RESUMO
The vasorelaxing effect of the methanol extract of the flowers of Crataegus gracilior, a Mexican medicinal plant used to treat some cardiovascular diseases, was assessed, and its possible chemical markers identified. The extract produced a potent vasodilator effect on isolated rat aortic rings (EC50 = 1.83 ± 1.39 µg/mL; Emax = 100 ± 3.4%). Vitexin, the most commonly identified flavonoid in the flowers and used to standardise some Crataegus species, was not found at all in this plant sample. Instead, daucosterol, and corosolic and euscapic acids were purified. The two triterpene acids have been reported to possess beneficial effects on cardiovascular diseases. These results indicate that the vasodilator effect might induce the hypotensive effect claimed by users, and that euscapic and corosolic acids may be the main vasodilator compounds, and can then be employed as the chemical markers towards the future standardisation of the extract.
Assuntos
Crataegus/química , Flores/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Vasodilatadores/farmacologia , Animais , Aorta/efeitos dos fármacos , Apigenina/análise , Relação Dose-Resposta a Droga , Flavonoides/análise , Masculino , Metanol , México , Plantas Medicinais/química , Ratos Wistar , Triterpenos/análise , Triterpenos/farmacologia , Vasodilatadores/análise , Vasodilatadores/químicaRESUMO
A phytochemical study of the methanol-soluble fraction of an aqueous extract of a sample of Psittacanthus calyculatus collected from the host plant Prosopsis laevigata (Smooth Mesquite) using several techniques, including co-chromatography coupled with UV detection, chromatographic purifications and IR, NMR and MS studies, resulted in the identification of gallic acid, two flavonol-3-biosides and the nonprotein amino acid N-methyl-trans-4-hydroxy-L-proline.