Cardiovascular effects ofArbutus unedo L. in spontaneously hypertensive rats

Abstract

In order to examine the effect of Arbutus unedo extract on the development of genetic hypertension, three groups of six male spontaneously hypertensive rats (SHR) from 4 to 10 weeks of age, received orally an aqueous extract of the root of this Ericaceae plant at doses of 5, 50 and 250 mg/kg/24 h. The fourth group (n = 6) received tap water only and served as a control. A significant (p < 0.01) reduction of indirect systolic blood pressure (BP) was observed after 4 weeks of treatment with the two highest doses but this effect attenuated 2 weeks later. The continuous measurement of direct BP in conscious 10‐week‐old rats indicated that chronic treatment with Arbutus did not significantly alter the BP level, the heart rate (HR), the cardiac baroreflex sensitivity and the sympathetic nervous and renin– angiotensin system activities. In contrast, Arbutus (50 mg/kg/24 h) attenuated the pressor responses to phenylephrine and angiotensin I. Finally, a diuretic effect was evidenced in the group receiving the highest dose. It is concluded that chronic oral administration of Arbutus unedo slowly delayed the development of hypertension but did not alter the final level of BP and HR in the SHR. The vascular and renal effects of this plant, which may account for its use in folk medicine, require a more detailed analysis. © 1998 John Wiley & Sons, Ltd.

Phytochemical and Toxicological Studies of An Aqueous Trunk Bark Extract of Parkia biglobosa (Jacq.) Benth (Mimosaceae)

“…According to Mc Namara 23 , sterols and polyterpenes have necrotic and cytotoxic properties in rodents. As for saponosides, they have a haemolytic action explaining the toxic effect of some of them 24 whereas alkaloids cause bradycardia 25,26 . Several authors 27,28,29,26,30,31,32 , showed the beneficial effects of phenols and flavonoids on the cardiovascular system of laboratory animals through their cardioinhibitory, vasodilatory and hypotensive activities.…”

Efficacy of <b><i>Melissa officinalis</i></b> in Suppressing Ventricular Arrhythmias following Ischemia-Reperfusion of the Heart: A Comparison with Amiodarone

“…According to the similar pattern of ECG alteration after administering M. officinalis and amiodarone, the effects of lemon balm may be partly via the same pathways involved in the action of amiodarone; M. officinalis contains alkaloid compounds such as saponins and glycosides which could cause inhibition of cation channels [ 24 ]. Gazola et al [ 16 ] reported that the extract of M. officinalis significantly reduced the cardiac rate of rat isolated heart, and suggested that this effect may provoke muscarinic receptor stimulation by the activity of its alkaloid compounds [ 25 ]. In our study, we did not observe the negative chronotropic effect of M. officinalis extract.…”

Etude des effets pharmacologiques de l’extrait aqueux de <i>Heliotropium indicum</i> Linn. (Boraginaceae) sur le coeur isolé de rat et l’aorte isolée de cobaye

“…En effet Burkill (1985) indique que les saponines et l'héliotrine contenus dans l'extrait aqueux de cette plante seraient à l'origine de son activité anti-inflammatoire et de son pouvoir cicatrisant. Tandis que les tanins et les flavonoïdes par un relâchement de l'endothelium vasculaire (Slowing et al, 2001 ;Lih-Geen et al, 2008) et les alcaloïdes par induction d'une bradycardie (Ziyyat et Boussairi, 1998), seraient responsables de la réduction de l'hypertension artérielle (Gazola et al, 2004).…”