Gymnemic acids are glycoside

Glycoside

In chemistry, a glycoside is a molecule in which a sugar is bound to a non-carbohydrate moiety, usually a small organic molecule. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme...

s isolated from the leaves of Gymnema sylvestre

Gymnema sylvestre

Gymnema sylvestre is a herb native to the tropical forests of southern and central India where it has been used as a natural treatment for diabetes for nearly two millennia.-Description:...

(Asclepiadaceae

Asclepiadaceae

According to APG II, the Asclepiadaceae is a former plant family now treated as a subfamily in the Apocynaceae...

). Gymnemic acids like ziziphin

Ziziphin

Ziziphin, a triterpene glycoside which exhibits taste-modifying properties, has been isolated from the leaves of Ziziphus jujuba .Among ziziphin's known homologues found in this plant, it is the most anti-sweet...

 and hodulcine

Hodulcine

Hodulcine , are glycosides , which were isolated from the leaves of Hovenia dulcis Thunb. also known as Japanese Raisin Tree....

 are anti-sweet compounds, or sweetness inhibitors. After chewing the leaves, solutions sweetened with sucrose

Sucrose

Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...

 taste like water.

More than 20 homologues of gymnemic acid are found in the leaves. Gymnemic acid 1 has the highest anti-sweet properties. It suppresses the sweetness of most of the sweeteners including intense artificial sweeteners such as aspartame

Aspartame

Aspartame is an artificial, non-saccharide sweetener used as a sugar substitute in some foods and beverages. In the European Union, it is codified as E951. Aspartame is a methyl ester of the aspartic acid/phenylalanine dipeptide. It was first sold under the brand name NutraSweet; since 2009 it...

 and natural sweeteners such as thaumatin

Thaumatin

Thaumatin is a low-calorie sweetener and flavour modifier. The substance, a natural protein, is often used primarily for its flavour-modifying properties and not exclusively as a sweetener....

, a sweet protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

. The anti-sweet activity is reversible, but sweetness recovery on the tongue can take more than 10 minutes.