Inhibitory effect of norditerpenes on LPS-induced TNF-alpha production from the Okinawan soft coral, Sinularia sp.

An ethanol (EtOH) extract of the soft coral (Sinularia sp.), collected in Okinawa, demonstrated a potent inhibitory effect on lipopolysaccharide (LPS)-induced tumor necrosis factor-alpha (TNF-alpha) production by murine macrophage-like cells (RAW264.7). The activity-guided purification of the EtOH extract resulted in the isolation of two norditerpenes, norcembrenolide (1) and sinuleptolide (2). These structures were identified from the spectroscopic data. Norcembrenolide (1) and sinuleptolide (2) inhibited TNF-alpha production in a dose-dependent manner, and showed a more potent effect than prednisolone at the concentration of 33 microg/ml. They also exhibited an inhibitory effect on nitric oxide (NO) production not influenced by cytotoxicity.