RESUMO
Açai (Euterpe oleracea Mart.) a fruit from the Amazon region, largely consumed in Brazil is rich in polyphenols. Experiments were undertaken to determine whether hydro-alcoholic extract obtained from stone of açaí induces a vasodilator effect in the rat mesenteric vascular bed precontracted with norepinephrine (NE) and, if so, to elucidate the underlying mechanism. Açai stone extract (ASE, 0.3-100 microg) induced a long-lasting endothelium-dependent vasodilation that was significantly reduced by N(G)-nitro-l-arginine methyl ester (l-NAME) and (1)H-[1,2,3] oxadiazolo [4,4-a] quinoxalin-l-one (ODQ) and abolished by KCl (45 mM) plus l-NAME. In vessels precontrated with NE and KCl (45 mM) or treated with K(Ca)(+2) channel blockers (charybdotoxin plus apamin), the effect of ASE was significantly reduced. However this effect is not affect by indomethacin, glybenclamide and 4-aminopiridine. Atropine, pyrilamine, yohimbine and HOE 140 significantly reduced the vasodilator effect of acetylcholine, histamine, clonidine and bradykinin, respectively, but did not change the vasodilator effect of ASE. In cultured endothelial cells ASE (100 microg/mL) induced the formation of NO that was reduced by N(G)-nitro-l-arginine (l-NA, 100 microM). The present study demonstrates that the vasodilator effect of ASE is dependent on activation of NO-cGMP pathway and may also involve endothelium-derived hyperpolarizing factor (EDHF) release. The vasodilator effect suggest a possibility to use ASE as a medicinal plant, in the treatment of cardiovascular diseases.
Assuntos
Arecaceae , Endotélio Vascular/efeitos dos fármacos , Artérias Mesentéricas/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Animais , Arecaceae/química , Fatores Biológicos/metabolismo , Brasil , Células Cultivadas , GMP Cíclico/metabolismo , Relação Dose-Resposta a Droga , Células Endoteliais/efeitos dos fármacos , Endotélio Vascular/metabolismo , Fatores Relaxantes Dependentes do Endotélio/metabolismo , Frutas , Guanilato Ciclase/metabolismo , Masculino , Mesentério/irrigação sanguínea , Óxido Nítrico/metabolismo , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Plantas Medicinais , Canais de Potássio/efeitos dos fármacos , Ratos , Ratos Wistar , Fatores de Tempo , Vasoconstritores/farmacologia , Vasodilatadores/isolamento & purificaçãoRESUMO
Morphogenesis from several explant types excised from in-vitro-grown plantlets of a Brazilian eggplant (Solanum melongena L.) variety (F-100) was evaluated in response to thidiazuron (TDZ). Leaves and cotyledons were found to be the most responsive explants. Optimal shoot bud induction rates (75-100 buds/explant) were achieved in the presence of 0.2 µM TDZ. Organogenic calli were transferred to growth regulator free MS medium before shoot excision. Rooting was induced on half-strength MS medium supplemented with 0.6 µM IAA.
