Immunosuppressive Sesquiterpene Alkaloids from Tripterygium wilfordii

Nine new sesquiterpene pyridine alkaloids [wilfornines A (1), B (2), C (3), D (4), E (5), F (8), and G (9); wilfordinines I (6) and J (7)] and six known compounds (10−15) were isolated from a clinically used extract (TII) of Tripterygium wilfordii. The structures of 1−9 were elucidated by spectroscopic and chemical methods. The inhibitory effects on cytokine production of 1−3 and several related compounds were evaluated. Compounds 10 and 14 showed significant inhibitory effects on cytokine production.