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Atividade hipoglicemiante da у-conglutina (Lupinus albus): antevisão de um possível mecanismo de ação via lectina
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A у-conglutina, é uma proteína com atividade de lectina, extraída da semente seca do Lupinus albus, estando descrita por ter efeito hipoglicemiante, em modelo animal e na espécie humana. Neste trabalho, explorou-se a competência de lectina desta proteína, para explicar uma possível relação, com o seu efeito hipoglicemiante. Os resultados revelam que a у-conglutina liga-se in vitro, à insulina humana e aos receptores glicosilados das HepG2 (células dos hepatócitos humanos), podendo significar que a у-conglutina poderá ligar-se aos receptores membranares da insulina das células HepG2, por um mecanismo via lectina, podendo apresentar uma ação mimética à da insulina ajudando na recaptação da glucose. Foi igualmente comprovada in vivo o seu efeito hipoglicemiante quando administrada em ratinhos (60 mg/kg), na sua forma nativa. Estudos sobre a y-conglutina desnaturada e a repercussão na atividade de lectina, resultaram em resultados inesperados nos ensaios in vivo, uma vez que a administração da у-conglutina desnaturada em ratinhos (60 mg/kg) apresentou, tal com a y-conglutina nativa, um efeito hipoglicemiante. Este efeito hipoglicemiante da у-conglutina desnaturada, revelou ser mais intenso nos primeiros 30 min, comparativamente ao efeito causado pela у-conglutina na sua forma nativa, para o mesmo período de tempo. Do mesmo modo, a у-conglutina desnaturada liga-se à insulina humana em ensaios in vitro, o que contraria os dados existentes na literatura.
у-Conglutin, a lectin like protein extracted from the dry seed of Lupinus albus, is well known for its hypoglycemic effect on human and animal models. In this work we explored if у-conglutin being a lectin has a possible relationship with its hypoglycemic effect. The results showed that у-conglutin links to the human insulin in in vitro assays and that this protein links to the glycosylated receptors of the human hepatocyte cells (HepG2) membrane. These findings could mean that у-conglutin links to the insulin receptor, by a lectin mechanism, and could have a mimetic action of this hormone helping in the recapture of glucose. We also proved, in in vivo assays, the hypoglycemic effect of у-conglutin when administrated to mice’s (60 mg/kg) when the native structure was preserved. We also studied the repercussion in the lectin activity of у-conglutin when this protein was denaturated. We had some unexpected results in in vivo assays because the administration of denaturated у-conglutin to mice’s (60 mg/kg) led to a hypoglycemic effect, just like у-conglutin in her native form. In the first 30 minutes, this effect was more intense for the у-conglutin denaturated than the у-conglutin in native form. The unexpected results don’t stop here since у-conglutin denaturated also binds to the human insulin in vitro assays, results that go against other data showed.
у-Conglutin, a lectin like protein extracted from the dry seed of Lupinus albus, is well known for its hypoglycemic effect on human and animal models. In this work we explored if у-conglutin being a lectin has a possible relationship with its hypoglycemic effect. The results showed that у-conglutin links to the human insulin in in vitro assays and that this protein links to the glycosylated receptors of the human hepatocyte cells (HepG2) membrane. These findings could mean that у-conglutin links to the insulin receptor, by a lectin mechanism, and could have a mimetic action of this hormone helping in the recapture of glucose. We also proved, in in vivo assays, the hypoglycemic effect of у-conglutin when administrated to mice’s (60 mg/kg) when the native structure was preserved. We also studied the repercussion in the lectin activity of у-conglutin when this protein was denaturated. We had some unexpected results in in vivo assays because the administration of denaturated у-conglutin to mice’s (60 mg/kg) led to a hypoglycemic effect, just like у-conglutin in her native form. In the first 30 minutes, this effect was more intense for the у-conglutin denaturated than the у-conglutin in native form. The unexpected results don’t stop here since у-conglutin denaturated also binds to the human insulin in vitro assays, results that go against other data showed.
Descrição
Tese de mestrado, Qualidade Alimentar e Saúde, 2020, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Lupinus albus у-conglutina Lectina Diabetes Atividade hipoglicemiante Teses de mestrado - 2020