Immunosuppressive terpenoids from extracts of Tripterygium wilfordii

The clinically used extract (TΠ) of Tripterygium wilfordii Hook f. give 19 new compounds, including five kaurane diterpenes (1–5), one manoyl oxide diterpene (6), and one abietane diterpene (7), three ursene triterpenes (8, 9 and 15), six oleanane triterpenes (10–13, 16 and 19), and three friedelane triterpenes (14, 17 and 18), as well as 15 known compounds (20–34). Their structures were elucidated by spectroscopy and X-ray analysis. Based on the screening of isolated compounds and other compounds reported in previous papers [J. Nat. Prod. 62 (1999) 1522; J. Nat. Prod. (2001) in press; Phytochemistry 53 (2000) 805], we identified the main components that are responsible for the therapeutic effect of TΠ.