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

Studies on synthesis and influence of sterically driven Ni(II)-terpyridine (NNN) complexes on BSA/DNA binding and anticancer activity

The present work demonstrates the synthesis, structural diversity and coordination behavior of some selected new Ni(II)-Tpy complexes. The structural analysis revealed the coordination of the selected terpyridine ligands with the core metal atom in two different modes via dimeric species (1:1 fashion) through the Cl-bridging and a bis(Tpy)-Ni complex (2:1 fashion). Perhaps the most striking manifestations of these Ni(II)-Tpy complexes are BSA/DNA binding ability and anticancer activity. In addition, the cytotoxicity studies of Tpy ligand (4-([2,2':6',2″-terpyridin]-4'-yl)phenyl 5-methylthiophene-2-carboxylate) and the Ni(II) complexes were carried out using lung cancer cell line (A549), breast cancer cell line (MCF-7) and normal cell line (Vero cell). The cytotoxicity results were compared with the cisplatin control group. Notably, bis-terpyridyl complex 3C (R = 4-([2,2':6',2″-terpyridin]-4'-yl)phenyl 4-isopropoxybenzoate) demonstrates better activity with the IC50 value of 23.13 ± 3 μm for A549 and 22.7 ± 3 for MCF-7. The DFT calculations reveal the significant energy differences of HOMO and LUMO for the ligands and their corresponding Ni(II) complexes. The Tpy ligands and Ni(II)-Tpy complexes were investigated for BSA binding and further all the Ni(II) complexes were analyzed for DNA binding studies.

Synthesis, characterization and evaluation of new anti-inflammatory iron charge transfer complexes

The novelty and the essential purpose of this research is the preparation of new anti-inflammatory iron complexes in water green solvent using critical micelle concentration of anionic surface active agent (SAA). Three new anti-inflammatory iron complexes have been prepared. Thiophene-electron (es) donor (D) Schiff base (2-(2-OH-benzylidene)-amino)-4, 5, 6, 7-tetrah ydrobenzo[b] thiophene-3-carbonitrile) has been prepared. Molecular structures of all samples were confirmed based on CNH analysis, 1H NMR and 13C NMR spectra. The molecular structure of Schiff base is further confirmed by computational chemistry using the DFT-B3LYP method, 6-31G (d) basis set. Observed and simulated 1H NMR, UV-Vis. IR/Raman spectra confirmed the molecular structure of D. This Schiff base is intercalated to ferric chloride (FeCl3) giving pure iron charge transfer complex (CTCs). In vitro and kinetic studies confirmed Fe-CTC complexes had (concentration-dependent) potent antimicrobial-, good anti-inflammatory activities. Free radical scavenging activity nitrous oxide (NO.) of Fe (III)CTCs is attributed to geometry Fe(III) ions as distorted octahedral (either monoclinic or triclinic single crystals) via functional groups (-C]N-O, NH2). Elemental analysis and EDS spectra confirmed strong binding between iron and hetero atoms (N, S, O) of D molecules.

Copper and Copper Complexes in Tumor Therapy

Copper (Cu), a crucial trace element in physiological processes, has garnered significant interest for its involvement in cancer progression and potential therapeutic applications. The regulation of cellular copper levels is essential for maintaining copper homeostasis, as imbalances can lead to toxicity and cell death. The development of drugs that target copper homeostasis has emerged as a promising strategy for anticancer treatment, with a particular focus on copper chelators, copper ionophores, and novel copper complexes. Recent research has also investigated the potential of copper complexes in cancer therapy.

Design, Synthesis, and In Silico and In Vitro Cytotoxic Activities of Novel Isoniazid-Hydrazone Analogues Linked to Fluorinated Sulfonate Esters

Cancer is a life-threatening disease, and significant efforts are still being made to treat it. In this study, we synthesized and characterized novel hybrid molecules (10-18) containing hydrazone and sulfonate moieties and tested their cell growth inhibitory effect on human colon cancer cells (DLD-1), human prostate cancer cells (PC3), and human embryonic kidney cells (HEK-293T) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method for 72 h. In cell culture studies, all tested hybrid molecules except for 12 and 13 showed significant cytotoxic activities at a micromolar level with IC50 values in the range of 10.28-214.0 μM for the PC3 cell line and 13.49-144.30 μM for the DLD-1 cell line. Compounds 4 (10.28 μM) and 5 (11.22 μM) demonstrated the highest cytotoxicity against the PC3 cell line. Against the DLD-1 cell line, compounds 1 (22.53 μM), 4 (13.49 μM), 5 (19.33 μM), 6 (17.82 μM), 8 (24.71 μM), 9 (17.56 μM), and 10 (17.90 μM) in the series showed anticancer activity at lower micromolar levels compared to cisplatin (26.70 μM). Moreover, the study was handled computationally, and molecular docking studies were performed for compounds 1, 4, and 5 for PC3-FAK and PC3-Scr and compounds 4, 6, and 9 for the DLD-1-TNKS target. In this study, compound 4 was found to be the most effective and promising molecule for both targets.

Synthesis of novel hydrazide Schiff bases with anti-diabetic and anti-hyperlipidemic effects: in-vitro, in-vivo and in-silico approaches

The increasing global incidence of non-insulin-dependent diabetes mellitus (NIDDM) necessitates innovative therapeutic solutions. This study focuses on the design, synthesis and biological evaluation of Schiff base derivatives from 2-bromo-2-(2-chlorophenyl) acetic acid, particularly hydrazone compounds 4a and 4b. Both in-vitro and in-vivo assays demonstrate these derivatives' strong antidiabetic and anti-hyperlipidemic properties. In a 15-d experiment, we administered 4a and 4b at doses of 2.5 and 5 mg/kg body weight, which effectively improved symptoms of alloxan-induced diabetes in mice. These symptoms included weight loss, increased water consumption and high blood glucose levels. The compounds also normalized abnormal levels of total cholesterol (TC), triacylglycerol (TG) and low-density lipoprotein cholesterol (LDL-C), while raising the levels of high-density lipoprotein cholesterol (HDLC). Computational analysis showed that these compounds effectively inhibited the α-glucosidase enzyme by interacting with key catalytic residues, specifically Asp214 and Asp349. These computational results were confirmed through in-vitro tests, where 4a and 4b showed strong α-glucosidase inhibitory activity, with IC50 values of 0.70 ± 0.11 and 10.29 ± 0.30 µM, respectively. These compounds were more effective than the standard drug, acarbose, which had an IC50 value of 873.34 ± 1.67 µM. Mechanistic studies further indicated competitive inhibition, reinforcing the therapeutic potential of 4a and 4b for NIDDM treatment.Communicated by Ramaswamy H. Sarma.

8-hydroxyquinoline-N-oxide copper(II)- and zinc(II)-phenanthroline and bipyridine coordination compounds: Design, synthesis, structures, and antitumor evaluation

Fourteen novel tumor-targeting copper(II) and zinc(II) complexes, [Cu(ONQ)(QD1)(NO3)]·CH3OH (NQ3), [Cu(ONQ)(QD2)(NO3)] (NQ2), [Cu(NQ)(QD2)Cl] (NQ3), [Cu(ONQ)(QD1)Cl] (NQ4), [Cu(ONQ)(QD3)](NO3) (NQ5), [Cu(ONQ)(QD3)Cl] (NQ6), [Zn(ONQ)(QD4)Cl] (NQ7), [Zn(ONQ)(QD1)Cl] (NQ8), [Zn(ONQ)(QD5)Cl] (NQ9), [Zn(ONQ)(QD2)Cl] (NQ10), [Zn(ONQ)(QD6)Cl] (NQ11), [Zn(ONQ)(QD7)Cl] (NQ12), and [Zn(ONQ)(QD3)Cl] (NQ13) supported on 8-hydroxyquinoline-N-oxide (H-ONQ), 2,2'-dipyridyl (QD1), 5,5'-dimethyl-2,2'-bipyridyl (QD2), 1,10-phenanthroline (QD3), 4,4'-dimethoxy-2,2'-bipyridyl (QD4), 4,4'-dimethyl-2,2'-bipyridyl (QD5), 5-chloro-1,10-phenanthroline (QD6), and bathophenanthroline (QD7), were first synthesized and characterized using various spectroscopic techniques. Furthermore, NQ1-NQ13 exhibited higher antiproliferative activity and selectivity for cisplatin-resistant SK-OV-3/DDP tumor cells (CiSK3) compared to normal HL-7702 cells based on results obtained from the cell counting Kit-8 (CCK-8) assay. The complexation of copper(II) ion with QD2 and ONQ ligands resulted in an evident increase in the antiproliferation of NQ1-NQ6, with NQ6 exhibiting the highest antitumor potency against CiSK3 cells compared to NQ1-NQ5, H-ONQ, QD1-QD7, and NQ7-NQ13 as well as the reference cisplatin drug with an IC50 value of 0.17 ± 0.05 μM. Mechanistic studies revealed that NQ4 and NQ6 induced apoptosis of CiSK3 cells via mitophagy pathway regulation and adenosine triphosphate (ATP) depletion. Further, the differential induction of mitophagy decreased in the order of NQ6 > NQ4, which can be attributed to the major impact of the QD3 ligand with a large planar geometry and the Cl leaving group within the NQ6 complex. In summary, these results confirmed that the newly synthesized H-ONQ copper(II) and zinc(II) coordination metal compounds NQ1-NQ13 exhibit potential as anticancer drugs for cisplatin-resistant ovarian CiSK3 cancer treatment.

Design, spectroscopic characterization, in silico and in vitro cytotoxic activity assessment of newly synthesized thymol Schiff base derivatives

Cancer is a global public health problem affecting millions of people every year. New anticancer drug candidates are needed to overcome the resistance to drugs used in the treatment of various types of cancer. In this study, two new series of benzenesulfonate-based thymol derivatives (14-19 and 20-25) were synthesized for the first time as promising chemotherapeutic agents and characterized using FT-IR, 1D NMR (1H- and 13C-NMR, APT, DEPT 135), 2D NMR (HETCOR and HMBC), and elemental analysis (CHNS). Antiproliferative activity of the molecules was determined against cancer cell lines, namely, the human lung adenocarcinoma cell line (A549) and the colorectal adenocarcinoma cell line (DLD-1), using MTT method for both 48 and 72 h. Compounds (14-25) showed cytotoxic activities against A549 with IC50 values ranging from 9.98 to 81.83 μM, respectively, compared to cisplatin (6.65 μM). These compounds exhibited antiproliferative activities against DLD-1 cancer cells at concentrations ranging from 4.29 to 53.62 μM, respectively, compared to cisplatin (9.91 μM). Especially, compound 16 displayed significant cytotoxicity on A549 and DLD-1 cancer cells with IC50 values of 9.98 and 10.75 μM, respectively. Finally, molecular docking studies were performed with Bcl-2, VEGFR-2, EGFR, and HER2 targets using the Schrödinger 2021-2 Maestro Glide program. The binding energy values and binding interactions of compounds 16 and 22 were determined to be the result of their interactions with these targets. Schrödinger 2021-2 Qikprop wizard drug similarity ratios and ADME prediction of all compounds 14-25 were also calculated.Communicated by Ramaswamy H. Sarma.

Preliminary anticancer evaluation of new Pd(II) complexes bearing NNO donor ligands

In this study we presented a novel series of NNO tridentate ligands generating imino, amido and oxo donor pocket for Pd(II) coordination. All the compounds were meticulously characterized by elemental analysis and advanced spectroscopic techniques, including FTIR, proton and carbon NMR. The synthesized compounds underwent rigorous evaluation for their potential as anti-cancer agents, utilizing the aggressive breast cancer cell lines MDA-MB (ATCC) and MCF-7 as a crucial model for assessing growth inhibition in cancer cells. Remarkably, the MTT assay unveiled the robust anti-cancer activity for all palladium complexes against MDA-MB-231 and MCF-7 cells. Particularly, complex [Pd(L1)(CH3CN)] exhibited exceptional potency with an IC50 value of 25.50 ± 0.30 µM (MDA-MB-231) and 20.76 ± 0.30 µM (MCF-7), compared to respective 27.00 ± 0.80 µM and 24.10 ± 0.80 µM for cisplatin, underscoring its promising therapeutic potential. Furthermore, to elucidate the mechanistic basis for the anti-cancer effects, molecular docking studies on tyrosine kinases, an integral target in cancer research, were carried out. The outcome of these investigations further substantiated the remarkable anticancer properties inherent to these innovative compounds. This research offers a compelling perspective on the development of potent anti-cancer agents rooted in the synergy between ligands and Pd(II) complexes and presenting a promising avenue for future cancer therapy endeavors.

An Insight into the Effect of Schiff Base and their d and f Block Metal Complexes on Various Cancer Cell Lines as Anticancer Agents: A Review

Over the last few decades, an alarming rise in the percentage of individuals with cancer and those with multi-resistant illnesses has forced researchers to explore possibilities for novel therapeutic approaches. Numerous medications currently exist to treat various disorders, and the development of small molecules as anticancer agents has considerable potential. However, the widespread prevalence of resistance to multiple drugs in cancer indicates that it is necessary to discover novel and promising compounds with ideal characteristics that could overcome the multidrug resistance issue. The utilisation of metallo-drugs has served as a productive anticancer chemotherapeutic method, and this approach may be implemented for combating multi-resistant tumours more successfully. Schiff bases have been receiving a lot of attention as a group of compounds due to their adaptable metal chelating abilities, innate biologic properties, and versatility to tweak the structure to optimise it for a specific biological purpose. The biological relevance of Schiff base and related complexes, notably their anticancer effects, has increased in their popularity as bio-inorganic chemistry has progressed. As a result of learning about Schiff bases antitumor efficacy against multiple cancer cell lines and their complexes, researchers are motivated to develop novel, side-effect-free anticancer treatments. According to study reports from the past ten years, we are still seeking a powerful anticancer contender. This study highlights the potential of Schiff bases, a broad class of chemical molecules, as potent anticancer agents. In combination with other anticancer strategies, they enhance the efficacy of treatment by elevating the cytotoxicity of chemotherapy, surmounting drug resistance, and promoting targeted therapy. Schiff bases also cause cancer cell DNA repair, improve immunotherapy, prevent angiogenesis, cause apoptosis, and lessen the side effects of chemotherapy. The present review explores the development of potential Schiff base and their d and f block metal complexes as anticancer agents against various cancer cell lines.

Design of N-heterocycle based-phthalonitrile/metal phthalocyanine-silver nanoconjugates for cancer therapies

This study reports the anticancer properties of carbazole-containing phthalonitrile/phthalocyanine-modified silver nanoparticles for the first time. In this study, a new mono-substituted phthalonitrile namely 3-[9H-carbazole-9-ethoxy]phthalonitrile and its metal phthalocyanines {M = Zn, Co, and Mn(Cl)} were synthesized by template cyclotetramerization of phthalonitrile derivatives. The newly synthesized compounds were characterized using UV-vis, FT-IR, 1H NMR, 13C NMR, and mass spectroscopy. The resultant compounds were successfully linked to the surface of silver nanoparticles. The characterization of the surficial modification was carried out by applying the TEM technique. The cytotoxic activities of the studied nanoconjugates were tested against A549, DLD-1, and Wi38 cell lines by performing a (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay with/without irradiation. Although the functionalization of silver nanoparticles increased the solubility of phthalocyanines in aqueous media, the presence of phthalonitrile/phthalocyanine derivatives on the silver nanoparticles' surface improved their biological properties. All the studied biological candidates exhibited antiproliferative activities against the cell lines. The IC50 values calculated were between 6.80 and 97.99 μM against the studied cell lines in the dark. However, the IC50 values determined were between 3.11 and 88.90 μM with irradiation. The highest IC50 values obtained were 3.11 and 3.52 μM against the DLD-1 cell line for nanoconjugates 1-AgNP and 3-AgNP, respectively. The findings indicated that the compounds may be utilized as anticancer agents after further studies.

Docking Studies, Cytotoxicity Evaluation and Interactions of Binuclear Copper(II) Complexes with S-Isoalkyl Derivatives of Thiosalicylic Acid with Some Relevant Biomolecules

The numerous side effects of platinum based chemotherapy has led to the design of new therapeutics with platinum replaced by another transition metal. Here, we investigated the interactions of previously reported copper(II) complexes containing S-isoalkyl derivatives, the salicylic acid with guanosine-5'-monophosphate and calf thymus DNA (CT-DNA) and their antitumor effects, in a colon carcinoma model. All three copper(II) complexes exhibited an affinity for binding to CT-DNA, but there was no indication of intercalation or the displacement of ethidium bromide. Molecular docking studies revealed a significant affinity of the complexes for binding to the minor groove of B-form DNA, which coincided with DNA elongation, and a higher affinity for binding to Z-form DNA, supporting the hypothesis that the complex binding to CT-DNA induces a local transition from B-form to Z-form DNA. These complexes show a moderate, but selective cytotoxic effect toward colon cancer cells in vitro. Binuclear complex of copper(II) with S-isoamyl derivative of thiosalicylic acid showed the highest cytotoxic effect, arrested tumor cells in the G2/M phase of the cell cycle, and significantly reduced the expression of inflammatory molecules pro-IL-1β, TNF-α, ICAM-1, and VCAM-1 in the tissue of primary heterotopic murine colon cancer, which was accompanied by a significantly reduced tumor growth and metastases in the lung and liver.

Synthesis and biological evaluation of salophen nickel(II) and cobalt(III) complexes as potential anticancer compounds

Recent in vitro investigations of N,N'-bis(salicylidene)-1,2-phenylenediamine (SAP) iron(III) complexes substituted with alkyl (ethyl, propyl, butyl) carboxylates at position 4 in tumor and leukemia cells revealed strong cytotoxic activity. In continuation of this study, analogous nickel(II) and cobalt(III) complexes were synthesized and tested in HL-60 leukemia, and cisplatin-sensitive and -resistant A2780 ovarian cancer cell lines. The biological activity depended on the extent of cellular uptake and the formation of reactive oxygen species (ROS). Inactive [(Ni(II)SAP] complexes (1-3) only marginally accumulated in tumor cells and did not induce ROS. The cellular uptake of [Co(III)SAP]Cl complexes (4-6) into the cells depended on the length of the ester alkyl chain (ethyl, 4 < propyl, 5 < butyl, 6). The cytotoxicity correlated with the presence of ROS. The low cytotoxic complex 4 induced only few ROS, while 5 and 6 caused a good to outstanding antiproliferative activity, exerted high ROS generation, and induced cell death after 48 h. Necrostatin-1 prevented the biological effects, proving necroptosis as part of the mode of action. Interestingly, the effects of 5 and 6 were not reversed by Ferrostatin-1, but even enhanced upon simultaneous application to the tumor cells.