Chemical constituents from the leaves and stems of Schisandra rubriflora.

Six new nortriterpenoids, schirubridilactones A-F (1-6), as well as 14 known compounds, were isolated from the leaves and stems of Schisandra rubriflora. The structures of 1-6 were elucidated on the basis of spectroscopic methods including HSQC, HMBC, (1)H-(1)H COSY, and ROESY NMR experiments. The relative stereochemistry of 1 was confirmed through single-crystal X-ray analysis. In addition, compounds 1-6 showed anti-HIV-1 activity with EC(50) values in the range 14.3-80.8 microg/mL and selectivity indices in the range 2.2-9.0.