Adsorção do complexo H[Ru(III)Cl2(H2EDTA)] sobre a superfície da sílica gel modificada com [3-(2-aminoetil) aminopropil]trimetoxissilano em soluções etanólicas Adsorption of H[Ru(III)Cl2(H2EDTA)] complex on modified silica gel surface with [3-(2-aminoethyl)aminopropyl]trimethoxysilane in ethanol solutions

<abstract language="eng">Silica gel was functionalized with [3-(2-aminoethyl)aminopropyl&#093;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 (Gñ), 2,07 x 10(4) L/mol and the average number of ligand bonded by one metal ion on the support (ñ) was ~ 1

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 IC(50) concentrations of 3.8 and 9.5 µM, respectively, with 72 h of incubation. Intracellular amastigotes were inhibited by the compound, with an IC(50) 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

Effect of BenzCo on the interaction between <i>Leishmania amazonensis</i> and mouse peritoneal macrophages.

<p>The survival percentage was calculated by multiplying the percentage of infected macrophages by the mean number of internalized parasites per infected macrophage. The data are expressed as the means from three independent experiments. *<i>p</i><0.05, compared with the control group.</p

Flow cytometry analysis of <i>L. amazonensis</i> treated with BenzCo and stained with propidium iodide (PI).

<p>(A) Untreated promastigotes. (B) Promastigotes treated with 5.0 µM amphotericin B. (C and D) Promastigotes treated with 66.0 and 131.0 µM BenzCo, respectively. (E) Untreated axenic amastigotes. (F) Axenic amastigotes treated with 10.0 µM amphotericin B. (G and H) Axenic amastigotes treated with 66.0 and 131.0 µM BenzCo, respectively. The bold numbers show the percentage of PI-positive cells in the upper left quadrant.</p

Effect of BenzCo on lipid peroxidation in the (A) promastigote and (B) axenic amastigote forms.

<p>Each bar represents the mean ± standard error of at least three independent experiments. *<i>p</i><0.05, significant difference of each group from control.</p

Ultrastructural effect of BenzCo on promastigote forms of <i>Leishmania amazonensis</i> after treatment with 3.8 and 7.8 µM of BenzCo for 72 h at 25°C, observed by transmission electron microscopy.

<p>(A) Control. (B–E) Parasites treated with 3.8 µM. (E–H) Parasites treated with 7.8 µM. Arrows indicate swollen mitochondria, and the asterisk indicates autophagic vacuoles. f, flagellum; fp, flagellar pocket; k, kinetoplast; m, mitochondrion; n, nucleus. Bars = 1 µm.</p

Flow cytometry analysis of Rhodamine 123-labeled (A–C) promastigotes and (D–F) axenic amastigotes of <i>L. amazonensis.</i>

<p>(A) Untreated promastigotes. (B) Promastigotes treated with 50.0 µM CCCP. (C) Promastigotes treated with 66.0 µM BenzCo. (D) Untreated axenic amastigotes. (E) Axenic amastigotes treated with 200.0 µM CCCP. (F) Axenic amastigotes treated with 197.0 µM BenzCo. The numbers in bold represent the percentage of collapsed ΔΨm cells in the upper right quadrant.</p