ATIVIDADE BIOLÓGICA DE Vassobia breviflora (Sendtn.) Hunz. (SOLANACEAE), FRENTE À CÉLULAS B16F10 E MODELO IN VIVO DE MELANOMA

• Autor(a) principal: Viana, Altevir Rossato
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional Universidade Franciscana
• Texto Completo: http://www.tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/608
• topic: Antioxidante, Antitumoral, Citotoxicidade, Solanaceae, C57BL/6.; Antioxidant, Antitumor, Cytotoxicity, Solanaceae, C57BL/6; Ciências da Saúde e da Vida

Cancer is the second largest cause of death in the world, only behind cardiovascular disease. This pathology is able to circumvent mechanisms of proliferative suppression, growing and surviving in hostile environments. Melanoma is a type of malignant tumor, has high metastatic potential and may be resistant to conventional anticancer agents. Although it does not correspond to the most frequent type of neoplasia, it represents a high mortality rate because of its capacity of metastases and as untreated difficulties. Due to these factors, the search for alternatives is highly encouraged. Many of the anticancer medicaments have their origin from natural, semi-synthetic and synthetic products. In Brazil, due to the richness of the national flora and the lack of knowledge about its bioactive products, the projects that seek this knowledge are important. The objective of the present study was to verify the antitumor activity in vitro and in vivo of a plant of the family Solanaceae, present in Rio Grande do Sul. Vassobia breviflora is known for its antitumor potential, mainly due to the presence of vitanolides, Withaferin A (WA). However, the studies found with the Brazilian plant are scarce. The vegetal species used in the work was extracted from a private property in the region of Boca do Monte, in the municipality of Santa Maria, RS. It was cataloged by the herbarium of the Federal University of Santa Maria and its aqueous extract was prepared with the dried leaves, extracted at room temperature. Controls were made using the commercially acquired WA active principle and the standard chemotherapy for melanoma, Temozolomide. Verification of the amount of WA was conducted by high performance liquid chromatography (HPLC). The tests for the detection of antioxidant compounds in the extract were made from the analysis of total phenols, diammonium salt - 2,20-azino-bis (acid 3-ethylbenzthiazoline-6-sulfônico) (ABTS) e 2,2-diphenyl-1-picrylhydrazil (DPPH). The cytotoxic potential was investigated from the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT), in B16F10 cells. In vivo tests were conducted in the C57BL/6 line of isogenic mice, inoculated subcutaneously with the B16F10 line melanoma and treated for 30 days orally with the different treatments. The project was approved by the institution's animal ethics committee. During the treatment period, the weights of the animals were checked weekly with the aid of an analytical balance. The volume of the tumor by the measurement of the tumor mass, with a digital caliper and the survival time by the Kaplan Meyer curve. After the euthanasia of the animals, they had the tumors removed and weighed. In addition, other organs, such as spleen, lymph node, liver, lung, brain and kidney were removed and fixed for later histopathological analysis, and properly conditioned and frozen for biochemical and gene analyzes. The statistic of the results was performed by the statistical package for the social (SPSS) version 23.0. To compare the treatments, one-way analysis of variance (ANOVA) was performed, followed by the Tukey post hoc test. The results demonstrated a presence of WA in the aqueous extract of Brazilian Vassobia breviflora, as well as its antioxidant potential. The MTT assay in the B16F10 cell line showed cytotoxic ability of treatment with the aqueous extract of Vassobia breviflora, when compared to the controls. In the in vivo model the survival of the animals treated with the combination between the aqueous extract in the highest concentration and the chemotherapeutic Temozolomide was better in relation to the other treatments, compared to the control. The weight and volume of the tumors in the different treatments used did not vary significantly in relation to the control group. It is concluded that from the in vitro results, the plant species studied has a cytotoxic potential. However, for the in vivo assays, it is believed that the aqueous extract does not have a significant potential in the control of melanoma development, requiring models with the use of the ethanolic extract and other fractions of the constituents of the vegetal species for the best evaluation. As well as the use of melanoma induction by other routes of inoculation. Ex vivo tests will be needed to better elucidate the activity of the plant against this model of melanoma.