ISOLATION, PURIFICATION, AND CHARACTERIZATION OF IMMUNOSUPPRESSIVE COMPOUNDS FROM TRIPTERYGIUM - TRIPTOLIDE AND TRIPDIOLIDE

Crude extracts derived from the root of Tripterygium wilfordii Hook f (TWHf) have previously been demonstrated to have immunosuppressive pro perties and have been used as anti-rheumatic therapy in Chinese tradit ional medicine. Although these extracts contain a large number of chem ical components, the precise nature of the compound(s) responsible for this therapeutic effect has not been established with certainty. An a queous extract of TWHf resolved into chemical components by medium-pre ssure and high-performance liquid chromatography. Immunosuppressive fr actions were identified with a mixed lymphocyte reaction (MLR) and che mically characterized by nuclear magnetic resonance spectroscopy and m ass spectrometry. Two major peaks of immunosuppressive activity were i dentified. These were the closely related diterpenoid triepoxides, tri ptolide and tripdiolide. No other immunosuppressive compounds were ide ntified using MLR as the biologic screening assay. Triptolide and trip diolide may be responsible for the anti-rheumatic properties of crude aqueous extracts of TWHf represent a novel class of immunosuppressive drugs with potential clinical utility.