Dolabellane Diterpenoids from the Xisha Soft Coral Clavularia viridis .

Twelve new members ( 1 - 12 ) of the dolabellane family, co-occurring with three related known diterpenoids ( 13 - 15 ), were isolated from the Xisha soft coral Clavularia viridis . Their structures were determined by extensive spectroscopic analysis, modified Mosher's method, and X-ray diffraction analysis. Clavuperoxylides A ( 3 ) and B ( 4 ) represent the first examples of dolabellanes containing peroxyl groups, especially the novel peroxide bridge in 4 , whereas clavufuranolides A-C ( 9 - 11 ) are the first example of dolabellane diterpenoids comprising a tetrahydrofuran ring. The possible biogenetic relationship of all the isolates was proposed. In bioassay, several compounds exhibited considerable cytotoxicity against A549 and P388 cell lines. Compound 7 exhibited inhibitory activity against protein tyrosine phosphatases 1B (PTP1B), an anti-diabetic target, representing the first report of PTP1B inhibitory activity for dolabellane diterpenoids.