Quassin (Qua)

Quassin is a white bitter, crystalline substance extracted from the quassia tree. It is one of the most bitter substances found in nature with a bitter threshold of 0.08 ppm and it is 50 times more bitter than quinine. Quassin is used as a medicine in traditional Chinese medicine. Extracts of the Bitter tree (or bitter wood) (Quassia amara L. or Picrasma excelsa) are also used as additives in soft drinks. Although its skeleton possesses 20 carbon atoms, quassin is not a diterpene but rather a triterpene lactone, which derives from euphol by loss of 10 carbon atoms including C4. Quassin and neoquassin were quantified in food additives by qNMR and HPLC based on molar absorption coefficient ratios using 1,4-bis(trimethylsilyl)benzene-d4 and 4HBA as internal standards, respectively. The differences in quantitation values between qNMR and HPLC analyses were below 1.2%.