Este trabalho objetivou maximizar a extração de fenólicos e flavonoides totais bem como a atividade antioxidante de erva-mate tostada (Ilex paraguariensis) frente ao radical livre 1,1-difenil-2-picrilhidrazila (DPPH) em função do tempo (5, 7,5 e 10 min) e a temperatura de extração (60, 75 e 90°C). Os dados foram submetidos à metodologia de superfície de resposta e os resultados mostraram que as equações polinomiais foram significativas, não apresentaram falta de ajuste e obtiveram coeficientes de determinação ajustados acima de 98%, comprovando a sua adequação para fins preditivos. Usando a função de desejabilidade, as condições ótimas para maximizar a extração de compostos antioxidantes foram de 10 min de extração a 90°C, e o chá preparado sob estas condições experimentais apresentou 427,74 mg de equivalentes de ácido gálico por litro e 80,02% de inibição da o radical DPPH. O teor de flavonoides foi altamente correlacionado (r = 0,9046, p < 0,001) com a atividade antioxidante.

This study focused on maximizing the extraction of total phenolics and flavonoids as well as the antioxidant activity measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay from roasted yerba mate (Ilex paraguariensis) as a function of time (5, 7.5 and 10 min) and temperature of extraction (60, 75 and 90°C). The data were subjected to Response Surface Methodology and the results showed that polynomial equations were significant, did not present lack of fit, and presented adjusted determination coefficients above 98%, proving their suitability for prediction purposes. Using the desirability function, the optimum operating conditions to obtain a higher extraction of antioxidants was found to be 10 min of extraction at 90°C, and the tea prepared under these experimental conditions presented 427.74 mg of gallic acid equivalents per liter and 80.02% of inhibition of the DPPH radical. The flavonoid content was highly correlated (r = 0.9046, p < 0.001) to the antioxidant capacity.

Nos poucos estudos publicados comparando óleos essenciais de espécimes femininos e masculinos de espécies Baccharis, fortes diferenças entre as composições de ambas as amostras foram sempre encontradas. Os experimentos realizados nesta pesquisa utilizam estratégias para minimizar a interferência de fatores genéticos e ecológicos. Os óleos essenciais das folhas de espécimes femininos e masculinos de cinco espécies Baccharis foram pesquisados com uso de um cromatógrafo gasoso acoplado a um espectrômetro de massas e a um detector de ionização de chama (CG-EM-DIC): B. caprariaefolia e B. dracunculifolia, já pesquisadas anteriormente com objetivos similares; e B. coridifolia, B. semiserrata var. elaegnoides e B. pentaptera, as duas últimas ainda não mencionadas na literatura química. Os resultados foram acompanhados por análise hierárquica de grupos, verificando-se a formação de grupos indicativos da grande similaridade entre óleos essenciais dos espécimes masculinos e femininos de todas as cinco espécies. O estudo reafirma o valor das observações de campo na pesquisa de produtos naturais, e aponta fatores genéticos e ecológicos como principais responsáveis por diferenças no metabolismo secundário das plantas estudadas.

In the few studies published on essential oils from female and male specimens of Baccharis species, strong differences between the compositions of both samples were always found. The experiments conducted in this study make use of strategies to minimize the interference from genetic and environmental factors. Essential oils from leaves of female and male specimens of five Baccharis species were investigated by gas chromatography-mass spectrometry plus flame ionization detector (GC-MS-FID): B. caprariaefolia and B. dracunculifolia, which have been previously studied with similar aims; and B. coridifolia, B. semiserrata var. elaegnoides and B. pentaptera, the latter two not yet mentioned in the literature. The results were followed by hierarchical cluster analysis, verifying the formation of groups indicative of the great similarity of essential oils from male and female specimens of all five species. The study reinforces the value of field observation in natural product research and points genetic and ecological factors as main responsible for differences in the secondary metabolites of the studied plants.

The bark of Croton cajucara Benth. is used in Brazilian folk medicine to treat gastrointestinal disorders. Transdehydrocrotonin (DHC) isolated from the bark of Croton cajucara has antiulcerogenic activity25. The presence of similar activity in semi-synthetic crotonin obtained from dehydrocrotonin from Croton cajucara was observed in gastric ulcer-induced models (HCl/ethanol, ethanol, indomethacin, stress and pylorus ligature). The aim of the present study was to assess the mechanisms involved in the antiulcerogenic activity of semi-synthetic crotonin. We investigated the effects of semi-synthetic crotonin on the response to histamine of right atria isolated from guinea pigs and on the response to carbachol of stomach fundus strips from rats. Semi-synthetic crotonin (3, 10 or 30 mM) induced a shift to the right in the concentrationresponse curves to carbachol in the isolated rat stomach at the pD2 level (pD2: 5.42±0.05, 5.76±0.061, 5.77±0.076, 6.48±0.012, respectively), without any alteration in the maximum response. Semi-synthetic crotonin also induced a shift to the right in the concentration-response curves to histamine in guinea pig right atria, pD2 (5.54±0.06, 6.01±0.06, 5.89±0.06, 5.92±0.03) and (%) maximum response (80±6.18, 118±6.18, 114±6.18, 122±1.4), respectively. Thus, the protective effect of semi-synthetic crotonin on induced gastric lesions could be due to antagonism of histaminergic and cholinergic effects on gastric secretion.