Lappanolides A−N, fourteen undescribed sesquiterpenoids from Saussurea costus (Syn. Saussurea lappa) and their anti HBV activity

Abstract

Lappanolides A−N (1–14), 14 undescribed sesquiterpenoids, along with 23 known ones (15–37), were isolated from the roots of Saussurea costus, which were primarily categorized into eudesmane, guaiane, and germacrane types. Lappanolide A (1) possessed an unprecedented pseudo-disesquiterpenoids. Their structures and absolute configurations were established using physical data analyses (HRESIMS, IR, 1D and 2D NMR) and ECD calculations. All isolated compounds were tested for anti-hepatitis B virus (anti-HBV) activity. Ten compounds (1, 9, 11, 12, 19, 22, 28, 29, 31, and 36) exhibited activities against HBsAg secretions as determined by ELISA assay, with IC₅₀ values ranging from 5.2 to 45.7 μM. In particular, compounds 28 and 29 showed inhibition of HBsAg secretion with IC₅₀ values of 5.28 and 5.30 μM, and CC₅₀ values of 9.85 and 6.37 μM, respectively, though they all exhibited low selectivity. Several compounds displayed cytotoxicity in the MTT assay. Among them, compound 28 was the most notable and was chosen for further study using flow cytometry. The result showed that it significantly induced HepG2 cell arrest in the S phase and induced apoptosis.