Immunosuppressive terpenoids from extracts of Tripterygium wilfordii

The clinically used extract (T-Pi) 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 T-Pi. (C) 2001 Elsevier Science Ltd. All rights reserved.