title: Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels.
abstract: German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (-)-α-bisabolol, farnesene, umbelliferone; 3-30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (-)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (-)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (-)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium.
authors.affiliation: School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, England, UK. Electronic address: Richard.roberts@nottingham.ac.uk.
authors.forename: R E
authors.initials: RE
authors.lastname: Roberts
authors.forename: S
authors.initials: S
authors.lastname: Allen
authors.forename: A P Y
authors.initials: AP
authors.lastname: Chang
authors.forename: H
authors.initials: H
authors.lastname: Henderson
authors.forename: G C
authors.initials: GC
authors.lastname: Hobson
authors.forename: B
authors.initials: B
authors.lastname: Karania
authors.forename: K N
authors.initials: KN
authors.lastname: Morgan
authors.forename: A S Y
authors.initials: AS
authors.lastname: Pek
authors.forename: K
authors.initials: K
authors.lastname: Raghvani
authors.forename: C Y
authors.initials: CY
authors.lastname: Shee
authors.forename: J
authors.initials: J
authors.lastname: Shikotra
authors.forename: E
authors.initials: E
authors.lastname: Street
authors.forename: Z
authors.initials: Z
authors.lastname: Abbas
authors.forename: K
authors.initials: K
authors.lastname: Ellis
authors.forename: J K
authors.initials: JK
authors.lastname: Heer
authors.forename: S P H
authors.initials: SP
authors.lastname: Alexander
mesh_terms: D000818:Animals; D020843:Chamomile; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D009924:Organ Culture Techniques; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D013157:Splenic Artery / Q000187:drug effects* / Q000502:physiology; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D010936:Plant Extracts; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents
keywords: (−)-α-bisabolol; Apigenin; German chamomile; Luteolin; Umbelliferone; Vasodilatation