Unveiling the Interaction of Vanadium Compounds with Human Serum Albumin by Using1H STD NMR and Computational Docking Studies

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.

Comparison of the Effects on Bovine Serum Albumin Induced by Different Forms of Vanadium

Various forms of vanadium coexist in vivo, and the behavior mechanism is different. An investigation of the separate and simultaneous binding of three vanadium forms with bovine serum albumin (BSA) was performed. VO(acac)₂/NaVO₃/VOSO₄ bound to site I of BSA, and their binding constants were 4.26 × 10⁵, 9.18 × 10³, and 4.31 × 10² L mol^-1 at 298 K, respectively. VO(acac)₂ had the strongest binding ability to BSA and had the most influence on the secondary structure of BSA and the microenvironment of around amino acid residues. The effect of NaVO₃ and VOSO₄ coexistence on the binding of VO(acac)₂ to BSA was therefore further investigated. Both NaVO₃ and VOSO₄ had an effect on the binding of VO(acac)₂ and BSA, with NaVO₃ having the most noticeable effect. NaVO₃ interfered with the binding process of VO(acac)₂ and BSA, increased the binding constant, and changed the binding forces between them. Competition and allosteric effect may be responsible for the change of binding process between VO(acac)₂ and BSA in the presence of NaVO₃/VOSO₄.

Vanadium and insulin: Partners in metabolic regulation

Since the 1970s, the biological role of vanadium compounds has been discussed as insulin-mimetic or insulin-enhancer agents. The action of vanadium compounds has been investigated to determine how they influence the insulin signaling pathway. Khan and coworkers proposed key proteins for the insulin pathway study, introducing the concept "critical nodes". In this review, we also considered critical kinases and phosphatases that participate in this pathway, which will permit a better comprehension of a critical node, where vanadium can act: a) insulin receptor, insulin receptor substrates, and protein tyrosine phosphatases; b) phosphatidylinositol 3'-kinase, 3-phosphoinositide-dependent protein kinase and mammalian target of rapamycin complex, protein kinase B, and phosphatase and tensin homolog; and c) insulin receptor substrates and mitogen-activated protein kinases, each node having specific negative modulators. Additionally, leptin signaling was considered because together with insulin, it modulates glucose and lipid homeostasis. Even in recent literature, the possibility of vanadium acting against metabolic diseases or cancer is confirmed although the mechanisms of action are not well understood because these critical nodes have not been systematically investigated. Through this review, we establish that vanadium compounds mainly act as phosphatase inhibitors and hypothesize on their capacity to affect kinases, which are critical to other hormones that also act on common parts of the insulin pathway.

Characterizing the interaction between methyl ferulate and human serum albumin by saturation transfer difference NMR

Methyl ferulate (MF) is an alkyl ferulate ester that widely exists in edible plants and has application value in the food and medicine industries. Thus, its effect on biological macromolecules should be considered. In this study, we exploit saturation transfer difference NMR (STD-NMR) to characterize the interaction of all protons of MF with human serum albumin (HSA) at the molecular level. STD-NMR and K_a (1.298 × 10³ M⁻¹) revealed that protons H1–6 and H8 bound to HSA with a medium affinity. Binding epitope mapping further showed that the aromatic ring played a key role in the HSA–MF interaction. STD-NMR site-marker-displacement experiments and circular dichroism spectroscopy revealed that MF prefered to bind to site II of HSA without changing the basic skeleton of HSA. Computer simulations confirmed these experimental results. Overall, this work elucidates the molecular level interaction of MF with HSA and provides new insights into the possibility of the potential applications of MF in the food and medicine industries.

STD-NMR technique characterized the recognition mechanism of methyl ferulate and human serum albumin qualitatively and quantitatively.

Vanadium in Biological Action: Chemical, Pharmacological Aspects, and Metabolic Implications in Diabetes Mellitus

Vanadium compounds have been primarily investigated as potential therapeutic agents for the treatment of various major health issues, including cancer, atherosclerosis, and diabetes. The translation of vanadium-based compounds into clinical trials and ultimately into disease treatments remains hampered by the absence of a basic pharmacological and metabolic comprehension of such compounds. In this review, we examine the development of vanadium-containing compounds in biological systems regarding the role of the physiological environment, dosage, intracellular interactions, metabolic transformations, modulation of signaling pathways, toxicology, and transport and tissue distribution as well as therapeutic implications. From our point of view, the toxicological and pharmacological aspects in animal models and humans are not understood completely, and thus, we introduced them in a physiological environment and dosage context. Different transport proteins in blood plasma and mechanistic transport determinants are discussed. Furthermore, an overview of different vanadium species and the role of physiological factors (i.e., pH, redox conditions, concentration, and so on) are considered. Mechanistic specifications about different signaling pathways are discussed, particularly the phosphatases and kinases that are modulated dynamically by vanadium compounds because until now, the focus only has been on protein tyrosine phosphatase 1B as a vanadium target. Particular emphasis is laid on the therapeutic ability of vanadium-based compounds and their role for the treatment of diabetes mellitus, specifically on that of vanadate- and polioxovanadate-containing compounds. We aim at shedding light on the prevailing gaps between primary scientific data and information from animal models and human studies.

Metabolic effects of VO(dmpp)2– anex vivo1H-HRMAS NMR study to unveil its pharmacological properties

VO(dmpp)₂ameliorates liver metabolic profile of obese pre-diabetic Zucker rats after 4 weeks of treatment, as demonstrated byex vivo¹H-HRMAS NMR study.

EPR and 51V NMR studies of prospective anti-diabetic bis(3-hydroxy-4-pyridinonato)oxidovanadium(iv) complexes in aqueous solution and liposome suspensions

EPR/⁵¹V-NMR parallel studies of [VO(3,4-HPO)₂] complexes in MOPS buffer and POPC liposome suspensions provide information regarding solvents for oral administration.

Investigating the interaction mechanism of fluorescent whitening agents to human serum albumin using saturation transfer difference-NMR, multi-spectroscopy, and docking studies

Characterization of the interaction between two fluorescent whitening agents and human serum albumin: ¹H STD-NMR, multi-spectroscopy, and docking studies.

Characterization of the interaction between acotiamide hydrochloride and human serum albumin: 1H STD NMR spectroscopy, electrochemical measurement, and docking investigations

The comprehensive investigation of acotiamide hydrochloride and HSA interaction provides a convictive explanation for its binding mechanism.

In vitro investigation of the interaction between the hepatitis C virus drug sofosbuvir and human serum albumin through 1H NMR, molecular docking, and spectroscopic analyses

The qualitative and quantitative investigation of sofosbuvir and HSA interaction provides a convictive explanation for its binding mechanism.

Reactivity and Speciation of Anti-Diabetic Vanadium Complexes in Whole Blood and Its Components: The Important Role of Red Blood Cells

Reactions with blood components are crucial for controlling the antidiabetic, anticancer, and other biological activities of V(V) and V(IV) complexes. Despite extensive studies of V(V) and V(IV) reactions with the major blood proteins (albumin and transferrin), reactions with whole blood and red blood cells (RBC) have been studied rarely. A detailed speciation study of Na3[V(V)O4] (A), K4[V(IV)2O2(citr)2]·6H2O (B; citr = citrato(4-)); [V(IV)O(ma)2] (C; ma = maltolato(-)), and (NH4)[V(V)(O)2(dipic)] (D; dipic = pyridine-2,6-dicarboxylato(2-)) in whole rat blood, freshly isolated rat plasma, and commercial bovine serum using X-ray absorption near-edge structure (XANES) spectroscopy is reported. The latter two compounds are potential oral antidiabetic drugs, and the former two are likely to represent their typical decomposition products in gastrointestinal media. XANES spectral speciation was performed by principal component analysis and multiple linear regression techniques, and the distribution of V between RBC and plasma fractions was measured by electrothermal atomic absorption spectroscopy. Reactions of A, C, or D with whole blood (1.0 mM V, 1-6 h at 310 K) led to accumulation of ∼50% of total V in the RBC fraction (∼10% in the case of B), which indicated that RBC act as V carriers to peripheral organs. The spectra of V products in RBC were independent of the initial V complex, and were best fitted by a combination of V(IV)-carbohydrate (2-hydroxyacid moieties) and/or citrate (65-85%) and V(V)-protein (15-35%) models. The presence of RBC created a more reducing environment in the plasma fraction of whole blood compared with those in isolated plasma or serum, as shown by the differences in distribution of V(IV) and V(V) species in the reaction products of A-D in these media. At physiologically relevant V concentrations (<50 μM), this role of RBC may promote the formation of V(III)-transferrin as a major V carrier in the blood plasma. The results reported herein have broad implications for the roles of RBC in the transport and speciation of metal pro-drugs that have broad applications across medicine.