Effects of extract, fractions and 2,3-dihydromyricetin-3-O-α-L-rhamnoside from Pradosia huberi (Ducke) Ducke on rat isolated mesenteric arteries
Pradosia huberi (Ducke) Ducke (Sapotaceae), an Amazonian species, is popularly known as "casca-doce" and used in the folk medicine for the treatment of gastritis. The ethanol extract of the bark contains mainly polyphenolic compounds, which are known to show a large number of activities, including cardioprotective and vasorelaxant effects. The aim of this study was to evaluate the pharmacological properties induced by P. huberi ethanol extract (PHEE) and fractions and 2-3-dihydromyricetin-3-O-α-L-rhamnoside derived from this extract, in isolated rat mesenteric arteries. PHEE was separated and the following fractions were obtained: CHCl3, CHCl3:AcOEt (1:1), AcOEt, AcOEt:MeOH (1:1) and MeOH. We isolated 2-3-dihydromyricetin-3-O-α-L-rhamnoside from the MeOH fraction, which was identified by¹H and 13C NMR spectra and compared with data in the literature. PHEE (1-100 µg/mL) induced concentration-dependent relaxations of 10 µM phenylephrine-induced tone (EC50=17,1±2,9 µg/mL; Emax=87.4±2.9 %, n=8). The MeOH fraction also relaxed mesenteric rings (EC50=31±2.0 µg/mL; Emax=54±12.5%, n=6) but less effectively when compared to PHEE. Both effects were completely abolished after removal of the vascular endothelium. The AcOEt:MeOH (1:1) fraction and the isolated flavonoid were ineffective in eliciting vasorelaxation. The study demonstrates that PHEE and MeOH fraction of Pradosia huberi possess a vasorelaxant effect, which may be completely dependent upon endothelium. The isolated flavonoid is not responsible for this vasorelaxant effect.
| Main Authors: | , , , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedade Brasileira de Farmacognosia
2010
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-695X2010000400013 |
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