quassin

Quassin is a natural bitter compound found in the wood of certain trees in the genus Quassia, most notably Quassia amara and Quassia excelsa. It is recognized as one of the most intensely bitter natural substances, and bitterness often occurs together with related compounds such as isoquassin in plant extracts.

Chemically, quassin is a quassinoid, a class of degraded triterpenoids with lactone rings. It is lipophilic and typically occurs in extracts as a mixture, with isoquassin (a glycoside) closely associated. The extreme bitterness of quassin makes it useful as a natural bittering agent in flavorings and bitters.

Occurrence and uses: Quassin is primarily obtained from the wood of Quassia species. In traditional medicine, quassin-containing preparations have been used as stomach tonics or digestive aids, though robust clinical evidence is limited. In modern products, quassin extracts serve as bittering agents or flavor enhancers in certain bitters and beverages, and historically have been used in some folk remedies.

Safety and effects: In high doses, quassin can act as an irritant and may cause nausea, vomiting, or other adverse effects. Because of potential toxicity and variability in preparations, its use is subject to regulatory limits as a flavoring agent in many jurisdictions. As with many bioactive plant compounds, clinical benefits are not well established, and use should follow appropriate guidelines.