Studies on the active principles of Schisandra sphenanthera Rehd. et Wils. The structures of schisantherin A, B, C, D, E, and the related compounds.

Deoxyschisandrin (VIII) and five new lignans, named schisantherin A, B, C, D, and E, were isolated from the active fraction of the fruits of Schisandra sphenanthera Rehd. et Wils. Their configurations and conformations were established by exhaustive spectral analysis as well as chemical degradations as shown in Ia, Ib; IIa, IIb; IIIa, IIIb; IVa, IVb, and Va, Vb respectively, and their absolute configurations at biphenyl, at C6, C7, and C8 were all assigned to be S form. The position of the methylenedioxyl group in the structures of gamma-schisandrin and Wuweizisu C (as described in the literature), isolated from Schisandra chinensis, must be corrected as shown in VI and VII respectively. In pharmacologica studies and preliminary clinical trials, schisantherin A, B, C, and D showed good effect in lowering the serum glutamic-pyruvic transaminase level of the patients suffering from chronic virus hepatitis. Schisantherin E and deoxyschisandrin were not effective.