Antioxidant potential of yerba mate (Ilex paraguariensis St. Hil.) extracts in Saccharomyces cerevisae deficient in oxidant defense genes / Potencial antioxidante de extratos de erva-mate (Ilex paraguariensis St. Hil.) em Saccharomyces cerevisiae deficientes para genes de defesa oxidante

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 (ctt1 e ctt1sod1). 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 sod1ctt1). The TM extract was more effective than OX. I. paraguariensis extracts showed a potential to be explored in the development of new products.(AU)

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 (ctt1 e ctt1sod1). 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 sod1ctt1). O extrato TM foi mais eficaz em relação ao OX. Extratos de I. paraguariensis apresentaram potencial para ser explorado no desenvolvimento de novas formulações.(AU)

[Natural ocurrence of entomopathogenic fungi in soils cultivated with Paraguay tea (Ilex paraguariensis St. Hil.) in Misiones, Argentina]. / Ocurrencia natural de hongos entomopatógenos en suelos cultivados con yerba mate (Ilex paraguariensis St. Hil.) en Misiones, Argentina.

This study aimed to morphologically isolate, identify and characterize entomopathogenic fungi present in soils cultivated with Paraguay tea (Ilex paraguariensis). A survey of native entomopathogenic fungi was conducted from 40 soil samples grown with Paraguay tea in the province of Misiones, Argentina, from May 2008 to June 2010. The soil dilution plate methodology on selective culture media was used to isolate microorganisms. Taxonomic identification was performed using macroscopic and microscopic characters and specific keys. Twenty nine strains, belonging to the species Beauveria bassiana (n = 17), Metarhizium anisopliae (n = 2) and Purpureocillium lilacinum (n = 10) were isolated and identified.