Platinum-based anticancer agents are widely used in cancer therapy due to their efficacy in killing cancer cells through interactions with the DNA. However, their clinical application is limited by severe side effects and the development of drug resistance, which have been related to their lack of specificity and mechanism of action. To overcome these challenges, novel platinum(II) complexes, K[Pt(Butene-ASA)Cl3] (Compound 1) and [Pt(L-Ala)(Butene-ASA)Cl] (Compound 2), were previously synthesized and characterized. Particularly, Compound 2 showed cytotoxic activity comparable to that of cisplatin (DDP) against all tested cancer cell lines in a previous study. The current investigation employed electrospray ionization mass spectrometry (ESI-MS) to analyze the interactions of these complexes with model biomolecules, including an oligonucleotide (8mer), peptide (Angiotensin I, AT1), and protein (Cytochrome c, CytC). DDP and oxaliplatin (OxPt) were used as reference substances. Tandem mass spectrometry (MS/MS) and UV-Vis spectroscopy enabled the identification of the platination sites on the model biomolecules. Compound 2 demonstrated lower reactivity toward DNA than DDP, while both compounds 1 and 2 exhibited a significant shift in reactivity toward peptides and proteins, particularly compared to DDP and OxPt. The results suggest that Zeise's salt derivatives may preferentially target peptides and proteins rather than DNA, which could provide a novel mechanism of action for platinum-based anticancer agents. These findings expand the understanding of platinum(II) complex reactivity and highlight their potential for developing alternative therapeutic strategies aimed at overcoming the limitations of traditional platinum-based drugs.
The successful clinical use of metal-based anticancer agents depends heavily on a detailed understanding of their absorption, distribution, metabolism, excretion, and toxicology (ADMET) profiles. This review evaluates the ADMET properties of anticancer complexes involving platinum, palladium, gold, ruthenium, copper, and zinc. Unlike traditional organic medicines, the ADMET processes of these compounds are often complex and nonlinear, due to their unique coordination chemistry, ligand-exchange kinetics, and dynamic speciation changes. The review highlights how structural differences in metal analogs influence their pharmacokinetics, systemic disposition, and distinct toxicity profiles. Ultimately, gaining a thorough understanding of these ADMET nuances is vital for designing next-generation metallodrugs with optimized tissue distribution, minimal systemic toxicity, and improved therapeutic effectiveness.
New heteroligand metal complexes, [M(phen) (PAR) (OAc)]·H2O (M = Mn(II) (1), Cu(II) (3)) and [Co(phen) (PAR) (H2O)]OAc·H2O (2), incorporating 4-(2-pyridylazo)resorcinol (PAR) as the primary ligand and 1,10-phenanthroline (phen) as the secondary ligand, were synthesized and comprehensively characterized. Elemental analysis, FT-IR spectroscopy, thermal analysis, magnetic susceptibility measurements, and molar conductivity studies confirmed the proposed compositions and coordination modes of the complexes. Spectroscopic data revealed that PAR coordinates to the metal center in its deprotonated form through the resorcinol oxygen atom and the azo and pyridyl nitrogen atoms, while phen acts as a bidentate N,N-donor ligand. The electrochemical properties of the complexes were investigated by cyclic voltammetry using a glassy carbon electrode in DMF containing 0.1 M TBAP as the supporting electrolyte. All complexes exhibited well-defined redox behavior governed predominantly by diffusion-controlled electrochemical processes. The antioxidant activities of the synthesized complexes were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and cupric ion reducing antioxidant capacity (CUPRAC) assays, revealing notable antioxidant responses in both methods. Density functional theory (DFT) calculations, including HOMO-LUMO and molecular electrostatic potential (MEP) analyses, provided insights into the electronic structures and reactive sites of the complexes. Furthermore, molecular docking studies demonstrated favorable binding affinities toward xanthine oxidase (XO) and Keap1 receptors. The stability of the predicted protein-ligand interactions was further confirmed by 100 ns molecular dynamics simulations, which revealed stable trajectories, compact binding modes, and persistent intermolecular interactions throughout the simulation period.
The reactivity of two tridentate salicylthiosemicarbazones (H2L1 = 3-methoxysalicylaldehyde thiosemicarbazone; H2L2 = 3-methoxysalicylaldehyde N,N-dimethyl-thiosemicarbazone), with the [MV ≡ N]2+ core (M = Re, 99mTc), is here described, leading to the formation of heteroleptic complexes of the general composition [MN(L)P] (P = triphenylphosphine, PPh3; tris(2-cyanoethyl)phosphine, PCN). The [ReN(L)PPh3] complexes were prepared in good yield starting from [ReVNCl2(PPh3)2] precursor and in lower quantity from (Bu4N)[ReNVICl4]. Complexes were fully characterised by elemental analyses, spectroscopic, spectrometric techniques and X-ray diffraction. Single-crystal X-ray diffraction analysis of [ReN(L1)PPh3] and [ReN(L2)PPh3] showed the formation of a distorted square base pyramid geometry with the rhenium atom located 0.57 Å above the pyramid base and the nitride ion in apical position. The basal plane is occupied by the S,N,O-thiosemicarbazonate and the triphenylphosphine ligands. Superimposable complexes were obtained in high yield at tracer level with technetium-99m and under carried-added conditions. In technetium complexes, triphenylphosphine can be successfully replaced with PCN, forming corresponding complexes in high yield; this substitution was unfeasible with cold rhenium. Based on the collected preliminary results, it is reasonable to assume that [99mTc][TcN(L)P] (L = bisdeprotonated ligand; P = monophosphine) could be a promising platform for developing new potential technetium-99m-based radiotracers. However, improvements in labelling efficiency and stability must be addressed to fully realise its potential.
Green synthesis of nanomaterials offers a sustainable approach for water remediation. In this study, nickel oxide nanoparticles (NiONPs) were synthesized using the Cynara scolymus L. head (CSH) extract via an eco-friendly, cost-effective route and evaluated for antibacterial and catalytic performance. Phytochemicals present in the CSH extract directed nanoparticle nucleation and growth, producing uniformly dispersed CSH-NiONPs with enhanced functional properties. The shape and morphologies of the prepared CSH-NiONPs were studied through different analytical techniques. A characteristic UV-vis absorption band at 328 nm was observed, while XRD analysis revealed an average crystallite size of 26.57 nm. SEM-EDX and HR-TEM analyses confirmed particle sizes in the range of 18-45 nm along with elemental purity. The biosynthesized CSH-NiONPs exhibited a strong antibacterial activity against Escherichia coli and Salmonella typhimurium, with inhibition zones of 38.12 ± 0.28 mm and 41.12 ± 0.22 mm and low MICs of 9.76 and 3.12 μg/mL, respectively. Molecular docking showed that while gentamicin strongly binds aminoglycoside 3-N-acetyltransferase, CSH-NiONPs interact weakly and nonspecifically, indicating minimal potential to promote resistance. Moreover, CSH-NiONPs efficiently catalysed NaBH4-assisted reduction of 4-nitrophenol, achieving ∼95% conversion in 15 min. These findings demonstrate CSH-NiONPs as multipurpose, sustainable nanomaterials for simultaneous microbial and chemical water remediation.
In this study, the structural, electronic, and biological characteristics of newly synthesized transition metal complexes FeABNF, CoABNF, and NiABNF, resulting from the chelation compounds albendazole (AB) and nifuroxazide (NF), were studied. The synthesized compounds were found to have excellent yields with high percentage yields (∼80%). Thermal analysis showed that these complexes were highly stable with decomposition temperatures above 300°C. Molar conductivity tests revealed that FeABNF is a 1:1 electrolyte with a value of 38.95 Ω-1·cm2·mol-1, NiABNF is a 1:2 electrolyte with a value of 88.17 Ω-1·cm2·mol-1, while CoABNF is a nonelectrolyte with a value of 9.86 Ω-1·cm2·mol-1. FT-IR analysis proved that these complexes are bidentate due to their N and O donor atoms. The electronic spectra and magnetic moments confirmed that these compounds had octahedral geometry. The DFT calculation and biological assays showed that the complexes exhibited enhanced antimicrobial activity compared to the free ligands. The investigated compounds exhibited variable antibacterial and antifungal activities, with the metal complexes generally showing enhanced activity compared to the free ligands. However, the degree of activity was found to depend on the nature of the metal ion and the tested microbial strain. The most potent antibacterial action was exhibited by NiABNF and CoABNF complexes, which exhibited 28-30-mm inhibition zones and 91%-94% activity index, and good antifungal activity against Candida albicans, 20 mm. Anti-inflammatory activity order was determined as the NiABNF complex with IC50: 56.97 μM and 93% inhibition. These findings were supported at the molecular docking level, as the NiABNF complex had the highest binding affinity to DNA gyrase B (PDB: 4DUH, -8.90 kcal/mol) and SARS-CoV-2 main protease (6LU7, -9.40 kcal/mol) via hydrogen bonding and hydrophobic interactions, which make it a promising therapeutic agent. Both experimental and computational studies reported the same order of bioactivity: NiABNF > CoABNF > FeABNF > free ligands.
Three new V (III) complexes with triazole ligands were obtained and fully characterized using regular analytical techniques, including the unequivocal determination of the structure of complex VL 3 D by single-crystal x-ray diffraction analysis. The formation of VL 3 D involves an oxidation process from V (III) to V (IV) that can occur under conditions similar to those of biological assays. The biological activity of these complexes was explored on six human cancer cell lines exhibiting lower IC50 values in five of them when compared to cisplatin, noteworthy the fact that complex VL 2 probed to be more effective against A549 (IC50 = 1.07 μM). At the same time, VL 1 showed remarkable activity on HCT-15 (IC50 = 3.14 μM). Interestingly and in contrast to cisplatin, the vanadium complexes showed little effect on the healthy fibroblast cells. Mechanistic studies of cell death revealed that VL 3 selectively induced late-stage apoptosis without promoting necrosis in A549 cells, whereas VL 2 did not significantly affect apoptotic or necrotic pathways under the conditions tested. These results were complemented with in silico studies and displacement assays, demonstrating the affinity of the complexes for DNA. The results presented in this work are relevant, as there are few reports of similar V (III) compounds explored as potential anticancer agents.
This study aimed to biosynthesize silver nanoparticles using Elaeagnus angustifolia flower buds-an Iranian medicinal plant extract rich in bioactive phytochemicals and evaluate their antimicrobial potential through complementary broth microdilution (MIC/MBC) and agar well diffusion assays, alongside an assessment of their anticancer and biomolecular interaction properties. The synthesis leverages natural reducing and capping agents (phenols, flavonoids, tannins) to produce stable, spherical AgNPs (FEA@AgNPs), characterized by UV-vis (λ max = 439 nm), XRD (∼10 nm, face-centered cubic), FESEM, TEM (6.61 nm), and FT-IR. A zeta potential of -32.68 mV confirmed colloidal stability. The nanoparticles were stable for over a month, indicating that E. angustifolia flower aqueous extract is suitable for their preparation and stabilization. FEA@AgNPs showed moderate activity against S. aureus (12 vs. 24 mm for gentamicin) and no agar diffusion inhibition against E. coli, despite a MIC of 37.5 μg/mL in the broth assay. The antioxidant results show 55% DPPH radical scavenging at 160 μg/mL. Notably, they induced dose- and time-dependent cytotoxicity in PC3 and AGS cancer cells, with IC50 values of 7.49 and 5.33 μg/mL, respectively, after 72 h (p < 0.05). Spectroscopic analyses revealed a strong binding affinity to calf thymus DNA and human serum albumin, suggesting biomolecular interaction capacity relevant to drug delivery. This work provides a green, efficient route to multifunctional AgNPs, bridging traditional herbal knowledge and bioinorganic nanomedicine for potential applications in infection control and oncology.
In this study, the Schiff base (E)-4-chloro-2-(((4-(phenylamino)phenyl)imino)methyl)phenol (Sadpa), obtained from the condensation reaction of 5-chloro-2-hydroxybenzaldehyde and N1-phenylbenzene-1,4-diamine and reported for the first time in the literature, together with its Co(II) and Pd(II) complexes, was synthesized. The structure of the Schiff base was determined by spectroscopic methods such as elemental analysis, FT-IR, 1H/13C-NMR, and XRD, while the structures of the metal complexes were examined in detail using FT-IR, UV-Vis, MS, thermal, and elemental analysis. Furthermore, the electrochemical behavior of both the Sadpa ligand and the Co(II) and Pd(II) complexes was investigated, as well as their potential interactions with DNA. The double cathodic peak observed in the Sadpa-Co and Sadpa-Pd complexes reveals the coexistence of both ligand and metal-centered redox processes. It is observed that the Sadpa-Pd(II) complex exhibits more stable and higher affinity binding than the Co(II) complex. This indicates that factors such as coordination geometry and charge density of the metal center play a decisive role in the DNA-binding behavior. In addition, the catalytic effects of the complexes in the transfer hydrogenation of D-glucose to D-sorbitol were investigated. The Sadpa-Pd(II) complex showed the most efficient and selective catalytic activity in the transfer hydrogenation of D-glucose to D-sorbitol under micorwave irradiation, with 97.98% selectivity for D-sorbitol at 96.50% conversion, indicating that it can act as a mimetic of the aldose reductase enzyme. Mannitol was produced as the only by-product in minor amounts during the catalysis.
Eco-friendly approaches for nanoparticle synthesis have gained attention due to their sustainability and reduced environmental impact. Zinc oxide nanoparticles (ZnO NPs) exhibit versatile bioactivities, but conventional synthesis methods often involve toxic reagents. ZnO NPs were synthesized through a one-step bioreduction process, utilizing the crude leaf extract of Sida cordifolia L. and employing the combustion method at 400°C. Characterization of the nanoparticles was analyzed through UV-Vis spectroscopy, FTIR, XRD, DLS, and SEM to assess structural and morphological properties. Antibacterial efficacy was tested through the resazurin plate assay, and antioxidant activity was evaluated through the hydrogen peroxide scavenging assay. UV-Vis shows a characteristic peak at ∼370 nm, which corresponds to the fundamental band gap transition of ZnO. FTIR and DLS verified organic moiety incorporation and nanoparticle size, respectively, while XRD confirmed the wurtzite structure. The average diameter of synthesized nanoparticles was between 88.5 and 90.2 nm. SEM provides detailed insights into their size, shape, surface morphology, and structural features. Functionalized nanoparticles demonstrated enhanced antibacterial efficacy against E. coli, K. pneumoniae, S. aureus, and E. faecalis with MICs of 12.5 μg/mL for Gram-positive bacteria (S. aureus and E. faecalis), 100 μg/mL for E. coli, and 12.5 μg/mL for K. pneumoniae. Antioxidant activity shows concentration-dependent radical scavenging. At a concentration of 3.12 μg/mL, ZnO NPs exhibited 28.7 ± 1.2% scavenging activity, which progressively increased to 64.3 ± 2.5% at 100 μg/mL. This one-pot green synthesis provides a simple, scalable approach to biofunctionalized ZnO NPs with potent antibacterial and antioxidant properties, offering potential for biomedical applications.
Guanidine-containing molecules represent a versatile class of nitrogen-rich compounds whose unique structural and physicochemical features underpin a rich and tunable coordination chemistry. Their capacity to act as strong donor ligands, stabilize a variety of metal centers in different oxidation states, and access multiple coordination modes has established guanidine and guanidine-like cores as pivotal components in medicinal inorganic chemistry. This review provides a focused overview of metallodrugs for antitumor applications in which guanidine or guanidine-like ligands play a central role in metal coordination, highlighting how the coordination modes of the guanidine core translate into their application as anticancer metallodrugs. By correlating coordination mode, metal center, and ligand design with anticancer performance, this work underscores the potential of guanidine-based ligand platforms for the development of next-generation metal-based therapeutics.
Invasive fungal infections, especially those caused by Candida spp., have been classified as a serious global threat. The emergence of species intrinsically resistant to current drugs, along with the increase in acquired resistance, places significant pressure on the need to develop novel and more effective antifungal agents. A limited number of studies have shown the potential of palladium organometallic complexes as promising antifungal alternatives. Although the mechanism of antifungal activity of these complexes remains unaddressed, the findings support the idea that designing palladium (II) complexes could represent the next generation of antifungals. In this work, we synthesized four cyclopalladated complexes, 1a, 1b, 2a, and 2b, from Schiff base-amine phosphanes and evaluated their antifungal potential. Specifically, we assessed their spectrum of activity against several medically relevant Candida spp., their capacity to overcome resistance to current antifungal drugs, antibiofilm properties, uptake by fungal cells, in vivo toxicity, and intracellular effects. The most promising complexes, 1b and 2b, induce strong oxidative stress and lipid peroxidation, inhibit lipolysis, and disrupt vacuole integrity. Moreover, the rational design of the complexes allowed us to infer important structure-activity relationships. Our findings highlight the potential of palladium complexes as promising scaffolds for future antifungal therapeutic strategies and open new horizons for further development.
In this study, maghemite nanoparticles (gamma-Fe2O3 NPs) were successfully synthesized using Croton macrostachyus stem bark extract (CMSBE) and hexahydrate ferric chloride (FeCl3.6H(2)O). The biomolecules found in the plant extract were screened through visual observations, and these molecules were used as reducing, capping and stabilizing agents during the synthesis of gamma-Fe2O3 NPs. The synthesized gamma-Fe2O3 NPs were characterized via different spectroscopy techniques (UV-Vis, FT-IR, XRD, SEM and TGA/DTA). In UV-Vis spectra, the maximum absorption peak of gamma-Fe2O3 NPs was observed at 410 nm; this is due to the charge transfer from O2- into Fe (0), confirming the formation of gamma-Fe2O3 NPs. For the synthesis of gamma-Fe2O3 NPs, the synthesis parameters, including temperature (70 degrees C), pH (7), reaction time (50 min), FeCl3.6H(2)O concentration (6 mM) and extract volume (7.5 mL), were systematically optimized. In FT-IR spectra, the band was observed at 530 cm(-1) due to Fe-O stretching vibration, and this validates the formation of gamma-Fe2O3 NPs. The XRD analysis confirmed the crystalline nature of the nanoparticles with an average crystallite size of 4.12 nm. The SEM image showed the quasispherical-shaped particles with noticeable agglomeration. Therefore, most of the characterization methods confirm the formation of gamma-Fe2O3 NPs. TGA/DTA analysis showed a total weight loss of 29.74% and high thermal stability at higher temperatures. The synthesized gamma-Fe2O3 NPs using CMSBE exhibited notable antibacterial activity against both gram-positive (Bacillus [25.6 +/- 0.06] and Staphylococcus aureus [26.25 +/- 0.06]) and gram-negative (Escherichia coli [28.2 +/- 0.01] and Klebsiella pneumoniae [24.5 +/- 0.02]) bacteria as well as antifungal activity against Saccharomyces cerevisiae (12.05 +/- 0.03) at 100 mu g/mL. This eco-friendly synthesis approach is presented as a promising route for producing biocompatible gamma-Fe2O3 NPs with potential applications in biomedical fields.
The straightforward catalytic synthesis of guanidine ligands has been evaluated as a strategy for rapidly developing ruthenium metallodrugs as antitumor agents. A series of structurally guanidine ligands, obtained via guanylation reactions, were used as scaffolds for generating RAPTA-C derivatives. Consequently, a novel family of guanidine-ruthenium derivatives was synthesized, fully characterized, and assessed as potential alternatives to platinum-based chemotherapy. Their antitumor activity was evaluated in vitro across various cancer cell lines, using RAPTA-C and cisplatin as metallodrug controls. Two ruthenium-guanidine derivatives were identified as the most promising candidates, exhibiting IC50 values between 3 and 5 mu M across multiple cancer cell lines. These compounds were selected for further investigation. Notably, their significant cytotoxicity in triple-negative breast cancer (TNBC) cells suggests a mechanism of action independent of receptor status. In vitro experiments, such as cell cycle assessment, apoptosis detection, Matrigel invasion tests, and measurement of ROS production, corroborated this hypothesis. Compared to cisplatin and RAPTA-C, the most promising ruthenium complexes, RuG3 and RuG8, demonstrated enhanced cytotoxicity across various cancer cell lines. As a proof of concept, fluorescence lifetime imaging microscopy (FLIM) was used to visualize the intracellular distribution of a luminescent derivative in MCF7 breast cancer cells. The results showed homogeneous cytoplasmic distribution, while the guanidine ligand contributed to increased stability. Furthermore, photophysical studies showed that in aqueous solution, the protonation of the guanidine group triggers the isomerization of the luminescent complex, yielding the active and more symmetrical species. Finally, in vivo safety studies in mice highlighted the potential of the selected compound as a promising candidate for further preclinical development in MIC. Overall, these findings provide valuable insights into the use of guanidines as ancillary ligands for designing new ruthenium-based antitumor agents as an alternative to platinum-based chemotherapy.
Diabetes is associated with oxidative stress and a decrease in antioxidant defenses. Oxidative stress interferes with insulin secretion and action, which affects beta-cell function and causes diabetes and apoptosis. The strong link between oxidative stress and the pathogenesis of diabetes highlights the need to identify and develop therapeutics that are rich in antioxidant activity to ameliorate the disease and its complications. Therefore, the aim of this preliminary study was to evaluate the antioxidant potential of copper(II) bis(N-methyl-N-phenyl dithiocarbamate) and bismuth(III) tris(N-methyl-N-phenyl dithiocarbamate) complexes as a step toward developing therapeutics for mitigating oxidative stress in diabetes. Three in vitro assays including 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing ability of plasma (FRAP), and Trolox equivalent antioxidant capacity (TEAC) were utilized to assess the antioxidant properties of the two complexes, with Trolox and ascorbic acid serving as standards. The two complexes displayed concentration-dependent antioxidant activity in all the assays employed. In the DPPH assay, the Bi(III) and Cu(II) complexes effectively neutralized DPPH radicals at concentrations of 31.62 mu g/mL and 37.13 mu g/mL, respectively. In the FRAP assay, the Bi(III) complex demonstrated greater antioxidant capacity than both standards, while the Cu(II) complex demonstrated lower antioxidant activity compared to the standards. In the TEAC assay, both complexes exhibited a high radical scavenging activity with the Bi(III) complex demonstrating higher activity than the Cu(II) complex. However, dose-dependent radical scavenging activities were exhibited by both. These preliminary results suggest that the two complexes could be promising therapeutic candidates, but further studies in cell culture and animal models are required to validate their efficacy.
Poly(methyl methacrylate) (PMMA) nanocomposite films reinforced with zinc oxide/graphene oxide (ZnO/GO) nanohybrids were fabricated and systematically characterized for potential biomedical and wound-healing applications. ZnO nanoparticles were synthesized via a hydrothermal route and subsequently hybridized with GO and then incorporated into the PMMA matrix at different loadings (0-1.2 wt.%) using a solution casting method. Structural analyses by X-ray diffraction and FTIR spectroscopy confirmed the effective incorporation and homogeneous dispersion of the ZnO/GO nanohybrids without disrupting the PMMA molecular structure. Optical studies revealed a pronounced enhancement in UV-shielding performance with increasing nanofiller content. Thermogravimetric analysis demonstrated improved thermal stability, attributed to strong interfacial interactions between PMMA and the nanohybrids. Mechanical measurements showed significant improvements in Young's modulus, tensile strength, and toughness, accompanied by only a slight decrease in elongation at break, indicating an optimal balance between stiffness and flexibility. In addition, swelling behavior was notably reduced with higher filler loading, reflecting enhanced dimensional stability. In vitro cytocompatibility tests using human fibroblast (HFB4) cells confirmed excellent biocompatibility, with cell viability exceeding 99% at the highest nanohybrid concentration. These findings demonstrate that PMMA-ZnO/GO nanocomposites are promising multifunctional materials for antibacterial and bioactive wound-dressing applications.
The search for metal-based anticancer agents with improved efficacy and reduced side effects is ongoing. The activities of these anticancer drugs depend on their aqueous stability, substitutional reactivity at target sites (cytotoxicity) and nontarget sites (toxicity), as well as their transportation and cell bioavailability. In this study, six square-planar Pt(II) and Pd(II) complexes (Pt/PdL1Cl-3), all bearing the bis(azaaryl)amine (azaaryl = quinoline or phenanthridine) chelating ligands, were synthesised and characterised by various spectroscopic methods. Their biochemical interactions with bovine serum albumin (BSA)/deoxyribonucleic acid (DNA) and rates of ligand exchange with biological nucleophiles (guanine and thiourea) were probed spectrophotometrically. DFT-optimised molecular structures in Gaussian 9 were computed. Molecular docking simulations of the optimised structures at the receptors of CT-DNA, BSA and relevant enzymes that upregulate cancer progression were conducted. The metal complexes showed moderate to strong interactions (K b ca.104) with calf thymus DNA (CT-DNA) and BSA. On BSA, the metal complexes were predominantly bound in Subdomain IIIA. Ethidium bromide's (EtBr) competitive binding titrations and docking simulations suggested that these complexes are bimodal DNA binders, functioning both as groove binders and partial intercalators. The rates of chloride substitutions decreased in the order: PdL1Cl > PdL2Cl > PdL3Cl and PtL1Cl > PtL2Cl > PtL3Cl. Molecular docking of PtL1Cl predicted stronger binding affinity towards proteins associated with the inhibition of proteases for cervical (PDB: 5VBN), breast (4DRH) and prostate cancers (PDB: XPO1). The in vitro cytotoxic effects of uncoordinated ligands (L1-L3) and their respective Pt/PdL1Cl-3 metal complexes were tested at a single dose of 10 μM in the human breast (MCF-7, T47D and MDA-MB-231), cervical (HeLa and CaSki) and pancreatic (PANC-1 and CFPAC-1) cancer cell lines, as well in a noncancerous human dermal fibroblasts (FG-0) cell line. The Pt/PdL1Cl complexes showed promise as lead inhibitory compounds against breast (T47D, MDA-MB-231) and pancreatic (PANC-1) cancer cells. The efficacy of PtL1Cl against the T47D cell line was superior to that of the anticancer drug cisplatin.
Tolcapone, a clinically approved drug for the treatment of Parkinson's disease as an adjunct therapy, has recently emerged as a potential modulator of amyloid-β aggregation and toxicity, which are hallmark features of Alzheimer's disease and are also involved in ocular neurodegenerative disorders, including glaucoma and age-related macular degeneration. Despite these noteworthy findings, the molecular basis of the interaction between amyloid-β and tolcapone remains poorly understood, and the mechanisms by which tolcapone affects metal-amyloid-β species have yet to be explored. In this work, we investigate the binding interactions of tolcapone with both copper-free amyloid-β and copper-associated amyloid-β complexes, using a combination of techniques including UV-vis spectroscopy, circular dichroism, mass spectrometry, and surface plasmon resonance. The results reveal that tolcapone binds directly to amyloid-β monomers. Furthermore, in vitro assays confirm the capacity of tolcapone to act as a radical scavenger and to compete with amyloid-β for the binding of copper ions. Altogether, our findings suggest that tolcapone exerts a multifaceted protective effect, potentially inhibiting toxic metal-free and metal aggregation pathways by preventing metal coordination to amyloid-β or disrupting preformed amyloid-β-metal complexes, thus offering new perspectives to explore and develop its analogs for the treatment of neurodegenerative disorders.
