Olea europaea leaf extract exerts L-type Ca(2+) channel antagonistic effects.
BACKGROUND
In Southern Europe Olea europaea leafs are known as a folk remedy for hypertension. Cardiovascular diseases are still the leading causes of morbidity and mortality in industrialized countries with hypertension being one of the main risk factors.


OBJECTIVE
We investigated effects of a commercial Olea europaea leaf extract (OLE) on isolated hearts and cultured cardiomyocytes.


METHODS
Isolated rabbit hearts were perfused according to the Langendorff technique and connected to a 256-channel epicardial mapping system. Voltage clamp experiments were performed in cultured neonatal rat cardiomyocytes using a perforated-patch technique.


RESULTS
OLE caused a concentration-depended decrease in systolic left ventricular pressure and heart rate as well as an increase in relative coronary flow and a slight, but not significant prolongation of PQ-time. There were no significant changes between the groups in the activation-recovery interval and its dispersion, total activation time, peak-to-peak amplitude, percentage of identical breakthrough-points and similar vectors of local activation. Voltage clamp experiments in cultured neonatal rat cardiomyocytes showed a significant decrease in maximum I(Ca,L) by OLE which was reversible upon wash-out.


CONCLUSIONS
OLE suppresses the L-type calcium channel directly and reversibly. Our findings might help to understand the traditional use of OLE in the treatment of cardiovascular disease.
Scheffler
A
A
Klinik für Herzchirurgie, Herzzentrum Leipzig, Strümpellstr. 39, 04289 Leipzig, Germany. anja.scheffler@medizin.uni-leipzig.de
Rauwald
H W
HW
Kampa
B
B
Mann
U
U
Mohr
F W
FW
Dhein
S
S
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005060:Europe; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008519:Medicine, Traditional; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D031658:Olea / Q000737:chemistry*; D018408:Patch-Clamp Techniques; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D018515:Plant Leaves; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D010936:Plant Extracts