Lobopaucinoids A-Q, bioactive terpenoids from the soft coral Lobophytum pauciflorum collected in the South China Sea.

Two undescribed rearranged diterpenoids, lobopaucinoids A and B (1 and 2), along with thirteen undescribed lobane-type diterpenoids lobopaucinoids C-O (3-15) including a C (11) and two C (12 and 13) undescribed norditerpenoids, were isolated from the soft coral Lobophytum pauciflorum Ehrenberg (Sarcophytidae family) collected from Xisha Islands of the South China Sea. Additionally, two undescribed prenyleudesmane-type diterpenoids, lobopaucinoids P and Q (16 and 17), as well as two known lobane diterpenoids (18 and 19), were also obtained. Their structures were elucidated based on comprehensive spectroscopic data, Mosher's method, Mo(OAc) or Rh(OCOCF)-induced circular dichroism experiment, quantum chemical calculations, and single-crystal X-ray diffraction and literature comparison. Biological evaluation indicated that compounds 3, 4 and 15 exhibited weak anti-inflammatory activities with the rates from 24.34 % to 35.13 % at the concentration of 20 μM. In addition, compound 1 showed significant hepatoprotective activity in zebrafish model.