ABSTRACT
Abstract The production of compounds via enzymatic esterification has great scientific and technological interest due to the several inconveniences related to acid catalysis, mainly by these systems do not fit to the concept of “green chemistry”. Besides, natural products as clove oil present compounds with excellent biological potential. Bioactives compounds are often toxic at high doses. The evaluation of lethality in a less complex animal organism can be used to a monitoring simple and rapid, helping the identification of compounds with potential insecticide activity against larvae of insect vector of diseases. In this sense, the toxicity against Artemia salina of clove essential oil and its derivative eugenyl acetate obtained by enzymatic esterification using Novozym 435 as biocatalyst was evaluated. The conversion of eugenyl acetate synthesis was 95.6%. The results about the evaluation of toxicity against the microcrustacean Artemia salina demonstrated that both oil (LC50= 0.5993 µg.mL–1) and ester (LC50= 0.1178 µg.mL–1) presented high toxic potential, being the eugenyl acetate almost 5 times more toxic than clove essential oil. The results reported here shows the potential of employing clove oil and eugenyl acetate in insecticide formulations.
Resumo A produção de compostos via esterificação enzimática possui grande interesse científico e tecnológico devido às inúmeras inconveniências relacionadas com a catálise ácida, principalmente por estes sitemas não se adequarem ao atual termo “tecnologias limpas”. Além disso, produtos naturais como o óleo de cravo, apresentam compostos com excelentes potenciais biológicos. Compostos bioativos são quase sempre tóxicos em altas doses. A avaliação da letalidade em um organismo animal menos complexo pode ser usada para um monitoramento simples e rápido, servindo também para a identificação de compostos com potencial atividade inseticida contra larvas de insetos vetores de doenças. Neste sentido, foi determinada a toxicidade frente a Artemia salina do óleo essencial de cravo e do seu derivado acetato de eugenila obtido por esterificação enzimática com lipase Novozym 435. A conversão da reação de síntese de acetato de eugenila foi de 95,6%. Os resultados referentes à avaliação da toxicidade frente ao microcrustáceo Artemia salina demonstraram que tanto o óleo (LC50= 0,5993 µg.mL–1) quanto o éster (LC50= 0,1178 µg.mL–1) apresentam elevado potencial toxicológico, sendo que o éster apresenta aproximadamente 5 vezes mais toxicidade em relação ao óleo. Estes resultados demonstram o potencial emprego do óleo de cravo e de acetato de eugenila em formulações de inseticidas.
Subject(s)
Animals , Artemia/drug effects , Oils, Volatile/toxicity , Clove Oil/toxicity , Insecticides/toxicity , Eugenol/analogs & derivatives , Eugenol/chemical synthesis , Eugenol/toxicity , Dose-Response Relationship, Drug , Esterification/drug effects , Larva/drug effects , Lipase/toxicityABSTRACT
Abstract Yerba-mate (Ilex paraguariensis St. Hil) is mainly consumed as “chimarrão”, a hot drink highly appreciated in Brazil, Argentina, Paraguay and Uruguay. This study evaluated the antioxidant potential of aqueous extracts of I. paraguariensis precipitated with ethanol. The leaves were processed as for tea product (TM) and oxidized (OX). The antioxidant potential was evaluated in cells of Saccharomyces cerevisiae deficient in antioxidant defense genes. Three strains evaluated were: a wild (EG) and two mutants (ctt1Δ e ctt1Δsod1Δ). These strains were pre-treated with the yerba-mate extracts (TM e OX) and submitted to oxidative stress induced by hydrogen peroxide. None of the extracts produced loss of cell viability. The extracts exerted antioxidant activity, protecting the strains (except sod1∆ctt1∆). The TM extract was more effective than OX. I. paraguariensis extracts showed a potential to be explored in the development of new products.
Resumo A erva-mate (Ilex paraguariensis St. Hil) é consumida principalmente como “chimarrão”, uma bebida quente muito apreciada no Brasil, Argentina, Paraguai e Uruguai. Este estudo avaliou o potencial antioxidante de extratos aquosos de I. paraguariensis precipitado com etanol. Folhas de erva-mate foram processados de maneira semelhante ao processamento do chá-preto (OX) e na forma de mate (TM). O potencial antioxidante foi avaliado sobre células de Saccharomyces cerevisiae deficientes para genes de defesa antioxidante. Três linhagens celulares foram estudadas: uma selvagem (EG) e duas mutantes (ctt1Δ e ctt1Δsod1Δ). As linhagens foram pré-tratadas com os extratos de erva-mate (TM e OX) e submetidos ao estresse oxidativo induzido por peróxido de hidrogênio. Nenhum dos extratos produziu perda de viabilidade celular. Os extratos exerceram atividade antioxidante, protegendo as linhagens (exceto a sod1Δctt1Δ). O extrato TM foi mais eficaz em relação ao OX. Extratos de I. paraguariensis apresentaram potencial para ser explorado no desenvolvimento de novas formulações.
Subject(s)
Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/physiology , Beverages , Plant Extracts/pharmacology , Ilex paraguariensis , Argentina , Brazil , Cell Survival/drug effects , Plant Leaves , Antioxidants/pharmacologyABSTRACT
The mechanism of consumption coagulopathy observed in cases of human envenomation by Bothrops jararaca is well established. However, this mechanism may vary according to the animal species studied. In order to study both the clinical and laboratory aspcts of bothropic envenomation in dogs, a sublethal defibrinating dose of venom (100 µg/kg) was given intravenously. A coagulopathy similar to that observed in humans - including fibronogen depletion, consumption of factors II, X, V and antithrombin III, and moderate thrombocytopenia -was observed. The presence of circulatin activated platelets was also noted. Neutrophilic leukocytosis, lymphopenia, and monocytosis occurred at different times. Erythrocytic values remained normal in dogs treated with B. jararaca venom compared with those treated with saline alone. The erythrocyte sedimentation rate fell rapidly after venom administration and this fall was correlated logarithmically with fibrinogen concentration. Since the effect of envenomation in dogs is similar to that in humans, it was concluded that the dog can be used as a good animal model for studying human venom-induced coagulopathy