RESUMO
The berries of a number of Vaccinium species do reduce blood pressure. The berries Vaccinium arctostaphylus, the species native to Iran have been advocated for the treatment of hypertension in the country's folk medicine. The objective was to examine the possible hypotensive activity of aqueous extract of Vaccinium arctostaphylus berries in rat model of two-kidney, one-clip hypertension. Rats were subjected to sham operation or the placement of plexiglass clips on left renal arteries. Four weeks later, renal artery clipped rats were given intravenous injection of normal saline or the extract at 10, 25, 75 or 100 mg/kg, and mean blood pressure and heart rate were measured before and 20, 40 and 60 minutes after drug administration. Compared to sham group, renal artery clipped groups had a significantly higher mean blood pressure, heart and right kidney weights, lower left kidney weights and significantly indifferent heart rate. Compared to vehicle treatment, the extract at 75 and 100 mg/kg, but not at 10 or 25 mg/kg, did significantly reduce mean blood pressure at 20, 40 and 60 minutes after administration without changing the heart rate. The findings showed, that in agreement with Iran's folk medicine, the aqueous extract of Vacinium arctostaphylus berries did lower blood pressure. The exact hypotensive mechanism remains to be investigated