Three Pt-Pt Complexes with Donor-acceptor Feature: Anticancer Activity, DNA Binding Studies and Molecular Docking Simulation

Cytotoxic activity and influence on acetylcholinesterase of series dinuclear platinum(II) complexes with aromatic nitrogen-containing heterocyclic bridging ligands: Insights in the mechanisms of action

Herein, the stability, lipophilicity, in vitro cytotoxicity, and influence on acetylcholinesterase of five dinuclear platinum(II) complexes with the general formula [{Pt(en)Cl}₂(μ-L)]²⁺ (L is a different aromatic nitrogen-containing heterocyclic bridging ligands pyrazine (pz, Pt1), pyridazine (pydz, Pt2), quinoxaline (qx, Pt3), phthalazine (phtz, Pt4) and quinazoline (qz, Pt5), while en is bidentate coordinated ethylenediamine) were evaluated. The most active analyzed platinum complexes induced time-dependent growth inhibition of A375, HeLa, PANC-1, and MRC-5 cells. The best efficiency was achieved on HeLa and PANC-1 cells for Pt1, Pt2, and Pt3 at the highest concentration, while Pt1 was significantly more potent than cisplatin at a lower concentration. Additionally, a lower effect on normal cells was observed compared to cisplatin, which may indicate potentially fewer side effects of these complexes. Selected complexes induce reactive oxygen species and apoptosis on tumor cell lines. The most potent reversible acetylcholinesterase (AChE) inhibitors were Pt2, Pt4, and Pt5. Pt1 showed similar inhibitory potential toward AChE as cisplatin, but a different type of inhibition, which could contribute to lower neurotoxicity. Docking studies revealed that Pt2 and Pt4 were bound to the active gorge above the catalytic triad. In contrast, the other complexes were bound to the edge of the active gorge without impeding the approach to the catalytic triad. According to this, Pt1 represents a promising compound with potent anticancer properties, high selectivity, and low neurotoxicity.

Antimicrobial activity of mono- and polynuclear platinum and palladium complexes

Introduction. Infectious diseases remain a serious threat to humanity worldwide as bacterial pathogens grow more diverse. Bacteria, fungi, and parasites develop resistance to clinically approved antimicrobials, which reduces the efficacy of available drugs and treatment measures. As a result, there is an ever growing demand for new highly effective pharmaceuticals. This review describes mono- and polynuclear platinum and palladium complexes with antimicrobial properties. We compared several groups of antibacterial agents: antibiotics, antioxidant biologically active substances, antimicrobial nanoparticles, nanocomposite materials, biopolymers, micellar systems, and plant extracts. Study objects and methods. The review covered relevant articles published in Web of Science, Scopus, and Russian Science Citation Index for the last decade. The list of descriptors included such terms as mononuclear and binuclear complexes of platinum, palladium, and antimicrobial activity. Results and discussion. Chelates of platinum, palladium, silver, iridium, rhodium, ruthenium, cobalt, and nickel are popular therapeutic agents. Their antimicrobial activity against pathogenic microorganisms can be enhanced by increasing their bioavailability. Metalbased drugs facilitate the transport of organic ligands towards the bacterial cell. The nature of the ligand and its coordination change the thermodynamic stability, kinetic lability, and lipophilic properties of the complex, as well as the reactivity of the central atom. Polynuclear platinum and palladium complexes contain two or more bound metal (coordinate) centers. Covalent bonding with bacterial DNA enables them to form a type of DNA adducts, which is completely different from that of mononuclear complexes. Conclusion. Metal-based drugs with functional monodentate ligands exhibit a greater antimicrobial effect compared to free ligands. Poly- and heteronuclear complexes can increase the number of active centers that block the action of bacterial cells. When combined with other antibacterial agents, they provide a synergistic effect, which makes them a promising subject of further research.