Antihypertensive activity of Salvia elegans Vahl. (Lamiaceae): ACE inhibition and angiotensin II antagonism.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvia elegans Vahl. (Lamiaceae), recognized with the popular name of "mirto" is widely used in Mexico for healing purposes, and also them as antihypertensive treatment. AIM OF THE STUDY: The high prevalence of this illness and the side effects of antihypertensive drugs conducted us to the evaluation of the Salvia elegans extract on angiotensin II action. MATERIALS AND METHODS: The acute response of blood pressure to angiotensin II administration was measured in mice. We also tested in vitro the inhibitory effect on angiotensin convertase enzyme. Additionally, characterization of the pharmacological effect of the extract fraction was obtained. RESULTS: We obtained dose-response curve for the administration of complete extract and extract fractions. Due to the hydroalcoholic extract (SeHA) treatment blood pressure decreased significantly from systolic dose of 0.75 mg kg(-1) (p<0.05) and even had an antihypertensive effect that was greater than that treatment with losartan. SeHA extract decreased the E(max) of the AG II hypertensive effect by about 20% in both systolic and diastolic pressures, treatment with losartan also decreased the same parameter between 6% and 8% for systolic and diastolic pressures, respectively. Fractions SeF8 and SeF8-8 showed similar levels of AG II ED(50) for both pressures compared with losartan, these fractions showed major compounds with maximum absorbance peaks at 221, 289 and 330 nm typical of flavonoids. In the inhibition assay the activity of angiotensin converting enzyme (ACE), the extract SeHA showed percentage inhibition (%IACE) of 50.27+/-5.09% (n=5). SeBuOH fraction is found to have greater inhibitory capacity of achieving a IACE 78.40+/-2.24% (n=5), which was similar to the values obtained in the presence of the SeF8-22 fraction (82.61+/-1.74%) and lisinopril (87.18+/-1.16%). The changes in the value of K(M) suggest that components of the extracts and fractions were recognized by the enzyme's active site. The main compounds of the fractions SeBuOH, SeF8-22 were by flavonoid and phenyl propanoid types, according to UV absorption spectra of the fractions. CONCLUSIONS: The experimental results demonstrated the antihypertensive effect of Salvia elegans and it was due to the AG II antagonism and inhibition of angiotensin converting enzyme.