Metodologias analíticas para determinação do perfil químico, atividade imunomoduladora e citotóxica do látex de Euphorbia tirucalli L

• Ano de defesa: 2019
• Autor(a) principal: Souza, Larissa Silva de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Química; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Química
• Palavras-chave em Português: Triterpenes; Immunomodulatory activity; Cytotoxic activity; Euphorbia tirucalli L.; Triterpenos; Atividade imunomoduladora; Atividade citotóxica; Látex; Ésteres; Química; 54
• Link de acesso: http://repositorio.ufes.br/handle/10/10785

Euphorbia tirucalliL. is widely used by Brazilian popular medicine, mainly for its anticancer activity. However, its commercialization was banned by ANVISA due to the presence of some compounds considered toxic, such as diterpene esters. Therefore, the present study characterized the latex of this plant by different analytical methods as well as analyzed its immunomodulatory and cytotoxic activity. The latex was collected by two procedures in dichloromethane: methanol solution (3: 1, 100 mL) and in 100 mL of distilled water.The former was concentrated as a crude extract and the second was partitioned with hexane and dichloromethane. Partitions and crude extract were subjected to phytochemical analysis using three different methods: FT-ICR MS (ESI (-) and APCI (+)), GC-MS andNMR (1H-NMR, 13C NMR, COSY, HSQC and HMBC). The cytotoxic potential was evaluated using the crude extract in RAW 264.7 and AGS macrophages. The evaluation of immunomodulatory activity was made through the detection of nitric oxide and cytokines such as TNF-aand IL-6. The CG-MS technique showed the presence of some esters of fatty acids, such as myristic, palmitic, stearic, oleic and linoleic and, mainly, triterpenes such as euphol and tirucallol. By NMR, most of the signals were related to the triterpenoids euphol and tirucallol. However, when the latex was analyzed by ESI (-) FT-ICR MS, a large variety of molecules of different classes of natural products (fatty acids, diterpenes, triterpenes, steroids) were found. By APCI (+) FT-ICR MS, the ion in m/z426,38, related to the mass of the euphol and tirucallol triterpenes, was the most intense peak, with mass error -0.11, indicating high precision. The diterpene esters of 4-deoxyphorbol and ingenol were identified only by ESI (-) FT-ICR MS and by ESI (-) FT-ICR MS/MS. When biologically evaluated, the crude latex showed immunomodulatory activity, since it reduced the production of proinflammatory cytokines TNF-a, IL-6 and NO, and the effect on NO reduction was more expressive, obtaining results similar to the standard L-NAME, as well as significant cytotoxic activity (IC50=69.43 ± 1.29 µg/mL) against gastric adenocarcinoma cells (AGS) without damaging healthy cells. Thus, it was found that Euphorbia tirucalli latex consists mainly of the triterpenes euphol and tirucallol, which may be the main responsible for the antineoplastic activity attributed to the plant, but many other smaller compounds can be determined by FT-ICR MS, such as diterpene esters . It has antitumor potential, as it acts selectively against cancerous cells and still prevents the progression of the tumor, since it has an important immunomodulatory effect.