Abstract
The vasodilator effects of Ouratea semiserrata stem hydroethanolic extract (OSE) and its ethyl acetate fraction (OSR) were evaluated in endothelium-intact aortic rings. OSR produced a more potent vasodilatation (IC50 = 3.5 ± 0.8 μg/ml) than OSE (IC50 > 30 μg/ml). OSR also presented a higher content of total proanthocyanidins (21.8 ± 1.5 %) in comparison to OSE (6.5 ± 0.4 %), suggesting that compounds of this class play a role in the vasorelaxing activity. The vasodilatation mechanism of OSR was further investigated. In endothelium-intact aortic rings, its vasorelaxing effect was completely abolished by L-NAME (300 μM), a nitric oxide (NO) synthase inhibitor, but not by a muscarinic antagonist (atropine, 1 μM) nor by a cyclo-oxygenase inhibitor (indomethacin, 10 μM). The OSR vasodilator effect was completely abolished in endothelium-denuded vessels. Furthermore, OSR did not change the vasodilatation produced by SIN-1, an NO donor, in endothelium-denuded vessels. These findings led us to conclude that OSR, a proanthocyanidin rich fraction of O. semiserrata, induces vasodilatation by a mechanism dependent on endothelium-derived factors, likely NO.
Key words
Ouratea semiserrata
- Ochnaceae - proanthocyanidin-rich fraction - vasodilator effects - rat aorta - nitric oxide
References
-
1 Corrêa M P. Dicionário de Plantas Úteis do Brasil e das Exóticas Cultivadas. Vol. 1 - 6 Rio de Janeiro; J Di Giorgio 1974
-
2
Braga F C, Wagner H, Lombardi J A, Oliveira A B.
Screening the Brazilian flora for antihypertensive plant species for in vitro angiotensin-I-converting enzyme-inhibiting activity.
Phytomedicine.
2000;
245
245-50
-
3
Velandia J R, De Carvalho M G, Braz-Filho R.
Novel trichloro- and tetrachloroisoflavones isolated from Ouratea semiserrata
.
Nat Prod Lett.
1998;
12
191-8
-
4
Delle Monache F, D’Albuquerque I L, Marini-Bettolo G B.
Su di una nuova proantocianidina dimera da Ouratea
.
Ann Chim.
1967;
57
1364-71
-
5
Delle Monache F, Ferrari F, D’Albuquerque I L, Marini-Bettolo G B.
Sterechimica delle proantocianidine da Ouratea sp. (Ochnaceae).
Farmaco.
1970;
25
96-105
-
6
Hertog M GL, Feskens E JM, Hollman P CH, Katan M B, Kromhout D.
Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study.
Lancet.
1993;
342
1007-11
-
7
Knekt P, Jarvinen R, Reunanen A, Maatela J.
Flavonoid intake and coronary mortality in Finland: a cohort study.
Br Med J.
1996;
312
478-81
-
8
Muldoon F M, Kritchevsky S B.
Flavonoids and heart disease.
Br Med J.
1996;
312
458-9
-
9
Duarte J, Vizcaíno F P, Utrilla P, Jiménez J, Tamargo J, Zarzuelo A.
Vasodilatory effects of flavonoids in rat aortic smooth muscle. Structure-activity relationships.
Gen Pharmacol.
1993;
24
857-62
-
10
Herrera M D, Zarzuelo A, Jiménez J, Marhuenda E, Duarte J.
Effects of flavonoids on rat aortic smooth musckle contractility: structure-activity relationships.
Gen Pharmacol.
1996;
27
273-7
-
11
Fitzpatrick D F, Hirschfield S L, Coffey R G.
Endothelium-dependent vasorelaxing activity of wine and other grape products.
Am J Physiol.
1993;
65
774-8
-
12
Anbriambeloson E, Magnier C, Haan-Archipoff G, Lobstein A, Anton R, Beretz A, Stoclet J C.
Natural dietary polyphenolic compounds cause endothelium-dependent vasorelaxation in rat thoracic aorta.
J Nutr.
1998;
128
2324-33
-
13
Lemos V S, Freitas M R, Muller B, Lino Y D, Queiroga C EG, Côrtes S F.
Dioclein, a new nitric oxide- and endothlium-dependent vasodilator flavonoid.
Eur J Pharmacol.
1999;
386
41-6
-
14
Lüscher T F.
The endothelium in hypertension: bystander, target or mediator?.
J Hypertens.
1994;
12
S105-116
-
15
Vanhoutte P M, Boulanger C M.
Endothlium-dependent responses in hypertension.
Hypertens Res.
1995;
18
87-98
-
16
Hiermann A, Kartnig T h, Azzam S.
Ein Beitrag zur quantitativen Bestimmung der Procyanidine in Crataegus
.
Sci Pharm.
1986;
54
331-7
-
17
Middleton E, Kandaswami C, Theoharides T C.
The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer.
Pharmacol Rev.
2000;
52
673-751
-
18
Packer L, Rimbach G, Virgili F.
Antioxidant activity and biologic properties of a procyanidin-rich extract from pine (Pinus maritima) bark, pycnogenol.
Free Rad Biology Med.
1999;
27
704-24
-
19
Mombouli J V, Vanhoutte P M.
Endothelial dysfunction: from physiology to therapy.
J. Mol. Cell. Cardiol..
1999;
31
61-74
-
20
Moncada S, Palmer R MJ, Higgs E A.
Nitric oxide: physiology, pathophysiology, and pharmacology.
Pharmacol Rev.
1991;
43
109-42
-
21
Busse R ., Fleming I.
Endothelial dysfunction in atherosclerosis.
J Vasc Res.
1996;
33
181-94
-
22
Rice-Evans C A, Miller N J, Paganga G.
Structure-antioxidant activity relationships of flavonoids and phenolic acids.
Free Rad Biol Med.
1996;
20
933-56
-
23
Andriantsitohaina R, Andriambeloson E, Stoclet J C.
Pharmacological approaches of endothelial nitric oxide-dependent vasorelaxation induced by polyphenols from plant extracts.
Methods Enzymol.
1999;
301
522-32
Fernão Castro Braga
Faculdade de Farmácia da UFMG
Av. Olegário Maciel 2360
CEP 30.180-112
Belo Horizonte
Brazil
Phone: +55 31 3339-7675
Fax: +55 31 3339-7666
Email: fernao@dedalus.lcc.ufmg.br