Title The isolation and chemical investigation of cardiac glycosides from Australian plants

A number of plants belonging mainly to the Apocynaceae and Asclepiadaceae families have been screened for the presence of cardio—active constituents. Of those which gave positive indication of the presence of cardiac glycosides, Gomphocarpus fruticosus (R.Br.), Cerbera floribunda, Cerbera dilatata, and. Cerbera manghas were selected for further investigation. Two substances were isolated from Gomphocarpus fruticosus; Gomphoside — a pure compound, and Afroside — a mixture of two substances which could not be separated by chromatography on alumina. Gomphoside, 029H4408, contains neither methoxyl nor acetyl groups, but forms a diacetate, C33H4801O, which is unstable to chromium trioxide in acetic acid. Although gomphoside gives a negative Keller-Kiliani reaction, a quantitative oxidation by periodic acid indicates the presence of two free adjacent hydroxyl groups in the molecule. Hydrolysis of gomphoside gives gomphogenin, 023H3405, which does not give a colour reaction with : tetranitromethane. The acetylation of gomphogenin yields acetyl-gomphogenin, 025H3606’ which is unstable to chromium trioxide in acetic acid