Wilfordonols A–D: four new norsesquiterpenes from the leaves of Tripterygium wilfordii

Four new norsesquiterpenes wilfordonols A–D (1–4), along with three known compounds, sarmentol B (5), boscialin (6), and (+)-loliolide (7), were isolated from the leaves of Tripterygium wilfordii Hook.f.. The structures of the new compounds were elucidated on the basis of their spectroscopic analysis, and the absolute configuration of the compounds was confirmed by CD and modified Mosher's method. At a concentration of 10 μM, compounds 4, 6, and 7 inhibited signal transducer and activator of transcription 1 translocation by 34.27 ± 1.02%, 48.93 ± 1.76%, and 70.31 ± 2.20%, respectively.