Metabólitos secundários de origem vegetal: uma fonte potencial de fármacos antitrombóticos

Cardiovascular diseases are responsible for the largest number of deaths among humans worldwide, including heart attacks, strokes, and thrombosis. The treatment of thrombosis is generally through the administration of anticoagulant and/or antiplatelet drugs, which have some clinical limitations. Plants synthesize a wide variety of bioactive metabolites in response to different stimuli. This review focuses on a number of molecules of vegetal origin belonging to different chemical classes, with significant anticoagulant and antiplatelet effects. Their promising antithrombotic profile confirms the potential of natural products as a source of lead molecules for drug development in the prevention and treatment of thrombosis.

Estudio teórico de la isomerización del ácido maleico en ácido fumárico: un enfoque basado en el concepto de superficie de energía potencial

A comparative study based on potential energy surfaces (PES) of 2-butanedioic and hypothetic 2-butanedioic/HCl acids is useful for understanding the maleic acid isomerization. The PES enables locating conformers of minimum energy, intermediates of reactions and transition states. From contour diagrams, a set of possible reaction paths are depicted interconnecting the proposed structures. The study was carried out in absentia and in the presence of the catalyst (HCl), using an solvatation model provided by the Gaussian software package. Clearly, the effect of HCl is given by new reaction paths with lower energetic barriers in relation to the reaction without catalyzing.

Alvejamento químico de caulins Brasileiros: efeito do potencial eletroquímico da polpa e do ajuste do pH

Samples of Kaolin from different regions in Brazil were characterized by XRD, SEM and chemical analysis. A chemical bleaching study with pH adjustment was accomplished with the fractions below 37 μm, after classification by screening. The main objective was to evaluate the conditions of chemical bleaching that most increase the brightness of these kaolin's samples. Increases between 2.63 and 2.98% in the brightness (ISO) were observed after the chemical bleaching. We could say that the reduction of Fe3+ to Fe2+ during the chemical bleaching promoted an increase in the brightness, based on the Pourbaix Diagrams.

Caracterização espectroscópica multivariada do potencial antioxidante de vinhos

In this work the antioxidant capacity of red wine samples was characterized by conventional spectroscopic and chromatographic methodologies, regarding chemical parameters like color, total polyphenolic and resveratrol content, and antioxidant activity. Additionally, multivariate calibration models were developed to predict the antioxidant activity, using partial least square regression and the spectral data registered between 400 and 800 nm. Even when a close correlation between the evaluated parameters has been expected many inconsistencies were observed, probably on account of the low selectivity of the conventional methodologies. Models developed from mean-centered spectra and using 4 latent variables allowed high prevision capacity of the antioxidant activity, permitting relative errors lower than 3%.

Materiais híbridos orgânico-inorgânicos (ormosil) obtidos por sol-gel com potencial uso como filtro solar

This work aimed at the synthesis and characterization of particles of modified silica containing the organic filter dibenzoylmethane (DBM) by the hydrolytic sol-gel method, with modifications to the Stöber route. The structures of the resulting Xerogels were characterized by diffuse reflectance UV-VIS spectroscopy in the solid state, infrared absorption spectroscopy, Scanning Electron Microscopy (SEM) and 29Si Nuclear Magnetic Resonance (29Si NRM). The results showed favorable formation of hybrid organic-inorganic nanoparticles with efficient absorption/reflectance of radiation in the UV / VIS range, which enables their potential use as sunscreen.

Sorção de atrazina e de mesotriona em latossolos e estimativa do potencial de contaminação

Following application herbicides usually reach the soil and undergo several dissipation processes which determine their effects on target organisms and on the environment. This work aimed to evaluate atrazine and mesotrione sorption in Oxisols and estimate their potential impact on the environment. We observed that atrazine sorption was influenced by soil organic matter content and its hydrophobic character. Clay fraction was the main factor influencing mesotrione sorption followed in a lesser extent by soil organic matter content. In contrast to atrazine, mesotrione retention was favored by the higher carboxylic substitution in the aliphatic chains of soil organic matter. Atrazine and mesotrione were considered compounds that are likely to pose an appreciable risk of causing deleterious effects on the environment.

Synthesis of geranylhydroquinone derivatives with potencial cytotoxic activity

Natural geranylhydroquinone 1 and geranyl-p-methoxyphenol 2 were prepared by Electrophilic Aromatic Substitution (EAS) reactions between geraniol and 1,4-hydroquinone or p-methoxyphenol respectively, using BF3∙Et2O as a catalyst. Furthermore, natural geranylquinone 3, geranyl-1,4-dimethoxyquinone 4 and the new geranyl-4-methoxyphenyl acetate 5 were obtained by chemical transformations of 1 and 2. The compounds were evaluated for their in vitro cytotoxicity activities against cultured human cancer cells of PC-3 human prostate cancer, MCF-7 and MDA-MB-231 breast carcinoma, and Dermal Human Fibroblasts DHF. IC50 values were in the µM range.

Potencial da palha de cana-de-açúcar para produção de etanol

Sugarcane straw biomass accounts for 1/3 of the energy potential of sugarcane and represents a rich source of sugars. Studies have been intensified for the use of this biomass along with bagasse for the production of cellulosic ethanol. Development of this technological path will allow for taking full advantage of sugarcane, increasing ethanol production without expanding the area cultivated. However, in order for this technology to be viable certain challenges must be overcome, including establishment of appropriate conditions of pretreatment and hydrolysis of these materials for release of fermentable sugars.

Absorção de bário por plantas de arroz (Oryza sativa L.) e mobilidade em solo tratado com baritina sob diferentes condições de potencial redox

Two parallel tests were carried out to evaluate barium solubility in soils treated with barite under reducing conditions: one in leaching columns and another with potted plants cultivated with rice. Soils were treated with three doses of barite and kept at two humidity levels. The reduction (-200 mV) condition promoted an increase in barium in the geochemical fraction of higher liability, higher concentrations of barium in the leached extracts, and higher absorption by rice plants. As a result of increased uptake and accumulation of barium, the plants showed stunted growth

Isolamento e avaliação do potencial citotóxico de derivados fenólicos de Schinus terebinthifolius Raddi (Anacardiaceae)

The EtOH extract from leaves of S. terebinthifolius was subjected to partition between EtOH:H2O and hexane, CH2Cl2, and EtOAc. The phases obtained were evaluated in vitro against human tumoral cell lines and the EtOAc phase exhibited activity. Chromatographic procedures afforded gallic acid (1), methyl (2) and ethyl (3) gallates, trans-catechin (4), quercitrin (5), and afzelin (6), being the first occurrence of 1, 4 and 6 in S. terebinthifolius.In vitro cytotoxic evaluation of 1 - 6 indicated that gallic acid (1) displayed higher activity than ethyl gallate (3) against HL-60 and HeLa cells, while compounds 2, 4 - 6 were inactive.

Avaliação do potencial anticorrosivo de tiossemicarbazonas solubilizadas em microemulsão

In this paper, thiosemicarbazones 4-N-cinnamoyl-thiosemicarbazone (CTSC), 4-N-(2'-methoxycinnamoyl)-thiosemicarbazone (MCTSC), and 4-N-(4'-hydroxy-3'-methoxybenzoyl)- thiosemicarbazone (HMBTSC) were solubilized in an oil-in-water (O/W) microemulsion system (ME_OCS), forming systems CTSC_ME_OCS, MCTSC_ME_OCS and HMBTSC_ME_OCS. The effectiveness of these systems in the process of inhibiting AISI 1020 carbon steel corrosion was evaluated in a saline solution (NaCl 0.5%), using a galvanostatic method. The tested thiosemicarbazones showed higher inhibitory effects (85.7% for CTSC_ME_OCS, 84.0% for MCTSC_ME_OCS, and 83.3% for HMBTSC_ME_OCS). The surfactant OCS (dissolved in H2O) and the ME_OCS system showed lower efficacies, with 71.0% for OCS and 74.0% for ME_OCS system.

Potencial uso de serpentinito no armazenamento mineral do CO2

Rising anthropogenic CO2 emissions are considered a major contributor to the greenhouse effect. There are several options for reducing atmospheric CO2 levels, and among these alternatives, Carbon Capture and Storage (CCS) has been identified as an effective and promising approach. This work investigated the feasibility of using serpentinite as a vehicle for carbon storage presenting a source-sink match. The main results of the work confirmed that serpentinite is appropriate for the carbonation process due to the high concentration of Mg in its composition.

Avaliação do potencial de uso da hidroxiapatita para fertilização de solos

Plants absorb phosphorus from the soil, which has low levels of this element due to the poor solubility of these compounds in soil and high adsorption capacity of the element by soil particles. Therefore, the purpose of this study was to assess, using hydroxyapatite nanoparticles synthesized in the laboratory, the amount of phosphorus available under different conditions. The results showed that the phosphorus compound had highest solubility in hydroxyapatite sintered at 300°C in an oven for 2h and diluted to 0.05M with MilliQ water, corroborating the theory that the stronger the agglomeration of the nanoparticles, the fewer the pores and the poorer their solubility.

Método hidrometalúrgico para reciclagem de metais terras raras, cobalto, níquel, ferro e manganês de eletrodos negativos de baterias exauridas de Ni-MH de telefone celular

A hydrometallurgical method for the recovery of rare earth metals, cobalt, nickel, iron, and manganese from the negative electrodes of spent Ni - MH mobile phone batteries was developed. The rare earth compounds were obtained by chemical precipitation at pH 1.5, with sodium cerium sulfate (NaCe(SO4)2.H2O) and lanthanum sulfate (La2(SO4)3.H2O) as the major recovered components. Iron was recovered as Fe(OH)3 and FeO. Manganese was obtained as Mn3O4.The recovered Ni(OH)2 and Co(OH)2 were subsequently used to synthesize LiCoO2, LiNiO2 and CoO, for use as cathodes in ion-Li batteries. The anodes and recycled materials were characterized by analytical techniques.

Perfil de flavonoides e avaliação do potencial antioxidante e citotóxico de Bauhinia purpurea (Fabaceae) da região amazônica

Bauhinia purpurea (Fabaceae). Plants of the Bauhinia species (Fabaceae) are used in the treatment of several infections and diseases, especially diabetes. In this paper, with an aim to contribute to the knowledge of the chemistry and therapeutic potential of the Amazonian species of the genus Bauhinia, flavonoid profiles in the leaves and branches of Bauhinia purpurea collected in Manaus and São Gabriel da Cachoeira/AM were analyzed by HPLC-DAD and ESIMS. Differences in the flavonoid profiles were detected along with the presence of rutin and isoquercitrin in the leaves collected in Manaus. All samples showed antioxidant activity, however, no cytotoxic activity against cell lines MDA-MB435 (breast), HCT-8 (colon), and SF-295 (glioblastoma) could be detected.