Eleven new highly oxygenated triterpenoids from the leaves and stems of Schisandra chinensis

Eleven new triterpenoids, schinchinenins A-H (1-8) and schinchinenlactones A-C (9-11) together with three known triterpenoids, henrischinins A-C (12-14), were isolated from the leaves and stems of Schisandra chinensis by bioassay-guided fractionation. Schinchinenin A (1) is the first example of a highly oxygenated triterpenoid characterized by a 5/5/7/6/5-fused pentacyclic ring and a 3-one-2-oxabicyclo-[3.2.1]-octane moiety. Schinchinenins E and F (5 and 6) are highly oxygenated triterpenoids that contain a hydroperoxyl moiety, which is rare in compounds from the Schisandra genus. The structures and stereochemistry of 1-11 were elucidated using spectroscopic analysis, single-crystal X-ray diffraction, computational optical rotation, chemical transformation, and CD exciton chirality methods. The activities of compounds 1, 2, 7, and 12-14 against HSV-2 and adenovirus were evaluated for the first time, and of these compounds, 13 was the most active inhibitor of HSV-2, with a selectivity index value as high as 29.95.