RESUMO A jurubeba (Solanum paniculatum L.) é uma planta usada na medicina tradicional, para problemas hepáticos, além de ser empregada como colagoga, emenagoga, cicatrizante, febrífuga, anti-inflamatória, antipirética, tônica, descongestionante, diurética e na inapetência. Assim, objetivou-se com o presente estudo avaliar a atividade antioxidante, os teores de compostos fenólicos e de alcaloides totais dos extratos aquosos preparados a partir de folhas de jurubeba submetidas à secagem. As folhas de jurubeba foram secas em diferentes temperaturas (40, 50, 60 e 70 °C) e velocidades (0,4 e 0,8 m s-1) do ar de secagem. Os extratos aquosos das folhas, submetidas a secagem, foram avaliados por meio de leitura de absorbância em espectrofotômetro. O aumento da temperatura do ar de secagem reduziu o teor de compostos fenólicos e alcaloides totais dos extratos aquosos das folhas, enquanto que o aumento da velocidade do ar aumentou o teor dessas substâncias, já a atividade antioxidante não foi influenciada pelo incremento da temperatura do ar na velocidade de 0,4 m s-1, mas sob a velocidade do ar de 0,8 m s-1 houve redução com o aumento da temperatura. A secagem das folhas de jurubeba pode ser realizada com temperatura de 40 ou 50 °C e velocidade do ar de secagem de 0,4 m s-1.

ABSTRACT ‘Jurubeba’ (Solanum paniculatum L.) is a medicinal plant used in traditional medicine for liver problems, in addition to being used as a cholagogue, emmenagogue, healing agent, febrifuge, anti-inflammatory, antipyretic, tonic, decongestant, diuretic and against inappetence. Thus, the objective of this study was to evaluate the antioxidant activity, concentration of phenolic compounds and total alkaloids of aqueous extracts prepared from ‘Jurubeba’ leaves subjected to drying. ‘Jurubeba’ leaves were dried at different temperatures (40, 50, 60 and 70 °C) and velocities (0.4 and 0.8 m s-1) of the drying air. Aqueous extracts of the leaves, subjected to drying, were evaluated by absorbance reading in a spectrophotometer. Increase in drying air temperature reduced the contents of total phenolics and total alkaloids of the leaf aqueous extracts, whereas increment in air velocity increased the concentration of these substances. Antioxidant activity was not influenced by the increase in air temperature at air velocity of 0.4 m s-1, but under air velocity of 0.8 m s-1 there was reduction with increasing temperature. Drying of ‘Jurubeba’ leaves can be carried out with temperature of 40 or 50 °C and drying air velocity of 0.4 m s-1.

DETECTION AND QUANTIFICATION OF SILVER NANOPARTICLES BY spICP-MS. The growing interest in nanotechnology has led to an increase in the production and application of nanoparticles worldwide. Due to the unique functional properties of nanoparticles, these materials are being used by many industries, including the agricultural and food sectors. Among the commercially available nanomaterials, it is possible to highlight those produced with silver nanoparticles. One of the most promising techniques for the analysis of metallic nanoparticles is the Inductively coupled plasma mass spectrometry (ICP-MS) performed in single particle mode (spICP-MS). However, the use of the technique in the detection and measurement of nanoparticles requires that the equipment be operated differently than when used to analyze dissolved metal solutions. Thus, this article presents the use of the spICP-MS technique for the measurement and quantification of nanoparticles, as well as their validation. The method proved to be adequate for the purpose, presenting a satisfactory result for the selectivity test and recovery of 83.7 (40 nm) and 77.6% (80 nm). The detection limits, determined for the most frequent size, dissolved silver concentration and particle concentration, were 17.5 nm, 0.736 ng mL-1;, 146 particles mL-1;, respectively. Thus, the results obtained indicated the possibility of using the technique to determine the size and concentration of silver nanoparticles.

Senna ocidentalis é uma planta daninha, nativa do Brasil, sendo considerada infestante de culturas e plantações, e é responsável por perdas de produção de diversas culturas, principalmente de soja. O objetivo deste trabalho foi avaliar se o extrato e frações de Croton argenteus possuem atividade fitotóxica sobre S. ocidentalis. O extrato etanólico bruto (EEB) e as frações hexânica (FH), clorofórmio (FCL) e acetato de etila (FAE) foram testados na germinação, crescimento, aumento do estresse oxidativo, síntese de ATP, L- malato e succinato. O extrato bruto e frações atrasaram a germinação das sementes de S. ocidentalis e diminuíram a porcentagem final de germinação. O estresse oxidativo também aumentou nas plântulas tratadas, comprovado pelo aumento na síntese de catalase, peroxidase e superóxido dismutase, glutationa redutase e peroxidação lipídica, sendo evidente que a fração acetato de etila é mais fitotóxica. Os resultados indicam que o extrato bruto e frações de C. argenteuscomprometem o metabolismo energético mitocondrial, pela inibição na síntese de ATP mitocondrial, com diminuição na produção de L- malato e succinato. A fração acetato de etila de C. argenteus apresentou alta atividade inibitória sobre a germinação e crescimento, e estes efeitos ocorrem pelas alterações no metabolismo mitocondrial e aumenta o estresse oxidativo, levando a morte das plântulas.

Senna ocidentalis is a weed, native to Brazil, considered to infest crops and plantations, and is responsible for yield losses of several crops, particularly soybean. The aim of this work was to evaluate if theCroton argenteus extract and fractions possess phytotoxic activity on S. ocidentalis. The crude ethanolic extract (CEE) and its hexanic (HF), chloroformic (CLF) and ethyl acetate (EAF) fractions were tested in germination, growth, oxidative stress increase, Adenosine triphosphate, L-malate and succinate synthesis. The crude extract and its fractions slowed down the germination of S. ocidentalis and decreased the final percentage of germination. Oxidative stress was also increased in the seedlings, by an increase of catalase, peroxidase, superoxide dismutase, glutathione reductase and lipid peroxidation; and it became clear that the ethyl acetate fraction was more phytotoxic. The results indicate that the crude extract and fractions of C. argenteus compromise the mitochondrial energy metabolism, by the inhibition of mitochondrial ATP production, with a decrease in the production of L-malate and succinate. The ethyl acetate fraction of C. argenteus showed high activity on germination and growth, and these effects take place by means of mitochondrial metabolism alterations and increase the oxidative stress, leading the seedling death.

The volatile oil obtained from the leaves of Hydrocotyle bonariensis Lam (Araliaceae) was analyzed by GC, Chiral-GC and GC-MS. It was identified 14 compounds and the monoterpene (+)-limonene (53.6%) and sesquiterpene γ-muurolene (10.5%) were the main components. The allelopathic effects of the oil were evaluated against two seeds, Lactuca sativa and Allium cepa. The results show that the oil exhibited inhibition effects in the germination and seedling growth of plants species relative to the control.