Blood pressure lowering effect of the aqueous extract of <i>Satureja</i>

Abstract

Satureja punctata Benth. Briq. (Lamiaceae) is a small shrub known by its vernacular name “Lomishet”. It is used in Ethiopian traditional medicine for the treatment of hypertension, diabetes, liver disease, headache and febrile illness. Mean Arterial Blood Pressure (MABP) lowering effect and vasorelaxant activity of the aqueous extract of aerial parts of the plant were studied. Intravenous administration of the aqueous extract at different doses brought a fall in MABP in normotensive guinea pigs and also in renovascular hypertensive guinea pigs. The extract also caused a dose-dependent relaxation of precontracted aorta; with a maximum relaxation of 98.19% achieved at 40 mg/ml. Preparative reversed-phase HPLC analyses of the extract resulted in the isolation of two phenolic compounds, namely, rosmarinic acid and linarin. The structures of these compounds were elucidated using UV, IR, MS, and NMR (1D and 2D) techniques. Furthermore, rosmarinic acid showed significant (p < 0.01) reduction of MABP in normotensive guinea pigs at doses of 0.75, 1.50 and 3.00 mg/kg. The findings of this study suggest that the aerial parts of S. punctata have genuine antihypertensive activity.