Eleven new sulfonated alkaloids (1 - 11) having diverse structures were isolated from an aqueous extract of the Isatis indigotica root (ban lan gen). Their structures were determined by spectroscopic data analysis, chemical method, and theoretical calculation, of which (-)-4 was proved by single crystal X-ray diffraction.
Keywords: Cruciferae; Isatis indigotica; isatindosulfonic acids; isatithienopysulfonic acids; isatithiomidosulfonate A; sulfonated alkaloid.