Effects of methanol extracts from roots, leaves, and fruits of the Lebanese strawberry tree (Arbutus andrachne) on cardiac function together with their antioxidant activity.
BACKGROUND
Several plant-derived natural products have been used in clinical phase for applications in neurological, cardiovascular, and inflammatory diseases. Arbutus andrachne L. (Ericacea) is an evergreen shrub native to the Mediterranean region. Traditionally, the fruits and leaves of Arbutus tree are well known and used as antiseptics, diuretics, blood tonic, and laxatives.


OBJECTIVE
Data regarding the biological effects of compounds derived from the Lebanese Arbutus andrachne are not available. In the present work, we studied the antioxidant activity of methanol extracts of leaves, fruits, and roots of the plant against electrolysis; together with their effects on the cardiodynamics of isolated perfused rabbit hearts.


METHODS
In vitro electrolysis of the different root, leaves, and fruits methanol extracts was evaluated by the amount of free radicals that has been reduced by increasing the concentration of root extracts ranging from 0.5 to 2 mg after 1, 2, 3, and 4 min. Left ventricular pressure (LVP), heart rate (HR), and coronary flow (CR) were investigated in isolated rabbit heart after administration of 0.5, 1, 2, and 2 mg of each methanol extracts plotted against time (0, 0.5, 1.5, 5, and 10 min), according to the Langendorff method. Lipid peroxidation study was performed by the colorimetric method on myocard tissue after incubation with 500 μl of the different methanol extracts. The amount of MDA was determined at 500 nm absorbance after 5 min incubation.


RESULTS
Among the different methanol extracts, the roots showed the highest in vitro antioxidant activity, particularly observed at concentration of 2 mg which completely inhibits free radical generation after 4 min. LVP decreases by 32% at the dose of 2 mg of root extracts after 5 min. No significant effect was observed by the three tested extracts on the heart rate. The three methanol extracts did not show any significant effect on the coronary flow. Moreover, the roots show an increase in the coronary flow at a concentration of 1 and 2 mg/ml during 1 min. Electrolysis on heart tissue treated with the roots extracts shows a decrease in the MDA level from 70.51 ± 6.71 to 48.58 ± 4.15 nmole/g of tissue.


CONCLUSIONS
Methanol extracts of the roots possess antihypertensive effect that may result from its ability to decrease the LVP together with its protective role by inhibiting free radical generation and significantly decreasing the MDA level of heart tissue.
a Laboratoire De Valorisation Des Ressources Naturelles Et Produits De Santé (VRNPS) , EDST, Faculty of Pharmacy, Lebanese University , Hadath , Lebanon ;
Emna
E
Abidi
b Laboratoire De Recherche Et Développement Des Médicaments Et Des Produits Naturels, (RDMPN) , EDST, Faculty of Pharmacy, Lebanese University , Hadath , Lebanon ;
Jean
J
Habib
b Laboratoire De Recherche Et Développement Des Médicaments Et Des Produits Naturels, (RDMPN) , EDST, Faculty of Pharmacy, Lebanese University , Hadath , Lebanon ;
Ahmad
A
Yassine
c Laboratoire De Stress Oydatif Et Antioxidants , Faculty of Medical Sciences, Lebanese University, Rafic Hariri University Campus , Hadath , Lebanon ;
Nathalie
N
Chahine
d Human Genetics and Multifactorial Diseases, Faculty of Pharmacy , Monastir , Tunisia.
Touhami
T
Mahjoub
a Laboratoire De Valorisation Des Ressources Naturelles Et Produits De Santé (VRNPS) , EDST, Faculty of Pharmacy, Lebanese University , Hadath , Lebanon ;
Assem
A
Elkak
D000818:Animals; D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D029791:Ericaceae / Q000737:chemistry* / Q000254:growth & development; D005638:Fruit / Q000737:chemistry / Q000254:growth & development; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D000432:Methanol / Q000737:chemistry; D009206:Myocardium / Q000378:metabolism*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry / Q000254:growth & development; D018517:Plant Roots / Q000737:chemistry / Q000254:growth & development; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism; D016277:Ventricular Function, Left / Q000187:drug effects; D017725:Ventricular Pressure / Q000187:drug effects
D000975:Antioxidants; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D000432:Methanol
Antioxidant; histopathology; isolated heart