Interaction of haloperidol with human serum albumin and effect of metal ions on the binding

Investigation of the interaction between S-isoalkyl derivatives of the thiosalicylic acid and human serum albumin

S-isoalkyl derivatives of thiosalicylic acid (isopropyl-(L1), isobutyl-(L2) and isoamyl-(L3)) were selected in order to investigate the binding interaction with the human serum albumin (HSA) using different spectroscopic methods and molecular docking simulation. Association constants and number of binding sites were used to analyze the quenching mechanism. The experimental results showed that the fluorescence quenching of HSA by L1, L2 and L3 occurs because of static quenching and that binding processes were spontaneous, with the leading forces in bonding by hydrogen bonding, hydrophobic interactions, and electrostatic interactions. Fluorescence spectroscopy, UV-Vis spectroscopy and synchronous fluorescence spectroscopy showed that ligands (L1, L2 and L3) can bind to HSA and that the binding of ligands induced some microenvironmental and conformational changes in HSA. The calculated distance between the donor and the acceptor according to fiFörster's theory confirms the energy transfer efficiency between the acceptor and HSA. Results of site marker competitive experiments showed that the tested compounds bind to HSA in domain IIA (Site I). Molecular dynamics and docking calculations demonstrated that L3 binds to the Sudlow site I of HSA with lower values of binding energies compared to L1 and L2, indicating the formation of the most stable ligand-HSA complex. Understanding the binding mechanisms of S-isoalkyl derivatives of the thiosalicylic acid to HSA may provide valuable data for the future studies of their biological activity and application as potential antitumor drugs.

Antipsychotics and dietary interventions: Pharmacodynamics, pharmacokinetics, and synergisms in therapy

Antipsychotic (AP) medications are the primary treatment for severe mental illnesses, including schizophrenia and severe mood disorders. APs are currently categorized into typical or first-generation APs and atypical or second-generation APs. Although both first-generation and second-generation APs are considered effective in treating psychotic symptoms in severe mental disorders, they differ in their mechanisms, treatment strategies, and side effect profiles. Because of their potential motor and metabolic side effects, which often compromise patient adherence and clinical outcomes, whether and how to use APs remains controversial. The use of dietary interventions in combination with APs is emerging as a viable strategy to reduce AP adverse effects while maintaining their efficacy and enhance patient adherence to treatment. In contrast to drugs that possess a well defined molecular mechanism of action, dietary interventions act in pleiotropic ways by nature. While providing a holistic approach to patient care this pleiotropy needs to be analyzed and systematized to enhance the efficacy and safety of the combination of them with APs. Guidelines for this type of treatment are still needed. In this review, we explore the pharmacological properties, therapeutic applications, and limitations of APs, and discuss the potential benefits and limitations of those dietary interventions that are employed to improve the efficacy and counteract side effects of APs discussing also their mechanisms of action. Finally, we critically discuss the main results of clinical studies combining APs and dietary interventions and provide a view on future directions in terms of research and clinical use of these combinations. SIGNIFICANCE STATEMENT: Antipsychotic drugs are useful in a variety of psychiatric conditions, yet their use is hampered by issues of efficacy and safety. An important step toward therapy optimization is their use in combination with dietary interventions (ie, dietary supplements and nutraceuticals) that have shown promising results in clinical trials.

The Molecular Recognition of Lurasidone by Human Serum Albumin: A Combined Experimental and Computational Approach

Lurasidone (LUR) is an antipsychotic drug whose interaction with human serum albumin (HSA) plays a crucial role in its pharmacokinetic and pharmacodynamic properties. A thorough understanding of LUR's binding mechanism to HSA is crucial for predicting its transport, distribution, and potential drug interactions.

METHODS

The interaction between LUR and HSA was investigated using fluorescence and circular dichroism (CD) spectroscopy, followed by molecular docking simulations. Binding characteristics were analyzed through quenching mechanisms, thermodynamic parameters, and competitive site marker experiments.

RESULTS

This study revealed a systematic decrease in HSA fluorescence intensity with increasing LUR concentration, indicating a static quenching mechanism driven by non-fluorescent complex formation. Binding constants suggest enhanced complex stability at higher temperatures, with thermodynamic analysis confirming an endothermic, hydrophobic interaction. Competitive site marker assays and synchronous fluorescence spectra confirmed that LUR primarily binds to site I (subdomain IIA) near tryptophan residues. Conformational changes in HSA, observed as a decrease in α-helix content, further demonstrate the structural impact of LUR binding.

CONCLUSIONS

These findings offer key insights into the molecular interactions between LUR and HSA, enhancing our understanding of LUR's pharmacokinetics and its potential interactions with other drugs. Understanding these binding characteristics can aid in optimizing LUR's clinical application and predicting possible interactions with other biomolecules.

Detecting biomarkers associated with antipsychotic-induced extrapyramidal syndromes by using machine learning techniques

BACKGROUND

Antipsychotic-associated extrapyramidal syndromes (EPS) are a common side effect that may result in discontinuation of treatment. Although some clinical features of individuals who develop specific EPSs are well defined, no specific laboratory parameter has been identified to predict the risk of developing EPS.

METHODS

Three hundred and ninety hospitalizations of patients under antipsychotic medication were evaluated. Machine learning techniques were applied to laboratory parameters routinely collected at admission.

RESULTS

Random forests classifier gave the most promising results to show the importance of parameters in developing EPS. Albumin has the maximum importance in the model with 4.28% followed by folate with 4.09%. The mean albumin levels of EPS and non-EPS group was 4,06 ± 0,40 and 4,24 ± 0,37 (p = 0,027) and folate level was 6,42 ± 3,44 and 7,95 ± 4,16 (p = 0,05) respectively. Both parameters showed lower levels in EPS group.

CONCLUSIONS

Our results suggest that relatively low albumin and folate levels may be associated with developing EPS. Further research is needed to determine cut-off levels for these candidate markers to predict EPS.

Effect of Caffeine and Flavonoids on the Binding of Tigecycline to Human Serum Albumin: A Spectroscopic Study and Molecular Docking

Human serum albumin (HSA) has a very significant role in the transport of drugs, in their pharmacokinetic and pharmacodynamic properties, as well as the unbound concentration of drugs in circulating plasma. The aim of this study was to look into the competition between tigecycline (TGC) and alkaloid (ALK) (caffeine (CAF)), and flavonoids (FLAVs) (catechin (CAT), quercetin (QUE), and diosmin (DIO)) in binding to HSA in simulated physiological conditions using multiple spectroscopic measurements and docking simulations. Fluorescence analysis was used to find the binding and quenching properties of double HSA-TGC and triple HSA-TGC-CAF/FLAV systems. The conformational change of the HSA was analyzed using synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism. Obtained results of spectroscopic analyses indicate that triple complexes of HSA-TGC-CAF/FLAVs are formed without problems and have higher binding affinities than double HSA-TGC. In addition, TGC does not change the microenvironments around the tryptophan (Trp) and tyrosine (Tyr) residues in the presence of ALK and FLAVs. Ultimately, the binding affinity, competition, and interaction nature were explored by docking modeling. Computational outcomes are in good accordance with experimentally obtained results. Accordingly, concluding remarks may be very useful for potential interactions between common food components and drugs.

Revealing the complexity of distinct manganese species-protein interactions through multi-spectroscopy

The effect of manganese (Mn) on protein conformation is closely related to its chemical species. To further realize the behavior of different species of Mn in vivo, this study is designed to analyze the separate and simultaneous interactions of Mn(ii) and Mn(iii) with bovine serum albumin (BSA) using multi-spectroscopy. The results demonstrated that the interaction of Mn(ii) or Mn(iii) with BSA is a process of static quenching and Mn(iii) formed a more stable complex. The binding constants and thermodynamic constants indicated that a 1:1 complex was formed between Mn(ii)/Mn(iii) and BSA through a moderate binding force, and hydrophobic interaction played an important role in the binding. UV-Vis spectroscopy, synchronous fluorescence spectroscopy and three-dimensional fluorescence spectroscopy results revealed that the conformation changes in BSA induced by Mn(ii)/Mn(iii) binding. The results of the ternary systems suggested that both Mn species interfered the interaction of the other with BSA. The conformation of BSA may change more to adapt to the simultaneous binding to Mn (ii) and Mn (iii) when two Mn species coexist.

Comprehensive insights into the interactions of dicyclohexyl phthalate and its metabolite to human serum albumin

Phthalate esters (PAEs) are a type of persistent organic pollutants and have received widespread concerns due to their adverse effects on human health. Dicyclohexyl phthalate (DCHP) and its metabolite monocyclohexyl phthalate (MCHP) were selected to explore the mechanism for interaction of PAEs with human serum albumin (HSA) through molecular docking and several spectroscopic techniques. The results showed that DCHP/MCHP can spontaneously occupy site I to form a binary complex with HSA, and DCHP exhibited higher binding affinity to HSA than MCHP. At 298 K, the binding constants (K_b) of DCHP and MCHP to HSA were 24.82 × 10⁴ and 1.04 × 10⁴ M^-1, respectively. Hydrogen bonds and van der Waals forces were the major driving forces in DCHP/MCHP-HSA complex. The presence of DCHP/MCHP induced the secondary structure changes in HSA, and the pi electrons of the benzene ring skeleton of DCHP/MCHP played a key role in this binding processes. Exposure of DCHP/MCHP to TM4 cells revealed that interactions between PAEs and serum albumin can affect their cytotoxicity; DCHP showed higher toxicity than MCHP. The binding affinity of PAEs with HSA may be a valuable parameter for rapid assessment of their toxicity to organisms.

Interaction between olanzapine and human serum albumin and effect of metal ions, caffeine and flavonoids on the binding: A spectroscopic study

In this study, the binding of olanzapine (OLZ) to human serum albumin (HSA) and the influence of metal ions (Ca²⁺, Mg²⁺, Cu²⁺, Zn²⁺, Fe³⁺), caffeine (CAF) and flavonoids (diosmin (DIO), catechin (CAT), quercetin (QUE)), on their affinity, was investigated by fluorescence spectroscopy and UV-vis absorption spectroscopy. Fluorescence experiments suggest that OLZ quench the fluorescence of HSA through the mixed quenching mechanism and non-radiation energy transferring as a result of the HSA-OLZ complex formation. OLZ spontaneously bind in the site I on HSA, and according to thermodynamic parameters, the reaction was spontaneous and mainly driven by hydrogen bonds and van der Waals interactions. The presence of Mⁿ⁺ ions, CAF, DIO and CAT decreased binding affinity between OLZ and HSA which indicates that they could compete against OLZ in the site I. Contrary, in the presence of QUE the binding affinity of the HSA-OLZ system enhanced, which may be explained by conformational changes in HSA (non-competitive interference).

Synthesis, characterization, HSA/DNA interactions and antitumor activity of new [Ru(η6-p-cymene)Cl2(L)] complexes

Three new ruthenium(II) complexes were synthesized from different substituted isothiazole ligands 5-(methylamino)-3-pyrrolidine-1-ylisothiazole-4-carbonitrile (1), 5-(methylamino)-3-(4-methylpiperazine-1-yl)isothiazole-4-carbonitrile (2) and 5-(methylamino)-3-morpholine-4-ylisothiazole-4-carbonitrile (3): [Ru(η⁶-p-cymene)Cl₂(L1)]·H₂O (4), [Ru(η⁶-p-cymene)Cl₂(L2)] (5) and [Ru(η⁶-p-cymene)Cl₂(L3)] (6). All complexes were characterized by IR, UV-Vis, NMR spectroscopy, and elemental analysis. The molecular structures of all ligands and complexes 4 and 6 were determined by an X-ray. The results of the interactions of CT-DNA (calf thymus deoxyribonucleic acid) and HSA (human serum albumin) with ruthenium (II) complexes reveal that complex 4 binds well to CT-DNA and HSA. Kinetic and thermodynamic parameters for the reaction between complex and HSA confirmed the associative mode of interaction. The results of Quantum mechanics (QM) modelling and docking experiments toward DNA dodecamer and HSA support the strongest binding of the complex 4 to DNA major groove, as well as its binding to IIa domain of HSA with the lowest ΔG energy, which agrees with the solution studies. The modified GOLD docking results are indicative for Ru(p-cymene)LCl··(HSA··GLU292) binding and GOLD/MOPAC(QM) docking/modelling of DNA/Ligand (Ru(II)-N(7)dG7) covalent binding. The cytotoxic activity of compounds was evaluated by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay. Neither of the tested compounds shows activity against a healthy MRC-5 cell line while the MCF-7 cell line is the most sensitive to all. Compounds 3, 4 and 5 were about two times more active than cisplatin, while the antiproliferative activity of 6 was almost the same as with cisplatin. Flow cytometry analysis showed the apoptotic death of the cells with a cell cycle arrest in the subG1 phase.

Thermodynamic investigation of the interaction between ionic liquid functionalized gold nanoparticles and human serum albumin for selective determination of glutamine

The excellent biocompatible and monodispersed gold nanoparticles (AuNPs) functionalized by amino based ionic liquid (IL) have been synthesized for the demonstration of their interaction with human serum albumin (HSA). Amino based IL stabilizes the surface of AuNPs and provides a colorimetric sensor platform. The size of synthesized IL–AuNPs was identified by use of transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. Molecular interaction of functionalized AuNPs with HSA have been investigated using multispectroscopic techniques, such as UV-Vis, fluorescence and Fourier transform infra-red (FT-IR) spectroscopy. The fluorescence and synchronous fluorescent intensity together indicated that IL–AuNPs exhibits a strong ability to quench the intrinsic fluorescence of HSA via a dynamic quenching mechanism. Moreover, the binding constant (K_a), Stern–Volmer quenching constant (K_SV) and different thermodynamic parameters, namely Gibb's free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) have been evaluated at different temperatures. This interactive study focuses on the nature of surface modification of IL–AuNPs via HSA for selective detection of glutamine (Glu) with a lower limit of detection of 0.67 nM in the linear range of 10–100 nM for Glu.

The excellent biocompatible and monodispersed gold nanoparticles (AuNPs) functionalized by amino based ionic liquid (IL) have been synthesized for the demonstration of their interaction with human serum albumin (HSA).