Terminalagin, a New Ellagitannin from Kakadu Plum (<i>Terminalia ferdinandiana</i>)

Kakadu plum (Terminalia ferdinandiana) reportedly has the highest ascorbic acid levels of all plants worldwide and its juice reactivates functions of the retinoblastoma gene (RB) product, a tumor suppressor gene. In this study, the juice of the Kakadu plum was fractionated to identify the constituent active compounds. A novel ellagitannin, named terminalagin, was isolated from Kakadu plum (Terminalia ferdinandiana) juice via bioassay-guided isolation. The structure was determined using spectroscopic analysis and partial hydrolysis. Terminalagin has a corilagin substructure and a 2,4-(S)-hexahydroxydiphenoyl (HHDP) ester moiety that is not usually found in natural products. The results of this study enrich the structural database of ellagitannins and should provide invaluable aid for their further utilization in cancer prevention.