Silver(I) complexes containing N-heterocyclic carbene azole drugs: Synthesis, characterization, cytotoxic activity, and their BSA interactions.

Cancer is one of the main public health problems globally, there is a public demand for better drugs. Rational strategies or approaches are used to improve the success of drug discovery. Our strategy was to the repurposing of well-known antifungal agents as potential anticancer drugs, such as Clotrimazole (CTZ) and Ketoconazole (KTZ). We prepared the respective iodide imidazolium salt L1: (CTZ-Me)I and L2: (KTZ-Me)I to be the intermediates toward the synthesis of its respective NHC ligand and achieve the respective silver(I)-monoNHC and silver(I)-bisNHC derivatives: [Ag(L1)I] (1), [AgI(L2)] (2) [Ag(L1)2]I. (3), [Ag(L2)2]I. (4), as well as their corresponding coordination compounds [Ag(CTZ)2]NO3 (5) and [Ag(KTZ)2]NO3 (6) where these ligands (CTZ and KTZ) coordinate to silver through the N-imidazole atom. These compounds (L1, L2 and complexes 1-6) exhibited significant activity against the tested cancer cell lines (B16-F1, murine melanoma strains and CT26WT, murine colon carcinoma). The silver(I) complexes were more active than the free ligands, complexes 2 and 4 being the most selective in B16-F1 cancer cell line. Two possibles biological targets such as DNA and albumin were examined for the observed anticancer activity. Results show that DNA is not the main target, however, the interactions with albumin suggest it can transport/delivery the metal complexes.

Mono and dinuclear platinum and palladium complexes containing adamantane-azole ligands: DNA and BSA interaction and cytotoxicity.

Synthesis of dinuclear oxadiazole-adamantane platinum(II) and palladium(II) complexes (PtO, PdO) and mononuclear thiazolidine derivative complexes (PtT, PdT) was described. Characterization was performed by elemental analysis, infrared, UV-visible, 1H, 13C, 195Pt NMR spectra, MS spectroscopy and single crystal X-ray diffraction. The cytotoxicity by MTT assay against tumor and normal cell lines with or without extracellular GSH was also investigated. In general, mononuclear complexes containing thiazolidine-adamantane ligands were more cytotoxic than oxadiazole-adamantane derivatives. PtT complex proved to be as active as cisplatin. Dinuclear compounds were considered inactive to cells in evaluated conditions, due to their high stability with ligands in a chelated and bridged way. Results suggest that GSH cannot be considered a target. DNA- and BSA-binding interactions were evaluated using UV-visible and fluorescence spectroscopy, intercalating dyes and molecular docking. Upon coordination to platinum(II), the cytotoxic effect was appreciably improved against tested cell lines, in comparison to free thiazolidine ligand. Comparing thiazolidine derivatives, it is noticeable that the less active compound (PdT) presents stronger interaction with BSA, while PtT has the weaker interaction with BSA and relatively strong binding to isolated DNA, resulting in the most cytotoxic complex. This work shows that the presence of metal is significant but it should be available for interaction. The high lability of palladium complex made this stay retainable in BSA and two metal atoms do not increase activity if it is not able to do any interaction.