Anti-inflammatory lindenane sesquiterpenoid dimers from the roots of Chloranthus holostegius var. trichoneurus

Two new lindenane-type sesquiterpenoid dimers, chlotrichenes C and D (1 and 2) together with five known lindenane-type sesquiterpenoid dimers (3–7) were isolated from the roots of Chloranthus holostegius var. trichoneurus, a famous natural medicine named as “Sikuaiwa” for subduing swellings and relieving pain. The structures including absolute configuration were elucidated by their 1D and 2D NMR, HRESIMS, and ECD data. Compounds 1 and 2 were classical [4 + 2] lindenane-type sesquiterpenoid dimers that differed from known analogs in oxidation profile, side chain profile, and double bond position. The new isolates and compound 3 exhibited significant inhibitory activity on IL-1β production (IC₅₀: 1–15 μM) in LPS-induced THP-1 cells and other compounds exhibited inhibitory activity on NO production in LPS-induced RAW 264.7 cells (IC₅₀: 24–33 μM).