Linderaggrenolides A–N, Oxygen-Conjugated Sesquiterpenoid Dimers from the Roots of Lindera aggregata

Linderaggrenolides A–N (1–14), 14 new lindenane sesquiterpenoid dimers with oxygen bridges were isolated from the roots of Lindera aggregata. Their structures were elucidated on the basis of comprehensive spectroscopic data analysis, with the absolute configurations established by empirical approaches, electronic circular dichroism calculations, and X-ray crystallography. Compounds 8 and 9 were found to exhibit significant transforming growth factor-β inhibitory activity, with IC₅₀ values of 25.91 and 21.52 μM, respectively.