Rosana L. Sernaglia

Benzaldehyde Thiosemicarbazone Derived from Limonene Complexed with Copper Induced Mitochondrial Dysfunction in Leishmania amazonensis

Background Leishmaniasis is a major health problem that affects more than 12 million people. Treatment presents several problems, including high toxicity and many adverse effects, leading to the discontinuation of treatment and emergence of resistant strains. Methodology/Principal Findings We evaluated the in vitro antileishmanial activity of benzaldehyde thiosemicarbazone derived from limonene complexed with copper, termed BenzCo, against Leishmania amazonensis. BenzCo inhibited the growth of the promastigote and axenic amastigote forms, with IC50 concentrations of 3.8 and 9.5 µM, respectively, with 72 h of incubation. Intracellular amastigotes were inhibited by the compound, with an IC50 of 10.7 µM. BenzCo altered the shape, size, and ultrastructure of the parasites. Mitochondrial membrane depolarization was observed in protozoa treated with BenzCo but caused no alterations in the plasma membrane. Additionally, BenzCo induced lipoperoxidation and the production of mitochondrial superoxide anion radicals in promastigotes and axenic amastigotes of Leishmania amazonensis. Conclusion/Significance Our studies indicated that the antileishmania activity of BenzCo might be associated with mitochondrial dysfunction and oxidative damage, leading to parasite death.

Oxidative dimerization of Ru(III)-EDTA complex on the surface of functionalized silica gel

The present paper deals with the reaction of oxidative dimerization of the H[Ru(III)Cl2(H2EDTA)].4.5 H2O complex on the surface of silica gel functionalized (SF) with [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEATS), generating the dimeric (EDTA)2Ru2(IV,IV) complex immobilized on the surface of this silica through the coordination with amide bonds. The oxidation of water by the anchored dimeric complex proceeded rapidly and was observed by the evolution of O2 and the decrease in pH, yielding the SF-AEATS/(EDTA)2Ru2(III1/2 ,III1/2). This anchored dimer was characterized by electronic, vibrational and EPR spectroscopies. The electrochemical behavior of a modified carbon paste electrode prepared with SF-AEATS/(EDTA)2Ru2(III1/2 ,III1/2) was also studied.

Adsorção do complexo H[Ru(III)Cl2(H2EDTA)] sobre a superfície da sílica gel modificada com [3-(2-aminoetil) aminopropil]trimetoxissilano em soluções etanólicas

Silica gel was functionalized with [3-(2-aminoethyl)aminopropyl]trimethoxysilane group (SF-AEATS) and the characterization by chemical analysis (N) and infrared spectroscopy confirmed the functionalization. The capacity of the modified silica to adsorb the complex Ru(III)-EDTA from ethanolic solution was studied. The selectivity coefficients of the complex formed on the support obtained was (Gn), 2,07 x 104 L/mol and the average number of ligand bonded by one metal ion on the support (n) was ~ 1.

Adsorption of a copper (II) complex on calcium phosphate intercalated with 4-aminobenzoic acid: synthesis and electrochemical investigation

In this study, the adsorption isotherm of copper (II) on a calcium phosphate host intercalated with 4-aminobenzoic acid in an ethanol solution was investigated. This gave a maximum adsorption capacity of 1.74 mmol g-1. The material was incorporated into a carbon-paste electrode, and its electrochemical properties were investigated. However, for a dopamine solution, the anodic peak current increased owing to the electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, showing good repeatability. The modified electrode is very stable and reproducible. The electrode sensor was successfully applied for dopamine determination in pharmaceutical preparations.