Abstract Pitaya is a rich source of bioactive compounds, such as polyphenols and betalains. Moreover, these compounds has been associated with reduced risk of type 2 diabetes mellitus. The aim of this study is to evaluate the effect of this fruit on glycemia and oxidative stress in aloxan-induced diabetic mice. Thus, considering that In the in vivo assays, the mice were divided into 5 groups (n = 6): (a) healthy group treated with water; (b) diabetic mice treated with metformin at 200 mg/kg body weight diluted in water; (c) untreated diabetic mice; (d) diabetic mice treated with pitaya at 200 mg/kg and (e) diabetic mice treated with pitaya at 400 mg/kg of body weight diluted in water. The results shows that pitaya was able significantly to reduce blood glucose (p < 0.05) (200 mg/kg); significantly reduce cholesterol (200 and 400 mg/kg) and significantly increase HDL-c (400 mg/kg) levels. In the oxidative stress experiment, Malondialdehyde levels in the liver were significantly reduced (p < 0.05) in the groups treated with pitaya, when compared to the other groups, suggesting lower lipid peroxidation. The consumption of pitaya reduced the blood glucose and cholesterol and increase the HDL, in addition, the lipid peroxidation - which is common in diabetic patients, was reduced.

RESUMO Investigamos o padrão de forrageamento de A. mellifera em cinco tipos comerciais de melão (Amarelo, Cantaloupe, Charentais, Gália e Pele de Sapo) cultivados lado a lado. Observamos também se esta espécie de abelha pode discriminar entre flores dos cinco tipos de melão e se mostra preferência por flores de qualquer um deles. Os resultados mostraram que as abelhas visitam flores de todos os tipos de melão ao longo do dia coletando pólen e néctar em padrões similares de forrageamento. No entanto, elas visitaram significativamente mais flores do tipo Cantaloupe, seguido dos tipos Pele de Sapo e Amarelo, enquanto os melões tipo Gália e Charentais foram os menos visitados pelas abelhas. Este comportamento tem implicações para o uso de A. mellifera na polinização do melão, exigindo que as abelhas sejam manejadas de acordo com o tipo de melão cultivado. Ele também destaca a necessidade de descobrir o que faz com que as flores de alguns tipos de melão sejam mais visitadas do que de outros, a fim de selecionar, dentro dos tipos de melão menos visitados, cultivares mais atraentes para as abelhas.

ABSTRACT We investigated the foraging pattern of A. mellifera in five commercial types of melon (Yellow, Cantaloupe, Charentais, Galia and Piel de Sapo) grown side by side. We also observed if this bee species can discriminate between flowers of the five melon types and if it shows preference for flowers of any of them. Results showed that the bees visit flowers of all types of melon throughout the day collecting pollen and nectar in similar foraging patterns. However, they visited significantly more flowers of the Cantaloupe type followed by the types Piel de Sapo and Yellow, while the melons type Galia and Charentais were the least visited by the bees. This behavior has implications for the use of A. mellifera for melon pollination, requiring that the bees be managed according to the type of melon cultivated. It also highlights the need to find out what makes flowers of some melon types to be more visited than others in order to select within the less visited types of melon for cultivars more attractive to the bees.

ABSTRACT Graviola leaves (Annona muricata L., Annonaceae) are used by some people to try to treat or even cure cancer, even though over-consumption of the fruit, which contains the neurotoxins annonacin and squamocin has caused an atypical form of Parkinson's disease. In previous analyses, the fruits were extracted with methanol under ambient conditions before analyses. In the present study, UPLC–QTOF–MS and NMR were used to analyze freeze-dried graviola leaves that were extracted using dry methanol and ethanol at 100 ºC and 10 MPa (100 atm) pressure in a sealed container. Methanol solubilized 33% of the metabolites in the lyophilized leaves. Ethanol solubilized 41% of metabolites in the lyophilized leaves. The concentrations of total phenolic compounds were 100.3 ± 2.8 and 93.2 ± 2.0 mg gallic acid equivalents per g of sample, for the methanolic and ethanolic extracts, respectively. Moreover, the toxicophore (unsaturated γ-lactone) that is present in neurotoxic acetogenins was found in the lipophilic portion of this extract. The concentrations of the neurotoxins annonacin and squamocin were found by UPLC–QTOF–MS to be 305.6 ± 28.3 and 17.4 ± 0.89 µg/g-dw, respectively, in the dried leaves. Pressurized methanol solubilized more annonacin and squamocin than ethanol. On the other hand, a hot, aqueous infusion solubilized only 0.213% of the annonacin and too little of the squamocin to be detected. So, graviola leaves contain significant amounts of the neurotoxins annonacin and squamocin, as well as some potentially healthy phenolic compounds. Finally, the potential neurotoxicity of whole leaves in dietary supplements could be much higher than that of a tea (hot aqueous infusion) that is made from them.

Muitos trabalhos mostram a importância da biomassa microbiana do solo (BMS), principalmente como fonte/dreno de C e de N em plantações florestais; contudo, são escassos os trabalhos relacionados ao fósforo microbiano (PBM), sobretudo aqueles relativos aos métodos de determinação do PBM nesses ecossistemas. O presente trabalho foi realizado com o objetivo de avaliar métodos de determinação do PBM em solo com diferentes coberturas vegetais. O trabalho consistiu da análise de amostras de Latossolo Vermelho-Amarelo distrófico muito argiloso (LVAd) localizado no município de Viçosa (MG), coletadas nas profundidades de 0 a 5 e 5 a 10 cm, em áreas com as seguintes coberturas vegetais: pínus (Pinus taeda), eucalipto (Eucalyptus grandis) e floresta nativa. Para determinação do P microbiano, foram empregados os métodos fumigação-extração (FE), irradiação com micro-ondas-extração (IE) e irradiação com micro-ondas-extração com membrana de troca aniônica (EMTA). Em termos gerais, menores teores de PBM foram obtidos com o método irradiação-extração. Considerando a cobertura vegetal, foi detectada diferença significativa entre os três métodos sob floresta de eucalipto e floresta nativa, principalmente na camada superficial. Sob pínus, apenas o método IE diferiu dos demais, na camada subsuperficial. Menores coeficientes de variação (CV) foram obtidos com o FE, retratando maior precisão do método. Entretanto, o método IE mostrou-se, em termos operacionais, o mais adequado à determinação do PBM quando se tem maior número de amostras. Com relação às coberturas vegetais, a grande variabilidade observada nos CVs obtidos para cada cobertura, nos três métodos testados, inviabiliza a escolha de um único método que apresente maior precisão na avaliação do PBM.

Many studies have shown the importance of the soil microbial biomass, mainly as source/sink of carbon (C) and nitrogen (N) in forest stands. However, there are few studies focused on microbial P (MPH), especially in relation to the determination methods of MPH in these ecosystems. For an evaluation of the methods used to determine microbial P (MPH) in soils, three methods were evaluated: fumigation-extraction (FE); radiation with microwave-extraction (RE); and radiation by microwave-extraction with a membrane for anionic exchange (EMAE). Samples of a very clayey dystrophic Red-Yellow Latosol (LVAd) were collected at depths of 0-5 cm and 5-10 cm in soils under pine (Pinus taeda), eucalypt plantations (Eucalyptus grandis), and native forest, in Viçosa, state of Minas Gerais. In general, lower MPH contents were obtained by the RE than by the FE method. The MPH contents established by the three methods in the areas with eucalypt and native forest varied significantly in the surface layer. Under pine, only the RE method was significantly different in the 5-10 cm layer. The lowest coefficients of variation (CV) were obtained by FE, expressing the greater precision of this method. Under the studied conditions, however, where a large-scale analysis of samples is required, the RE method turned out to be, in terms of functionality, most adequate for the MPH determination. In relation to the stands, none of the three tested methods could be indicated as uniquely most precise method for the evaluation of the MPH, due to the great variability in the CV for each forest type.