Camellianols A–G, Barrigenol-like Triterpenoids with PTP1B Inhibitory Effects from the Endangered Ornamental Plant Camellia crapnelliana

Seven new naturally occurring barrigenol-like compounds, camellianols A–G (17), and 10 known triterpenoids were isolated from the twigs and leaves of the cultivated endangered ornamental plant Camellia crapnelliana. According to the ECD octant rule for saturated cyclohexanones, the absolute configurations of camellianols D (4) and E (5) were defined. The backbones of the remaining new isolates are assumed to have the same absolute configuration as compounds 4, 5, and harpullone (12). Compounds 2, 3, 9, 10, 13, and 16 exhibited inhibitory effects on the protein tyrosine phosphatase 1B (PTP1B) enzyme, with IC50 values less than 10 μM.