ACE activity during the hypotension produced by standardized aqueous extract of Cecropia glaziovii Sneth: A comparative study to captopril effects in rats

ACE activity during the hypotension produced by standardized aqueous extract of Cecropia glaziovii Sneth: A comparative study to captopril effects in rats

Author Ninahuaman, M. F. M. L. Google Scholar
Souccar, C. Google Scholar
Lapa, A. J. Google Scholar
Lima-Landman, M. T. R. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract To evaluate the effect of the standardized aqueous extract (AE) of Cecropia glaziovii Sneth on the plasma angiotensin I converting enzyme (ACE-EC 3.4.15. 1) activity, rats were treated with a single dose of AE (1 g/kg, p.o.) or repeatedly (0.5 g/kg/bid, p.o.) for 60 days. Captopril (50 mg/kg, p.o.) was used as positive control on the same animals. the effects on the blood pressure were recorded directly from the femoral artery (single dose), or indirectly by the tail cuff method (repeated doses) in conscious rats. the plasma ACE activity was determined spectrofluorimetrically using Hypuril-Hystidine-Leucine as substrate. the arterial blood pressure, heart rate and plasma ACE activity were not significantly modified within 24 h after a single dose administration of AE. Comparatively, blood pressure in captopril treated rats was reduced by 7-16% and heart rate was increased by 10-20% from 30 min to 24 h after drug administration. ACE activity after captopril presented a dual response: an immediate inhibition peaking at 30 min and a slow reversal to 32% up-regulation after 24 h. To correlate the drug effects upon repeated administration of either compound, normotensive rats were separated in three groups: animals with high ACE (48.8 +/- 2.6 nmol/min/ml), intermediate ACE (39.4 +/- 1.4 nmol/min/ml) and low ACE (23.5 +/- 0.6 nmol/min/ml) activity, significantly different among them. Repeated treatment with AE reduced the mean systolic blood pressure (121.7 +/- 0.5 min Hg) by 20 min Hg after 14 days. the hypotension was reversed upon washout 60 days afterwards. Likely, repeated captopril administration decreased blood pressure by 20mm Hg throughout treatment in all groups. After 30 days treatment with AE (0.5 g/kg/bid, p.o.) the plasma ACE activity was unchanged in any experimental group. After captopril (50 mg/ kg/bid, p.o.) administration the plasma ACE activity was inhibited by 50% within I h treatment but it was up-regulated by 120% after 12 h in all groups. It is concluded that the hypotension produced by prolonged treatment with AE of C. glaziovii is unrelated to ACE inhibition. (C) 2006 Elsevier GmbH. All rights reserved.
Keywords angiotensin converting enzyme
hypotension
Cecropia glaziovii
phytomedicine
antihypertensive
Language English
Date 2007-05-01
Published in Phytomedicine. Jena: Elsevier Gmbh, Urban & Fischer Verlag, v. 14, n. 5, p. 321-327, 2007.
ISSN 0944-7113 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 321-327
Origin http://dx.doi.org/10.1016/j.phymed.2006.12.010
Access rights Closed access
Type Article
Web of Science ID WOS:000247200100004
URI http://repositorio.unifesp.br/handle/11600/29710

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