Aqueous ethanolic extracts of the marine sponge Tedania digitata possessed a number of pharmacological properties. The active constituent, a new N-methylated purine nucleoside, was isolated by ion-exchange chromatography and the structure elucidated by spectral methods, particularly 13C NMR and mass spectroscopy, combined with chemical degradations. Mild acid hydrolysis of the glycosyl bond gave D-ribose while strong acid ...