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 C18 (11) and two C17 (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, Mo2(OAc)4 or Rh2(OCOCF3)4-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.