Pyrone derivatives and metals: From natural products to metal-based drugs

Multipurpose Iron-Chelating Ligands Inspired by Bioavailable Molecules

Because of their capacity to bind metals, metal chelators are primarily employed for therapeutic purposes, but they can also find applications as colorimetric reagents and cleaning solutions as well as in soil remediation, electroplating, waste treatment, and so on. For instance, iron-chelation therapy, which is used to treat iron-overload disorders, involves removing excess iron from the blood through the use of particular molecules, like deferoxamine, that have the ability to chelate the metal. The creation of bioinspired and biodegradable chelating agents is a crucial objective that draws inspiration from natural products. In this context, starting from bioavailable molecules such as maltol and pyrogallol, new molecules have been synthetized and characterized by potentiometry, infrared spectroscopy and cyclic voltammetry. Finally, the ability of these to bind iron has been investigated, and the stability constants of ferric complexes are measured using spectrophotometry. These compounds offer intriguing scaffolds for an innovative class of versatile, multipurpose chelating agents.

Research Progress of Metal Anticancer Drugs

Cancer treatments, including traditional chemotherapy, have failed to cure human malignancies. The main reasons for the failure of these treatments are the inevitable drug resistance and serious side effects. In clinical treatment, only 5 percent of the 50 percent of cancer patients who are able to receive conventional chemotherapy survive. Because of these factors, being able to develop a drug and treatment that can target only cancer cells without affecting normal cells remains a big challenge. Since the special properties of cisplatin in the treatment of malignant tumors were accidentally discovered in the last century, metal anticancer drugs have become a research hotspot. Metal anticancer drugs have unique pharmaceutical properties, such as ruthenium metal drugs with their high selectivity, low toxicity, easy absorption by tumor tissue, excretion, and so on. In recent years, efficient and low-toxicity metal antitumor complexes have been synthesized. In this paper, the scientific literature on platinum (Pt), ruthenium (Ru), iridium (Ir), gold (Au), and other anticancer complexes was reviewed by referring to a large amount of relevant literature at home and abroad.

Anticancer Tungstenocenes with a Diverse Set of (O,O-), (O,S-) and (O,N-) Chelates-A Detailed Biological Study Using an Improved Evaluation via 3D Spheroid Models

The synthesis, characterization and biological activity of tungstenocenes with varying biologically active (O,O-), (S,O-) and (N,O-) chelates are described. Complexes were characterized by ¹H and ¹³C NMR, elemental analysis, ESI-mass spectrometry, FT-IR spectroscopy and X-ray diffraction analysis. The aqueous stability was studied by UV/Vis spectroscopy and the W^IV to W^V process by cyclic voltammetry. The cytotoxicity was determined by the MTT assay in A549, CH1/PA-1 and SW480 cancer cells as well as in IMR-90 human fibroblasts. Extensive biological evaluation was performed in three other human cancer cell lines (HCT116, HT29 and MCF-7) in monolayer and multicellular tumor spheroid cultures to better understand the mode of action. Lead compounds showed promising in vitro anticancer activity in all cancer cell lines. Further studies yielded important insights into apoptosis induction, ROS generation, different patterns in metal distribution (detected by LA-ICP-TOF-MS), changes in KI67 (proliferation marker) expression and DNA interactions. The results based on qualitative and quantitative research designs show that complexes containing (S,O-) chelates are more active than their (O,O-) and (N,O-) counterparts. The most striking results in spheroid models are the high antiproliferative capacity and the different distribution pattern of two complexes differing only in a W-S or W-O bond.

Exploring pta Alternatives in the Development of Ruthenium-Arene Anticancer Compounds

Organoruthenium pyrithione (1-hydroxypyridine-2-thione) complexes have been shown in our recent studies to be a promising family of compounds for development of new anticancer drugs. The complex [(η⁶-p-cymene)Ru(pyrithionato)(pta)]PF₆ contains phosphine ligand pta (1,3,5-triaza-7-phosphaadamantane) as a functionality that improves the stability of the complex and its aqueous solubility. Here, we report our efforts to find pta alternatives and discover new structural elements to improve the biological properties of ruthenium anticancer drugs. The pta ligand was replaced by a selection of phosphine, phosphite, and arsine ligands to identify new functionalities, leading to improvement in inhibitory potency towards enzyme glutathione S-transferase. In addition, cytotoxicity in breast, bone, and colon cancers was investigated.

Highly Cytotoxic Molybdenocenes with Strong Metabolic Effects Inhibit Tumour Growth in Mice

A series of six highly lipophilic Cp-substituted molybdenocenes bearing different bioactive chelating ligands was synthesized and characterized by NMR spectroscopy, mass spectrometry and X-ray crystallography. In vitro experiments showed a greatly increased cytotoxic potency when compared to the non-Cp-substituted counterparts. In vivo experiments performed with the dichlorido precursor, (Ph₂ C-Cp)₂ MoCl₂ and the in vitro most active complex, containing the thioflavone ligand, showed an inhibition of tumour growth. Proteomic studies on the same two compounds demonstrated a significant regulation of tubulin-associated and mitochondrial inner membrane proteins for both compounds and a strong metabolic effect of the thioflavone containing complex.

Hydroxypyrone derivatives in drug discovery: from chelation therapy to rational design of metalloenzyme inhibitors

The versatile structural motif of hydroxypyrone is found in natural products and can be easily converted into hydroxypyridone and hydroxythiopyridone analogues. The favourable toxicity profile and ease of functionalization to access a vast library of compounds make them an ideal structural scaffold for drug design and discovery. This versatile scaffold possesses excellent metal chelating properties that can be exploited for chelation therapy in clinics. Deferiprone [1,2-dimethyl-3-hydroxy-4(1H)-one] was the first orally active chelator to treat iron overload in thalassemia major. Metal complexes of hydroxy-(thio)pyr(id)ones have been investigated as magnetic resonance imaging contrast agents, and anticancer and antidiabetic agents. In recent years, this compound class has demonstrated potential in discovering and developing metalloenzyme inhibitors. This review article summarizes recent literature on hydroxy-(thio)pyr(id)ones as inhibitors for metalloenzymes such as histone deacetylases, tyrosinase and metallo-β-lactamase. Different approaches to the design of hydroxy-(thio)pyr(id)ones and their biological properties against selected metalloenzymes are discussed.

Hydroxypyridinones as a Very Promising Platform for Targeted Diagnostic and Therapeutic Radiopharmaceuticals

Hydroxypyridinones (HOPOs) have been used in the chelation therapy of iron and actinide metals. Their application in metal-based radiopharmaceuticals has also been increasing in recent years. This review article focuses on how multidentate HOPOs can be used in targeted radiometal-based diagnostic and therapeutic radiopharmaceuticals. The general structure of radiometal-based targeted radiopharmaceuticals, a brief description of siderophores, the basic structure and properties of bidentate HOPO, some representative HOPO multidentate chelating agents, radiopharmaceuticals based on HOPO multidentate bifunctional chelators for gallium-68, thorium-227 and zirconium-89, as well as the future prospects of HOPO multidentate bifunctional chelators in other metal-based radiopharmaceuticals are described and discussed in turn. The HOPO metal-based radiopharmaceuticals that have shown good prospects in clinical and preclinical studies are gallium-68, thorium-227 and zirconium-89 radiopharmaceuticals. We expect HOPO multidentate bifunctional chelators to be a very promising platform for building novel targeted radiometal-based diagnostic and therapeutic radiopharmaceuticals.

Hydroxypyridinones as a Very Promising Platform for Targeted Diagnostic and Therapeutic Radiopharmaceuticals

Hydroxypyridinones (HOPOs) have been used in the chelation therapy of iron and actinide metals. Their application in metal-based radiopharmaceuticals has also been increasing in recent years. This review article focuses on how multidentate HOPOs can be used in targeted radiometal-based diagnostic and therapeutic radiopharmaceuticals. The general structure of radiometal-based targeted radiopharmaceuticals, a brief description of siderophores, the basic structure and properties of bidentate HOPO, some representative HOPO multidentate chelating agents, radiopharmaceuticals based on HOPO multidentate bifunctional chelators for gallium-68, thorium-227 and zirconium-89, as well as the future prospects of HOPO multidentate bifunctional chelators in other metal-based radiopharmaceuticals are described and discussed in turn. The HOPO metal-based radiopharmaceuticals that have shown good prospects in clinical and preclinical studies are gallium-68, thorium-227 and zirconium-89 radiopharmaceuticals. We expect HOPO multidentate bifunctional chelators to be a very promising platform for building novel targeted radiometal-based diagnostic and therapeutic radiopharmaceuticals.

Hydroxypyridinones as a Very Promising Platform for Targeted Diagnostic and Therapeutic Radiopharmaceuticals

Hydroxypyridinones (HOPOs) have been used in the chelation therapy of iron and actinide metals. Their application in metal-based radiopharmaceuticals has also been increasing in recent years. This review article focuses on how multidentate HOPOs can be used in targeted radiometal-based diagnostic and therapeutic radiopharmaceuticals. The general structure of radiometal-based targeted radiopharmaceuticals, a brief description of siderophores, the basic structure and properties of bidentate HOPO, some representative HOPO multidentate chelating agents, radiopharmaceuticals based on HOPO multidentate bifunctional chelators for gallium-68, thorium-227 and zirconium-89, as well as the future prospects of HOPO multidentate bifunctional chelators in other metal-based radiopharmaceuticals are described and discussed in turn. The HOPO metal-based radiopharmaceuticals that have shown good prospects in clinical and preclinical studies are gallium-68, thorium-227 and zirconium-89 radiopharmaceuticals. We expect HOPO multidentate bifunctional chelators to be a very promising platform for building novel targeted radiometal-based diagnostic and therapeutic radiopharmaceuticals.

Synthesis and Some Properties of New 5-Hydroxy-2-[(hetarylthio)methyl]-4H-pyran-4-ones

Abstract

The reaction of 2-thioxoazines with chlorokojic acid in the presence of KOH in DMF led to the formation of new hybrid molecules containing fragments of kojic acid and azaheterocycle linked by the SCH2 spacer. In silico prediction of bioavailability parameters was carried out, possible protein targets were predicted by the protein ligand docking method.

High Antiproliferative Activity of Hydroxythiopyridones over Hydroxypyridones and Their Organoruthenium Complexes

Hydroxypyr(id)ones are a pharmaceutically important class of compounds that have shown potential in diverse areas of drug discovery. We investigated the 3-hydroxy-4-pyridones 1a-1c and 3-hydroxy-4-thiopyridones 1d-1f as well as their Ru(η⁶-p-cymene)Cl complexes 2a-2f, and report here the molecular structures of 1b and 1d as determined by X-ray diffraction analysis. Detailed cell biological investigations revealed potent cytotoxic activity, in particular of the 3-hydroxy-4-thiopyridones 1d-1f, while the Ru complexes of both compound types were less potent, despite still showing antiproliferative activity in the low μM range. The compounds did not modulate the cell cycle distribution of cancer cells but were cytostatic in A549 and cytotoxic in NCI-H522 non-small lung cancer cells, among other effects on cancer cells.

Antimicrobial Properties of Gallium(III)- and Iron(III)-Loaded Polysaccharides Affecting the Growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, In Vitro

Antimicrobial resistance (AMR) has become a global concern as many bacterial species have developed resistance to commonly prescribed antibiotics, making them ineffective to treatments. One type of antibiotics, gallium(III) compounds, stands out as possible candidates due to their unique "Trojan horse" mechanism to tackle bacterial growth, by substituting iron(III) in the metabolic cycles of bacteria. In this study, we tested three polysaccharides (carboxymethyl cellulose (CMC), alginate, and pectin) as the binding and delivery agent for gallium on three bacteria (Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus) with a potential bioresponsive delivery mode. Two types of analysis on bacterial growth (minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC)) were carried out while iron(III)-loaded polysaccharide samples were also tested for comparison. The results suggested that gallium showed an improved inhibitory activity on bacterial growth, in particular gallium(III)-loaded carboxymethyl cellulose (Ga-CMC) sample showing an inhibiting effect on growth for all three tested bacteria. At the MIC for all three bacteria, Ga-CMC showed no cytotoxicity effect on human dermal neonatal fibroblasts (HDNF). Therefore, these bioresponsive gallium(III) polysaccharide compounds show significant potential to be developed as the next-generation antibacterial agents with controlled release capability.

An allomaltol derivative triggers distinct death pathways in luminal a and triple-negative breast cancer subtypes

Breast cancer is the most common cancer in women that shows a predisposition to metastasize to the distant organs. Kojic acid is a natural fungal metabolite exhibiting various biological activities. Compounds derived from kojic acid have been extensively studied and proved to demonstrate anti-neoplastic features on different cancer types. In the present study, allomaltol-structural analog of kojic acid and its seven derivatives including four novel compounds, have been synthesized, characterized and their possible impact on breast cancer cell viability was investigated. It was discovered that compound 5, bearing 3,4-dichlorobenzyl piperazine moiety, could decrease the viability of both MCF-7 and MDA-MB-231 cell lines distinctively. To ascertain the death mechanism, cells were subjected to different tests following the application of IC₅₀ concentration of compound 5. Data obtained from lactate dehydrogenase activity and gene expression assays pointed out that necrosis had taken place predominantly in MDA-MB-231. On the other hand, in MCF-7 cells, the p53 apoptotic pathway was activated by overexpression of the pro-apoptotic TP53 and Bax genes and suppression of the anti-apoptotic Mdm-2 and Bcl-2 genes. Furthermore, Bax/Blc-2 ratio was escalated by 3.5 fold in the study group compared to the control. Compound 5 did not provoke drug resistance in MCF-7 cells since the Mdr-1 gene expression, drug efflux, and H₂O₂ content remained unaltered. As for MDA-MB-231 cells, only a 1.4 fold increase in the Mdr-1 gene expression was detected. These results indicate the advantage of the allomaltol derivative over the chemotherapeutic agents conventionally used for breast cancer treatment that can be highly toxic and mostly lead to drug resistance. Thus, this specific allomaltol derivative offers an alternative therapeutic approach for breast cancer which needs further investigation.

Thiourea-Derived Chelating Ligands and Their Organometallic Compounds: Investigations into Their Anticancer Activity

Thiones have been investigated as ligands in metal complexes with catalytic and biological activity. We report the synthesis, characterization, and biological evaluation of a series of M^II/III complexes of the general formulae [M^II(cym)(L)Cl]X (cym = η⁶-p-cymene) or [M^III(Cp*)(L)Cl]X (Cp* = η⁵-pentamethylcyclopentadienyl), where X = Cl^- or PF₆^-, and L represents heterocyclic derivatives of thiourea. The thiones feature a benzyl-triazolyl pendant and they act as bidentate ligands via N,S-coordination to the metal centers. Several derivatives have been investigated by single-crystal X-ray diffraction analysis. NMR investigations showed a counterion-dependent shift of several protons due to the interaction with the counterions. These NMR investigations were complemented with X-ray diffraction analysis data and the effects of different counterions on the secondary coordination sphere were also investigated by DFT calculations. In biological studies, the Ir benzimidazole derivative was found to accumulate in the cytoplasm and it was the most cytotoxic derivative investigated.

Bismuth(III) Flavonolates: The Impact of Structural Diversity on Antibacterial Activity, Mammalian Cell Viability and Cellular Uptake

A series of homoleptic and heteroleptic bismuth(III) flavonolate complexes derived from six flavonols of varying substitution have been synthesised and structurally characterised. The complexes were evaluated for antibacterial activity towards several problematic Gram-positive (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE)) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. The cell viability of COS-7 (monkey kidney) cells treated with the bismuth flavonolates was also studied to determine the effect of the complexes on mammalian cells. The heteroleptic complexes [BiPh(L)₂ ] (in which L=flavonolate) showed good antibacterial activity towards all of the bacteria but reduced COS-7 cell viability in a concentration-dependent manner. The homoleptic complexes [Bi(L)₃ ] exhibited activity towards the Gram-positive bacteria and showed low toxicity towards the mammalian cell line. Bismuth uptake studies in VRE and COS-7 cells treated with the bismuth flavonolate complexes indicated that Bi accumulation is influenced by both the substitution of the flavonolate ligands and the degree of substitution at the bismuth centre.

Synthesis, Modification, and Biological Evaluation of a Library of Novel Water-Soluble Thiopyridone-Based Organometallic Complexes and Their Unexpected (Biological) Behavior

A series of 16 dinuclear thiopyridone-based organometallics with excellent water solubility, increased stability and remarkable cytotoxicity were synthesized and characterized. The complexes of this work formed dimeric species featuring a double positive charge in polar protic solvents, accounting for their outstanding solubility in aqueous solution. Most of them displayed higher antiproliferative activity than their parental thiomaltol complex, with unexpected cytotoxicity trends depending on the employed metal center, ligand modification, and cell line. Insights into their behavior in biological systems were gathered by means of amino-acid interaction studies, cytotoxicity tests in 3D spheroid models, laser ablation, cellular accumulation measurements, as well as cell cycle experiments.

The First Anticancer Tris(pyrazolyl)borate Molybdenum(IV) Complexes: Tested in Vitro and in Vivo-A Comparison of O,O-, S,O-, and N,N-Chelate Effects

The synthesis, characterization and biological activity of molybdenum(IV) complexes containing Trofimenko's scorpionato ligand, hydrotris(3-isopropylpyrazolyl)borate (TpiPr ), in addition to varying biologically active as well as other conventional ligands is described. Ligands employed include (O,O-) (S,O-) (N,N-) donors that have been successfully coordinated to the molybdenum center by means of oxygen-atom transfer (OAT) reactions from the known MoVI starting material, TpiPr MoO2 Cl. The synthesized complexes were characterized by standard analytical methods and where possible by X-ray diffraction analysis. The aqueous stability of the compounds was studied by means of UV/Vis spectroscopy and the impact of the attached ligand scaffolds on the oxidation potentials (MoIV to MoV ) was studied by cyclic voltammetry. Utilizing polyvinylpyrrolidone (PVP) as a solubilizing agent, adequate aqueous solubility for biological tests was obtained. Anticancer activity tests and preliminary mode of action studies have been performed in vitro and in vivo.

Oxovanadium(IV) Coordination Compounds with Kojic Acid Derivatives in Aqueous Solution

Hydroxypyrone derivatives have a good bioavailability in rats and mice and have been used in drug development. Moreover, they show chelating properties towards vanadyl cation that could be used in insulin-mimetic compound development. In this work, the formation of coordination compounds of oxovanadium(IV) with four kojic acid (5-hydroxy-2-(hydroxymethyl)-4-pyrone) derivatives was studied. The synthetized studied ligands (S2, S3, S4, and SC) have two or three kojic acid units linked through diamines or tris(2-aminoethyl)amine chains, respectively. The chemical systems were studied by potentiometry (25 °C, ionic strength 0.1 mol L^-1 with KCl), and UV-visible and EPR spectroscopy. The experimental data were analyzed by a thermodynamic and a chemometric (Multivariate Curve Resolution-Alternating Least Squares) approach. Chemical coordination models were proposed, together with the species formation constants and the pure estimated UV-vis and EPR spectra. In all systems, the coordination of the oxovanadium(IV) starts already under acidic conditions (the cation is totally bound at pH higher than 3-4) and the metal species remain stable even at pH 8. Ligands S3, S4, and SC form three coordination species. Two of them are probably due to the successive insertion of the kojate units in the coordination shell, whereas the third is most likely a hydrolytic species.

Towards Identification of Essential Structural Elements of Organoruthenium(II)-Pyrithionato Complexes for Anticancer Activity

An organoruthenium(II) complex with pyrithione (2-mercaptopyridine N-oxide) 1 a has previously been identified by our group as a compound with promising anticancer potential without cytotoxicity towards non-cancerous cells. To expand the rather limited research on compounds of this type, an array of novel chlorido and 1,3,5-triaza-7-phosphaadamantane (pta) organoruthenium(II) complexes with methyl-substituted pyrithiones has been prepared. After thorough investigation of the aqueous stability of these complexes, their modes of action have been elucidated at the cellular level. Minor structural alterations in the ruthenium-pyrithionato compounds resulted in fine-tuning of their cytotoxicities. The best performing compounds, 1 b and 2 b, with a chlorido or pta ligand bound to ruthenium, respectively, and a methyl group at the 3-position of the pyrithione scaffold, have been further investigated. Both compounds trigger early apoptosis, induce the generation of reactive oxygen species and G1 arrest in A549 cancer cells, and show no strong interaction with DNA. However, only 1 b also inhibits thioredoxin reductase. Wound healing assays and mitochondrial function evaluation have revealed differences between these two compounds at the cellular level.

Use of a fluorinated probe to quantitatively monitor amino acid binding preferences of ruthenium(ii) arene complexes

Speciation of Ru(ii) arene complexes in mixtures of amino acids with coordinating sidechains is easily resolved by ¹⁹F NMR.

From Catalysis to Cancer: Toward Structure-Activity Relationships for Benzimidazol-2-ylidene-Derived N-Heterocyclic-Carbene Complexes as Anticancer Agents

The promise of the metal(arene) structure as an anticancer pharmacophore has prompted intensive exploration of this chemical space. While N-heterocyclic carbene (NHC) ligands are widely used in catalysis, they have only recently been considered in metal complexes for medicinal applications. Surprisingly, a comparatively small number of studies have been reported in which the NHC ligand was coordinated to the Ru^II(arene) pharmacophore and even less with an Os^II(arene) pharmacophore. Here, we present a systematic study in which we compared symmetrically substituted methyl and benzyl derivatives with the nonsymmetric methyl/benzyl analogues. Through variation of the metal center and the halido ligands, an in-depth study was conducted on ligand exchange properties of these complexes and their biomolecule binding, noting in particular the stability of the M-C_NHC bond. In addition, we demonstrated the ability of the complexes to inhibit the selenoenzyme thioredoxin reductase (TrxR), suggested as an important target for anticancer metal-NHC complexes, and their cytotoxicity in human tumor cells. It was found that the most potent TrxR inhibitor diiodido(1,3-dibenzylbenzimidazol-2-ylidene)(η⁶-p-cymene)ruthenium(II) 1b^I was also the most cytotoxic compound of the series, with the antiproliferative effects in general in the low to middle micromolar range. However, since there was no clear correlation between TrxR inhibition and antiproliferative potency across the compounds, TrxR inhibition is unlikely to be the main mode of action for the compound type and other target interactions must be considered in future.

α-pyrones and their hydroxylated analogs as promising scaffolds against Mycobacterium tuberculosis

Tuberculosis ranks as the leading cause of global human mortality from a single infectious agent. To address the uprising issues of drug resistance, intense research efforts have been directed towards drug discovery. However, it is a long and economically challenging process that is often associated with high failure rates. Therefore, it seems prudent to take forward the core scaffolds that have already acclaimed clinical relevance. In this direction, hydroxylated α-pyrone scaffold has received US FDA approval for human use against HIV. Interestingly, literature review reveals the potential applicability of α-pyrones in TB drug discovery. On one hand, α-pyrones play a vital role in the cell wall of Mycobacterium tuberculosis and on the other hand natural α-pyrones display appreciable anti-TB activity. This review aims to rekindle the interest of researchers toward α-pyrone as a new anti-TB drug that may possibly tackle drug resistance and open a dual frontier in TB and HIV drug discovery.

Designing new iridium(iii) arene complexes of naphthoquinone derivatives as anticancer agents: a structure–activity relationship study

A series of iridium(iii) arene complexes of naphthoquinone derivatives have been synthesized and investigated for their suitability as potential anticancer drugs.

Tuning the cytotoxicity of ruthenium(ii) para-cymene complexes by mono-substitution at a triphenylphosphine/phenoxydiphenylphosphine ligand

The cytotoxic activities of novel Ru(ii) arene complexes with variably mono-substituted phosphine ligands have been assessed towards MDA-MB-231 and A2780 cancer cell lines.

Copper(II), cobalt(II) and nickel(II) complexes of lapachol: synthesis, DNA interaction, and cytotoxicity

Three novel copper(II), cobalt(II), and nickel(II) complexes of lapachol (Lap) containing 110-phenanthroline (phen) ligand, [M(Lap)₂(phen)] (M=Cu(II), 1, Co(II), 2, and Ni(II), 3), have been synthesized and characterized using, elemental analysis and spectroscopic studies. Their interactions with calf thymus DNA (CT DNA) were investigated using viscosity, thermal denaturation, circular dichorism, fluorescence quenching, and electronic absorption spectroscopy. The DNA cleavage abilities of 1-3 have been studied, where cleavage activity of copper complex 1 is more than the complexes 2 and 3. The in vitro cytotoxic potential of the complexes 1-3 against human cervical carcinoma (HeLa), human liver hepatocellular carcinoma (HepG-2), and human colorectal adenocarcinoma (HT-29) cells indicated their promising antitumor activity with quite low IC₅₀ values in the range of .15-2.41 μM, which are lower than those of cisplatin.

Cytotoxicity and preliminary mode of action studies of novel 2-aryl-4-thiopyrone-based organometallics

Organometallic 2-aryl-4-thiopyrone-based Ru(ii) and Rh(iii) complexes have been established and their potential as anticancer metallodrugs was investigated.