Structures and Radical Scavenging Activities of Novel Norstilbene Dimer, Longusone A, and New Stilbene Dimers, Longusols A, B, and C, from Egyptian Herbal Medicine Cyperus longus

The methanolic extract of the whole plant of Cyperus longus originating in Egypt was found to show scavenging activity for DPPH radical. By bioassay-guided separation, a norstilbene dimer, longusone A, with a tropilene structure and three stilbene dimers, longusols A, B, and C, were isolated as the active constituents together with 10 phenolic compounds. The structures of new compounds were elucidated on the basis of chemical and physicochemical evidence.