Gymnemic acids are a class of chemical compounds isolated from the leaves of Gymnema sylvestre (Asclepiadaceae).
[1] After chewing the leaves, solutions sweetened with sugar taste like water.
Chemically, gymnemic acids are triterpenoid glycosides.
[2] This is adorned with a sugar such as glucuronic acid and with various ester groups.
The anti-sweet activity is reversible, but sweetness recovery on the tongue can take more than 10 minutes.