RESUMO
Antioxidantes são compostos que atuam inibindo e/ou diminuindo os efeitos desencadeados pelos radicais livres e compostos oxidantes. Os chás são bebidas populares e fontes significativas de compostos fenólicos, sendo considerados importantes integrantes das dietas devido às suas propriedades antioxidantes. O presente trabalho teve como objetivo avaliar a ação antioxidante de uma variedade de chás e condimentos mais consumidos no Brasil. Os chás analisados foram das plantas: Pneumus boldus Mold., Matricaria recutita L., Cymbopogon citratus (DC) Stapf, Baccharis trimera (Less.) DC, Camelia sinensis (L) O. Kuntze (fermentado), Camelia sinensis (não-fermentado), Lippia alba N.E. Brown,Mentha arvensis L., e Pyrus malus L. Os condimentos analisados foram: Eugenia aromatica Baill, Cinnamonum zeylanicum Blume, Laurus nobilis L. e Origanum vulgare L. O método utilizado para avaliar a ação antioxidante foi o da atividade seqüestradora de radicais livres DPPH em solução metanólica. Todas as amostras analisadas demonstraram atividade em suas diferentes concentrações. Camelia sinensis (não-fermentada) foi a mais ativa com CI50= 0,14 mg/mL, cujos principais compostos antioxidantes são epigalocatequinas. Os condimentos mais ativos foram Cinnamonum zeylanicum (CI50 = 0,37 mg/mL), Eugenia aromatica Baill (CI50 = 0,46 mg/mL) e Laurus nobilis (CI50 = 0,76 mg/mL), cujo principal antioxidante relatado foi o eugenol.
Antioxidants are compounds that remove free-radicals or minimize their availability to generate oxidative stress. Teas are popular beverages providing a significant source of phenolic compounds, important components of the human diet due to their antioxidant properties. The present work had the objective of evaluate the antioxidant action of teas and seasonings more consumed in Brazil. The analysed teas were from the plants: Pneumus boldus Mold., Matricaria recutita L., Cymbopogon citratus (DC) Stapf, Baccharis trimera (Less.) DC, Camelia sinensis (L) O. Kuntze (fermented), Camelia sinensis (not-fermented), Lippia alba N.E. Brown, Mentha arvensis L. and Pyrus malus L. The studied seasonings were: Eugenia aromatica Baill, Cinnamonum zeylanicum Blume, Laurus nobilis L. and Origanum vulgare L. The antioxidant activity was measured by the DPPH free radical scavenging method. All analysed samples demonstrated antioxidant activities. Camelia sinensis (not-fermented) (IC50= 0.14 mg/mL), was the most active and active principles are epicalocatechins. The stronger antioxidant seasonings were Cinnamonum zeylanicum (IC50 = 0.37 mg/mL), Eugenia aromatica Baill (IC50= 0.46 mg/ mL and Laurus nobilis (IC50 = 0.76 mg/mL), which presented as main antioxidant component eugenol.
RESUMO
Aedes aegypti is the major vector of dengue fever, an endemic disease in Brazil. In an effort to find effective and affordable ways of controlling this mosquito, the larvicidal activities of essential oils from Croton species widely found in northeastern Brazil were analyzed. The essential oils were extracted by steam distillation, and their chemical composition was determined by gas liquid-chromatography coupled with mass spectroscopy. The main components were methyleugenol and alpha-copaene for C. nepetaefolius (LC50 of 84 ppm); alpha-pinene and beta-pinene for C. argyrophyloides (LC50 of 102 ppm); and alpha-pinene, beta-phelandrene, and trans-caryophyllene for C. sonderianus (LC50 of 104 ppm). Croton zenhtneri exhibited higher larvicidal activity with LC50 of 28 ppm, and the main active constituent was identified as anethole, a phenylpropanoid compound.