Terpenoids from the Stems of Fissistigma polyanthoides and Their Anti-Inflammatory Activity

Twelve new terpenoids (1–12) were isolated from the stems of Fissistigma polyanthoides, an anti-inflammatory medicinal plant traditionally used in Vietnam. Most of them (1–9) possess a sesquiterpenoid backbone (e.g., guaiane, germacrane, and cadinane) connected to a 2′-O-trans-cinnamoyl)-β-d-glucopyranose moiety, which is rare in Nature. Among them, compounds 4 (5/8-fused ring) and 6 (spiran [4,5] ring) represent uncommonly rearranged sesquiterpenoids. Compounds 10–12 are a novel monoterpene and two megastigmane derivatives, respectively. The individual structures were elucidated by combining NMR and MS data, and their configuration was established in NOESY and ECD experiments. Compounds 1–9 were also examined for their potential to interact with nuclear factor-kappa B activator protein 1 (NF-κB/AP-1) signaling by using the myelomonocytic reporter cell line THP-1Blue-CD14. Compounds 1–5 showed dose-dependent inhibitory effects [IC50 13.7 μM (1) to 49.0 μM (5)] on lipopolysaccharide-stimulated cells. However, compounds 1 to 4 also negatively affected cell viability in the same concentration range, while compound 5 was less potently cytotoxic.