Elgorashi_2004_Planta.Med_70_260

Twenty-three Amaryllidaceae alkaloids having several different ring types were evaluated for their acetylcholinesterase enzyme (AChE) inhibitory activity. The alkaloid 1- O-acetyllycorine (IC50 : 0.96 +/- 0.04) showed significant AChE inhibitory activity. In addition, crinine (IC50 : 461 +/- 14), crinamidine (IC50 : 300 +/- 27), epivittatine (IC50 : 239 +/- 9), 6-hydroxycrinamine (IC50 : 490 +/- 7), N-desmethyl-8alpha-ethoxypretazettine (IC50 : 234 +/- 13) N-desmethyl-8beta-ethoxypretazettine (IC50 : 419 +/- 8), lycorine (IC50 : 213 +/- 1), and 1,2-di- O-acetyllycorine (IC50 : 211 +/- 10) had weak activity. Lycorine-type alkaloids were the most active alkaloids with 1- O-acetyllycorine exhibiting inhibitory effects two-fold more potent than that of galanthamine.