Chemical constituents of Isatis indigotica.

From the roots of Isatis indigotica, ten compounds (1-10) were isolated. Compound 1 is a new alkaloid whose structure was elucidated as (E)-3-(3',5'-dimethoxy-4'-hydroxy-benzylidene)-2-indolinone. Compounds 2-4 were discovered for the first time from a natural source and compounds 5-7 were originally isolated from this species. In a preliminary study, compounds 4-8 showed antiendotoxic activities in vitro.