Arenarialins A-F, Anti-inflammatory Meroterpenoids with Rearranged Skeletons from the Marine Sponge .

Six new sesquiterpene quinone/hydroquinone meroterpenoids, arenarialins A-F (-), were isolated from the marine sponge collected from the South China Sea. Their chemical structures and absolute configurations were determined by HRMS and NMR data analyses coupled with DP4+ and ECD calculations. Arenarialin A () features an unprecedented tetracyclic 6/6/5/6 carbon skeleton, whereas arenarialins B-D (-) possess two rare secomeroterpene scaffolds. Arenarialins A-F showed inhibitory activity on the production of inflammatory cytokines TNF-α and IL-6 in LPS-induced RAW264.7 macrophages with arenarialin D regulating the NF-κB/MAPK signaling pathway.