Gymnemic acids from Gymnema sylvestre

Some compounds such as gymnemic acid from Gymnema sylvestre (Asclepiadaceae) (which depresses the preceived sweetness of sugars) are known to distort the taste of others ( ) and may play a role in "disguising" the presence of kairomones or nutritional substances. 

Since the initial reports of sweetness-inhibitory oleanane-type gymnemic acids from the leaves of Gymnema sylvestre, plant species of the family Asclepiadaceae have served as bountiful sources of sweetness-inhibitory compounds. The initial isolation and structural characterization of these compounds was very challenging, and these early investigations have been reviewed [19]. In 1989, gymnemic acids I-VI (90-95) were isolated with a common gymnemagenin (149) aglycone structure and a... 

Gholap, S., and A. Kar. 2005. Gymnemic acids from Gymnema sylvestre potentially regulates dexamethasone-induced hyperglycemia in mice. Pharmaceut. Biol. 43 (2) 192-195. 

FIGURE 40.1 Secondary metabolites production under the callus culture. (From Ahmed, A.B.A. et al.. In vitro production of gymnemic acid from Gymnema sylvestre (Retz) R.Br. Ex. Roemer Schultes through callus culture under stress conditions, In Jain, S.K. and Saxena, P.K. (eds.). Protocols for In Vitro Cultures and Secondary Metabolites Analysis of Aromatic and Medicinal Plants, Serious Methods in Molecular Biology, Vol. 547, Humana Press Inc., Totowa, NJ, 2009, p. 93. With permission.)... 

A substance isolated from the Indian shrub Gymnema sylvestre, has a profound ability to reduce perceived sweetness of sugar solutions. The effect was noticed over a century ago when two British inhabitants of an Indian village found that, after chewing the leaves of G sylvestre, the sweetness of their tea disappeared (7). The sweetness suppressing activity is due to a mixture of several triterpene saponins which have collectively been termed the gymnemic acids. For most people exposed to the effects of GA, sweetness suppression is complete and the effect lasts for about an hour. 

Gurmarin See gymnemic acid(s). Polypeptide isolated from the leaves of Gymnema sylvestre. Has also been synthesized. 

Antihyperglycemic effects of gymnemic acid IV, a compound derived from Gymnema sylvestre leaves in streptozotocin-diabetic mice. Sugihara Y, Nojima H, Matsuda H, Murakami T, Yoshikawa M, Kimura I. Department of Chemical Pharmacology, Toyama Medical and Pharmaceutical University, Sugitani, Japan. 

Bioactive Gymnemic Acids and Congeners from Gymnema sylvestre... 

Two new gymnemic acid congeners (1) have been isolated from the leaves of Gymnema sylvestre. A review of the Maillard reaction - in which oxidised derivatives of carbohydrates are proposed as important intermediates - has been published. Carbohydrate alcohols with other hydroxyl groups appropriately protected as acetals, ethers or benzoates are oxidised by "active" RUO2 - NaI04 under phase-transfer conditions to ketones, aldehydes or to... 

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