Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease II.

Čakurdová, M.: Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimer's disease II. Diploma thesis, Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany and Ecology, Hradec Králové, 2017. The aim of this work was focused on isolation of alkaloids from the fraction 1 (joined fractions 20-27), which was obtained from the summary alkaloid extract of Papaver rhoeas L. (Papaveraceae). The alkaloids were identified by structural analysis NMR, GC-MS, optical activity and melting point. Two alkaloids were identified as (-)-stylopine and (+)-rhoeadine. Isolated substances were tested on ability to inhibit the enzymes acetylcholinesterase, butyrylcholinesterase and prolyloligopeptidase. Obtained data were expressed as IC50 values: (-)-stylopine (IC50 AChE = 522 ± 67 µM, IC50 BuChE = >1000 µM, IC50 POP = >790 µM); (+)-rhoeadine (IC50 AChE = 915 ± 64 µM, IC50 BuChE = >1000 µM, IC50 POP = >790 µM). None of the isolated substances showed so potent cholinesterase inhibitory activity as the alkaloids galanthamine (IC50 AChE = 1.71± 0.065 µM, IC50 BuChE =42.30 ± 1.30 µM) and huperzine A (IC50 AChE = 0.033 ± 0.001 µM, IC50 BuChE = >1000 µM) or rivastigmine (IC50 AChE = 0.037 ± 0.001 µM, IC50 BuChE = 3.3 ± 0.3 nM)...