Biscroyunoid A, an Anti-Hepatic Fibrotic 19-<i>nor</i>-Clerodane Diterpenoid Dimer with a C-16-C-12' Linkage from <i>Croton yunnanensis</i>.
Li W, Gan L, Yuan FY, Sang J, Huang D, Yin AP, Pu R, Tang GH, Guo D, Yin S.
Biscroyunoid A (<b>1</b>), a 19-<i>nor</i>-clerodane diterpenoid dimer featuring a unique C-16-C-12' linkage and containing an unusual 4,7-dihydro-5<i>H</i>-spiro[benzofuran-6,1'-cyclohexane] motif, together with its biosynthetic precursor, croyunoid A (<b>2</b>), were isolated from <i>Croton yunnanensis</i>. Their structures were determined by spectroscopic, computational, and single-crystal X-ray diffraction methods. Compound <b>1</b> exerted an antihepatic fibrosis effect in LX-2 cells via inhibition of TGFβ-Smad2/3 signaling.