Hepatoprotective Tetrahydrobenzocyclooctabenzofuranone Lignans from Kadsura longipedunculata.

Three new tetrahydrobenzocyclooctabenzofuranone lignan glucosides, longipedunculatins A-C (1-3), a new dibenzocyclooctadiene lignan glucoside, longipedunculatin D (4), a new dibenzocyclooctadiene lignan (5), five new tetrahydrobenzocyclooctabenzofuranone lignans (6-10), and two new simple lignans (11, 12) were isolated from the roots of Kadsura longipedunculata. Their structures and absolute configurations were established using a combination of MS, NMR, and experimental and calculated electronic circular dichroism data. Compound 7 showed moderate hepatoprotective activity against N-acetyl-p-aminophenol-induced toxicity in HepG2 cells with a cell survival rate at 10 μM of 50.8%. Compounds 2, 7, and 12 showed significant in vitro inhibitory effects with an inhibition rate of 55.1%, 74.9%, and 89.8% on nitric oxide production assays at 10 μM.