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Advisor(s)
Abstract(s)
A maioria da população tende a fazer uso de produtos de origem natural, especialmente a utilização de plantas como alternativa de medicação. O extrato Vernonia condensata, conhecido vulgarmente como Boldo-Baiano, pertence a família Asteracea. É uma planta muito utilizada no Brasil, indicada para tratar distúrbios gastrointestinais e reduzir o colesterol no sangue, assim a sua caracterização permitirá a compreensão das suas potencialidades como agente terapêutico.
O estudo do efeito do extrato aquoso foi iniciado com a preparação do extracto desta planta em forma de infusão e decocção («chás») sendo analisado posteriormente a fim de explicar as atividades biológicas, como a atividade inibitória acetilcolinesterase, inibição da HMG-CoA redutase e a atividade antioxidante.
Analisou-se a composição química do extrato por HPLC-DAD e LC-MS, o que permitiu concluir que os principais compostos presentes nesta planta são o ácido clorogénico e cinarina. Seguidamente, o estudo das atividades biológicas do extracto aquoso foi realizado, apresentando um valor de atividade inibitória do enzima acetilcolinesterase de IC50 decocção de 411 ± 20 μg/ml e atividade antioxidante de EC50 decocção de 20 ± 0,6 μg/mL.
Foi ainda estudado o metabolismo in vitro por ação do suco gástrico usando pepsina a pH1 e suco pancreático usando pancreatina a pH8, simulando assim a digestão gastrointestinal. Os resultados obtidos permitiram concluir que durante o processo de digestão os compostos foram mantidos, não sendo registadas alterações na sua composição química e nem nas suas atividades (atividades antioxidante e inibitória de acetilcolinesterase).
As linhas célulares Caco-2 e HepG-2 foram usadas para testar a toxicidade do extrato aquoso, utilizando o teste MTT. Obteve-se um valor de IC50 decocção de 0,59 ± 0,006 mg / ml para as Caco-2 e um valor de IC50 decocção de 0,58 ± 0,01 mg/ml para as HepG-2, verificando que o extrato dessa planta não é tóxico para estas células.
Em relação à permeabilidade dos compostos do extrato aquoso, verificou-se que o ácido clorogénio permeia, in vitro, a barreira intestinal em maior quantidade do que a cinarina e a decocção de V. condensata foi capaz de reduzir a permeabilidade do colesterol numa quantidade semelhante à do fármaco, nas concentrações utilizadas.
Most people tend to make use of natural products, especially the use of plants as an alternative to medication. The Vernonia condensata extract, commonly known as Bilberry-Baiano, belongs to Asteraceae. It is a plant widely used in Brazil, indicated to treat gastrointestinal disorders and reduce blood cholesterol, thus its characterization will allow the understanding of its potential as a therapeutic agent. The study of the effect of aqueous extract was started with the preparation of the extract of this plant in the form of infusion and decoction ('teas') and subsequently analyzed in order to explain the biological activities such as acetylcholinesterase inhibitory activity, inhibition of HMG-CoA and antioxidant activity. We analyzed the chemical composition of the extract by HPLC-DAD and LC-MS, which showed that the major compounds present in this plant are chlorogenic acid and cynarin. Subsequently, the study of the biological activities of the aqueous extract was performed, showing a value of inhibitory activity of the enzyme acetylcholinesterase decoction IC50 of 411 ± 20 ug/ml and antioxidant activity EC50 decoction of 20 ± 0.6 mg/mL. Metabolism has also been studied in vitro by the action of gastric juices pH1 using pepsin and pancreatic juice using pancreatin pH8, simulating gastrointestinal digestion. The results showed that during the process of digestion the compounds were kept, not being tracked changes in its chemical composition nor in its activities (antioxidant activity and inhibition of acetylcholinesterase). The cell lines Caco-2 and HepG-2 were used to test the toxicity of the aqueous extract using MTT assay. This gave an IC50 value of 0.59 ± 0.006 mg/ml to Caco-2 and an IC50 value decoction 0.58 ± 0.01 mg/ml for the HepG-2, verifying that the extract of this plant do not is toxic to these cells. Regarding the permeability of the compounds of the aqueous extract, it was found that the permeate clorogénio acid in vitro the intestinal barrier in greater quantity than cynarin and V. condensata decoction was able to reduce the permeability of cholesterol in a similar amount the drug at the concentrations used.
Most people tend to make use of natural products, especially the use of plants as an alternative to medication. The Vernonia condensata extract, commonly known as Bilberry-Baiano, belongs to Asteraceae. It is a plant widely used in Brazil, indicated to treat gastrointestinal disorders and reduce blood cholesterol, thus its characterization will allow the understanding of its potential as a therapeutic agent. The study of the effect of aqueous extract was started with the preparation of the extract of this plant in the form of infusion and decoction ('teas') and subsequently analyzed in order to explain the biological activities such as acetylcholinesterase inhibitory activity, inhibition of HMG-CoA and antioxidant activity. We analyzed the chemical composition of the extract by HPLC-DAD and LC-MS, which showed that the major compounds present in this plant are chlorogenic acid and cynarin. Subsequently, the study of the biological activities of the aqueous extract was performed, showing a value of inhibitory activity of the enzyme acetylcholinesterase decoction IC50 of 411 ± 20 ug/ml and antioxidant activity EC50 decoction of 20 ± 0.6 mg/mL. Metabolism has also been studied in vitro by the action of gastric juices pH1 using pepsin and pancreatic juice using pancreatin pH8, simulating gastrointestinal digestion. The results showed that during the process of digestion the compounds were kept, not being tracked changes in its chemical composition nor in its activities (antioxidant activity and inhibition of acetylcholinesterase). The cell lines Caco-2 and HepG-2 were used to test the toxicity of the aqueous extract using MTT assay. This gave an IC50 value of 0.59 ± 0.006 mg/ml to Caco-2 and an IC50 value decoction 0.58 ± 0.01 mg/ml for the HepG-2, verifying that the extract of this plant do not is toxic to these cells. Regarding the permeability of the compounds of the aqueous extract, it was found that the permeate clorogénio acid in vitro the intestinal barrier in greater quantity than cynarin and V. condensata decoction was able to reduce the permeability of cholesterol in a similar amount the drug at the concentrations used.
Description
Tese de mestrado em Química, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2014
Keywords
Vernónia condensata Atividades biológicas Citotoxicidade Colesterol Ácido clorogénico e cinarina Teses de mestrado - 2014