Luís Flávio Souza de Oliveira

Imidazolium Salts as Antifungal Agents: Activity Against Emerging Yeast Pathogens, Without Human Leukocyte Toxicity

This study demonstrates the excellent in vitro antifungal activity profile of imidazolium ionic liquids (ILs) against species of opportunistic human mycoses. Several ILs were identified as more effective and less harmful than commercially available antifungal medications. Frequently, emerging yeast pathogens are resistant against commercial antifungal agents and, as a consequence, this class of imidazolium ILs represents a promising breakthrough in their treatment.

Avaliação in vivo do efeito hipocolesterolêmico e toxicológico preliminar do extrato bruto hidroalcoólico e decocção da Vitex megapotamica (Spreng) Moldenke (V. montevidensis Cham.)

The cardiovascular diseases are, in general, associated with high levels of serum lipids which have high incidence in middle-age men and women. Among other properties characterized by popular medicine, the Vitex megapotamica (Spreng) Moldenke (V. montevidensis Cham) - Taruma, decreases the serum cholesterol and triacylglycerol levels. The main proposition of the present study was to evaluate the hypocholesterolemic and hipolipidaemic potential of V. megapotamica and to analyze the preliminary toxicity. It was an induction hyperlipidaemic model using propiltiuracil 1.25 mg/kg weight and cholesterol 200 mg/ kg weight per oros in male rats, weigthing 300 ± 10 g. It was administred to the animals 300 mg/ kg of hydroalcoholic leaves extract of V. megapotamica or 300 mL of hull decoction per oros. After the end of each treatment, the lipid profile was essayed as well as glucose, when relevant. Our results confirmed the V. megapotamica extract and decoction hypolipidaemic effect by the decrease of cholesterol and triacylglycerides serum levels in concentration, via and preparation performed. Furthermore, the toxicological preliminary assays showed there was not extract and decoction damage induction in cardiac and hepatic tissues, as well as in kidney physiology by assays performed.

Synthesis and Biological Evaluation of Hydrazone Derivatives as Antifungal Agents

Emerging yeasts are among the most prevalent causes of systemic infections with high mortality rates and there is an urgent need to develop specific, effective and non-toxic antifungal agents to respond to this issue. In this study 35 aldehydes, hydrazones and hydrazines were obtained and their antifungal activity was evaluated against Candida species (C. parapsilosis, C. tropicalis, C. krusei, C. albicans, C. glabrata and C. lusitaneae) and Trichosporon asahii, in an in vitro screening. The minimum inhibitory concentrations (MICs) of the active compounds in the screening was determined against 10 clinical isolates of C. parapsilosis and 10 of T. asahii. The compounds 4-pyridin-2-ylbenzaldehyde] (13a) and tert-butyl-(2Z)-2-(3,4,5-trihydroxybenzylidine)hydrazine carboxylate (7b) showed the most promising MIC values in the range of 16–32 μg/mL and 8–16 μg/mL, respectively. The compounds’ action on the stability of the cell membrane and cell wall was evaluated, which suggested the action of the compounds on the fungal cell membrane. Cell viability of leukocytes and an alkaline comet assay were performed to evaluate the cytotoxicity. Compound 13a was not cytotoxic at the active concentrations. These results support the discovery of promising candidates for the development of new antifungal agents.

Genotoxicity and cytotoxicity of oxindole alkaloids from Uncaria tomentosa (cat's claw): Chemotype relevance.

ETHNOPHARMACOLOGICAL RELEVANCE Uncaria tomentosa (Willdenow ex Roemer & Schultes) DC. (Rubiaceae) or cats claw is a climber vine from the South American rainforest used in folk medicine for cancer treatment. Its antitumor activity has been mostly ascribed to pentacyclic oxindole alkaloids (POA) from stem bark and leaves while the activity of tetracyclic oxindole alkaloids (TOA) remains unknown. In recent times, the occurrence of three chemotypes based on its oxindole alkaloid profile was noticed in U. tomentosa, namely, chemotype I (POA cis D/E ring junction); chemotype II (POA trans D/E ring junction) or chemotype III (TOA). Consequently, the relationship between the chemotype and cytotoxic and genotoxic activities deserves attention. AIM OF THE STUDY To evaluate the influence of cats claw chemotypes on genotoxicity and cytotoxicity against non malignant and malignant human cell line models. MATERIAL AND METHODS Four authentic stem bark cats claw samples (SI-SIV) and two leaf samples (LII and LIII) were analyzed by HPLC-PDA, properly extracted and fractioned by ion-exchange to obtain oxindole alkaloid purified fractions (OAPFs). The freeze-dried fractions were assayed for genotoxicity and cytotoxicity against human leukocytes (non malignant cell line) by the micronuclei frequency method and the alkaline comet DNA assay, and the trypan blue method, respectively. Moreover, the cytotoxicity of each OAPF was evaluated against a human bladder cancer cell line (T24) and human glioblastoma cell line (U-251-MG) by MTT method (malignant cell lines). Additionally, the isomerization of oxindole alkaloids throughout the course of cell incubation was monitored by HPLC-PDA. RESULTS Based on HPLC-PDA analyses, sample SI was characterized as chemotype I, while samples SII and LII were characterized as chemotype II, and samples SIII, SIV and LIII as chemotype III. The chemotypes showed comparable cytotoxic activity toward malignant cell lines (T24 and U-251-MG) unlike human leukocytes (non malignant cell line), where this activity was clearly distinct. Chemotype II (POA trans D/E ring junction) showed a higher selectivity index (SI) against malignant cells (SI=1.11-3.04) than chemotype I (SI=0.10-0.19) and III (SI=0.21-0.57). No important genotoxic potential was found by micronuclei frequency and alkaline comet DNA assays. Despite the isomerization of oxindole alkaloids during the cell incubation, the chemotype of the cats claw samples remained unchanged. CONCLUSION Cats claw chemotypes showed different selectivity against human malignant cells, so that the correct identification of each chemotype seems to be important to better understand its antitumor potential.

Evaluation of genotoxic and cytotoxic effects of hydroalcoholic extract of Euphorbia tirucalli (Euphorbiaceae) in cell cultures of human leukocytes

Euphorbia tirucalli (L.), commonly known as aveloz, has been indiscriminately used in popular medicine to treat various illnesses. However, some components can have devastating consequences. Injury to a cells genetic material can cause mutations, cancer, and cell death. Our main goal in this work was to evaluate the genotoxic and cytotoxic effects of E. tirucalli extract on human leukocytes. For this purpose, we performed a phytochemical analysis to evaluate the plants components. In the second step, we treated cultured human leukocytes with different concentrations of the dry extract of the plant and then evaluated the oxidative and genotoxic profiles of these leukocytes. We found that at 1% and 10% concentrations, the aveloz extract acted as a genotoxic agent that could damage DNA and increase oxidative damage. We conclude that despite its popular use, aveloz can act as a genotoxic agent, especially when it contains phorbol ester. Avelozs indiscriminate use might actually promote tumors and therefore carry a considerable genetic risk for its users.

Antifungal activity against Cryptococcus neoformans strains and genotoxicity assessment in human leukocyte cells of Euphorbia tirucalli L.

In the last times, focus on plant research has increased all over the world. Euphorbia tirucalli L., a plant known popularly as Aveloz, and originally used in Africa, has been drawing attention for its use in the United States and Latin America, both for use as an ornamental plant and as a medicinal plant. E. tirucalli L. is a member of the family Euphorbiaceae and contains many diterpenoids and triterpenoids, in particular phorbol esters, apparently the main constituent of this plant, which are assumed to be responsible for their activities in vivo and in vitro. The in vitro antifungal activities of Euphorbia tirucalli (L.) against opportunistic yeasts were studied using microbroth dilution assay. The results showed that aqueous extract and latex preparation were effective against ten clinical strains of Cryptococcus neoformans in vitro (Latex and extract MIC range of 3.2 – > 411 μg/mL). Aiming the safe use in humans, the genotoxic effects of E. tirucalli were evaluated in human leukocytes cells. Our data show that both aqueous extract and latex preparation have no genotoxic effect in human leukocytes cells in vitro. Although the results cannot be extrapolated by itself for use in vivo, they suggest a good perspective for a therapeutic application in future. In conclusion, our results show that the aqueous extract and latex preparation from E. tirucalli L. are antifungal agents effectives against several strains of C. neoformans and do not provoke DNA damage in human leukocyte cells, considering the concentrations tested.

DETERMINACIÓN DE OCRATOXINA-A POR HPLC CON DETECCIÓN POR FLUORESCENCIA (HPLC-FL): UN NUEVO MÉTODO ESTANDARIZADO PARA MUESTRAS DE TRIGO

RESUMEN El objetivo principal de este estudio fue evaluar la presencia de Ocratoxina-A (OTA) en los granos del trigo y harina del trigo realizadas por un nuevo metodo de determinacion que usa la cromatografia liquida de alta resolucion (CLAR) acoplada al descubridor del fluorimetrio. El experimento uso seis muestras de grano de trigo del lugar del almacenamiento diferente a la industria local de Chapeco (SC), Brasil Sur, en agosto, 2008. El extracto de OTA era llevado a cabo usando el acetonitrila:agua (120:80 v/v) como solventes. Despues el suprenadante fue filtrado, y aplicado en la columna del inmunoafinidad especifica a OTA. Ademas, la columna se lavo con agua y la toxina era el eluido con el metanol. La determinacion del OTA se realizo por deteccion de fluorescencia acoplado al aparato de HPLC. Los volumenes de OTA en los granos del trigo y harina del trigo eran entonces los determinate y los resultados mostraron una concentracion de OTA menor que los limites exigidos por la legislacion internacional.Palabras clave: Ocratoxina-A, CLAR, metodos del fluorescencia, trigo.Este trabajo fue recibido el 4 de Mayo de 2009 y aceptado para ser publicado el 1 de Abril de 2010.The ochratoxins form a group of seven (7) secondary metabolites produced by some fungi belong to Aspergil-lus and Penicillium gender (8). However, the ochratoxin A (OTA) is the most natural abundant form in foods (7). Chemically they are composed by non-enzymatic bond between a s-fenilalanin and some isocumarine spe-cies by amide bond (5). It is happened under propitious conditions like water activity and temperatures above 30oC (9). The presence of OTA has been found in dif-ferent components of the diet, such as corn, barley, bean, peanut, coffee, soy, wheat, saracen, rye, rice, sorghum, and Para chestnut (5). The OTA effects on humans tissue has been reported like capable of causing nephrotoxic, nephrocarcinogenic and hepatotoxic events (5). However, the main toxic ef-

Is tartrazine really safe? In silico and ex vivo toxicological studies in human leukocytes: a question of dose

The use of food colorings has a long-recorded history. Tartrazine (TRZ) is a dye that confers a lemon-yellow color to food and is widely used in the manufacture of numerous food products, as well as in pharmaceuticals and cosmetics. However, few studies have addressed the toxicology of TRZ in human cells or tissues. Considering the frequent consumption of the TRZ dye in food products and the lack of toxicological data, the present study aimed to evaluate the cytotoxicity and genotoxicity of the TRZ dye in human leukocyte cultures and perform theoretical studies to predict its toxicity in silico. Leukocyte cultures were treated with TRZ at concentrations of 5, 17.5, 35, 70, 100, 200, 300, 400, and 500 μg mL-1. All groups were assayed in triplicates. The mutagenicity was evaluated using the micronucleus test, the nuclear division index, and the nuclear division cytotoxicity index, and the chromosomal instability was quantitatively evaluated by band cytogenetics. Genotoxicity was evaluated using the alkaline comet test. Viability was assessed using the Trypan Blue method. Statistical analyses were performed using analysis of variance followed by Tukeys post hoc test, with a p value <0.05 reflecting statistical significance. No mutagenicity or cytotoxicity was found for the dye at the concentrations evaluated. However, DNA damage was induced by TRZ at a concentration of 70 μg mL-1. These results were confirmed by the predictive data from the in silico evaluations. Further studies are required to confirm our data, considering the frequency of the use of TRZ in the diet of the population, including that of children, as well as the exposure to TRZ through drugs, cosmetics, and other non-food products.

Antifungal mechanism of action of Schinus lentiscifolius Marchand essential oil and its synergistic effect in vitro with terbinafine and ciclopirox against dermatophytes

The aim of this study was to evaluate the antifungal, antichemotactic and antioxidant activities of Schinus lentiscifolius essential oil, as well as its combined effect with terbinafine and ciclopirox, against dermatophytes.

Stability Study of Finasteride: Stability-Indicating LC Method, In Silico and LC–ESI-MS Analysis of Major Degradation Product, and an In Vitro Biological Safety Study

Stability studies of the pharmaceutically important compound finasteride were conducted in order to evaluate decomposition of the drug under forced degradation conditions. A simple stability-indicating liquid chromatography method was developed and validated for the evaluation of finasteride and degradation products formed in pharmaceutical preparations and the raw material. Isocratic LC separation was achieved on a C18 column using a mobile phase of o-phosphoric acid (0.1% v/v), adjusted to pH 2.8 with triethylamine (10% v/v) and acetonitrile (52:48 v/v), with a flow rate of 1.0 mL min-1. The alkaline degradation kinetics of the drug were also evaluated and could be best described as second-order kinetics under the experimental conditions applied for the tablets and raw material. Based on in silico studies and molecular weight confirmation, a comprehensive degradation pathway for the drug and the identity of its major product could be suggested without complicated isolation or purification processes. Furthermore, a biological safety study was performed to evaluate the effect of the degraded sample in relation to the intact molecule. The results showed that the degraded sample affected the cell proliferation. Therefore, these studies show that special care must be taken during the manipulation, manufacture and storage of this pharmaceutical drug.