Sinunanolobatone A, an Anti-inflammatory Diterpenoid with Bicyclo[13.1.0]pentadecane Carbon Scaffold, and Related Casbanes from the Sanya Soft Coral Sinularia nanolobata

A novel diterpenoid, sinunanolobatone A (1), featuring an unprecedented bicyclo[13.1.0]pentadecane carbon framework, along with two new casbane diterpenoids (2 and 3), and five known related ones (4-8) were isolated from the Sanya soft coral Sinularia nanolobata. The structures of the new compounds were established by detailed spectroscopic analysis, X-ray diffraction analysis, chemical reactions, or a quantum chemical computation method. A plausible biosynthetic pathway of 1 was proposed. In bioassay, the novel compound 1 showed significant inhibitory activity against lipopolysaccharide (LPS) induced inflammation in BV-2 microglial cells.

Automated summary

A novel diterpenoid, sinunanolobatone A (1), with an unprecedented carbon framework, along with new casbane diterpenoids (2 and 3) and known related compounds (4-8) were isolated from the Sanya soft coral Sinularia nanolobata. The structure of the new compounds was determined using various analytical methods and a biosynthetic pathway for compound 1 was proposed. Compound 1 exhibited significant inhibitory activity against LPS-induced inflammation in BV-2 microglial cells.