Pterocaullins A−D, four sesquiterpene lactones from Inula pterocaula

Abstract

Abstract Four new sesquiterpenes, pterocaullins A−D (1−4), along with ten known compounds were isolated from the whole plants of Inula pterocaula. Structures of new compounds were elucidated by the combined use of HRESIMS, 1D and 2D NMR and CD spectroscopic methods. The absolute structures of 1 and 2 were further confirmed by Cu Kα X-ray crystallographic analyses. In addition, all isolated compounds were tested for their inhibitory effects against LPS-induced NO production in RAW 264.7 macrophages. Pterocaullin B displayed potential anti-inflammatory activity with IC50 value of 7.03 μM.