Phytochemical constituents from the rhizomes of Kaempferia parviflora Wall. ex Baker and their acetylcholinesterase inhibitory activity

Phytochemical study on the rhizomes of Kaempferia parviflora led to the isolation of twenty-three compounds including six phenolic glycosides (1-6), thirteen flavones (7-19), and five phenolic compounds (20-23). Of these, the new compounds were determined to be 2,4-dihydroxy-6-methoxyacetophenone-2-beta-D-apiofuranosyl-(1 -> 6)-beta-D-glucopyranoside (1), 2-hydroxy-4-propionyl-phenyl O-beta-D-glucopyranoside (2), and 4-hydroxy-3,5-dimethoxyacetophenone 8-O-alpha-L-rhamnopyranosyl-(1 -> 6)-beta-D-glucopyranoside (3) and named as kaempanosides A-C, respectively. Their chemical structures were established based on HR-ESI-MS, 1D and 2D NMR spectra. All compounds 1-23 exhibited acetylcholinesterase inhibitory activity with IC50 values ranging from 57.76 to 253.31 mu M.