Vanadium(V) complexes derived from triphenylphosphonium and hydrazides: cytotoxicity evaluation and interaction with biomolecules

The development of coordination compounds with antineoplastic therapeutic properties is currently focused on non-covalent interactions with deoxyribonucleic acid (DNA). Additionally, the interaction profiles of these compounds with globular plasma proteins, particularly serum albumin, warrant thorough evaluation. In this study, we report on the interactions between biomolecules and complexes featuring hydrazone-type imine ligands coordinated with vanadium. The potential to enhance the therapeutic efficiency of these compounds through mitochondrial targeting is explored. This targeting is facilitated by the derivatization of ligands with triphenylphosphonium groups. Thus, this work presents the synthesis, characterization, interactions, and cytotoxicity of dioxidovanadium(V) complexes (C1-C5) with a triphenylphosphonium moiety. These VV-species are coordinated to hydrazone-type iminic ligands derived from (3-formyl-4-hydroxybenzyl)triphenylphosphonium chloride ([AH]Cl) and aromatic hydrazides ([H2L1]Cl-[H2L5]Cl). The structures of the five complexes were elucidated through single-crystal X-ray diffraction and vibrational spectroscopies, confirming the presence of dioxidovanadium(V) species in various geometries with degrees of distortion (τ = 0.03-0.50) and highlighting their zwitterionic characteristics. The molecular structural stability of C1-C5 in solution was ascertained using 1H, 19F, 31P, and 51V-nuclear magnetic resonance. Moreover, their interactions with biomolecules were evaluated using diverse spectroscopic methodologies and molecular docking, indicating moderate interactions (Kb ≈ 104 M-1) with calf thymus DNA in the minor groove and with human serum albumin, predominantly in the superficial IB subdomain. Lastly, the cytotoxic potentials of these complexes were assessed in keratinocytes of the HaCaT lineage, revealing that C1-C5 induce a reduction in metabolic activity and cell viability through apoptotic pathways.

A Siderophore Mimicking Gelation Component for Capturing and Self-Separation of Fe(III) from an Aqueous Solution of Mixture of Metal Ions

The carbohydrazide-based gelation component N2,N4,N6-(1,3,5-triazine-2,4,6-triyl)tris(benzene-1,3,5-tricarbohydrazide) (CBTC) was synthesized and characterized using various spectroscopic tools. CBTC and trimesic acid (TMA) get self-assembled to form metallogel with Fe3+, specifically through various noncovalent interactions in a DMSO and H2O mixture. The self-assembly shows remarkable specificity toward Fe(III) among different transition metal salts. It is pertinent to point out that the binding specificity for Fe3+ can also be found in nature in the form of siderophores, as they are mainly involved in scavenging iron selectively from the surroundings. DFT studies have been used to investigate the possible interaction between the different components of the iron metallogel. To determine the selectivity of CBTC for iron, CBTC, along with trimesic acid, is used to interact with other metal ions, including Fe(III) ions, in a single system. The gelation components CBTC and TMA selectively bind with iron(III), which leads to the formation of metallogel and gets separated as a discrete layer, leaving the other metal ions in the solution. Therefore, CBTC and TMA together show iron-scavenging properties. This selective scavenging property is explored through FE-SEM, XPS, PXRD, IR, and ICP-AES analysis. The FE-SEM analysis shows a flower-petal-like morphology for the Fe(III) metallogel. The resemblance in the CBTC-TMA-Fe metallogel and metallogel obtained from the mixture of different metal salts is established through FE-SEM images and XPS analysis. The release of iron from the metallogel is achieved with the help of ascorbic acid, which converts Fe3+ to Fe2+. In biological systems, iron also gets released similarly from siderophores. This is the first report where the synthesized gelation component CBTC molecule is capable of scavenging out iron in the form of metallogel and self-separating from the aqueous mixture in the presence of various other metal ions.

Synthesis of bioinspired sorbent and their exploitation for methylene blue remediation

In this research article, novel starch phosphate grafted polyvinyl imidazole (StP-g-PIMDZs) was synthesized. Firstly, a phosphate group was attached to starch polymer via a phosphorylation reaction. Next, 1-vinyl imidazole (VIMDZ) was grafted on the backbone of starch phosphate (StP) through a free radical polymerization reaction. The synthesis of these modified starches was confirmed by 1H NMR, 31P NMR and FT-IR techniques. The grafting of vinyl imidazole onto StP diminished the crystallinity. Due to the insertion of the aromatic imidazole ring, the StP-g-PIMDZs demonstrated greater thermal stability. The StP and StP-g-PIMDZs were used as sorbents for the adsorption of methylene blue dye (MBD) from the model solution. The maximum removal percentage for starch, StP, StP-g-PIMDZ 1, StP-g-PIMDZ 2 and StP-g-PIMDZ 3 was found to be 60.6%, 66.7%, 74.2%, 85.3 and 95.4%, respectively. The Pseudo second order kinetic model and Langmuir adsorption isotherm were best suited to the experimental data with R2 = 0.999 and 0.99, respectively. Additionally, the thermodynamic parameters showed that the adsorption process was feasible, spontaneous, endothermic and favored chemi-sorption mechanism.

A Vanadium(V) complexes derived from pyridoxal/salicylaldehyde. Interaction with CT-DNA/HSA, and molecular docking assessments

With the increasing development of metallopharmaceuticals, coordination compounds become viable alternatives for therapeutic uses. Despite the importance of platinum derivatives in this area, first-row transition metals complexes are welcome due to their characteristics. Vanadium is a promising metal in this context, as it has a range of compounds with different biological applications, including anticancer therapeutic effects. In this effort, the study of interactions between coordination compounds with deoxyribonucleic acid and with human serum albumin is fundamental. In this way, ten iminic ligands were synthesized by condensing p-substituted aromatic benzohydrazides (OH, CH₃, H, NO₂, and NH₂) with salicylaldehyde (L1As-L5As) or pyridoxal hydrochloride (L1P-L5P). These ligands have characteristics that allow the tridentate coordination of vanadium cations, leading to the formation of ten vanadium(V) complexes (C1As-C5As and C1P-C5P) with different structural features, all characterized by single-crystal X-ray diffraction, UV-Vis and infrared spectroscopies, and cyclic voltammetry. In addition, the complexes were tested for their interactions with calf thymus deoxyribonucleic acid and human serum albumin by spectroscopic assays and molecular docking calculations. These new results can contribute to further research and provide different ways to design new vanadium complexes with biological applications.