Ternary copper(II) complex of 5-hydroxytryptophan and 1,10-phenanthroline with several pharmacological properties and an adequate safety profile.

We report the synthesis and biological evaluation of a ternary copper complex, [Cu(5HTP)(phen)(H2O)](NO3).2H2O, with the antioxidant agent 5-hydroxytryptophan (5-HTP) and phenanthroline (phen, added to improve its lipophilicity and membrane transport). The crystal structure of the complex was determined by X-ray diffraction methods. The complex showed antioxidant, antimicrobial, antitumor and antimetastatic properties with an adequate safety profile. The interaction of the metal with phen promotes cellular copper accumulation and cytotoxicity on human lung A549 cell line (IC50 = 3.6 µM). Furthermore, the viability of the normal human fetal lung fibroblast cell line (MRC-5) is not altered by the complex. An oxidative stress mechanism for the anticancer effect has been determined: cellular increase of reactive oxygen species (ROS), decrease of the glutathione (GSH) and oxidized GSH (GSSG) ratio and alteration of the mitochondrial potential. The complex also displays antimetastatic activities with inhibition of cell adhesion, invasion and migration. It has not mutagenic behavior and no toxicity on Artemia salina indicating its potential to act as an effective and safety antimicrobial and antitumor drug.

Potential bio-protective effect of copper compounds: mimicking SOD and peroxidases enzymes and inhibiting acid phosphatase as a target for anti-osteoporotic chemotherapeutics.

Copper complexes with transformed methimazole ligand have been synthesized and characterized by elemental analysis, conductivity measurements, thermogravimetric analysis, EPR, FTIR and UV-Vis spectroscopies. Results support their stoichiometries and geometrical structures: [Cu(C4H5N2S)2Cl2]·2H2O(1), [Cu(C8H10N4S)SO4H2O](2) and [Cu(C8H10N4S)SO4](3). ((C4H5N2)2S: bis(l-methylimidazol-2-yl)sulfide; (C4H5N2S)2 = Bis[bis(l-methylimidazol-2-yl)disulfide]) Concurrently, the structurally distinct soluble species corresponding to complexes (1) and (2) were subsequently used in an in vitro investigation of their potential biological properties. In view of their possible pharmaceutical activity, the complexes were in vitro evaluated as phosphatase acid inhibitors. Their radical bio-protective effects were also studied measuring the effect against DPPH• and O2•- radicals. Additional catalytic properties as peroxidase mimics were evaluated using Michaelis-Menten kinetic model by means of phenol red and pyrogallol assays. The complexes exhibited catalytic bromination activity and the ability to oxidize pyrogallol substrate indicating that they can be considered as functional models. The relationships between the structures and the in vitro biological activities have also been considered. Serum protein albumin has attracted the greatest interest as drug carrier and the affinity of biological/pharmaceutical compound is relevant to the development of new medicine. In that sense, interaction studies by fluorescence and EPR spectroscopies were performed showing the binding capacity of the complexes.