The Effects of Aqueous Extract of Vaccinium Arctostaphylos Leaves on Blood Pressure in Renal Hypertensive Rats

Background: The leaves of Vaccinium arctostaphylos (Qare qat) is advocated for the treatment of hypertension in Iran' folk medicine. The objective of was to examine the possible hypotensive activity of aqueous extract of Vaccinium arctostaphylos leaves in rat model of two-kidney, one-clip hypertension. Methods: Rats were subjected to sham operation of the placement of Plexiglass clip on left renal arteries. Four weeks later, renal artery clipped rats were given intravenous injection of normal saline or the extract at 10, 25, or 75 mg/kg, and mean blood pressure and heart rate were measured before and 20, 40 and 60 minutes after vehicle or drug administration. Results: Compared to sham group, renal artery clipped groups had a significantly higher mean blood pressure, heart and right kidney weights, lower left kidney weight and significantly indifferent heart rate. Compared to vehicle treatment, the extract at 75 mg/kg, but not at 10 or 25 mg/kg, did reduce the mean blood pressure at 20, 40 and 60 minutes after administration without changing the heart rate. Conclusion: The findings showed that at a higher dose the extract did have hypotensive activity without changing the heart rate. The exact hypotensive mechanism remains to be investigated.