Bioactive 18(4 → 3)-abeo-abietanoid derivatives from the leaves of Tripterygium wilfordii

Abstract

Tripterlides A–F (1–6), six new abietane diterpenoid derivatives, together with six known abietane diterpenoids (7–12) were obtained from the leaves of Tripterygium wilfordii. Tripterlides A–C (1–3) were novel 14(13 → 12),18(4 → 3)-diabeo-abietanoids possessing a 6/6/5 tricyclic ring system. These unusual structures, including their absolute configurations, were determined from UV, IR, HRESIMS, 1D and 2D-NMR data and through comparisons of their experimental and calculated electronic circular dichroism (ECD) spectra. A plausible biosynthetic pathway for 1–3 was proposed. Furthermore, in an in vitro bioassay, 5, 6, 8, and 10–12 showed significant cytotoxic effects against five human cell lines, and 6, 8, 10–12 also exhibited moderate inhibitory activities on hypoxia-inducible factor 1 (HIF-1), which is relevant to tumor development.