Potencial inibitório do ácido elágico sobre a formação do complexo Keap1-Nrf2: implicações terapêuticas em doenças crônico-degenerativas / Inhibitory potential of ellagic acid on the formation of the keap1-Nrf2 complex: Therapeutical implications in chronic-degenerative diseases

Objetivos ­ Avaliar o potencial inibitório do ácido elágico sobre as interações do complexo Keap1-Nrf2, com o intuito de esclarecer um dos eventuais mecanismos associado à atividade antioxidante do ácido elágico. Métodos ­ Foram empregadas simulações de docagem molecular para prever o modo de ligação do ácido elágico no sítio ligante da proteína Keap1, o qual foi comparado com o modo de ligação obtido experimentalmente e descrito na literatura para o ligante natural, a proteína Nrf2, e um potente inibidor monoácido do complexo Keap1-Nrf2. Resultados ­ As simulações de docagem revelaram que o ácido elágico apresenta potencial para realizar uma rede de ligações de hidrogênio com resíduos de aminoácidos da proteína Keap1 considerados importantes para o reconhecimento do Nrf2, se assemelhando ao perfil observado para inibidores do complexo Keap1-Nrf2 descritos na literatura. Conclusão ­ O ácido elágico apresenta características químicas e espaciais favoráveis para a inibição do complexo Keap1-Nrf2 e a elucidação do seu modo de ligação pode auxiliar na identificação de novos produtos naturais com propriedades antioxidantes e potencializar o desenvolvimento de fármacos contra doenças crônico-degenerativas.

Process optimization of physicochemical properties of spray-dried Hydrocotyle umbellata L. extract

Abstract Hydrocotyle umbellata L., Araliaceae, is a species that is recommended in Ayurvedic medicine for its effects on the central nervous system, such as anxiolytic and memory-stimulant effects. Despite the medicinal potential of this species, its phytopharmaceutical and technological potential to produce standardized extracts has not been investigated. This study analyzes the influence of spray drying parameters on the contents of the chemical markers (total phenolic, total flavonoid, and hibalactone) and the functional properties of H. umbellata extract. The optimization of drying conditions was performed using a central composite design combined with response surface methodology and desirability function approach. The mathematical models fitted to experimental data indicated that all the evaluated drying parameters significantly influenced the chemical contents. The optimal conditions were: inlet temperature of 120 °C, feed flow rate of 4 mL min-1, and colloidal silicon dioxide:maltodextrin ratio of 16%:4%. Under these conditions, the powder samples had spherical particles and desirable physicochemical and functional properties, such as low water activity and moisture content, good product recovery, reconstitution, and flowability. Thus, spray drying might be a promising technique for processing standardized H. umbellata extracts.

Antinociceptive, anti-inflammatory and anxiolytic-like effects of the ethanolic extract, fractions and Hibalactone isolated from Hydrocotyle umbellata L. (Acariçoba) - Araliaceae.

Hydrocotyle umbellata Linn. (Araliaceae) is specie used in the treatment of inflammatory diseases. Crude extract (E-HU) was prepared from H. umbellata subterraneous parts and fractionated by liquid-liquid partition, resulting hexane fraction (HF-HU), dichloromethane fraction (DF-HU), ethyl acetate fraction (EAF-HU) and aqueous fraction (AF-HU). The hibalactone (HU-1) was isolated from the DF-HU and its structure was elucidated by 1H NMR and 13C NMR Spectroscopy, mass spectrometry and crystallographic x-ray analysis. The formalin-induced nociception was used to evaluate antinociceptive activity; carrageenan-induced edema and pleurisy tests to evaluate anti-inflammatory activity and light-dark box to evaluate anxiolytic-like activity in mice. The acute oral treatments with E-HU (1000mg/kg), DF-HU (150mg/kg), EAF-HU (400mg/kg) and HU-1 (33mg/kg) decreased the licking time in both phases of the formalin test. In the carrageenan-induced inflammation models, the treatment with the same doses of E-HU, DF-HU, EAF-HU and HU-1 reduced the paw edema formation and leukocytes account into pleural cavity. In silico findings suggest that hibalactone present anti-inflammatory activity by interacting with the enzymes 5-lipoxygenase and cyclooxygenase-2. In the light dark box, the treatments with DF-HU, EAF-HU and HU-1 revealed an anxiolytic like effect. Thus, the E-HU and fractions of H. umbellata showed antinociceptive, anti-inflammatory and anxiolytic like activities, as also hibalactone, a possible phytoconstituent responsible for the biological effects of this specie.

Search for a platelet-activating factor receptor in the Trypanosoma cruzi proteome: a potential target for Chagas disease chemotherapy

Chagas disease (CD) causes the highest burden of parasitic diseases in the Western Hemisphere and is therefore a priority for drug research and development. Platelet-activating factor (PAF) causes the CD parasite Trypanosoma cruzi to differentiate, which suggests that the parasite may express PAF receptors. Here, we explored the T. cruzi proteome for PAF receptor-like proteins. From a total of 23,000 protein sequences, we identified 29 hypothetical proteins that are predicted to have seven transmembrane domains (TMDs), which is the main characteristic of the G protein-coupled receptors (GPCRs), including the PAF receptor. The TMDs of these sequences were independently aligned with domains from 25 animal PAF receptors and the sequences were analysed for conserved residues. The conservation score mean values for the TMDs of the hypothetical proteins ranged from 31.7-44.1 percent, which suggests that if the putative T. cruzi PAF receptor is among the sequences identified, the TMDs are not highly conserved. These results suggest that T. cruzi contains several GPCR-like proteins and that one of these GPCRs may be a PAF receptor. Future studies may further validate the PAF receptor as a target for CD chemotherapy.

Search for a platelet-activating factor receptor in the Trypanosoma cruzi proteome: a potential target for Chagas disease chemotherapy.

Chagas disease (CD) causes the highest burden of parasitic diseases in the Western Hemisphere and is therefore a priority for drug research and development. Platelet-activating factor (PAF) causes the CD parasite Trypanosoma cruzi to differentiate, which suggests that the parasite may express PAF receptors. Here, we explored the T. cruzi proteome for PAF receptor-like proteins. From a total of 23,000 protein sequences, we identified 29 hypothetical proteins that are predicted to have seven transmembrane domains (TMDs), which is the main characteristic of the G protein-coupled receptors (GPCRs), including the PAF receptor. The TMDs of these sequences were independently aligned with domains from 25 animal PAF receptors and the sequences were analysed for conserved residues. The conservation score mean values for the TMDs of the hypothetical proteins ranged from 31.7-44.1%, which suggests that if the putative T. cruzi PAF receptor is among the sequences identified, the TMDs are not highly conserved. These results suggest that T. cruzi contains several GPCR-like proteins and that one of these GPCRs may be a PAF receptor. Future studies may further validate the PAF receptor as a target for CD chemotherapy.