Psiguadiols A-J, Rearranged Meroterpenoids as Potent PTP1B Inhibitors from .

Psiguadiols A-J (-), new meroterpenoids with rearranged skeletons, were isolated from the leaves of . Compounds - represent the first examples of 6,8-diformyl-5,7-dihydroxy-4-phenylchromane-coupled sesquiterpenoids with an unprecedented C-8-spiro-fused 6/6/9/4 tetracyclic ring system. Compounds and represent two unusual scaffolds featuring 1β,6β- and 3α,5α-epoxy rings, respectively. The combination of spectroscopic data analyses, comparison of experimental and calculated ECD data, and single-crystal X-ray diffraction data of , , and allowed for the assignment of the structures. A putative biosynthetic pathway for - is discussed. Compounds , , and exhibited inhibitory activities against PTP1B with IC values of 4.7, 6.2, and 9.2 μM, respectively. In addition, molecular docking was performed to investigate the mechanism of action.