Inhibitory effect of verbascoside isolated from Buddleja brasiliensis Jacq. ex Spreng on prolyl oligopeptidase activity

Abstract

The phenylpropanoid glycoside verbascoside [2-(3,4-dihydroxyphenylethyl)-1- O-α-l-rhamnopyranosyl-(1→3)-β-d-(4-O-caffeyl)-glucopyranoside] (1) has been isolated as the main constituent of the crude extract of Buddleja brasiliensis Jacq. ex Spreng from Southern Brazil. The crude extract, main fractions and the compound 1 were evaluated for inhibition of the enzymes acetylcholinesterase (AChE), dipeptidyl peptidase-IV (DPP-IV) and prolyl oligopeptidase (POP). Compound 1 showed weak activity against DPP-IV with an IC50 >> 150 μm and was inactive against AChE, with a pMIQ determined by bioautography of 9.6. In contrast, 1 displayed significant inhibition of POP in a dose-dependent manner with an IC50 value of 1.3 ± 0.2 μm, similar to the positive control, baicalin, with a POP IC50 of 12 ± 3 μm. Copyright © 2012 John Wiley & Sons, Ltd.