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 EC50 value of 5.82 microg/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.