Identification and biomimetic synthesis of iphionanes and cyperanes from Artemisia hedinii and their anti-hepatic fibrosis activity

Two novel skeleton sesquiterpenoids (1 and 6), along with four new iphionane-type sesquiterpenes (2−5) and six new cyperane-type sesquiterpenes (7−11), were isolated from the whole plant of Artemisia hedinii (A. hedinii). The two novel skeleton compounds (1 and 6) were derived from the decarbonization of iphionane and cyperane-type sesquiterpenes, respectively. Their structures were elucidated through a comprehensive analysis of spectroscopic data, including high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and 1D and 2D nuclear magnetic resonance (NMR) spectra. The absolute configurations were determined using electronic circular dichroism (ECD) spectra, single-crystal X-ray crystallographic analyses, time-dependent density functional theory (TDDFT) ECD calculation, density functional theory (DFT) NMR calculations, and biomimetic syntheses. The biomimetic syntheses of the two novel skeletons (1 and 6) were inspired by potential biogenetic pathways, utilizing a predominant eudesmane-type sesquiterpene (A) in A. hedinii as the substrate. All compounds were evaluated in LX-2 cells for their anti-hepatic fibrosis activity. Compounds 2, 8, and 10 exhibited significant activity in downregulating the expression of α-smooth muscle actin (α-SMA), a protein involved in hepatic fibrosis.