Cholinesterase-inhibitory diterpenoids and chemical constituents from aerial parts of Caryopteris mongolica

A diterpenoid diglucoside (12,19-di-O-β-d-glucopyranosyl-11-hydroxyabieta-8,11,13-triene-19-one), isoscutellarein 7-O-[β-d-xylopyranosyl-(1→2)]-β-d-glucopyranoside, isoscutellarein 7-O-[α-l-rhamnopyranosyl-(1→2)]-β-d-glucopyranoside, hypolaetin 7-O-[6″-O-(p-E-coumaroyl)]-β-d-glucopyranoside, hypolaetin 7-O-[6″-O-(E-caffeoyl)]-β-d-glucopyranoside, and 15 known compounds were isolated from aerial parts of the Mongolian medicinal plant Caryopteris mongolica. The cholinesterase-inhibitory activities of the constituents were estimated. The abietane diterpenoids (12-O-demethylcryptojaponol and 6α-hydroxydemethylcryptojaponol) showed potent inhibitory activity against acetylcholinesterase from human erythrocytes and electric eel, and against butyrylcholinesterase from horse serum.