Further New Diterpenoids as PTP1B Inhibitors from the Xisha Soft Coral Sinularia polydactyla.

A new prenyleudesmane type diterpene, sinupol (), and a new capnosane type diterpenoid, sinulacetate (), were isolated from the Xisha soft coral along with five known related diterpenes (- and ). Their structures, including absolute configurations, were determined by extensive spectroscopic analysis, the comparison of their NMR data with those of related compounds, and time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculations. Both new compounds ( and ) exhibited promising inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a potential drug target for the treatment of type II diabetes and obesity.