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Isoquinoline alkaloids isolated from Corydalis yanhusuo and their binding affinities at the dopamine D1 receptor
Zhong-Ze Ma1, Wei Xu, Niels H Jensen
1Bio-Organic and Natural Products Laboratory, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA.
Abstract:
Bioactivity-guided fractionation of Corydalis yanhusuo has resulted in the isolation of eight known isoquinoline alkaloids - tetrahydropalmatine, isocorypalmine, stylopine, corydaline, columbamine, coptisin, 13-methylpalmatine, and dehydrocorybulbine. The tertiary alkaloids were further analyzed by chiral HPLC to determine the ratios of d-and l-isomers. The isolated compounds were screened for their binding affinities at the dopamine D(1) receptor. Isocorypalmine had the highest affinity (K(i) = 83 nM). The structure-affinity relationships of these alkaloids are discussed.
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