Polar compounds isolated from the leaves of Calea prunifolia H.B.K. and their anti-adrenergic related vasodilator activity

The leaves of Calea prunifolia H.B.K., medicinal specie used in Colombian folk medicine for hypertension have been analysed for their chemical constituents, resulting in the isolation of one flavonoid glycoside, one quinic acid derivative and one kaurane diterpenoid glycoside. Their chemical structures were elucidated on the basis of spectral analysis, including HRMS, 1D- and 2D-NMR data. The vasodilator effect related to anti adrenergic activity of the three compounds was evaluated in isolated aortic rings from Wistar rats contracted cumulatively with phenylephrine (from 1× 10-9 to 5 × 10-5 mol L-1). Although these compounds were devoid of significant vasodilator activity when they were tested alone (1 µg mL-1), mixtures of them (1:1:1) and the own EtOH extract exerted preventive anti-adrenergic activity increasing the phenylephrine CE50 from 2.3 × 10-8 to 1.3 × 10-7 and 8.0 × 10-7 mol L-1, respectively.