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Miroslava Puchoňová, Jozef Švorec and Dušan Valigura

Abstract

A systematic study of the preparation of methylsalicylatocopper(II) complexes with or without N-donor ligand has resulted in three new dimeric complexes formation. The investigation has been targeted to two main aspects: the conditions of dimeric complexes preparation and the properties of obtained products. The common stoichiometric formula for all three complexes is Cu(x-MeSal)2(H2O)(ACN)z (where x-MeSal = 3- or 4-methylsalicylate anion, ACN = acetonitrile and z = 0, 1). Used spectral measurements mainly EPR spectroscopy gave the proof about the existence of dimeric “paddle-wheel” units in all three complexes. Moreover, it was concluded that acetonitrile molecules are more probably bonded to copper(II) atoms in apical positions of dimeric units. The water molecules are in coordination sphere only in the case when acetonitrile is not present. However data show that presence of 4-methylsalicylate anions led to strengthening of Cu-N bonds.

Open access

Barbora Kaliňáková, Daniela Hudecová, Peter Segľa, Martina Palicová and Jozef Švorec

Abstract

Probable mode of action of new copper complexes of 2-methylthionicotinate (2-MeSNic) of composition [Cu(2-MeSNic)2(H2O)2] and [Cu(2-MeSNic)2(MeNia)2(H2O)2]·H2O (where MeNia is N-methylnicotinamide) is described. Both partial growth inhibition of Candida albicans (IC50 ≥ 1.78 mmol·L−1, MIC ≥ 2.5 mmol·L−1) and leak of proteins into the extracellular space (more than 80 %) were observed in the presence of these copper complexes. The membrane damage was detected by staining with Hoechst 33342, propidium iodide and methylene blue. Ascorbic acid potentiated antifungal activity of copper complexes approximately seven-fold and induced the oxidative stress, respectively. The production of intracellular reactive oxygen species was visualized by dichlorofluorescein. Thiobarbituric acid-reactive substances were formed as a by-product of lipid peroxidation.