Vasorelaxant effects of the chloroformic crude extract of Bupleurum fruticosum L. (Umbelliferae) roots on rat thoracic aorta.
The chloroformic crude extract of roots of Bupleurum fruticosum L. (Umbelliferae) showed a concentration-dependent vasorelaxing effect on aortic rings endothelium-deprived and pre-contracted by norepinephrine (NE). The pharmacological effect was not produced through the stimulation of cyclooxygenase, adenyl cyclase, or guanylyl cyclase, since selective inhibitors did not prevent the extract-induced responses. The incubation of the aortic rings with the chloroformic extract (10(-4) g/ml) produced a depression of the concentration-contractile response curve to NE, in normal conditions, and this effect was more evident in Ca2+-free Tyrode solution, suggesting an action on the intracellular mobilization of Ca2+ ions. Moreover, the vasodilator action of Bupleurum fruticosum extract was resistant to the pre-treatment with nifedipine and to the pre-treatment with cyclopiazonic acid (blocker of Ca2+/ATPase). Finally, the chloroformic extract of Bupleurum fruticosum produced a reduction of the contraction obtained by caffeine, an opener of ryanodine-sensitive receptors, suggesting that the plant could elicit the vasorelaxing response by the blockade of ryanodine-sensitive Ca2+ channels of the sarcoplasmic reticulum.
Testai
Lara
L
Department of Psichiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy.
Silvio
Chericoni
C
Ammar
Bader
B
Luisa
Pistelli
P
Vincenzo
Calderone
C
Martinotti
Enrica
E
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D029972:Bupleurum; D002725:Chloroform; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D012997:Solvents; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
C051274:Bupleurum root extract; D010936:Plant Extracts; D012997:Solvents; D014665:Vasodilator Agents; D002725:Chloroform