Determining acetylcholinesterase inhibitory activity in plant extracts using a fluorimetric flow assay.
A fluorometric assay for acetylcholinesterase inhibitory activity was developed in a flow system using the fluorogenic substrate 7-acetoxy-1-methyl quinolinium iodide which is hydrolysed to the highly fluorescent 7-hydroxy-1-methyl quinolinium iodide. The detection limit of galanthamine is 0.5 microM, which is about 20 times more sensitive than in the colorimetric flow assay. In the presence of 30% methanol or of 5% acetonitrile, about 70% of the enzyme activity could still be detected. Various plant extracts have been screened using the described system including bulbs of Galanthus nivalis, Eucharis amazonica (E. x grandiflora), Crinum powelli and Nerine bowdenii (all members of the Amaryllidaceae), which showed strong AchE inhibitory activity.
Rhee
In Kyung
IK
Division of Pharmacognosy, Leiden/Amsterdam Centre for Drug Research, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands.
Appels
Natalie
N
Luijendijk
Teus
T
Irth
Hubertus
H
Verpoorte
Robert
R
D000110:Acetylcholinesterase / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000032:analysis*; D005470:Fluorometry / Q000295:instrumentation / Q000379:methods*; D019684:Magnoliopsida / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D018514:Plant Structures / Q000737:chemistry; D012680:Sensitivity and Specificity
D002800:Cholinesterase Inhibitors; D010936:Plant Extracts; D000110:Acetylcholinesterase