New aporphine alkaloids with selective cytotoxicity against glioma stem cells from Thalictrum foetidum

Seven new isoquinoline alkaloids, 9-(2'-formyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy dehydroaporphine ( 1 ), 9-(2'-formyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy oxoaporphine ( 2 ), 3-methoxy-2'-formyl oxohernandalin ( 3 ), (-)-9-(2'-methoxycarbonyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy aporphine ( 4 ), (-)-2'-methoxycarbonyl thaliadin ( 5 ), (-)-9-(2'-methoxyethyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy aporphine ( 6 ), (-)-3-methoxy hydroxyhernandalinol ( 7 ), together with six known isoquinoline alkaloids ( 8-13 ) were isolated from the roots of Thalictrum foetidum. Their structures were elucidated by extensive spectroscopic measurements. Compounds 1 and 2 showed significant selective cytotoxicity against glioma stem cells (GSC-3^# and GSC-18^#) with IC₅₀ values ranging from 2.36 to 5.37 μg·mL^-1.