Inhibition of Acetylcholinesterase Activity by Monoterpenoids with a p-Menthane Skeleton

Inhibition of acetylcholinesterase (AChE) activity by 17 kinds of monoterpenoids (hydrocarbons, alcohols, and ketones) with p- menthane skeletons was studied. Inhibition of AChE was measured by the colorimetric method. The terpene ketones showed stronger inhibition than the terpene alcohols. The terpene hydrocarbon compounds showed identical inhibitory activity with the terpene alcohols, but α-terpinene and (+)- p -menth-1-ene were equally strong inhibitors as the terpene ketones. Monoterpenoids used in this study were found to be competitive inhibitors.