Gymnema sylvestre R.Br. is a herb native to the tropical forests of southern and central India where it has been used as a herbal treatment for diabetes for nearly two millennia.
Gymnema sylvestre, also known as Gurmar and Meshashringi, whose Hindi name literally means ‘sugar destroyer’, has been used in Ayurveda for several centuries to regulate sugar metabolism.
The hypoglycemic (blood sugar-lowering) action of gymnema leaves was first documented in the late 1920s. This action is gradual in nature, differing from the rapid effect of many prescription hypoglycemic drugs. Gymnema leaves raise insulin levels by regeneration of the cells in the pancreas that secrete insulin. Other research has shown that gymnema also improves uptake of glucose into cells by increasing the activity of the glucose utilizing enzymes, and prevents adrenaline from stimulating the liver to produce glucose, thereby reducing blood sugar levels. The leaves are also noted for lowering serum cholesterol and triglycerides. It also abolishes the taste of sugar, which effectively suppresses and neutralizes the craving for sweets. The leaf extracts contain gymnemic acid which inhibits hyperglycemia and also acts as a cardiovascular stimulant.
The primary clinical application for this botanical is as an antidiabetic agent. Gymnema has been the subject of considerable research since the 1930s, with promising results for types 1 and 2 diabetes. Gymnema has been successful in controlling the blood sugar level without reducing it to below the normal blood sugar level, an effect seen with the use of insulin or oral hypoglycemic sulphonylurea compounds. Gymnema provides a simple and effective method to help maintain healthy glucose levels. Gymnema contains Gymnemic acid (GA), quercitol, lupeol, ß-amyrin and stigmasterol, which have glucose lowering properties. It works safely within your current regimen to promote proper pancreatic function.
Large climbers, rooting at nodes, leaves elliptic, acuminate, base acute to acuminate, glabrous above sparsely or densely tomentose beneath; Flowers small, in axillary and lateral umbel like cymes, pedicels long; Calyx-lobes long, ovate, obtuse, pubescent; Corolla pale yellow campanulate, valvate, corona single, with 5 fleshy scales. Scales adnate to throat of corolla tube between lobes; Anther connective produced into a membranous tip, pollinia 2, erect, carpels 2,unilocular; locules many ovuled; Follicle long, fusiform 1.
The major bioactive constituents of Gymnema sylvestris are a group of oleanane type triterpenoid saponins known as gymnemic acids. The latter contain several acylated (tigloyl, methylbutyroyl etc.,) derivatives of deacylgymnemic acid (DAGA) which is 3-O-glucuronide of gymnemagenin (3, 16, 21, 22, 23, 28-hexahydroxy-olean-12-ene)2. The individual gymnemic acids (saponins) include gymnemic acids I-VII, gymnemosides A-F, gymnemasaponins
Gymnema leaves contain triterpene saponins belonging to oleanane and dammarene classes. Oleanane saponins are gymnemic acids and gymnemasaponins, while dammarene saponins are gymnemasides. Besides this, other plant constituents are flavones, anthraquinones, hentri-acontane, pentatriacontane, α and β- chlorophylls, phytin, resins, d-quercitol, tartaric acid, formic acid, butyric acid, lupeol, β-amyrin related glycosides and stigmasterol. The plant extract also tests positive for alkaloids. Leaves of this species yield acidic glycosides and anthroquinones and their derivatives.
Gymnemic acids have antidiabetic, anti-sweetener and anti-inflammatory activities. The anti-diabetic array of molecules has been identified as a group of closely related gymnemic acids after it was successfully isolated and purified from the leaves of Gymnema sylvestre. Later, the phytoconstituents of Gymnema sylvestre were isolated, and their chemistry and structures were studied and elucidated.
Use as herbal medicine
While it is still being studied, and the effects of the herb are not entirely known, the herb has been shown to reduce blood sugar levels when used for an extended period of time. Additionally, Gymnema reduces the taste for sugar when it is placed in the mouth, thus some use it to fight sugar cravings. From extract of the leaves were isolated glycosides known as Gymnemic acids, which exhibit anti-sweet activity. This effect, however, is often short-lived.. Some postulate that the herb actually reduces cravings for sugar by blocking sugar receptors in the tongue.. It is currently being used in an all natural medication for diabetes with other ingredients such as cinnamon, chromium, zinc, biotin, banaba, huckleberry and bitter melon.
The active ingredient is thought to be gurmenic acid which has structure similar to saccharose. Extracts of Gymnema is not only claimed to curb sweet tooths but also for treatment of as varied problems as hyperglycemia, obesity, high cholesterol levels, anemia and digestion, glycosuria.
In 2005, a study made by King’s College, London, United Kingdom, showed that a water-soluble extract of Gymnema Sylvestre, caused reversible increases in intracellular calcium and insulin secretion in mouse and human β-cells when used at a concentration (0.125 mg/ml) without compromising cell viability. Hence these data suggest that extracts derived from Gymnema Sylvestre may be useful as therapeutic agents for the stimulation of insulin secretion in individuals with T2DM.
1. ^ AD kinghorn and CM Compadre. Less common high-potency sweeteners. In Alernative Sweeteners: Second Edition, Revised and Expanded, L O’Brien Nabors,Ed., New York, 1991. ISBN 0-8247-8475-8
2. ^ H Asare-Anane, GC Huang, SA Amiel, PM Jones & SJ Persaud (2005) Poster Presentations – Stimulation of insulin secretion by an aqueous extract of Gymnema sylvestre: role of intracellular calcium. Endocrine Abstracts, Volume 10 DP1.
The Useful Plants of India (UPI,1986); Publication and Information Directorate, CSIR New Delhi.
* Anturlikar, S.D. Gopumadhavan,S, Chauhan, School, Mitra, B.L., Mitra, S.K., Probe `V.34(3); P.211-221, 1995 (26 Ref.Eng).
* 3. Mukherjee, P.K.; Rajesh Kumar, M; Saha, K; Giri, S.N.; Pal, M; Saha, B.P. Journal of Scientific and Industrial Research, V.55(3) Page 178-181, 1995 (Eng.14 Ref)
* 4. Chakravarthi,D and Debnath, N.B. 1981 Isolation of Gymnemagenin, the Sapogenin from Gymnema Sylvestre R.Br. (Asclepiadaceae). Journal of the Institution of Chemists (India) 53, 155-158
* 5. Glaser,D.;Hellekant, Gwalior., Brouwer, J.N., and Van der wel. Happy (1984) Effects of Gymnemic Acid and on sweet taste perception in primates . Chemical Sciences 8,367-374.
* 6. Gupta, S.S(1961) Inhibitory effect of Gymnema Sylvestre (Gurmar) on adrenaline induced Hyperglycemia in rats, Indian Journal of Medical Sciences 15, 883-887.
* 7. Imoto, T.; Miyasaka, A., Ishima. R and Akasaka,K (1991) A novel peptide isolated from the leaves of Gymnema Sylvestre I. Characterization and its suppressive effect on the neural responses to sweet taste stimuli in the rat . Comparative Biochemistry and Physiology, 100A, 309-314.
* 8. Kennady, L.M. (1989) Gymnemic Acids; specificity and comperitive inhibitation. Chemical Senses 14, 853-858
* 9. Shanmugasundaram, K.R., Panneerselvam, C., Samudram, P and Shanmugasundaram E.R.B. (1983) Enzyme changes and glucose utilisation in diabestic rabbits; the effect of Gymnema Sylvestre, Journal of Agricultural and Food Chemistry 17, 704-708.
* 10. Stocklin, W.(1969b) Chemistry and Physiological properties of Gymnemic acid, the anti-saccharine principle of the leaves of Gymnema Sylvestre, Journal of Ethnopharmacology 7, 205-234.
* 11. Yoshikawa, K.,Amimoto, K, Arihara, School and Matsuura, K.(1989a) Structure Studies of new anti-sweet constituents from Gymnema Sylvestre. Trtrahedron Letters 30, 1103-1106
* 12. Yoshikawa,K, Amimoto,K, Arihara,S and Matsuura, K (1989b) Gymnemic Acid V,VI and VII from Gurmar, the leaves of Gymnema Sylvestre R.Br. Chemical and Pharmaceutical Bullitin 37, 852-854.
* 13. Yoshikawa,K, Arihara,S, Matsuura, K and Miyase,T (1992a) Demmarane Saponins from Gymnema Sylvestre, Phytochemistry 31, 237-241
* 14. Mukherjee,P.K., rajesh Kumar,M., Saha,K., Giri,S.N., Pal, M, Saha B.P. Preparation and evaluation of Tincture of Gymnema Sylvestre (Family- Asclepiadaceae) by Physico-Chemical, TLC and Spectroscopic characteristics. – Journal of Scientific and Industrial Research, V.55(3): P.178-181,1995 (Eng.14 Ref).
* 15. Anil, K.I., Nazaam,P.A., Joseph, L, Vijay Kumar, N.K. – Response of “Gurmar” for in vitro propagation. V.42(6); P 365-368, 1994 (Eng.Recd 1996,6 ref).
* 16. Bo Liu, Henry Asare-Anane, Altaf Al-Romaiyan, GuoCai Huang, Stephanie A Amiel, Peter M Jones, Shanta J Persaud – Characterisation of the Insulinotropic Activity of an Aqueous Extract of Gymnema Sylvestre in Mouse β-Cells and Human Islets of Langerhans.  Cellular Physiology and Biochemistry 2009;23:125-132.
– With thanks to Wikipedia for this information: http://en.wikipedia.org/wiki/Gymnema_sylvestre