Vascular effects of a polyphenolic fraction from Oxalis pes-caprae L.: role of α-adrenergic receptors Sub-types.
Autor: Fonseca, Diogo A.; Ferreira, Mónica; Campos, Maria Graça; Antunes, Pedro E.; Antunes, Manuel J.; Cotrim, Maria Dulce
Publication year: 2020
Natural product research
issn:1478-6427 1478-6419
doi: 10.1080/14786419.2018.1564291
Abstract:
Oxalis pes-caprae L. is a plant of the Oxalidaceae family, from which several compounds have been previously identified. Recently, we showed that an Oxalis pes-caprae L. extract inhibits the vasopressor effect of noradrenaline. In this work we aimed to explore the mechanisms involved in this effect. The results confirmed that the flavonoid fraction present in the extract inhibits noradrenaline-induced contractions and that this effect is concentration-dependent. Also, a parallel shift to the right in the noradrenaline concentration-response curve was observed, suggesting a decrease in efficacy and also in potency. Together these results support the assumption that the extract could exert a non-competitive antagonism on the α-adrenergic receptors. However, experiments in the presence of competitive antagonists for α-adrenergic receptor sub-types (i.e. prazosin, yohimbine and phentolamine) showed that the effect may not be directly mediated by α-adrenergic receptors. Thus, the interaction of this extract with the adrenergic system remains to be confirmed.
Language: eng
Rights:
Pmid: 30698035
Tags: Humans; Aged; Aged, 80 and over; Adult; Middle Aged; Dose-Response Relationship, Drug; Plant Leaves/chemistry; flavonoids; Norepinephrine/pharmacology; Plant Extracts/chemistry/*pharmacology; adrenergic; Adrenergic alpha-Agonists/pharmacology; Adrenergic alpha-Antagonists/pharmacology; human internal thoracic artery; Oxalidaceae/*chemistry; Oxalis pes-caprae L.; Polyphenols/*analysis; Prazosin/pharmacology; Receptors, Adrenergic, alpha/drug effects/metabolism; Thoracic Arteries/*drug effects; Vasoconstriction/*drug effects; Yohimbine/pharmacology
Link: https://pubmed.ncbi.nlm.nih.gov/30698035/
