A novel approach to Cestrum intermedium (mata-boi): anatomical and physical-chemical characterization, in vitro biological activities, and metabolites of a Brazilian native species

Abstract The Brazilian native species Cestrum intermedium, known as mata-boi, induces hepatotoxicity and death when ingested by cattle. While most studies on this species focus on toxicological features, our study is the first to describe the anatomy and in vitro biological activities of Cestrum intermedium. We investigated adult leaves and stems by histochemistry, described their anatomy, performed physical-chemical analysis, determined in vitro antioxidant and antimicrobial activities, and identified secondary metabolites. A few noteworthy anatomical features were the anomocytic stomata on the abaxial surface and the absence of trichomes, in addition to the circular shaped petiole with two projections on the adaxial surface. Histochemical analysis showed chemical markers such as alkaloids, usually reported as toxic, and terpenoids. Potassium nitrate (ATR-FTIR) and lupeol palmitate (NMR) were detected on the crude stem extract. Thermogravimetric and physical-chemical analysis provided fingerprint parameters for the species. Minimal Inhibitory Concentration (MIC) assay revealed that Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans were weakly inhibited by extract samples. Chloroform and ethyl acetate fractions presented high phenolic content, which resulted in in vitro antioxidant activity. These novel features expand the knowledge about this species, considering that previous studies mainly focused on its toxicity. Our study also provided characteristics that may help in avoiding misidentification between Cestrum members, especially when taxonomic keys cannot be employed, as in the absence of flowers and fruits.

Screening of whole yeast free-cells and optimization of pH and temperature for fructooligosaccharides production / Seleção de células inteiras de levedura e otimização dos parâmetros pH e temperatura para a produção de fruto-oligossacarídeos

Fructooligosaccharides are catalyzed by ß­fructofuranosidase enzyme, produced by many microorganisms. However, in order to achieve a more profitable, low time -consuming process with lower cost, researchers have sought alternatives. This study aimed to select and identify yeasts able to produce fructooligosaccharides and evaluate the influence of pH and temperature on their synthesis. Yeast suspensions, solutions of 500 g L-1 sucrose and three values of pH (4.5, 5.5, and 6.5) and temperature (40, 50, and 60ºC) were tested. Yeast species were identified by molecular techniques. Among 141 yeast isolates from grapes, 65 were able to synthesize fructooligosaccharides. The maximum concentration of fructooligosaccharides was 4.8% (w v-1), and Saccharomyces cerevisiae 222 produced 1-kestose and nystose.

Fruto-oligossacarídeos são catalisados pelas enzimas ß­fructofuranosidase, produzida por muitos micro -organismos. No entanto, para obter processos mais rentáveis, de menor custo e tempo, pesquisadores têm procurado alternativas. Este trabalho tem objetivo de selecionar e identificar leveduras capazes de produzir fruto-oligossacarídeos e avaliar a influência do pH e da temperatura na sua síntese. Suspensões de leveduras, soluções de sacarose de 500 g L- 1 e três valores de pH (4,5, 5,5 e 6,5) e de temperaturas de (40, 50 e 60ºC) foram utilizados. As espécies de leveduras foram identificadas por técnicas moleculares. De 141 isolados de leveduras de uvas, 65 foram capazes de sintetizar fruto-oligossacarídeos. A concentração máxima de fruto-oligossacarídeos foi de 4,8% (p v-1), e a levedura Saccharomyces cerevisiae 222 produziu 1-cestose e nistose.

Characterization of autochthonous wine yeasts isolated in vineyards of the State of Paraná, Brazil / Caracterização de leveduras vínicas autóctones isoladas em vinhedos do Estado do Paraná, Brasil

The transformation of grape must into wine is a complex microbiological process and is the product of the combined action of several genera and species of yeasts, dominated in the intermediate and final stages of fermentation by an alcohol-tolerant Saccharomyces sp. Current assay characterizes 42 autochthonous yeasts, isolated from the state of Paraná, southern Brazil, according to the following oenological properties: H2S production, fermentation rate, flocculation capacity, and killer phenotype (killer, sensitive and neutral characteristics). Current analysis is the first to evaluate killer phenotype in yeasts isolated from the State of Paraná, Brazil. With regard to their oenological traits, the yeasts evaluated were not suitable for winemaking and suggested that, depending on the harvest, the winemakers may face problems during the spontaneous wine production process.

A transformação do mosto de uva em vinho é um processo microbiológico complexo, resultado da ação combinada de diferentes gêneros e espécies de leveduras, no qual, entretanto, prevalece uma levedura, Saccharomyces sp. álcool-tolerante nos estágios intermediário e final da fermentação alcoólica. O objetivo deste trabalho foi caracterizar 42 leveduras autóctones isoladas da região sul do Brasil (Estado do Paraná) de acordo com as seguintes características enológicas: produção de H2S, taxa de fermentação, capacidade de floculação e fenótipo killer (características killer, sensível e neutra). Este estudo é o primeiro a avaliar fenótipo killer em leveduras isoladas do estado do Paraná. Com relação às características enológicas, as leveduras avaliadas não se mostraram promissoras para vinificação, sugerindo que, conforme a safra, o vinicultor pode enfrentar problemas durante o processo de fermentação espontânea das uvas para a elaboração de vinho.