The phytochemical investigation of the leaves and twigs of Croton yunnanensis resulted in the isolation of eight new clerodane furanoditerpenoids, named croyunfuranoids A-H (1-8), along with three known analogs (9-11). The structures of these compounds were elucidated using spectroscopic analyses, and their absolute configurations were determined through a combination of electronic circular dichroism (ECD) calculations and single-crystal X-ray diffraction. Notably, Croyunfuranoid D (4) is identified as a rare 18,19-dinor-clerodane diterpenoid. Additionally, the structure of a previously reported diterpenoid, crotonyunnan B, was revised. All isolated compounds were evaluated for their inhibitory activities on nitric oxide (NO) production in LPS-induced RAW 264.7 macrophages. Among them, compounds 5 and 6 demonstrated significant inhibitory effects, with IC50 values of 20.33 ± 2.31 and 22.80 ± 1.31 μmol·L-1, respectively.
Keywords: Clerodane furanoditerpenoid; Croton yunnanensis; Euphorbiaceae; NO inhibitory activity.
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