Blood shizonticidal activities of phenazines and naphthoquinoidal compounds against Plasmodium falciparum in vitro and in mice malaria studies

Due to the recent advances of atovaquone, a naphthoquinone, through clinical trials as treatment for malarial infection, 19 quinone derivatives with previously reported structures were also evaluated for blood schizonticide activity against the malaria parasite Plasmodium falciparum. These compounds include 2-hydroxy-3-methylamino naphthoquinones (2-9), lapachol (10), nor-lapachol (11), iso-lapachol (12), phthiocol (13) and phenazines (12-20). Their cytotoxicities were also evaluated against human hepatoma and normal monkey kidney cell lines. Compounds 2 and 5 showed the highest activity against P. falciparum chloroquine-resistant blood-stage parasites (clone W2), indicated by their low inhibitory concentration for 50% (IC50) of parasite growth. The therapeutic potential of the active compounds was evaluated according to the selectivity index, which is a ratio of the cytotoxicity minimum lethal dose which eliminates 50% of cells and the in vitro IC50. Naphthoquinones 2 and 5, with activities similar to the reference antimalarial chloroquine, were also active against malaria in mice and suppressed parasitaemia by more than 60% in contrast to compound 11 which was inactive. Based on their in vitro and in vivo activities, compounds 2 and 5 are considered promising molecules for antimalarial treatment and warrant further study.

Antifungal activity of extracts from Atacama Desert fungi againstParacoccidioides brasiliensis and identification ofAspergillus felis as a promising source of natural bioactive compounds

Fungi of the genus Paracoccidioides are responsible for paracoccidioidomycosis. The occurrence of drug toxicity and relapse in this disease justify the development of new antifungal agents. Compounds extracted from fungal extract have showing antifungal activity. Extracts of 78 fungi isolated from rocks of the Atacama Desert were tested in a microdilution assay against Paracoccidioides brasiliensis Pb18. Approximately 18% (5) of the extracts showed minimum inhibitory concentration (MIC) values≤ 125.0 µg/mL. Among these, extract from the fungus UFMGCB 8030 demonstrated the best results, with an MIC of 15.6 µg/mL. This isolate was identified as Aspergillus felis (by macro and micromorphologies, and internal transcribed spacer, β-tubulin, and ribosomal polymerase II gene analyses) and was grown in five different culture media and extracted with various solvents to optimise its antifungal activity. Potato dextrose agar culture and dichloromethane extraction resulted in an MIC of 1.9 µg/mL against P. brasiliensis and did not show cytotoxicity at the concentrations tested in normal mammalian cell (Vero). This extract was subjected to bioassay-guided fractionation using analytical C18RP-high-performance liquid chromatography (HPLC) and an antifungal assay using P. brasiliensis. Analysis of the active fractions by HPLC-high resolution mass spectrometry allowed us to identify the antifungal agents present in the A. felis extracts cytochalasins. These results reveal the potential of A. felis as a producer of bioactive compounds with antifungal activity.

Activity of phosphorus of synthetic Fe-K-P compounds in superphosphate fertilizers as affected by pH and ionic strength

The concentration of orthophosphate ions released from Fe-K-P compounds (Fe3KH8(PO4)6 .6H2O and Fe3KH14(PO4)8 .4H2O) present in superphosphates increases with pH, which initially suggests that the agronomic effectiveness of P fertilizers containing high amounts of these compounds would also increase with soil pH but studies considering activity, instead of concentration, are necessary. With this purpose, both compounds were synthesized under laboratory conditions, characterized by elemental chemical analysis, optical microscopy, X ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and used in a solubility study. Solutions of 0.01, 0.05 and 0.1 mol L-1 NaCl with pH adjusted to 3.0, 4.0, 5.0, 5.5, 6.0, 6.5, 7.0 and 7.5 were prepared for the solubility study of H8-syn, H14-syn and a phosphate rock (PR) from Brazil. The orthophosphate activity as H2PO4- and HPO4(2-) was calculated in each situation as related to pH and ionic strength using software MINTEQ. The remaining precipitates after equilibrium were chemically analyzed and subjected to X ray, SEM and EDS. Results of chemical analysis and instrumental techniques confirmed the preparation method. The activity of orthophosphate ions of both compounds tended to decrease under increasing pH and/or ionic strength of the solution, which in turn suggests that an increase in the solution pH does not necessarily promote an increase in the P bioavailability for plant uptake. This can be important when evaluating agronomic data of P fertilizers with high contents of these two Fe-K-P compounds.

Copper, zinc and manganese in soils of two watersheds in Santa Catarina with intensive use of pig slurry

Systematic pig slurry application to crop soils may lead to the accumulation of heavy metals in regions with intensive pig raising. The aim of this study was to evaluate the accumulation of Cu, Zn and Mn in soils under systematic pig slurry application. For this purpose, soil samples were collected from two of the most representative watersheds of Santa Catarina where the predominant activity is pig raising. In each watershed, 12 properties were chosen to evaluate the different systems of pig husbandry (complete cycle (CC), farrowing (FaU) and finishing units (FiU)). Based on information of the producers, soil samples were collected in areas with and without systematic manure application. To determine the total Cu, Zn and Mn content in soils and manure, a methodology proposed by the Environmental Protection Agency of the United States (USEPA), method nº 3050B, was used. For the available heavy metal content, Cu and Zn was extracted with HCl 0.1 mol L-1 and Mn with KCl 1 mol L-1. Data were subjected to multivariate analysis, using the canonical discriminant analysis to identify the metals that best differentiate the soils studied within each swine housing system. Successive pig slurry applications cause an increase in Cu, Zn and Mn availability in the soil and this indicates the need for monitoring of the metal concentrations over time. The critical values of Cu in the soil can be reached and exceeded more rapidly than Zn. The results showed that the soil type may be one of the attribute underlying the determination of public policies in pig raising and waste management because soils such as Inceptisols were shown to be more prone to possible contamination since they may more rapidly reach total critical Cu levels.

Forms and accumulation of copper and zinc in a sandy typic hapludalf soil after long-term application of pig slurry and deep litter

Successive applications of pig slurry and pig deep litter may lead to an accumulation of copper (Cu) and zinc (Zn) fractions in the soil profile. The objective of this study was to evaluate the Cu and Zn forms and accumulation in a Sandy Typic Hapludalf soil after long-term application of pig slurry and deep litter. In March 2010, eight years after initiating an experiment in Braço do Norte, Santa Catarina (SC), Brazil, on a Sandy Typic Hapludalf soil, soil samples were collected from the 0-2.5, 2.5-5.0, 5-10 and 10-15 cm layers in treatments consisting of no manure application (control) and with applications of pig slurry and deep litter at two levels: the single and double rate of N requirement for maize and black oat succession. The soil was dried, ground in an agate mortar and analyzed for Cu and Zn contents by 0.01 mol L-1 EDTA and chemically fractionated to determine Cu and Zn. The applications of Pig deep litter and slurry at doses equivalent to 90 kg ha-1 N increased the contents of available Cu and Zn in the surface soil layer, if the double of this dose was applied in pig deep litter or double this dose in pig slurry, Cu and Zn migrated to a depth of 15 cm. Copper is accumulated mainly in the organic and residual fractions, and zinc preferentially in the fraction linked to clay minerals, especially in the surface soil layers.

PHYTOAVAILABILITY OF COPPER IN INDUSTRIAL BY-PRODUCTS AND MINERAL FERTILIZERS

Alternative copper (Cu) sources could be used in fertilizer production, although the bioavailability of copper in these materials is unknown. The objective of this study was to evaluate the extractants neutral ammonium citrate (NAC), 2 % citric acid, 1 % acetic acid, 10 % HCl, 10 % H2SO4, buffer solution pH 6.0, DTPA, EDTA, water, and hot water in the quantification of available Cu content in several sources, relating them to the relative agronomic efficiency (RAE) of wheat grown in a clayey Latossolo Vermelho eutrófico (Oxisol) and Neossolo Quartzarênico (Typic Quartzipsamment). Copper was applied at the rate of 1.5 mg kg-1 as scrap slag, brass slag, Cu ore, granulated copper, and copper sulfate. The extractants 10 % HCl, 10 % H2SO4, and NAC extracted higher Cu concentrations. The RAE values of brass slag and Cu ore were similar to or higher than those of Cu sulfate and granulated Cu. Solubility in the 2nd NAC extractant, officially required for mineral fertilizers with Cu, was lower than 60 % for the scrap slag, Cu ore, and granulated copper sources. This fact indicates that adoption of the NAC extractant may be ineffective for industrial by-products, although no extractant was more efficient in predicting Cu availability for wheat fertilized with the Cu sources tested.

Mycorrhizal colonization and phenolic compounds accumulation on roots of Eucalyptus dunnii maiden inoculated with ectomycorrhizal fungi

Compatibility between Eucalyptus dunnii and the ectomycorrhizal fungi Hysterangium gardneri and Pisolithus sp. - from Eucalyptus spp. -, Rhizopogon nigrescens and Suillus cothurnatus - from Pinus spp.-, was studied in vitro. Pisolithus sp., H. gardneri and S. cothurnatus colonized the roots. Pisolithus sp. mycorrhizas presented mantle and Hartig net, while H. gardneri and S. cothurnatus mycorrhizas presented only mantle. S. cothurnatus increased phenolics level on roots. Pisolithus sp. and R. nigrescens decreased the level of these substances. The isolates from Eucalyptus seem to be more compatible towards E. dunnii than those from Pinus. The mechanisms involved could be related, at least in the cases of Pisolithus and Suillus, to the concentration of phenolics in roots.

Effects of leaf compounds, climate and natural enemies on the incidence of thrips in cassava

The objective of this study was to determine the effects of rainfall, temperature, sunlight and relative humidity, as well as predators and parasitoids, leaf chemical composition and levels of leaf nitrogen and potassium on the intensity of Scirtothrips manihoti (Thysanoptera: Thripidae) attack on cassava Manihot esculenta Crantz var. Cacau. The leaf compounds (E)-farnesene/trans-farnesol and D-friedoolean-14-en-3-one correlated significantly with the population of S. manihoti. Insect population decreased in the dry and cold season probably due to leaf senescence. Significative correlation was observed between Syrphidae with S. manihoti populations.

Plant compounds insecticide activity against Coleoptera pests of stored products

The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD50 from 2.72 to 39.71 mg g-1 a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis.

Latex production with depolymerizing compounds of actin cytoskeleton in rubber trees

The objective of this work was to assess stimulated latex flow from rubber trees (Hevea brasiliensis) with saturated macrolide (latrunculin A), 1, 5, and 10% potassium iodide in 2% methylcellulose compared with 0.3% ethylene in 2% methylcellulose (check) and 2% methylcellulose (blank). Latex output and contents of pure rubber, total solid, sucrose, inorganic phosphorus, thiol, and Mg2+ were measured. The treatments containing 1% KI or saturated macrolide increased latex yields compared to the blank with 2% methylcellulose alone. The 1% KI or saturated macrolide treatments were equal to that of 0.3% ethylene check treatment. However, 5 and 10% KI were harmful to bark of rubber trees, even caused prolonged tapping panel dryness.

Organic compounds from plant extracts and their effect on soil phosphorus availability

The objective of this work was to evaluate the effect of organic compounds from plant extracts of six species and phosphate fertilization on soil phosphorus availability. Pots of 30 cm height and 5 cm diameter were filled with Typic Hapludox. Each pot constituted a plot of a completely randomized design, in a 7x2 factorial arrangement, with four replicates. Aqueous extracts of black oat (Avena strigosa), radish (Raphanus sativus), corn (Zea mays), millet (Pennisetum glaucum), soybean (Glycine max), sorghum (Sorghum bicolor), and water, as control, were added in each plot, with or without soluble phosphate fertilization. After seven days of incubation, soil samples were taken from soil layers at various depths, and labile, moderately labile and nonlabile P fractions in the soil were analysed. Plant extracts led to an accumulation of inorganic phosphorus in labile and moderately labile fractions, mainly in the soil surface layer (0-5 cm). Radish, with a higher amount of malic acid and higher P content than other species, was the most efficient in increasing soil P availability.

Quantitative genetic analysis of methylxanthines and phenolic compounds in mate progenies

The objective of this work was to determine the contents of methylxanthines, caffeine and theobromine, and phenolic compounds, chlorogenic and caffeic acids, in 51 mate progenies (half-sib families) and estimate the heritability of genetic parameters. Mate progenies were from five Brazilian municipalities: Pinhão, Ivaí, Barão de Cotegipe, Quedas do Iguaçu, and Cascavel. The progenies were grown in the Ivaí locality. The contents of the compounds were obtained by high performance liquid chromatography (HPLC). The estimation of genetic parameters by the restricted maximum likelihood (REML) and the prediction of genotypic values via best linear unbiased prediction (BLUP) were obtained by the Selegen - REML/BLUP software. Caffeine (0.248-1.663%) and theobromine (0.106-0.807%) contents were significantly different (p<0.05) depending on the region of origin, with high individual heritability (ĥ²>0.5). The two different progeny groups determined for chlorogenic (1.365-2.281%) and caffeic (0.027-0.037%) acid contents were not significantly different (p<0.05) depending on the locality of origin. Individual heritability values were low to medium for chlorogenic (ĥ²<0.4) and caffeic acid (ĥ²<0.3). The content of the compounds and the values of genetic parameters could support breeding programs for mate.

Potential of antimicrobial volatile organic compounds to control Sclerotinia sclerotiorum in bean seeds

The objective of this work was to evaluate the potential of an artificial mixture of volatile organic compounds (VOCs), produced by Saccharomyces cerevisiae, to control Sclerotinia sclerotiorum in vitro and in bean seeds. The phytopathogenic fungus was exposed, in polystyrene plates, to an artificial atmosphere containing a mixture of six VOCs formed by alcohols (ethanol, 3-methyl-1-butanol, 2-methyl-1-butanol and phenylethyl alcohol) and esters (ethyl acetate and ethyl octanoate), in the proportions found in the atmosphere naturally produced by yeast. Bean seeds artificially contamined with the pathogen were fumigated with the mixture of VOCs in sealed glass flasks for four and seven days. In the in vitro assays, the compounds 2-methyl-1-butanol and 3-methyl-1-butanol were the most active against S. sclerotiorum, completely inhibiting its mycelial growth at 0.8 µL mL-1, followed by the ethyl acetate, at 1.2 µL mL-1. Bean seeds fumigated with the VOCs at 3.5 µL mL-1 showed a 75% reduction in S. sclerotiorum incidence after four days of fumigation. The VOCs produced by S. cerevisiae have potential to control the pathogen in stored seeds.

Reproducing the organic matter model of anthropogenic dark earth of Amazonia and testing the ecotoxicity of functionalized charcoal compounds

The objective of this work was to obtain organic compounds similar to the ones found in the organic matter of anthropogenic dark earth of Amazonia (ADE) using a chemical functionalization procedure on activated charcoal, as well as to determine their ecotoxicity. Based on the study of the organic matter from ADE, an organic model was proposed and an attempt to reproduce it was described. Activated charcoal was oxidized with the use of sodium hypochlorite at different concentrations. Nuclear magnetic resonance was performed to verify if the spectra of the obtained products were similar to the ones of humic acids from ADE. The similarity between spectra indicated that the obtained products were polycondensed aromatic structures with carboxyl groups: a soil amendment that can contribute to soil fertility and to its sustainable use. An ecotoxicological test with Daphnia similis was performed on the more soluble fraction (fulvic acids) of the produced soil amendment. Aryl chloride was formed during the synthesis of the organic compounds from activated charcoal functionalization and partially removed through a purification process. However, it is probable that some aryl chloride remained in the final product, since the ecotoxicological test indicated that the chemical functionalized soil amendment is moderately toxic.

Color of smoked loin from animals fed with bioactive compounds added to forage

The objective of this work was to evaluate the influence of the breed and of the addition of bioactive substances to forage on the color of smoked pork loin. Two pig breeds (Polish Landrace and the crossbreed Polish Landrace x Duroc), three types of bioactive components (organic selenium; 2% of canola oil and 1% of flaxseed oil; and 2% of flaxseed oil and 1% of canola oil), and a control treatment were evaluated. Computer image analysis included the color assessment of muscle, fat, connective tissues, and smoked loin surface. For Polish Landrace, selenium supplementation caused higher values of red, green, and blue color components of the muscle tissue, which were lower for the crossbreed. However, there was no difference in the color components of loin fat tissue of the Polish Landrace breed due to selenium supplementation. In the case of oil supplementation, values of the color components of the muscle tissue for the Polish Landrace x Duroc crossbreed were also lower. The color components of muscle, fat, connective tissues, and smoked loin surface depend on the pig breed and on the bioactive compounds added to the forage.