Elodexanthones A-J, Isoprenylated Xanthone Derivatives with Diverse Skeletons and Bioactivities from Hypericum elodeoides

Comprehensive Summary Elodexanthones A-J (1-10), two pairs of rearranged isoprenylated xanthone enantiomers with an unprecedent 6/6/5/6 tetracyclic core (1-2) along with seven new isoprenylated xanthones (3-9) and a pair of phenylpropanoid xanthones (10), were purified and enantio-separated from the whole plant of Hypericum elodeoides. Their structures including absolute configurations were characterized by the comprehensive analysis of NMR, HRESIMS, NMR calculations, and ECD calculations. Through Bayer-Villiger oxidation, Claisen condensation and electrophilic addition, the rearranged skeletons of elodexanthones A-B (1-2) were generated from isoprenylated xanthone precursors. The bioactivities evaluation exhibited that compounds 3, 5, 8-10 showed anti-inflammatory activity with the IC50 values in the range of 9.53-34.39 mu mol/L, and compounds 3-7, and 9 showed notable alpha-glucosidase inhibitory activity (IC50: 6.02-257.11 mu mol/L).