ABSTRACT Although numerous studies have been conducted with common bean regarding nitrogen (N) dose, time of application, and source in no-till (NT) soils in Brazil, the heterogeneity of the results makes it difficult to establish technical recommendations based on individualized studies. This meta-analysis aimed to rank the main factors influencing common bean response to N management in NT areas. The database consisted of 99 scientific papers that encompassed 160 trials and 2394 observations. In general, the probability of obtaining a positive response to N application in common bean productivity was 77 %, with an average 18 % increment (358 kg ha-1). The main factors that affect the response of common bean grain yield to N fertilization and the choice of the applied N dose are soil organic matter (OM) content and the preceding crop. In soils with OM content >20 g kg-1, the N dose that determines the highest economic return is 50 kg ha-1. For soils with OM content <20 g kg-1, the N dose to be applied is 70 and 100 kg ha-1 for crops preceded by legumes and grasses, respectively. The timing of the N application did not result in a significant difference in common bean yield in 62 % of the trials. However, the results showed that the average yield increase in the common bean went from 15 % (293 kg ha-1) with a single application to 32 % (622 kg ha-1) with split N applications. All N sources tested showed similar gains to those obtained with N application through urea. Excluding situations with high doses of N application (>100 kg ha-1), inoculating common bean seeds increased grain yields by 6 % on average (118 kg ha-1). The combined analysis of the available results demonstrated that the crop recommendations used in Brazilian soils under NT could be refined considering the soil OM concentration and preceding crop. Additionally, seed inoculation and N dose splitting in the form of common urea should be recommended.

Abstract Gold (Au0) and silver (Ag0) nanoparticles were synthesized using tannic acid (TA) as both reducing and stabilizer. Nanoparticles formation, stability, and interaction with TA were compared to citrate-coated nanoparticles and monitored by UV-Vis, zeta potential, and transmission electron microscopy. TA coating resulted in a red-shift and broadening of bands compared to citrate-coated nanoparticles (NPs-Cit). AgNPs-TA and AuNPs-TA are negatively charged with mean surface charge of -29.4 mV and -29.6 mV, respectively. TEM images showed polydispersety of AuNPs-TA (6-42 nm) and aggregation of AgNPs-TA (12-71 nm). In vitro assays of Leishmania amazonensis promastigotes showed an increment of antileishmanial activity for AgNPs-TA in relation to AgNPs-Cit, while AuNPs-TA and AuNPs-Cit did not affect the protozoas at tested concentrations. CC50 value for AgNPs-TA suggested that TA attenuates nanosilver toxicity comparatively to its precursor (Ag+). This investigation can contribute to the development of new, green, and fast produced drugs aiming at leishmaniasis treatment.

No processamento da maçã para obtenção do suco, ocorre a formação de uma elevada quantidade de resíduo, representado pelas cascas e sementes, no qual são encontradas diversas substâncias, como os compostos fenólicos, aos quais são atribuídas as propriedades antioxidantes. Este estudo teve como objetivo avaliar o conteúdo de compostos fenólicos totais e a atividade antioxidante in vitro de extratos e frações de ácidos fenólicos livres, esterificadas solúveis e esterificadas insolúveis, obtidos por diferentes solventes, a partir do resíduo da maçã cv. Gala pelos métodos DPPH (2,2-difenil-1-picrilhidrazilo) e ABTS [2,2'-azino-bis (3-etilbenzotiazolin) 6-ácido sulfônico], além da identificação dos ácidos fenólicos por cromatografia gasosa. O sistema acetona 75% (v/v) em água foi mais eficaz na extração dos compostos fenólicos totais. A atividade antioxidante neste extrato foi 4,83 e 25,46 µmol TEAC.g-1 de amostra com o método ABTS e de 7,43 e 39,15 µmol TEAC.g-1 pelo método DPPH, expressos em base úmida e seca, respectivamente. O teor de flavanóis foi 11,05 e 58,20 mg.100 g-1 em base úmida e seca, respectivamente. Houve uma correlação positiva entre o conteúdo de fenólicos totais e atividade antioxidante (r² = 0,9283). Foram identificados os ácidos fenólicos salícilico, gálico, propilgalato e sináptico nas três frações avaliadas, o primeiro estando presente em maior concentração em todas as frações estudadas. Os resultados indicam o potencial antioxidante do bagaço de maçã.

Apple processing to obtain juice produces a great amount of discarded material constituted by peel and seed. Several substances, including phenolic compounds, to which antioxidant activity is attributed, are found in these fractions. This work aimed at evaluating total phenolic compounds and in vitro antioxidant activity of extracts and phenolic fractions (free, soluble esterified and insoluble esterified) of apple, cv. Gala, residues. The methodologies used were DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid] to evaluate antioxidant activity and gas chromatography to determine phenolic acids. Extraction with 75% acetone (v/v) in water was the most efficient to obtain total phenolic compounds. The antioxidant activity in this extract was 4.83 and 25.46 µmol TEAC.g-1 by the ABTS method and 7.43 and 39.15 µmol TEAC.g-1 by the DPPH method for wet and dry samples, respectively. Flavanol contents in the same samples were 11.05 and 58.20 mg.100 g-1 for wet and dry samples, respectively. A positive correlation between total phenolics and antioxidant activity (r² = 0.9283) was observed. In the three fractions used, the following phenolic acids were identified: salicylic, gallic, propyl gallate and synaptic acid, being the first present in the highest amount in all the fractions studied. The results obtained showed the antioxidant potential of apple pomace.

A produção de uvas no Brasil está localizada nas regiões Sul, Sudeste e Nordeste. Constitui-se em atividade consolidada, com importância socioeconômica, principalmente nos Estados do Rio Grande do Sul e de Santa Catarina, os quais respondem por 97% da produção nacional de vinhos. A uva Isabel é uma das principais cultivares de Vitis labrusca, e a Niágara Rosada, resultado da mutação somática ocorrida na uva Niágara Branca (Vitis labrusca L. x Vitis vinifera L.). São destaques como uvas de mesa comuns, sendo variedades rústicas e, portanto, menos exigentes. O desenvolvimento do trabalho foi feito com o objetivo de determinar conteúdo total de compostos fenólicos, utilizando acetona como solvente em diferentes concentrações, a determinação da atividade antioxidante, do teor de antocianinas totais, flavanóis nos extratos da casca das uvas de mesa Niágara Rosada e Isabel. Os resultados médios do teor de fenólicos totais no extrato acetona 75% foi de 1.026,69 a 1.242,78 mg GAE/100g de peso seco nas cultivares Isabel e Niágara , respectivamente. A atividade antioxidante avaliada apresentou valores de 89,22 e 157,31 µmol TEAC/g de amostra com o método ABTS e de 197,00 e 189,82 µmol TEAC/g de amostra no método DPPH para as cultivares Isabel e Niágara. A quantidade de antocianinas foi baixa comparada com outros frutos. Os valores de polifenóis refletem-se nos valores de TEAC, e observa-se uma correlação positiva entre a média do conteúdo de polifenóis totais com a média dos valores TEAC, o que se pode atribuir aos compostos fitoquímicos presentes nas cascas.

Grape production in Brazil is located in the South, Southeast and Northeast regions. It is a consolidated activity of great social and economical importance mainly in Rio Grande do Sul and Santa Catarina states. These states are responsible for 97% of national wine production. Isabel grape is one of the main varieties of Vitis labrusca and Niagara Rosada is resulted from a somatic mutation in Niagara Branca grape (Vitis labrusca L. x Vitis vinifera L.). These varieties are well established as table grapes being rustier than others. This work intends to determine the total phenolic compounds content, by using acetone as solvent in different concentrations as well as the antioxidant activity, anthocyanins content, flavonoids in skin of Niagara Rosada and Isabel grapes. The results for total phenolic content in 75% acetone extract ranged, in average, from 1026.69 to 1242.78 mg GAE/100g of dry weight in Isabel and Niagara varieties, respectively. Antioxidant activity presented values of 89.22 and 157.31 µmol TEAC/g of sample with ABTS method and of 197.00 and 189.82 µmol TEAC/g of sample with DPPH method for Isabel and Niagara varieties, respectively. Anthocyanins content was low when compared to other fruits. TEAC values depended on polyphenols values and it was observed a positive correlation among averages of total polyphenol content and TEAC values, indicating a strong influence. This can be probably due to the phytochemical compounds present in grape skins.