Cembrane-Based Diterpenoids Isolated from the Soft Coral Sarcophyton sp.

Abstract

This research explored the chemical composition of the soft coral Sarcophyton sp., leading to the discovery of six previously unreported cembranoids, sarcophynoids D–I (1–6), and three known analog compounds (7–9). Structural elucidation of the new metabolites was achieved by spectroscopic methods, including one- and two-dimensional (1D and 2D) NMR (COSY, HSQC and HMBC), high-resolution electrospray ionization mass spectrometry (HRESIMS), quantum mechanical NMR (QM-NMR) methods, electronic circular dichroism (ECD) calculations, and comparison with literature data. All isolated substances were screened for antibacterial activities, and most exhibited moderate inhibitory effects against six pathogenic bacterial strains, with MIC values between 8 and 64 μg/mL. In addition, the effects of these compounds on LPS and IFN-γ stimulated RAW264.7 cells, focused on the release of NO and TNF-α, were also evaluated, but were inactive at 20 μM.