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Anticholinesterase activity of 7‐methoxyflavones isolated from Kaempferia parviflora
Author(s) -
Sawasdee Pattara,
Sabphon Chalisa,
Sitthiwongwanit Duangporn,
Kokpol Udom
Publication year - 2009
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.2858
Subject(s) - aché , acetylcholinesterase , butyrylcholinesterase , cholinesterase , rhizome , chemistry , inhibitory postsynaptic potential , stereochemistry , substituent , traditional medicine , ethyl acetate , pharmacology , potency , enzyme , biochemistry , in vitro , medicine
The rhizome of Kaempferia parviflora or kra‐chai‐dum (in Thai) is used traditionally as a folk medicine. The preliminary cholinesterase inhibitory screening of this plant extract exhibited significant acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Thirteen known methoxyflavones (1–13) were isolated and their structures were completely elucidated based on NMR analysis and compared with literature reports. Minor compounds 12–13 were reported for the first time from this species. The cholinesterase inhibitory test results showed that the highest potential inhibitors toward AChE and BChE were 5,7,4′‐trimethoxyflavone (6) and 5,7‐dimethoxyflavone (7), respectively, with the percentage inhibitory activity varying over 43–85%. The structure‐activity relationship study led to the conclusion that compounds bearing 5,7‐dimethoxy groups and a free substituent at C‐3 had a significant inhibitory effect at a concentration of 0.1 mg/mL, but those bearing a 5‐hydroxyl group reduced the inhibitory potency. On the other hand, flavones bearing a 3′‐ or 5′‐methoxy group did not influence the inhibitory effect. Interestingly, 5,7‐dimethoxyflavone (7) exhibited strong selectivity for BChE over AChE which may be of great interest to modify as a treatment agent for Alzheimer's disease. Copyright © 2009 John Wiley & Sons, Ltd.