Hypotensive and Vasorelaxant Effects of Citronellol, a Monoterpene Alcohol, in Rats

• Published in: Basic & clinical pharmacology & toxicology 2010-04, Vol.106 (4), p.331-337
• Main Authors: Bastos, Joana F. A., Moreira, Ítalo J. A., Ribeiro, Thaís P., Medeiros, Isac A., Antoniolli, Angelo R., De Sousa, Damião P., Santos, Márcio R. V.
• Format: Article
• Language: English
• Subjects: Animals; Antihypertensive Agents - administration & dosage; Antihypertensive Agents - pharmacology; Biological and medical sciences; Blood Pressure - drug effects; Cymbopogon citratus; Cymbopogon winterianus; Dose-Response Relationship, Drug; Hypotension - chemically induced; Lippia alba; Male; Medical sciences; Monoterpenes - administration & dosage; Monoterpenes - pharmacology; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Nifedipine - pharmacology; Oils, Volatile - administration & dosage; Oils, Volatile - pharmacology; Pharmacology. Drug treatments; Plant Oils - administration & dosage; Plant Oils - pharmacology; Rats; Rats, Wistar; Vasodilation - drug effects; Vasodilator Agents - administration & dosage; Vasodilator Agents - pharmacology
• ISSN: 1742-7835; 1742-7843
• DOI: 10.1111/j.1742-7843.2009.00492.x

:  Citronellol is an essential oil constituent from the medicinal plants Cymbopogon citratus, Cymbopogon winterianus and Lippia alba which are thought to possess antihypertensive properties. Citronellol‐induced cardiovascular effects were evaluated in this study. In rats, citronellol (1–20 mg/kg, i.v.) induced hypotension, which was not affected by pre‐treatment with atropine, hexamethonium, Nω‐nitro‐l‐arginine methyl ester hydrochloride or indomethacin, and tachycardia, which was only attenuated by pre‐treatment with atropine and hexamethonium. These responses were less than those obtained for nifedipine, a reference drug. In intact rings of rat mesenteric artery pre‐contracted with 10 μM phenylephrine, citronellol induced relaxations (pD2 = 0.71 ± 0.11; Emax = 102 ± 5%; n = 6) that were not affected by endothelium removal, after tetraethylamonium in rings without endothelium pre‐contracted with KCl 80 mM. Citronellol strongly antagonized (maximal inhibition = 97 ± 4%; n = 6) the contractions induced by CaCl2 (10−6 to 3 × 10−3 M) and did not induce additional effects on the maximal response of nifedipine (10 μM). Finally, citronellol inhibited the contractions induced by 10 μM phenylephrine or 20 mM caffeine. The present results suggest that citronellol lowers blood pressure by a direct effect on the vascular smooth muscle leading to vasodilation.