Inhibitory effect of Artemisia asiatica alkaloids on acetylcholinesterase activity from rat PC12 cells

We screened 42 Korean traditional tea plants to determine the inhibitory ef fect of acetylcholinesterase and attenuation of toxicity induced by amyloid -beta peptide, which were related to the treatment of Alzheimer's disease ( AD), The methanolic extract from Artemisia asiatica among tested 42 tea pla nts, showed the highest inhibitory effect (48%) on acetylcholinesterase in vitro, The methanolic extract was further separated with n-hexane, chlorofo rm, and ethyl acetate of water, in order. The chloroform solubles, which we re high in inhibitory effect of acetylcholinesterase, were repeatedly subje cted to open column chromatography on silica gel. From the highest inhibito ry fraction (78%) on acetylcholinesterase, the single compound was obtained by the Sep-Pak(R) Cartridge (C-18: reverse phase column). This compound wa s found to react positively on Dragendorff's reagent (potassium bismuth iod ide), which typically reacted with the alkaloid, This compound was purified by HPLC (mu-bondapack C-18 reverse phase column: 3.9 x 150 mm), The IC50 ( the concentration of 50% enzyme inhibition) value of this compound was 23 m u g/ml and the inhibitory pattern on acetylcholinesterase was mixed with co mpetitive/non-competitive type. We examined the effects of this compound on toxicity induced by A beta (25-35) in rat pheochromocytoma PC12 cells. Pre treatment of the PC12 cells for 2 h with an alkaloid of Artemisia asiatica (1200 mu g/ml) reduced the toxicity induced by A beta, This study demonstra ted that an alkaloid of Artemisia asiatica, which was metabolized to small molecule in digestive tract and then could pass through the blood-brain bar rier, appeared to be an acetylcholinesterase inhibitor with a blocker of ne urotoxicity induced by A beta in human brain causing Alzheimer's disease.