New lignans from the roots of Schisandra sphenanthera

Nine new lignans (1–8, 13) and five known ones (9–12, 14) have been isolated from the roots of Schisandra sphenanthera and were tested for their capacity to scavenge 2,2-diphenyl-1-Picryl-hydrazyl (DPPH). Of these lignans tested, compounds 1, 7, 8 and 13 exhibited noteworthy antioxidant activity with IC50 values of 92, 115, 35 and 48 μg/mL, respectively. The anti-oxidative haemolysis of human red blood cells (RBCs) activity of the most active compound 8, which is similar to that of vitamin C, was evaluated.

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