Bioatividade de fitocompostos da Aloe vera barbadensis em modelos de psoríase In Vitro e In Vivo

• Autor(a) principal: Amorim, Gustavo Modesto de
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/7133
• topic: Psoriasis; Chemerin; Aloeresin and acemannan; Psoríase; Aloe vera; Chemerina; Aloeresina e acemannan; Biotecnologia; 61

Psoriasis is an autoimmune, chronic inflammatory disease, affecting 2-3% of the world population. In the early stages of the disease onset, studies have shown chemerin as a triggering protein playing a key role. Brazilian national essential medicines list (RENAME) proposed the topic usage of Aloe vera barbadensis extract as a therapeutic approach for psoriasis for its immunomodulatory and anti-inflammatory effects. In order to investigate them, we adopted an In Vivo murine model with phenotype similar to psoriasis via topical application of imiquimod (IMQ) and treating animals with 70% Aloe vera cream for further comparison with controls. In addition, animal skin biopsies were tested for the enzymatic activity of the myeloperoxidase (MPO) as an indicator of neutrophil activity. As In Vitro model it was used an immortalized keratinocyte cell line to assess the wound healing potential of the Aloe vera freeze dried extract 200:1 (AVFDE) via Scratch Assay. Later, primary human dermal fibroblasts were used to evaluate the potential modulation on constitutive expression of chemerin and three proinflammatory cytokines. Culture supernatants of dermal fibroblasts were assessed against AVFDE and five of its phytoconstituents including the polyssacharide Acemannan (ACM). For this, we used ELISA and flow cytometry. We partially reproduced In Vivo human psoriatic phenotype in mice via IMQ induction and the MPO activity was shown to be lower in animals treated topically with 70% Aloe vera cream. It was observed in the In Vitro experiments that AVFDE 50ug/ml reduced the expression of MCP-1 chemokine and the concentration of 250ug/ml increased IL-8 expression. ACM 250ug/ml increased the expression levels of IL-8 and IL-6. Acemannan (ACM) at the two tested concentrations significantly reduced chemerin expression. Aloeresin A 20uM increased IL-6 expression. Either tested phytosterol, at any concentration range elicited effects on the expression levels of cytokines or chemerin. The results suggested that the therapeutic usage of Aloe vera extract as an immunomodulatory and / or anti inflammatory agent must be further evaluated. Although the extract demonstrated a potential benefit in the treatment of early stages of psoriasis it is essential that commercial plant extracts are standardized with a minimum content of bioactive phytocompounds as Acemannan within the marketed pharmaceutical formulations as stated by related regulatory organisms.