interaction of a Water-Soluble Pd(II) Complex Containing β-Amino Alcohol with Calf Thymus DNA

The interaction of water-soluble and fluorescent [Pd (HEAC) Cl₂] complex, in which HEAC is 2-((2-((2-hydroxyethyl)amino)ethyl)amino) cyclohexanol, with calf thymus DNA (ct-DNA) has been studied. This study was performed using electronic absorption and fluorescence emission spectroscopies, cyclic voltammetry and circular dichroism analyses, dynamic viscosity measurements, and molecular docking theory. From hypochromic effect observed in ct-DNA absorption spectra, it was found that the Pd(II) complex could form a conjugate with ct-DNA strands through the groove binding mode. The K_b values obtained from fluorescence measurements clearly assert the Pd(II) complex affinity to ct-DNA. The fluorescence quenching of the DNA-Hoechst compound following the successive additions of the Pd(II) complex to the solution revealed that the Pd(II) complex is located in the ct-DNA grooves, and Hoechst molecules have been released into solution; moreover, the resulting measurements from relative viscosity authenticate the Pd(II) complex binding to the grooves. Negative quantities of thermodynamic parameters imply that the Pd(II) complex binds to ct-DNA mainly by the hydrogen bonds and van der Waals forces; also, the Gibbs-free energy changes show the exothermic and spontaneous formation of the Pd(II) complex-DNA system. The electrochemical behavior of the Pd(II) complex in the attendance of ct-DNA was investigated using the cyclic voltammetry method (CV). Several quasi-reversible redox waves were observed along with increasing the anodic/cathodic peak currents, as well as a shift in anodic/cathodic peak potentials. Circular dichroism (CD) observations suggested that the Pd(II)-DNA interaction could alter ct-DNA conformation. The results of molecular modeling confirmed that groove mechanism is followed by the Pd(II) complex to interact with ct-DNA.

Metformin-Derived Water-Soluble Cobalt Complexes: Thermal, Spectroscopic, DNA Interaction, and Molecular Docking Studies

Novel three water-soluble cobalt (II) complexes of type [Co(metf)(o-phen)₂]Cl₂ (1), [Co(metf)(opda)₂]Cl₂ (2), and [Co(metf)(2-2'bipy)₂]Cl₂ (3) (Metf, metformin; o-phen, ortho-phenanthroline; opda, ortho-phenylenediamine; 2,2'-bipy, 2,2'-bipyridine) were synthesized and characterized by various analytical and spectral techniques. Based on these studies, octahedral geometry is assigned to these complexes. The stability of the complexes has been calculated from quantum chemical parameters using HOMO-LUMO energies. Thermal degradation pattern of the compounds was studied and Coats-Redfern method is used to determine kinetic parameters for complexes 1, 2, and 3 from thermal studies. The DNA interaction of these complexes was investigated by absorption, emission, and viscosity studies. From the spectral data, it was concluded that the complexes bind to DNA through groove mode of binding. The intrinsic binding constants (K_b) from absorption spectroscopy were 2.49 × 10⁴, 2.48 × 10⁴, and 2.64 × 10⁴ M^-1 for 1, 2, and 3, respectively, and Stern-Volmer quenching constants (K_sv) from emission spectroscopy were 0.21, 0.20, and 0.13, respectively. These complexes were screened for nuclease activity of pUC19 DNA, in the presence of H₂O₂. Discovery studio 2.1 software was used to evaluate binding affinity and interaction pattern of complexes with B-DNA receptor protein and the maximum dock score is seen for complex 2.

In vitro cytotoxicity, antibacterial activity and HSA and ct-DNA interaction studies of chlorogenic acid loaded on γ-Fe2O3@SiO2 as new nanoparticles

In this study, nanoparticles with both anticancer and antibacterial features were synthesized through loading chlorogenic acid (CGA) of essential oils on magnetic nanoparticles (MNPs). Characterization of γ-Fe₂O₃@SiO₂-CGA MNPs was performed using Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM) that show effective coating of the MNPs with SiO₂ and CGA ligand and spherical shape of the nanoparticles with a mean diameter of 16 nm, respectively. The cytotoxicity study demonstrated that γ-Fe₂O₃@SiO₂-CGA MNPs had fewer toxic effects on normal cells (Huvec) than on cancerous cells (U-87 MG, A-2780 and A-549), and could be a new potential candidate for use in biological and pharmaceutical applications. The interaction of calf thymus deoxyribonucleic acid (ct-DNA) with γ-Fe₂O₃@SiO₂-CGA MNPs indicated that the anticancer activity might be associated with the DNA binding properties of γ-Fe₂O₃@SiO₂-CGA MNPs. Moreover, the interaction of γ-Fe₂O₃@SiO₂-CGA MNPs with human serum albumin (HSA) suggests that the native conformation of HSA was preserved at the level of secondary structure, indicating that the γ-Fe₂O₃@SiO₂-CGA MNPs do not show any cytotoxicity effect when they are injected into the blood. Antibacterial tests were performed and represented γ-Fe₂O₃@SiO₂-CGA MNPs attained better antibacterial function than CGA as free.

Interaction of human hemoglobin (HHb) and cytochrome c (Cyt c) with biogenic chloroxine-conjugated silver nanoflowers: spectroscopic and molecular docking approaches

In this research, the biological activity of the antibacterial drug Chloroxine-conjugated biogenic AgNPs (COX-AgNPs) was investigated in simulated physiological conditions (pH = 7.40). Different spectroscopic methods such as UV-visible, fluorescence, and circular dichroism spectroscopic and docking simulation were employed to evaluate the structural changes in the most important blood proteins (human hemoglobin (HHb) and Cytochrome c (Cyt c)) in the presence of COX-AgNPs. The results showed that the COX-AgNPs can bind to HHb and Cyt c and the secondary structure of these proteins remains unchanged, which is crucial in providing insights into the side effects of newly synthesized drugs on their carriers.Communicated by Ramaswamy H. Sarma.

Probing the DNA Reactivity and the Anticancer Properties of a Novel Tubercidin-Pt(II) Complex

Herein, we reported on the synthesis of a novel Pt(II) neutral complex having as ligand the nucleoside tubercidin, a potent anti-tumor agent extracted from the bacterium Streptomyces Tubercidicus. In detail, the chelation of the metal by a diamine linker installed at C6 purine position of tubercidin assured the introduction of a cisplatin-like unit in the molecular scaffold. The behavior of the synthesized complex with a double-strand DNA model was monitored by CD spectroscopy and compared with that of cisplatin and tubercidin. In addition, the cell viability was evaluated against HeLa, A375 and WM266 human cancer cell lines using the MTT test. Lastly, the results of the apoptotic assay (FITC Annexin V) performed on the HeLa cancer cell line are also reported.

Multispectroscopic analysis, atomic force microscopy, molecular docking and molecular dynamic simulation studies of the interaction between [SnMe2Cl2(Me2phen)] complex and ct-DNA in the presence of glucose

In this study, the spectroscopic methods (UV-vis, fluorimetric), Atomic force microscopy, and computational studies (molecular docking and molecular dynamic simulation) were used to investigate the interaction of [SnMe₂Cl₂(Me₂phen)] complex with CT-DNA in the presence of glucose. The results showed the complex in the medium containing glucose has less effect on calf thymus DNA (ct-DNA) than the medium without glucose. Cytotoxicity of [SnMe₂Cl₂(Me₂phen)] complex on MCF-7 cells was examined and showed Sn(IV) complex possesses potential cytotoxicity against this cell line. Molecular docking study showed that Sn(IV) complex interacts with DNA by groove binding mode. Radius of gyration (Rg) was smaller upon binding of the Sn(IV) complex suggesting a more compact structure of DNA in the presence of Sn(IV) complex.Communicated by Ramaswamy H. Sarma.