Navegando por Assunto "Natural products"

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Acesso aberto (Open Access)
Efeito de uma espécie do gênero Varronia sobre a viabilidade celular, atividade antimicrobiana, toxicidade dérmica aguda e o processo de cicatrização (in vitro e in vivo)
(Universidade Federal do Pará, 2019-09-09) RIBERA, Paula Cardoso; FONTES JÚNIOR, Enéas de Andrade; http://lattes.cnpq.br/7056265073849866; https://orcid.org/ 0000-0002-6186-9581
Tissue damage, particularly to the skin, results in damage to cell structures, layers, and lineages to the fullest extent. Under these conditions, wound healing is the physiological process responsible for tissue repair. Inflammation is an important stage in tissue repair and; therefore, a strong target for clinical studies. The species Varronia multispicata is popularly used for the treatment of bruises, with recently discovered anti-inflammatory and analgesic effects. The present work aimed to investigate the effect of aqueous extract of Varronia multispicata leaves (VAR01) on cell viability, antimicrobial analysis, dermal toxicity, and in vitro and in vivo healing. In the in vitro assays, there were evaluated the cell viability in BALB/c 3T3 murine fibroblasts, the antimicrobial action by the microdilution method for determination of minimum inhibitory concentration and petri dish culture technique for the minimum bactericidal concentration. Healing assays were performed in cultured fibroblast monolayers. For in vivo assays in the dermal toxicity test, female Wistar rats were used and divided into the following groups: saline, 100mg/ml, 200mg/ml, and 1000mg/ml of VAR01; as for healing evaluation, Mus musculus mice were used and divided into 4 groups: sham, negative control, treated (VAR01 10%), and positive control (Dersani®). V. multispicata kept the cells viable for 24h, with reduction of fibroblasts in the 48h period at a concentration of 500 µg/ml. It showed no antimicrobial activity, presented in vitro and in vivo injury contraction capacity, did not promote death or behavioral changes, did not cause changes in water and feed intake, weight gain, relative weight, and organ histological analysis, showed a reduction in alkaline phosphatase concentrations in the group treated with 100 mg/ml extract when compared as control group. It was also revealed a reduction in alanine aminotransferase levels in the 100 mg/ml extract-treated group when compared to the control group. However, a significant increase in TGP concentrations was found in the 200 mg/ml group when compared to the control group. While assessing the degree of irritation, VAR01 did not show an irritant profile when administered acutely topically. Therefore, the extract is safe and of low toxicity, promising in the process of tissue regeneration with possible modulation in the inflammatory pathway, being a stimulating result for the following steps of biological activity evaluation and elucidation of the healing process.
Acesso aberto (Open Access)
Estudo da técnica de infusão de resina aplicada à fabricação de compósitos de matriz poliéster reforçados por fibras naturais da Amazônia
(Universidade Federal do Pará, 2014-03-26) RODRIGUES, Jean da Silva; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
In this work were produced unsaturated polyester composites reinforced by fibers of curaua, jute and raffia, arranged in the form of fabric in plan style and aligned fibers. The composites were manufactured by resin infusion process, studying the main parameters that govern the manufacturing method, such as permeability and porosity of the reinforcement and architecture of infusion. Natural fibers were characterized according to their physical, morphological and mechanical properties. The curaua fiber reinforced composites were made using fibers in nature and treated by an alkaline NaOH solution at different concentrations. The composites were characterized in tests of tensile and impact strength, beyond of the determination of their physical properties such as density, porosity and volume fractions of the constituents. The results showed that the composites obtained better performance in tensile and impact were those reinforced with aligned curaua fibers manufactured under vacuum of 101.3 kPa. The evaluation of the cross section of the specimens showed that composites can provide partial saturation of wires or fiber reinforcement due to the vacuum level used mainly in reinforcements in the form of fabric with relatively larger diameter wires. The infusion process proved to be a good method of making composites reinforced with natural fibers, because in addition to being more environmentally friendly because it is a closed mold process, enabled the manufacture of products with high fiber content and good mechanical properties.