Quassin is a white, bitter, crystalline substance that is the prototypical example of the family of

quassinoid Quassinoids are degraded triterpene lactones (similar to limonoids) of the Simaroubaceae plant family grouped into C-18, C-19, C-20, C-22 and C-25 types. The prototypical member of the group, quassin, was first described in the 19th century from ...

s. It can be extracted from the

quassia ''Quassia'' ( or ) is a plant genus in the family Simaroubaceae. Its size is disputed; some botanists treat it as consisting of only one species, ''Quassia amara'' from tropical South America, while others treat it in a wide circumscription as a ...

tree, from which it gets its name. It was first isolated in 1937 and its chemical structure was elucidated in 1961. 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 Quinine is a medication used to treat malaria and babesiosis. This includes the treatment of malaria due to ''Plasmodium falciparum'' that is resistant to chloroquine when artesunate is not available. While sometimes used for nocturnal leg cr ...

.Scientific Committee on Foo
Opinion of the Scientific Committee on Food on quassin (expressed on 2 July 2002).
SCF/CS/FLAV/FLAVOUR/29 Final Extracts of the bitterwood tree (''

Quassia amara ''Quassia amara'', also known as amargo, bitter-ash, bitter-wood, or hombre grande (spanish for ''big man'') is a species in the genus ''Quassia'', with some botanists treating it as the sole species in the genus. The genus was named by Carl Linn ...

'') containing quassin are used as additives in

soft drink A soft drink (see § Terminology for other names) is a drink that usually contains water (often carbonated), a sweetener, and a natural and/or artificial flavoring. The sweetener may be a sugar, high-fructose corn syrup, fruit juice, a su ...

s. Although its skeleton possesses 20 carbon atoms, quassin is not a

diterpene Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being ...

but rather a

triterpene Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squale ...

lactone Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the co ...

, which derives from euphol by loss of 10 carbon atoms including C4.

References

Bitter compounds Ethers Quassinoids