Chemical composition and evaluation of prolyl oligopeptidase and acetylcholinesterase inhibitory activities of <i>Leonurus Sibiricus</i> L. from Brazil

<p>Chemical investigation of the aerial parts of <i>Leonurus sibiricus</i> L. used in Brazilian folk medicine led to the identification of the following constituents: the labdane-type diterpenoid leojaponin, the phytosterols β-sitosterol and β-sitosterol glucoside and the alkaloid leonurine. The crude extracts obtained from methanol and methanol/1% HCl and pure compounds isolated from <i>L. sibirius</i> were investigated as acetylcholinesterase (AChE) and prolyl oligopeptidase (POP) inhibitors. Extracts obtained by maceration were active against POP (53–58%), but showed weak activity against AChE. The isolated leojaponin and leonurine were evaluated as POP inhibitors.</p