Avaliação do efeito do óleo essencial de alpinia zerumbet na reatividade vascular de artérias de resistência de ratos

• Ano de defesa: 2018
• Autor(a) principal: Rocha, Danilo Galvão
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Vasodilatadores; Artérias Mesentéricas; Canais de Cálcio; Óxido Nítrico
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/37846

Alpinia zerumbet is a plant from Zingiberaceae family, popularly known in Brazil as “Colônia”, used for anxiety and systemic arterial hypertension treatment. Several studies have already demonstrated its anti-hypertensive, vasodilator and antioxidant activities, among others, but no research aimed to verify the vasodilator effect of essential oil from Alpinia zerumbet (EOAz) in resistance vessels. Thus, the aim of this study was to evaluate the vasorelaxant effect of EOAz and to assess its mechanism of action in mesenteric small arteries isolated from Wistar rats. Therefore, the effect of EOAz (03 to 3000 µg/mL) was verified by isometric tension, measured in rings of second-order branch of the mesenteric artery (SOBMA), with intact endothelium, pre-contracted by KCl (80 mM) and U-46619 (03 µM). To study the mechanism of action, it was evaluated the influence of endothelium presence, and the influence of several inhibitors (TEA, 4-AP, Glybenclamide, Atropine, L-NAME, ODQ and indomethacin) on vasodilator effect of EOAz in SOBMA pre-contracted by U-46619. Some protocols were also performed targeting to study Ca2+ influx, through CaCl2 contraction in high K+ medium, as well as Ca2+ release from intracellular storages by caffeine and phenylephrine induced contraction in Ca2+ free medium. Results showed an endothelium-independent vasorelaxant effect of EOAz on SOBMA pre-contracted by KCl, with an EC50 of 33.17 µg/mL (CI95%: 28.11 to 39.38), and U-46619, with an EC50 of 21.52 µg/mL (CI95%: 17.68 to 25.95). Significantly higher potency (P<0,01) was observed for SOBMA pre-contracted by U-46619, when compared to those pre-contracted by KCl. Regarding the inhibitors, only ODQ and L-NAME produced significant alteration on EC50 when compared to Control, with values of 39.47 µg/mL (CI95%: 36.7 to 42.44; P<0,001), and 35.15 µg/mL (CI95%: 33.41 to 37.03), respectively. However, the inhibitors did not cause an Emax reduction. Concerning calcium assays, reduction on muscle contraction caused by incubation with EOAz was observed in all three protocols in a dose-dependent manner. Hence, our results suggest that essential oil of Alpinia zerumbet causes a vasodilator effect, mediated by inhibition of Ca2+ influx and Ca2+ release from intracellular storages, as well as an activation of NOS/GCs pathway.