Microwave-assisted synthesis of Vulcan Carbon supported Palladium-Nickel (PdNi@VC) bimetallic nanoparticles, and investigation of antibacterial and Safranine dye removing effects

As an alternative to antibiotics, nanoparticles (NPs) are increasingly being used for targeting bacteria. Nanotechnology holds great potential in the treatment of bacterial infections. Although the mechanisms of antibacterial activity of NPs are not fully understood, widely accepted explanations include oxidative stress induction, metal ion release, and non-oxidative processes. Several simultaneous gene changes would be required in the bacterial cell, making it difficult for bacterial cells to develop resistance to NPs. One important application of nanoparticles is in dye removal. Nanoparticle structures can be utilized effectively as adsorbents due to their reduced size and increased surface area, by combining noble metals, Palladium-Nickel (Pd-Ni), with a carbon structure known as Vulcan Carbon (VC), it is anticipated that the consumption of precious metals can be reduced while benefiting from the enhanced properties of the bimetallic structure. The PdNi@VC structure was synthesized using the microwave synthesis technique. Characterization techniques such as Transmission Electron Microscope (TEM) and X-Ray diffraction (XRD) were employed to confirm the formation of the bimetallic structure. According to the Debye-Scherrer equation, the size is 2.74 nm. In addition, photodegradation assays using simulator solar radiation yielded 67% efficacy against Safranine dye. In addition, The PdNi@VC had a high percentage of bacterial inhibition at the concentration of 200 g/ml against Staphylococcus aureus (S.aureus), and Escherichia coli (E.coli). This study focuses on the synthesis of bimetallic nanoparticles for antibacterial applications and investigates their effectiveness in dye removal from wastewater. The obtained results provide valuable insights for the implementation of innovative methods in these areas.

Palladium-based multifunctional nanoparticles for combined chemodynamic/photothermal and calcium overload therapy of tumors

Due to the high mortality and incidence rates associated with tumors and the specificity of the tumor microenvironment (TME), it is difficult to achieve a complete cure for tumors using a single therapy. In this study, calcium carbonate-modified palladium hydride nanoparticles (PdH@CaCO3) were prepared and utilized for the combined treatment of tumors through chemodynamic therapy (CDT)/photothermal therapy (PTT) and calcium overload therapy. After entering tumor cells, PdH@CaCO3 releases calcium ions (Ca2+) and PdH once it reaches the TME due to the pH reactivity of the calcium carbonate coating. The mitochondrial membrane potential is lowered by the Ca2+, leading to irreversible cell damage. Meanwhile, PdH reacts with excessive hydrogen peroxide (H2O2) in the TME via the Fenton reaction, generating hydroxyl radicals (·OH). Moreover, PdH is an excellent photothermal agent that can kill tumor cells under laser irradiation, leading to significant anti-tumor effects. In vitro and in vivo studies have demonstrated that PdH@CaCO3 could combine CDT/PTT and calcium overload therapy, exhibiting great clinical potential in the treatment of tumors.

Synthesis of phenylethanoid glycosides from acrylic esters of glucose and aryldiazonium salts via palladium-catalyzed cross-coupling reactions and evaluation of their anti-Alzheimer activity

Cinnamic acid-containing sugar compounds such as phenylethanoid glycosides are widely present in nature and display various biological activities. In this work, the synthesis of trans-cinnamic acid containing phenylethanoid glycosides was achieved via palladium-catalyzed cross-coupling reactions between glycosyl acrylic esters and aryldiazonium salts. A wide range of functionalized aryldiazonium salts were successfully coupled with 6-O- and 4-O-acrylic esters of glucose under optimized conditions. The reactions proceeded at room temperature in the absence of additives and base. The desired products were obtained in good to excellent yields. Selected compounds from the library were screened for anti-Alzheimer activity, while compound 16 displayed significant inhibitory activities against butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) enzymes.

Dithiobiureas Palladium(II) complexes' studies: From their synthesis to their biological action

Dithiobiureas coordination chemistry towards palladium (II) ions and their possible application is presented and discussed. 1,6-(4-Methoxyphenyl)-2,5-dithiobiurea and 1,6-(4-chlorophenyl)-2,5-dithiobiurea afford two Pd(II) complexes with the general formula [Pd2(H2L)Cl2(PPh3)2]. The metal ion forms one chelate ring with the dithiobiurea, and binds to a triphenylphosphine and an additional leaving group cisplatin like. One of the complexes (1) is endowed not only with stability in DMSO and aqua solutions containing a biological buffer but also with cytotoxicity versus gastric cancer cell lines. Complex 1 does not interact covalently to DNA models, neither activates p53 or Checkpoint Kinase 1 key proteins for DNA damage response. Thus, we propose that complex 1 exerts its action by activating Mitogen-Activated Protein Kinases [p38, Extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs)] as cell death inductors.

Synthesis, characterization, HSA binding, molecular docking, cytotoxicity study, and antimicrobial activity of new palladium(II) complexes with propylenediamine derivatives of phenylalanine

The four new ligands, propylenediamine derivatives of phenylalanine (R2-S,S-pddbaˑ2HCl; L1-L4) and their palladium(II) complexes (C1-C4) were synthesized and characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The interactions of new palladium(II) complexes with human serum albumin (HSA) were studied by fluorescence spectroscopy. All investigated compounds can be transported to target cells by binding to HSA, but complex C4 interacts most strongly. Molecular docking simulations were applied to comprehend the binding of the complex to the molecular target of HSA. Obtained results are in good correlations with experimental data regarding binding affinity by HSA. In vitro cytotoxicity activities were investigated on four tumor cell lines (mouse mammary (4 T1) and colon (CT26), human mammary (MDA-MD-468) and colon (HCT116)) and mouse mesenchymal stem cells as non-tumor control cells. Cytotoxic capacity was determined by MTT test and according to obtained results ligand L4 stands out as the most active and selective compound and as a good candidate for future in vivo testing. Further examination of the ligand L4 and corresponding complex C4 led to the conclusion that both induced cell death mainly by apoptosis. Ligand L4 facilitated cycle arrest in G0/G1 phase and decreased proliferative capacity of tumor cells. In vitro antimicrobial activity for ligands and corresponding Pd(II) complexes was investigated against eleven microorganisms (eight strains of pathogenic bacteria and three yeast species) using microdilution method. The minimum inhibitory concentration and minimum microbicidal concentration were determined.

Interactive effects of palladium (Pd) and microplastics (MPs) on metal bioaccumulation and biological responses in the Mediterranean mussel, Mytilus galloprovincialis

This study investigates the potential of MPs as carriers of pollutants as they can strengthen bioaccumulation of toxic metals on marine organisms. For the first time, the interaction of the metal palladium (Pd) with the widespread MPs, both with increasing concentrations in water environments from anthropogenic sources, was tested. Mytilus galloprovincialis, an important seafood product, was exposed to Pd (24 h) in two ways: water-dissolved and MPs-adsorbed, with depuration followed for 144 h. Quantification of Pd in tissues shown an accumulation 2-3 times higher (59 % of initial Pd) for mussels exposed to MPs-adsorbed Pd and higher in digestive gland than when exposed to water-dissolved Pd (25 %; higher in gills). Additionally, it was demonstrated that Pd induced oxidative stress and altered the feeding behavior of mussels. Therefore, this work support MPs as being vectors of metals (i.e. Pd) to enhance their bioaccumulation on marine organisms which highlights ecological risk of these emerging pollutants.

The development of folate-functionalised palladium nanoparticles for folate receptor targeting in breast cancer cells

Folate receptor-targeted therapy has excellent prospects for the treatment of breast cancer. A non-toxic concentration of folate-conjugated palladium-based nanoparticles was used to target the overexpressed folate receptor on breast cancer cells. The folate-conjugated nanoparticles were tailored to accumulate selectively in cancer cells relative to normal cells via the folate receptor. The MDA-MB-231, MDA-MB-468, MCF-7 breast cancer cell lines, and MCF-10A normal cell lines were used in the study. Qualitative and quantitative analysis of nanoparticle cellular uptake and accumulation was conducted using transmission electron microscopy and inductively coupled plasma-optical emission spectroscopy. The findings proved that folate-conjugated palladium nanoparticles successfully and preferentially accumulated in breast cancer cells. We conclude that folate-conjugated palladium nanoparticles can be potentially used to target breast cancer cells for radiopharmaceutical applications.

Bioinspired palladium-doped manganese oxide nanocorns: a remarkable antimicrobial agent targeting phyto/animal pathogens

Microbial pathogens are known for causing great environmental stress, owing to which emerging challenges like lack of eco-friendly remediation measures, development of drug-resistant and mutational microbial strains, etc., warrants novel and green routes as a stepping stone to serve such concerns sustainably. In the present study, palladium (Pd) doped manganese (II, III) oxide (Mn3O4) nanoparticles (NPs) were synthesized using an aqueous Syzygium aromaticum bud (ASAB) extract. Preliminary phytochemical analysis of ASAB extract indicates the presence of polyphenolics such as phenols, alkaloids, and flavonoids that can act as potential capping agents in NPs synthesis, which was later confirmed in FTIR analysis of pure and Pd-doped Mn3O4 NPs. XRD, Raman, and XPS analyses confirmed the Pd doping in Mn3O4 NPs. FESEM and HRTEM study reveals the mixed morphologies dominated by nanocorns appearance. Zeta potential investigation reveals high stability of the synthesized NPs in colloidal solutions. The developed Pd-doped Mn3O4 NPs were tested against two fungal phytopathogens, i.e., Sclerotinia sclerotiorum and Colletotrichum gloeosporioides, known for causing great economic losses in yield and quality of different plant species. The antifungal activity of synthesized Pd-doped Mn3O4 NPs displayed a dose-dependent response with a maximum of ~92%, and ~72% inhibition was recorded against S. sclerotiorum and C. gloeosporioides, respectively, at 1000 ppm concentration. However, C. gloeosporioides demonstrated higher sensitivity to Pd-doped Mn3O4 NPs upto 500 ppm) treatment than S. sclerotiorum. The prepared NPs also showed significant antibacterial activity against Enterococcus faecalis. The Pd-doped Mn3O4 NPs were effective even at low treatment doses, i.e., 50-100 ppm, with the highest Zone of inhibition obtained at 1000 ppm concentration. Our findings provide a novel, eco-benign, and cost-effective approach for formulating a nanomaterial composition offering multifaceted utilities as an effective antimicrobial agent.

Biodegradable nanoemulsion-based bioorthogonal nanocatalysts for intracellular generation of anticancer therapeutics

Bioorthogonal catalysis mediated by transition metal catalysts (TMCs) provides controlled in situ activation of prodrugs through chemical reactions that do not interfere with cellular bioprocesses. The direct use of 'naked' TMCs in biological environments can have issues of solubility, deactivation, and toxicity. Here, we demonstrate the design and application of a biodegradable nanoemulsion-based scaffold stabilized by a cationic polymer that encapsulates a palladium-based TMC, generating bioorthogonal nanocatalyst "polyzymes". These nanocatalysts enhance the stability and catalytic activity of the TMCs while maintaining excellent mammalian cell biocompatibility. The therapeutic potential of these nanocatalysts was demonstrated through efficient activation of a non-toxic prodrug into an active chemotherapeutic drug, leading to efficient killing of cancer cells.

Modulation of two-dimensional palladium nanozyme activity to enhance chemodynamic/photothermal combined therapy for melanoma

Nanozymes are artificial enzymes that mimic natural enzyme-like activities and exhibit tremendous potential for tumor chemodynamic therapy. However, the development of novel nanozymes with superior catalytic activities for nanotheranostics remains a formidable challenge. Herein, we report a facile synthesis of monodisperse palladium nanosheets (Pd nanosheets) and their assembly on graphene oxide (GO) that enhances the catalytic activities of Pd nanoparticles. Simultaneously, the obtained nanocomposites (rGO-Pd) could be applied as a smart near-infrared (NIR) light-responsive nanotheranostic for near infrared imaging-guided chemodynamic/photothermal combined therapy. Notably, rGO-Pd exhibited high peroxidase mimicking activities, which could catalyze the conversion of intratumoral H2O2 to ˙OH. Impressively, the reactive oxygen species (ROS) generation of rGO-Pd was further remarkably enhanced by the endogenous acidity of the tumor microenvironment and the exogenous NIR light-responsive photothermal effect. These collective properties of the rGO-Pd nanozyme enabled it to be a ROS generation accelerator for photothermally enhanced tumor chemodynamic therapy. Thus, the as-developed rGO-Pd may represent a promising new type of high-performance nanozyme for multifunctional nanotheranostics toward cancer.

Palladium Nanocapsules for Photothermal Therapy in the Near-Infrared II Biological Window

Recent developments in nanomaterials with programmable optical responses and their capacity to modulate the photothermal effect induced by an extrinsic source of light have elevated plasmonic photothermal therapy (PPTT) to the status of a favored treatment for a variety of malignancies. However, the low penetration depth of near-infrared-I (NIR-I) lights and the need to expose the human body to a high laser power density in PPTT have restricted its clinical translation for cancer therapy. Most nanostructures reported to date exhibit limited performance due to (i) activity only in the NIR-I region, (ii) the use of intense laser, (iii) need of large concentration of nanomaterials, or (iv) prolonged exposure times to achieve the optimal hyperthermia state for cancer phototherapy. To overcome these shortcomings in plasmonic nanomaterials, we report a bimetallic palladium nanocapsule (Pd Ncap)─with a solid gold bead as its core and a thin, perforated palladium shell─with extinction both in the NIR-I as well as the NIR-II region for PPTT applications toward cancer therapy. The Pd Ncap demonstrated exceptional photothermal stability with a photothermal conversion efficiency of ∼49% at the NIR-II (1064 nm) wavelength region at a very low laser power density of 0.5 W/cm2. The nanocapsules were further surface-functionalized with Herceptin (Pd Ncap-Her) to target the breast cancer cell line SK-BR-3 and exploited for in vitro PPTT applications using NIR-II light. Pd Ncap-Her caused more than 98% cell death at a concentration of just 50 μg/mL and a laser power density of 0.5 W/cm2 with an output power of only 100 mW. Flow cytometric and microscopic analyses revealed that Pd Ncap-Her-induced apoptosis in the treated cancer cells during PPTT. Additionally, Pd Ncaps were found to have reactive oxygen species (ROS) scavenging ability, which can potentially reduce the damage to cells or tissues from ROS produced during PPTT. Also, Pd Ncap demonstrated excellent in vivo biocompatibility and was highly efficient in photothermally ablating tumors in mice. With a high photothermal conversion and killing efficiency at very low nanoparticle concentrations and laser power densities, the current nanostructure can operate as an effective phototherapeutic agent for the treatment of different cancers with ROS-protecting ability.

Down-Regulation of HSP by Pd-Cu Nanozymes for NIR Light Triggered Mild-Temperature Photothermal Therapy Against Wound Bacterial Infection: In vitro and in vivo Assessments

Purpose

We aimed to develop an oxidative-stress-activated palladium-copper nanozyme to reduce bacterial's heat sensitivity by down-regulating heat shock proteins to overcome the shortcomings of conventional photothermal antimicrobial therapy and achieve mild photothermal bactericidal efficacy.

Methods

We first synthesized palladium-copper nanozymes (PC-NPs) by hydration and used transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy to demonstrate their successful preparation. Their photothermal therapy (PTT) and chemo-dynamic therapy (CDT) activities were then determined by a series of photothermal performance tests and peroxidase-like performance tests, and the destruction of heat shock proteins by reactive oxygen species (ROS) was verified at the protein level by Western Blotting tests, providing a basis for the effective bacteria-killing by the mild-temperature photothermal treatment subsequently applied. We also validated this promising programmed and controlled antimicrobial treatment with palladium-copper nanozymes by in vivo/in vitro antimicrobial assays. A hemolysis assay, MTT cytotoxicity test and histopathological analysis were also performed to assess the in vivo safety of PC-NPs.

Results

In the micro-acidic environment of bacterial infection, PC-NPs showed peroxidase-like activity that broke down the H2O2 at the wound into hydroxyl radicals and down-regulated bacterial heat shock proteins. The application of PC-NPs increased bacteria's sensitivity to subsequent photothermal treatment, enabling the elimination of bacteria via mild photothermal treatment.

Conclusion

The programmed synergistic catalytic enhancement of CDT and mild photothermal therapy achieves the most efficient killing of bacteria and their biofilms, which brings future thinking in the relationship between heat shock proteins and oxidative stress damage in bacteria.

Anticancer Behavior of Pyrrolidine-Based Palladium(II) Complexes and Biophysical Approach on Their DNA, BSA Binding Activity, Molecular Docking, and DFT Study

A series of pyrrolidine-based Pd(II) complexes, [Pd(AEP)Cl2] (C-1), [Pd(AEP)(OH2)2]2+(C-2), [Pd(AEP)(L-cys)]+ (C-3), [Pd(AEP)(N-ac-L-cys)] (C-4), [Pd(AEP)(GSH)] (C-5), and [Pd(AEP)(DL-meth)]2+ (C-6) (where, AEP = 1-(2-aminoethyl)pyrrolidine, L-cys = l-cysteine, N-ac-L-cys = N-acetyl-l-cysteine, GSH = glutathione, and DL-meth = dl-methionine), as anticancer drug candidates have been synthesized and characterized. The DNA binding property of the complexes was executed by gel electrophoresis and spectrophotometric and viscometric methods, and their interaction with BSA was also investigated by various spectroscopic methodologies. The binding activity of the Pd(II) complexes with DNA and BSA were assessed to evaluate their binding mode and binding constants. Molecular docking was performed to correlate with the experimental results on the interaction of the complexes with DNA and BSA. The changes in the microenvironmental and structural properties of BSA are monitored by a synchronous and 3D fluorescence study. The structural properties were evaluated by DFT and TD-DFT studies. The anticarcinogenic activity of the Pd(II) complexes was assessed by PASS prediction software to corroborate with the experimental results of the anticancer activity of the complexes. The ROS generation in cancer cell lines has been investigated, and the cell death mechanism through apoptosis was confirmed by measuring the protein expression. All these complexes have excellent anticancer activity compared to ancillary ligands. The cancer cell line (HCT116) shows almost similar or better cell inhibition activity when treated with the Pd(II) complexes compared to cisplatin, whereas the adverse effect is minimum on a normal cell (NKE). Both the Pd(II) and Pt(II) complexes carrying the same ligands reveal almost similar antiproliferative activity.

Novel chiral Schiff base Palladium(II), Nickel(II), Copper(II) and Iron(II) complexes: Synthesis, characterization, anticancer activity and molecular docking studies

In this study, two chiral Schiff base ligands (L1 and L2) were synthesized from the condensation reaction of (S)-2-amino-3-phenyl-1-propanol with 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde as metal precursors for the preparation of transition metal complexes with Pd(II), Fe(II), Ni(II) and Cu(II). The compounds were characterized by using X-ray (for L1-Pd(II)), NMR, FT-IR, UV-Vis, magnetic susceptibility, molar conductivity, and elemental analysis. The in vitro cytotoxic effects of ligands (L1 and L2) and their metal complexes on colon cancer cells (DLD-1), breast cancer cells (MDA-MB-231) and healthy lung human cell lines were investigated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5‑diphenyl tetrazolium bromide (MTT) assay. Among the synthesized compounds, L1-Pd(II) was particularly found to be the most potent anticancer drug candidate in this series with IC50 values of 4.07, and 9.97 µM in DLD-1 and MDA-MB-231 cell lines, respectively. In addition, molecular docking results indicate that Glu122, Asn103, Ala104, Lys126, Phe114, Leu123, and Lys126 amino acids are the binding site of the colon cancer antigen protein, in which the most active complex, L1-Pd(II) can inhibit the current target.

Hydrogel-Encapsulated Heterogenous Mesoporous Resin Catalyst for In Situ Anti-Cancer Agent Production under Biological Conditions

A heterogenous Palladium anchored Resorcinol-formaldehyde-hyperbranched PEI mesoporous catalyst, made by one-pot synthesis, was used successfully for in situ Suzuki-Miyaura cross coupling synthesis of anticancer prodrug PP-121 from iodoprazole and boronic ester precursors. The mesoporous catalyst with the non-cytotoxic precursors were tested in 2D in vitro model with excellent cytocompatibility and a strong suppression of PC3 cancer cell proliferation, underscored by 50% reduction in PC3 cells viability and 55% reduction in cell metabolism activity and an enhanced rate of early and late apoptosis in flow cytometry, that was induced only by successful in situ pro drug PP121 synthesis from the precursors. The 3D gelatin methacrylate hydrogel encapsulated in vitro cell models underscored the results with a 52% reduction in cell metabolism and underscored apoptosis of PC3 cells when the Pd anchored catalyst was combined with the precursors. In situ application of Suzuki-Miyaura cross coupling of non-cytotoxic precursors to cancer drug, along with their successful encapsulation in an injectable hydrogel could be applied for tumor point drug delivery strategies that can circumvent deleterious side effects and poor bioavailability chemotherapy routes with concomitant enhanced efficacy.

Biological activity of bis-(morpholineacetato)palladium(II) complex: Preparation, structural elucidation, cytotoxicity, DNA-/serum albumin-interaction, density functional theory, in-silico prediction and molecular modeling

In an effort to discover a novel potential bioactive compound, a mono-nuclear Pd(II) complex with an amino acid derivative as ligand was synthesized and characterized through experimental and computational methodologies. A square-planar configuration was suggested for palladium(II) complex utilizing density functional theory. MEP map and Mulliken atomic charge were detected electrophilic and nucleophilic regions of the compound for reactions. The lipophilicity and cytotoxic activity of the complex was more effective than cisplatin. Also, OSIRIS DataWarrior revealed proper oral bioavailability and good drug-likeness for the compound. In-vitro binding behavior of the Pd(II) complex with DNA and serum albumin (BSA) were fully determined via variety of procedures including fluorescence, UV-Vis, CD, viscosity, gel electrophoresis experiments and molecular simulation. The negative signs of ΔH° and ΔS° for Pd(II) complex-CT-DNA/-BSA systems indicated the existence of hydrogen bonding/van der Waals interactions for both binding systems. Additionally, docking simulation illustrated the interaction of Pd(II) complex with the minor groove of DNA and the hydrophobic cavity of the BSA (drug binding site I).

Facile synthesis of biogenic palladium nanoparticles using biomass strategy and application as photocatalyst degradation for textile dye pollutants and their in-vitro antimicrobial activity

Among biological applications, plant-mediated Pd NPs for multi-drug resistance (MDR) developed in pathogenic bacteria were synthesized with the help of biomass of lemon peel, a biological material, with a non-toxic, environmentally friendly, human-nature green synthesis method. Characterization of synthesized Pd NPs was carried out by UV-Vis spectrometry, Transmissive Electron Microscopy (TEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) techniques. According to TEM analysis, Pd NPs were confirmed to be in a spherical shape and the mean particle size was determined to be 4.11 nm. The crystal structure of Pd NPs was checked using XRD analysis and the mean particle size was observed to be 6.72 nm. Besides, the antibacterial activity of Pd NPs was determined against Escherichia coli (E. coli) (ATCC 8739), Bacillus subtilis (B. subtilis ATCC 6633), Staphylococcus aureus (S. aureus ATCC 6538), Klebsiella pneumoniae (K. pneumoniae ATCC 11296) and Serratia marcescens (S. marcescens ATCC) bacteria. Antibacterial activity was determined to be high in Pd NPs which is in conformance with the results acquired. The Pd NPs showed good photocatalytic activity, after 90 min illumination, about 81.55% and 68.45% of MB and MO respectively were catalysed by the Pd NPs catalyst, and 74.50% of RhB dyes were removed at 120 min of illumination. Within the scope of this project, it is recommended to use Pd NPs obtained by the green synthesis in the future as an antibacterial agent in biomedical use and for the cleaning of polluted waters.

Insights into Two Novel Orthopalladated Chromophores with Antimicrobial Activity against Escherichia coli

Advanced chromophoric tools, besides being biologically active, need to meet the expectations of the technological demands including stability, colour retention, and proper solubility for their target. Many coordination compounds of conjugated ligands are antibacterial dyes, able to combine a strong dyeing performance with a useful biological activity. Specifically, palladium (II) complexes of Schiff base ligands are known for their relevant activity against common bacteria. In this article, we report the synthesis and comprehensive experimental and theoretical characterization of two novel Pd(II) chromophore complexes obtained from a cyclopalladated Schiff base as two different chelating azo dyes. The antibacterial response of these two novel complexes was tested against the ubiquitous Escherichia coli bacterium in an aqueous medium and revealed a noteworthy antimicrobial activity, higher than when compared with their uncoordinated biologically active ligands.

Palladium-Catalyzed Direct Synthesis and Insecticidal Activity of Arylmatrine Derivatives

Pd(OAc)₂/NiXantphos efficiently catalyzed the direct arylation at the C-14 position of matrine, leading to 38 arylmatrine derivatives (1a-19a and 1b-19b) in good yields. Most of these matrine analogues showed enhanced insecticidal effects superior to the parent compound matrine. Among them, the 3,5-diphenylbenzene analogue (8b) exhibited the most potent in vivo antifeedant activity (EC₅₀ = 0.19 mg/mL) against Spodoptera exigua (Hübner), with approximately 25-fold more activity than matrine, for which the preliminary mechanism of action was verified through enzyme inhibition activities and molecular docking. Compound 8b as well displayed in vitro antiproliferation activity on Sf9 insect cells (IC₅₀ = 8.1 μM), and its apoptotic induction effect was illustrated by morphological observation and DNA fragment analysis. Overall, the above results provide further information on the potential of arylmatrine-type lead compounds for the prevention and control of insect pests.

Coumarin-Palladium(II) Complex Acts as a Potent and Non-Toxic Anticancer Agent against Pancreatic Carcinoma Cells

Pancreatic carcinoma still represents one of the most lethal malignant diseases in the world although some progress has been made in treating the disease in the past decades. Current multi-agent treatment options have improved the overall survival of patients, however, more effective treatment strategies are still needed. In this paper we have characterized the anticancer potential of coumarin-palladium(II) complex against pancreatic carcinoma cells. Cells viability, colony formation and migratory potential of pancreatic carcinoma cells were assessed in vitro, followed by evaluation of apoptosis induction and in vivo testing on zebrafish. Presented results showed remarkable reduction in pancreatic carcinoma cells growth both in vitro and in vivo, being effective at micromolar concentrations (0.5 μM). Treatments induced apoptosis, increased BAX/BCL-2 ratio and suppressed the expression of SOX9 and SOX18, genes shown to be significantly up-regulated in pancreatic ductal adenocarcinoma. Importantly, treatments of the zebrafish-pancreatic adenocarcinoma xenografts resulted in significant reduction in tumor mass, without provoking any adverse toxic effects including hepatotoxicity. Presented results indicate the great potential of the tested compound and the perspective of its further development towards pancreatic cancer therapy.

Cytotoxic Action of Palladium-Based Compound on Prostate Stem Cells, Primary Prostate Epithelial Cells, Prostate Epithelial Cells, and Prostate Cell Lines

Objective

Prostate cancer is one of the most common types of cancer found to occur in males and is ranked as the second-highest cause of cancer-associated deaths among male patients. In this study, we have shown the influence of a new palladium-based anticancer agent in contrast to the six distinct prostate cancer lines and the primary cultures.

Methods

In this study, we have used six distinct prostate cell lines, that is, PNT2-C2, LNCaP, BPH-1, PC-3, PNT1A, and P4E6. The MTP and ATP assay were performed to evaluate the growth of the cell and the flow cytometry to investigate the status of the cell cycle. The antigrowth effect of the palladium complex was evaluated against different cell lines at three time zones 24 h, 48 h, and 72 h. [PdCl(terpy)] (capsule)-2H2O is synthesized by direct encapsulation of equimolar amounts of capsule ions into [Pd (terpy) Cl] Cl-2H2O.

Results

A comparative analysis was done on 25 mM etoposide and 12 mM cisplatin, cytotoxic agents. The lowest IC50 value at 72 hours was 0.128 mM for BPH-1 cell lines with 0.139 mM, whereas PNT2-C2 cells were found to be most resistant with IC50 values of 0.829 mM. The antigrowth effect of palladium complex on cell lines was measured using the MTS assay at 24, 48, and 72 hours. BPH-1, PNT2-C2, and PNT1A either possess normal tissues or have benign prostatic hyperplasia tissues whereas P4E6, PC-3, and LNCaP cell lines possess malignant origin. The Pd complex exhibited significant cytotoxic action in stem cells when compared against etoposide. An antigrowth effect was reported for Pd complex at lower concentration, but it was more cytotoxic than etoposide with significant cytotoxicity (P=0.001).

Conclusion

The palladium complex experienced a substantial antigrowth influence over most of the prostate tumor cell lines and the primary cultures, eventually, leading to the implementation of this Pd complex in the treating procedure of metastatic prostate cancer, which is tremendously resistant to the traditional treatment.

Palladium Nanoplate-Based IL-6 Receptor Antagonists Ameliorate Cancer-Related Anemia and Simultaneously Inhibit Cancer Progression

In recent years, targeted therapies and immunotherapeutics, along with conventional chemo- and radiotherapy, have greatly improved cancer treatments. Unfortunately, in cancer patients, anemia, either as a complication of cancer progression or as the result of cancer treatment, undermines the expected therapeutic efficacy. Here, we developed a smart nanosystem based on the palladium nanoplates (PdPLs) to deliver tocilizumab (TCZ, a widely used IL-6R antibody) to the liver for specific blockade of IL-6/IL-6R signaling to correct anemia. With chemical modifications, this nanosystem delivered a large mass of TCZ and enhanced liver delivery, inducing a marked suppression of hepcidin expression as a result of diminished IL-6 signaling. Through this mechanism, significant suppression of tumor progression was realized (at least in part) because of the corrected anemia after treatment.

Pd-Immobilized Schiff Base Double-Layer Macrocycle: Synthesis, Structures, Peroxidase Mimic Activity, and Antibacterial Performance

Di-, tri-, and tetra-aldehydes have been employed to access new [2 + 2] [2 + 3] and [2 + 4] double-layer Schiff base macrocycles. The [2 + 3] compound has been used for the immobilization of Pd and the resulting composite has been employed as a peroxidase-like mimetic using 3,3',5,5'-tetramethylbenzidine (TMB) as the substrate; the optimum conditions together with the catalytic kinetics of the enzyme-like activity is discussed. Based on the peroxidase-like catalytic activity, the Pd@Schiff base composite was found to exhibit excellent bactericidal activity against both Escherichia coli (Gram-negative bacterium) and Staphylococcus aureus (Gram-positive bacterium) in the presence of relatively low concentrations of H₂O₂. Furthermore, cytotoxicity measurements illustrate the biosafety of the Pd composite. The above-mentioned findings have the potential to guide the innovation of new Pd-based composites as enzyme mimetics and antibacterial materials.

Heteroleptic pincer palladium(II) complex coated orthopedic implants impede the AbaI/AbaR quorum sensing system and biofilm development by Acinetobacter baumannii

Implant-associated infections mediated by Acinetobacter baumannii biofilms have become a major concern in the healthcare sector. As biofilm formation by this important pathogen is mediated by quorum sensing, quorum sensing inhibitors (QSI) have gained much attention. The present study confirms that novel thiazolinyl-picolinamide based palladium(II) complexes had good biofilm disruptive and QSI properties against A. baumannii. Key QS-mediated virulence factors like pili mediated surface motility and polysaccharide production were inhibited by the best Pd(II) complex (E). This also showed potent inhibitory activity against both the standard and clinical strains of A. baumannii. Molecular docking analysis also proved the potent binding affinity of Pd(II)-E with the virulence targets. The Pd(II) complex also disrupted preformed biofilms and down-regulated the expression of QS mediated virulence genes in the biofilms established on implant material (titanium plates). As a whole, the present study showed that the novel thiazolinyl-picolinamide based Pd(II) complexes offer a promising anti-infective strategy to combat biofilm-mediated implant infections.

Anti-neuropathic pain activity of a cationic palladium (II) dithiocarbamate by suppressing the inflammatory mediators in paclitaxel-induced neuropathic pain model

BACKGROUND

Neuropathic pain is a chronic pain state that negatively impacts the quality of life. Currently, available therapies for the treatment of neuropathic pain often lack efficacy and tolerability. Therefore, the search for novel drugs is crucial to obtain treatments that effectively suppress neuropathic pain.

OBJECTIVES

The present study was undertaken to investigate the antinociceptive properties of (1,4-bis-(diphenylphosphino) butane) palladium (II) chloride monohydrate (Compound 1) in a paclitaxel (PTX)-induced neuropathic pain model.

METHODS

Initially, behavioral tests such as mechanical and cold allodynia as well as thermal and tail immersion hyperalgesia were performed to investigate the antinociceptive potential of Compound 1 (5 and 10 mg/kg, b.w). RT-PCR was performed to determine the effect of Compound 1 on the mRNA expression level of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and proinflammatory cytokines such as tumor necrosis factor-alpha (TNF)-α, interleukin (IL)-1β, and IL-6. In addition, antioxidant protein, nitric oxide (NO), and malondialdehyde (MDA) levels were also determined.

RESULTS

The results demonstrated that once-daily dosing of Compound 1 significantly suppressed the PTX-induced behavioral pain responses dose-dependently. The mRNA gene expressions of iNOS, COX-2, and inflammatory cytokines were markedly reduced by Compound 1. Furthermore, it enhanced the level of antioxidant enzymes and lowered the level of MDA and NO production.

CONCLUSION

These findings suggest that the antinociceptive potential of Compound 1 in the PTX-induced neuropathic pain model is via suppression of oxidative stress and inflammation. Thus, Compound 1 might be a potential candidate for the therapeutic management of PTX induced neuropathic pain.