Bioactive Lignans from the Leaves and Stems of Schisandra wilsoniana

Three new dibenzocyclooctadiene lignans, marlignans M–O (1–3), together two known ones, were isolated from the leaves and stems of Schisandra wilsoniana. The structures of 1–3 were elucidated by spectroscopic methods, including extensive 1D- and 2D-NMR techniques. Compound 2 showed anti-HIV-1 activity with an EC 50 value of 5.82 μg/mL and a therapeutic index (TI) of more than 12.8. Compound 3 showed obvious bioactivity in inhibiting Epstein-Barr virus early antigen (EBV-EA) activation.