Additional New Tetracyclic Tetraterpenoid: Methyl Tortuoate D from Soft Coral Sarcophyton tortuosum

Under the guidance of chemical prescreening by direct infusion electrospray ionization mass spectrometry (DI ESI-MS), a new tetracyclic tetraterpenoid, methyl tortuoate D (1) was isolated from the soft coral Sarcophyton tortuosum collected from the South China Sea. Its structure and relative stereochemistry were established by MS, and 1D- and 2D-NMR spectroscopic techniques.