Gymnemic acids are a class of chemical compounds isolated from the leaves of Gymnema sylvestre (Asclepiadaceae). They are anti-sweet compounds, or sweetness inhibitors.[1] After chewing the leaves, solutions sweetened with sugar taste like water.
Chemically, gymnemic acids are triterpenoid glycosides. The central structure is the aglycone gymnemagenin (C30H50O6). This is adorned with a sugar such as glucuronic acid and with various ester groups. These variations give rise to the different gymnemic acids.[2] More than 20 homologs of gymnemic acid are known.[3]
Gymnemic acid I has the highest anti-sweet properties. It suppresses the sweetness of most of the sweeteners including intense artificial sweeteners such as aspartame and natural sweeteners such as thaumatin, a sweet protein. The anti-sweet activity is reversible, but sweetness recovery on the tongue can take more than 10 minutes.[4]
| Gymnemic acids | |||||
|---|---|---|---|---|---|
| Chemical structure | |||||
| Name | Gymnemic acid I | Gymnemic acid II | Gymnemic acid III | Gymnemic acid IV | |
| R1 | 2-methylbutanoyl | 2-methylbutanoyl | tigloyl | ||
| R2 | acetyl | H | |||
| 122168-40-5 | 122144-48-3 | 122074-65-1 | 121903-96-6 | ||
| PubChem ID | 11953919 | 91617872 | 14264066 | 14264063 | |
| C43H66O14 | C43H68O14 | C41H66O13 | C41H64O13 | ||
| Molar mass (g/mol) | 806.98 | 809.00 | 766.97 | 764.95 | |
Other anti-sweeteners: