Dolabellane Diterpenoids from the Xisha Soft Coral .

Twelve new members (-) of the dolabellane family, co-occurring with three related known diterpenoids (-), were isolated from the Xisha soft coral . Their structures were determined by extensive spectroscopic analysis, modified Mosher's method, and X-ray diffraction analysis. Clavuperoxylides A () and B () represent the first examples of dolabellanes containing peroxyl groups, especially the novel peroxide bridge in , whereas clavufuranolides A-C (-) 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 exhibited inhibitory activity against protein tyrosine phosphatases 1B (PTP1B), an anti-diabetic target, representing the first report of PTP1B inhibitory activity for dolabellane diterpenoids.