Citrus canker is a very destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity and low toxicity to plants and the environment. The objectives of the present study were (1) to extract, purify and evaluate the secondary metabolites with antibiotic activity produced by Pseudomonas aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306), (2) to determine the potential of semi-purified secondary metabolites in foliar application to control citrus canker under greenhouse conditions, and (3) to identify antibiotic activity in orange leaf mesophyll infected with strain 306, by electron microscopy. Two pure bioactive compounds were isolated, an organocopper antibiotic compound (OAC) and phenazine-1-carboxamide. Phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The OAC showed a high level of antibiotic activity with a minimum inhibitory concentration of 0.12 μg mL-1. In greenhouse tests for control of citrus canker in orange trees, the semi-purified fraction F3d reduced lesion formation by about 97%. The concentration used was 500 times lower than that for the recommended commercial copper-based product. Electron microscopy showed that F3d altered the exopolysaccharide matrix and caused cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by inducing P. aeruginosa LV strain have a high potential to be used as a bioproduct to control citrus canker.

Arctium lappa L. (Asteraceae) is used in folk medicine around the World, and shows several kinds of biological activity, particularly in vitro antitumor activity in different cell lines. This study evaluated the antiproliferative activity of the crude extract, semipurified fractions, and isolated compounds from the leaves of A. lappa, through bioassay-guided testing in Caco-2 cells. The crude extract was obtained with a 50% hydroethanolic extract and then partitioned with hexane, ethyl acetate, and n-butanol. The ethyl-acetate fraction (EAF) showed antiproliferative activity. This fraction was subjected to sequential column chromatography over silica gel to afford onopordopicrin (1), mixtures of 1 with dehydromelitensin-8-(4'-hydroxymethacrylate) (2), a mixture of 2 with dehydromelitensin (3), mixture of 1 with melitensin (4), dehydrovomifoliol (5), and loliolide (6). The compounds were identified by spectroscopic methods (NMR, MS) and comparison with literature data. This is the first description of compounds 2–5 from this species. The compounds tested in Caco-2 cells showed the following CC50 (µg/mL) values: 1: 19.7 ± 3.4, 1 with 2: 24.6 ± 1.5, 2 with 3: 27 ± 11.7, 1 with 4: 42 ± 13.1, 6 30 ± 6.2; compound 5 showed no activity.

Porophyllum ruderale (Jacq.) Cass. is a plant native to Brazil and in the northwest region of the state of Paraná, Brazil, aerial parts of P. ruderale have been used popularly in the treatment of lesions caused by Leishmania sp.. In this study the antileishmanial and cytotoxic activities of the crude extract, fractions, and isolated compounds from aerial parts of P. ruderale was evaluated. The dichloromethane extract was submitted to chromatography to yield compounds active against Leishmania amazonensis. Their structures were established by comparison of their spectroscopic data with literature values. The activities of crude extract against promastigote and axenic amastigote forms of L. amazonensis (IC50) were 60.3 and 77.7 μg/mL, respectively. Its cytotoxic activity against macrophage cells (CC50) was 500 μg/mL. The thiophene derivatives isolated were: 5-methyl-2,2′:5′,2″-terthiophene (compound A) and 5′-methyl–[5–(4–acetoxy-1–butynyl)]–2,2′-bithiophene (compound B). The activity of compound A against promastigote and axenic amastigote forms were 7.7 and 19.0 μg/mL and of compound B were 21.3 and 28.7 μg/mL, respectively. The activity of the isolated compounds against promastigote and axenic amastigote forms was better than that of the crude extract and more selective against protozoa than for macrophage cells.

Application and evaluation of propolis, the natural antioxidant in Italian-type salami Aplicação e avaliação de própolis, o antioxidante natural, em salame tipo Italiano SummaryThis study aimed to characterize propolis with respect to its antioxidant activity and apply it to the elaboration of Italian-type salami. A propolis sample was collected and subjected to chemical and physicochemical characterization and its antioxidant capacity determined. Four salami formulations were developed: F1 (no antioxidants); F2 (addition of 0.01% BHT); F3 (addition of 0.01% propolis) and F4 (addition of 0.05% propolis). The salamis were evaluated with respect to their physicochemical properties and lipid oxidation. The characterization of the propolis showed a high level of waxes and low levels of phenolic compounds and flavonoids, although in sufficient quantity to prove their antioxidant activity. The Italian-type salamis showed moisture, protein and lipid contents which conformed to the limits preconized by Brazilian legislation. The F4 formulation (0.05% propolis) showed a better result when compared to the formulations F3 (0.01% propolis) and F1 (no antioxidant). However, formulation F2 (0.01% BHT) showed the lowest value of lipid oxidation. The results showed that propolis inhibits oxidative action and can be added to meat products as a natural antioxidant. Keywords: Meat products; Shelf life; Lipid oxidation. ResumoO presente estudo teve por finalidade caracterizar a própolis quanto à sua atividade antioxidante e aplicá-la na elaboração de salame tipo italiano. Amostra de própolis foi coletada e submetida à caracterização físico-química, química e capacidade antioxidante. Quatro formulações de salame foram elaboradas: F1 (sem antioxidante), F2 (adição BHT 0,01%), F3 (adição de própolis 0,01%) e F4 (adição de própolis 0,05%). Os salames foram avaliados quanto às propriedades físico-químicas e oxidação lipídica. A caracterização da própolis mostrou alto teor de ceras e baixo teor de compostos fenólicos e flavonoides, porém em quantidades suficientes para comprovar sua atividade antioxidante. Os salames tipo italiano apresentaram teor de umidade, proteínas e lipídeos conforme limites preconizados pela legislação brasileira. A formulação F4 (0,05% de própolis) apresentou melhor resultado quando comparado às formulações F3 (0,01% de própolis) e F1 (sem antioxidante). No entanto, a F2 (0,01% de BHT) foi a formulação que apresentou menor valor de oxidação lipídica. Os resultados demonstraram que a própolis inibe a ação oxidativa, podendo ser adicionada em produtos cárneos como antioxidante natural. Palavras-chave: Produtos cárneos; Prazo de validade; Oxidação lipídica.

Alzheimer’s disease (AD) is the most common form of dementia and has no cure. Therapeutic strategies focusing on the reduction of oxidative stress, modulation of amyloid-beta (Aβ) toxicity and inhibition of tau protein hyperphosphorylation are warranted to avoid the development and progression of AD. The aim of this study was to screen the crude extracts (CEs) and ethyl-acetate fractions (EAFs) of Guazuma ulmifolia , Limonium brasiliense , Paullinia cupana , Poincianella pluviosa , Stryphnodendron adstringens and Trichilia catigua using preliminary in vitro bioassays (acetylcholinesterase inhibition, antioxidant activity and total polyphenol content) to select extracts/fractions and assess their protective effects against Aβ 25–35 toxicity in SH-SY5Y cells. The effect of the EAF of S . adstringens on mitochondrial membrane potential, lipid peroxidation, superoxide production and mRNA expression of 10 genes related to AD was also evaluated and the electropherogram fingerprints of EAFs were established by capillary electrophoresis. Chemometric tools were used to correlate the in vitro activities of the samples with their potential to be evaluated against AD and to divide extracts/fractions into four clusters. Pretreatment with the EAFs grouped in cluster 1 ( S . adstringens , P . pluviosa and L . brasiliense ) protected SH-SY5Y cells from Aβ 25-35 -induced toxicity. The EAF of S . adstringens at 15.62 μg/mL was able completely to inhibit the mitochondrial depolarization (69%), superoxide production (49%) and Aβ 25-35 -induced lipid peroxidation (35%). With respect to mRNA expression, the EAF of S . adstringens also prevented the MAPT mRNA overexpression (expression ratio of 2.387x) induced by Aβ 25–35 , which may be related to tau protein hyperphosphorylation. This is the first time that the neuroprotective effects of these fractions have been demonstrated and that the electropherogram fingerprints for the EAFs of G . ulmifolia , L . brasiliense , P . cupana , P . pluviosa and S . adstringens have been established. The study expands knowledge of the in vitro protective effects and quality control of the evaluated fractions.