Triptolide: structural modifications, structure-activity relationships, bioactivities, clinical development and mechanisms.

Triptolide, a principal bioactive ingredient of Tripterygium wilfordii Hook F, has attracted extensive exploration due to its unique structure of a diterpenoid triepoxide and multiple biological activities. This review will focus on the structural modifications, structure-activity relationships, pharmacology, and clinical development of triptolide in the last forty years.