Anti-cholinesterase Activities of Hydrolysable Tannins and Polyhydroxytriterpenoid Derivatives from Terminalia chebula Retz. Fruit

In the present study, 48 hydrolysable tannins and 12 polyhydroxytriterpenoid derivatives were isolated from Terminalia chebula fruit and assessed for their inhibitory activities on cholinesterases in vitro. Among them, phyllanemblinin F (compound 35), chebulanin (36), 23-Galloyl arjunolic acid (55), and Arjunetin (= 24-deoxy sericoside) (56) showed strong inhibition against acetylcholinesterase (AChE) with IC50 values of 24.02, 21.36, 67.25, and 47.85 mu M, respectively. Though corilagin (15) and several gallotannins (8, 12, 14) exhibited weak inhibitory activity against butyrylcholinesterase, the majority of compounds from T. chebula showed inhibition of AChE. Since cognitive dysfunction is closely related to diminution of cholinergic transmission, our results suggest that compounds from T. chebula could be used as potential treatment for dementia.