The physicochemical properties of metal complexes determine their potential applications as antitumor agents. In this study, the antitumor properties of mononuclear cobalt(II) and copper(II) coordination compounds (stoichiometry: [Co(iaa) 2 (H 2 O) 2 ]·H 2 O (iaa = imidazole-4-acetate anion), [Co(1-allim) 6 ](NO 3 ) 2 (1-allim = 1-allylimidazole), [Cu(iaa) 2 H 2 O] and [Cu(1-allim) 4 (NO 3 ) 2 ]) and their ligands have been evaluated on human lung carcinoma A549 cells and normal bronchial BEAS-2B cells. Designing the chemical structure of new antitumor agents the possible interactions with macromolecules such as DNA or proteins should be take into account. PCR gene tlr4 product served as DNA model, whereas lysozyme and phage-derived endolysin (both peptidoglycan degrading enzymes) were applied as protein/enzyme model. The interactions were analysed using PCR-HRM and circular dichroism, FT-IR, spectrophotometry, respectively. Additionally, the antimicrobial properties of the complexes at a non-cytotoxic concentration were analyzed against S. aureus, E. coli, P. aeruginosa and C. albicans strains. The results obtained in this study showed the selective cytotoxicity of metal complexes, mainly [Cu(1-allim) 4 (NO 3 ) 2 ] towards tumor cells. From all tested compounds, only [Co(iaa) 2 (H 2 O) 2 ] . H 2 O non-covalently interacts with DNA. Cu(II) and Co(II) complexes did not affect the secondary conformation of tested proteins but modified the hydrolytic activity of enzymes (lysozyme and endolysin). Moreover, only [Co(iaa) 2 (H 2 O) 2 ] . H 2 O exhibited the antifungal properties. In conclusion, Co(II) and Cu(II) metal complexes bearing two imidazole-4-acetate ligands seemed to be promising antitumor and antifungal agents for future drug design and application.

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Metal complexes are currently potential therapeutic compounds. The acquisition of resistance by cancer cells or the effective elimination of cancer-affected cells necessitates a constant search for chemical compounds with specific biological activities. One alternative option is the transition metal complexes having potential as antitumor agents. Here, we present the current knowledge about the application of transition metal complexes bearing nickel(II), cobalt(II), copper(II), ruthenium(III), and ruthenium(IV). The cytotoxic properties of the above complexes causing apoptosis, autophagy, DNA damage, and cell cycle inhibition are described in this review.

The constantly growing resistance of bacteria to antibiotics and other antibacterial substances has led us to an era in which alternative antimicrobial therapies are urgently required. One promising approach is to target bacterial pathogens using metal complexes. Therefore, we investigated the possibility of utilizing series of manganese(II) complexes with heteroaromatic ligands: Alcohol, aldehyde, ketone, and carboxylic acid as inhibitors for biofilm formation of Pseudomonas aeruginosa. To complete the series mentioned above, Mn-dipyCO-NO3 with dipyridin-2-ylmethanone (dipyCO) was isolated, and then structurally (single-crystal X-ray analysis) and physicochemically characterized (FT-IR, TG, CV, magnetic susceptibility). The antibacterial activity of the compounds against representative Gram-negative and Gram-positive bacteria was also evaluated. It is worth highlighting that the results of the cytotoxicity assays performed (MTT, DHI HoloMonitorM4) indicate high cell viability of the human fibroblast (VH10) in the presence of the Mn(II) complexes. Additionally, the inhibition effect of catalase activity by the complexes was studied. This paper focused on such aspects as studying different types of intermolecular interactions in the crystals of the Mn(II) complexes as well as their possible effect on anti-biofilm activity, the structure–activity relationship of the Mn(II) complexes, and regularity between the electrochemical properties of the Mn(II) complexes and anti-biofilm activity.

Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2′-PyBIm): [(η6-p-cymene)RuIIClL1]PF6 (Ru(II) complex), mer-[RuIIICl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[RuIIICl4(CH3CN)2]2[RuIVCl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis.