Efeito inibitÃrio do extrato aquoso do guaranÃ, do chà verde e da epigalocatecina-3 galato sobre a atividade da enzima que degrada a insulina em prÃstata de rato

AUTOR(ES)

Juliany Silveira Braglia CÃsar Vieira

DATA DE PUBLICAÇÃO

2006

RESUMO

Insulin degrading enzyme (IDE) is an intracellular protein that degrades insulin and others peptides and hormones. Insulin degradation is important both in the control of cellular responses to the hormone and in the interaction of the hormone with their target tissues. Multiple cellular functions are related to the IDE in addition to degradation, including binding and regulatory functions. IDE is regulated in conditions of cellular proliferation and apoptosis, showing an increase or decrease in quantity and activity under these respective conditions. It has been demonstrated that the proteasome function is necessary for cancer cells to survive and that vegetable and fruit consumption are associated in the reduction of cancer risk. Catechins (water-soluble polyphenols) present in many diets including green tea, guarana, fruits and vegetables show inhibitory effects on the proteasome activity and induce tumor cell apoptosis. The present study evaluated the effect of aqueous green tea and guaranà extract (GTE and GE) and the pure catechins found in these extracts, epigallocatechin-3-gallate (EGCG), (-) epicatechin (EC) and (+) catechin (C) on the activity of IDE in vitro. Cytosolic fractions of a rat prostate homogenate were incubated with 125I-insulin in the presence of GTE: 87.5 to 70 μg/ML, GE: 175 to 1400 μg /ML and EGCG: 50 to 300 μg /ML.The results showed that GTE and GE are capable of inhibiting the activity of IDE and that this effect was mimicked only by EGCG. The presence of a gallate group in the EGCG it seems to be important for its inhibitory effect on 125I-insulin degradation, suggesting a structure-activity relationship in this inhibitory effect. The inhibitory effect of guaranà extract may be due to its tannins

ASSUNTO(S)

guaranà catecinas prÃstata chà verde catechins insulin-degrading enzyme green tea enzima que degrada a insulina ciencias biologicas prostate guarana

Documentos Relacionados

• AnÃlise da expressÃo do gene LSP1 no diagnÃstico da hiperplasia prostÃtica benigna e do cÃncer de prÃstata
• Efeito inibitÃrio do prÃ-condicionamento isquÃmico a distÃncia sobre a migraÃÃo de neutrÃfilos: Mecanismos e mediadores.
• Guaraná, a máquina do tempo dos Sateré-Mawé
• Efeito da castraÃÃo e do tratamento com estradiol sobre a quantidade e atividade de enzima que degrada insulina (IDE) em fraÃÃo citosÃlica de Ãtero de ratas
• VariaÃÃes transcricionais dos genes AR, SRD5A2, KLK2, PCA3, KLK3 e PSMA e implicaÃÃes no diagnÃstico molecular do cÃncer de prÃstata