Quassin

Quassin is a white bitter, crystalline substance extracted from the quassia tree. It is the bitterest substance found in nature. Quassin is used as a medicine in traditional Chinese medicine. Extracts of the Bitter tree are also used as additives in soft drinks.

Although its skeleton possesses 20 carbon atoms Quassin is not a diterpene but a triterpene lactone, which derives from euphol by loss of 10 carbon atoms including C4. Synonyms are (+)-Quassin or Nigakilactone D; Extracts of Quassia amara L. or Picrasma excelsa (Sw.) Planch may be referred to as quassia or Bitter wood extract (synonym).