Dimeric sesquiterpenoids and anti-inflammatory constituents of Sarcandra glabra

Three novel dimeric sesquiterpenoids named sarglanoids A-C (1-3), two undescribed monomeric sesquiterpenoids named sarglanoids D (4) and E (5), and seven known compounds (6-12), were isolated and characterized from Sarcandra glabra. Compound 1 represents the first heterodimeric sesquiterpenoid composed of a eudesmane and an eremophilane moiety. Compound 2 possesses two eremophilane monomers featuring an undescribed dimerization pattern. Compound 3 is a symmetric eudesmane dimer with a rare 1,4-epoxy bridge. The structures of 1-5 were fully identified by spectroscopic methods and single-crystal X-ray diffraction experiments. Compounds 3 and 6 suppressed the LPS-triggered inflammatory responses in RAW 264.7 cells.