Gymnema
Botanical Description & Habitat
Gymnema sylvestre
Also Gymnema melicida
Family
Asclepiadaceae
Common Names
Gurmar
Merasingi
Meshashringi
Habitat
India, and Southern China and tropical and subtropical regions of Southeast Asia.
Medicinal Parts
Leaf and sometimes the stem.
Historical Properties & Uses
Gymnema is an Indian Ayurvedic medicine coming into modern use after two thousand years of folklore use in India for diabetes, snakebites, diuretic, stomachic, urinary antiseptic, and other assorted uses.
Gymnema has the peculiar property of neutralizing the sweet flavor of sugar if placed on the tongue prior to the sugar. In fact, the common name "gurmar" means sugar destroyer.
Most studies confirm the antidiabetic property of gymnema. The plant prevents the absorption and activity of glucose molecules. The word "control" best describes the action of gymnema on diabetes. It is not a cure, and does not substitute for proper dietary habits, but its use will significantly help to keep blood sugar levels with acceptable limits.
There is some literature floating around the industry stating gymnema neutralizes up to 50% of ingested sugar, i.e., makes it unavailable for involvement in pancreatic and blood sugar functions, but these numbers are apparently not derived from the experimental literature.
Method of Action
Gymnema is an Effective Hypoglycemic and Antidiabetic Agent
The main component of gymnema is a brittle, black acidic resin known as gymnemic acid. This substance is responsible for the herb's ability to neutralize the taste of sugar.
It is believed by some to cause a temporary anesthesia of the tongue, which somehow selectively blocks the taste mechanism for sweetness. The acid has been broken down into at least four fractions. Hentriacontane, a glucoside, along with gymnemic acid, are responsible for the anti-glucose properties. The leaves also contain chlorophyll, xanthopylls, carotene, phytol, pentatriacontane, and lime salts.
Among the basic pharmacological properties of gymnema are the following: antiviral; increases oxygen uptake and blood pressure; increases secretions of liver and pancreas. The leaves have been found to stimulate the heart, uterus, circulatory system, and to raise urine output.
In one early study, gymnema in some diabetic patients at a dose of 4g/day significantly lowered blood glucose levels and total urinary glucose excretion. Several other patients dropped out of this study after the preparation failed to have any effect.
In a very thorough animal study, gymnema greatly reduced the blood glucose levels in alloxan-induced diabetic rabbits. It was thought gymnema effects were mediated through stimulation of insulin release resembling what was observed with sulfonylureas, or through inhibition of intestinal absorption of glucose as observed with the biguanides, or through stimulation of one of the insulinogenic signals promoting insulin release.
Gymnema reversed the glycogen and protein depletions and lipid accumulation in the diabetic animals. The idea gymnema works by increasing the levels of circulating insulin was supported by observations of altered enzyme activities in the liver, kidney and muscles. Most of the insulin-dependent enzymes 0(hexokinase, glycogen synthetase, glyceraldehyde-3-phosphate dehydrogrenase, and glucose-6-phosphate dehydrogenase) were significantly more active in the gymnema-treated animals than in control diabetic animals.
It also increased the activity of enzymes affecting the utilization of glucose by insulin-dependent pathways: phosphorylase, gluconeogenic enzymes, and sorbitol dehydrogenase. Pathological changes in liver and kidney were reversed by the treatment. The study reports in great detail findings supporting the notion gymnema corrects the metabolic derangements in diabetic rabbit liver, kidney and muscle tissues.
Other studies have found similar normalizing effects of various enzymes and chemicals of the kidney, heart, liver and brain, including hexuronic acid, hexoses, hexosamines, non-aminopolysaccharides, hyaluronic acid, heparin sulfate, chondroitin sulfates and sialic acid.
In another study utilizing alloxan diabetic rabbits, and one human patient, gymnema brought down the fasting blood glucose levels, together with serum cholesterol and triglyceride levels, while improving serum protein levels. The hypoglycemic action took several weeks to develop.
Orally administered gymnema liquid extract corrected high blood glucose levels in moderately (150-250 mg%) alloxan diabetic rats. This effect lasted for more than two weeks after treatment stopped. The herb did not reduce blood sugar levels in severe and toxic diabetic animals (240-400 mg%, and over-400 mg%), but it did significantly prolong survival time. The lack of hypoglycemic effect in the severe and toxic groups may suggest alloxan destroys the pancreas "B" cells in these groups so completely they cannot be rejuvenated by treatment with gymnema (or anything else).
Oral administration in normal rats apparently has no significant effect, but only in rats made hyperglycemic experimentally (alloxan; anterior pituitary-treated; tolbutamide; adrenaline). In some experimental and clinical trials no effect is observed even in diabetic subjects. We have obviously much more to learn about the action of gymnema.
While gymnema does not lower blood sugar levels in normal subjects it does appear to prevent a rise in blood sugar levels in normal subjects. This result has been attributed to a pancreotrophic effect due to sensitization of beta-cells of islets of Langerhans for secreting larger amounts of insulin in response to glucose. In addition, g. sylvestre markedly inhibit somatotropin- and corticotropin-induced elevations in blood sugar levels.
It is of interest to note some authors are speaking of the "adaptogenic" nature of gymnema, since it increases the body's ability to adapt to the presence of sugar. The increase in longevity noted above was ascribed to "cardiotonic and adaptogenic characteristics produced by increasing resistance and immunity in diabetic animals." It would have to be a characteristic of a true adaptogen to "normalize" function, not just prolong life. Recently, researchers have reported gymnema prevents death due hypoglycemia in rats injected with beryllium nitrate. That gymnema prevents both rises and falls in blood sugar and causes no significant change in normal blood sugar levels is in full harmony with the concept of an "adaptogen."
All of the talk about gymnema blocking sugar metabolism at some peripheral site overlooks the much more likely action of the herb on central nervous system sites, suggested by the research review above shows gymnema inhibits adrenocortical activity and prevents the normal hyperglycemic response of the anterior pituitary gland which acts in turn by inhibiting peripheral glucose metabolism induced by somatotropin and corticotropin hormones.
A direct insulin-secreting action on the pancreas can also not be ruled out.
Gymnema is an Effective Treatment for Some Snakebites
There is at least partial confirmatory evidence gymnema can be used to treat certain snake bites. Gymnema was found to inhibit the action of ATPase, a toxic component of Naja Naja venom, apparently by active competition for the same binding sites.
Drug Interactions & Precautions
Known Interactions
Gymnema, insofar as its diuretic action increases the renal excretion of sodium and chloride, may potentiate the hyperglycemic and hyperuremic effects of glucose elevating agents.
Possible Interactions
The use of diuretics may require dosage adjustments of antidiabetic drugs.
Comments
The antidiabetic ability of this herb may be decreased by concomitant use of acetazolamide, oral contraceptives, corticosteroids, dextrothyroxine, epinephrine, ethanol, glucagon, guanethideine and marijuana.
The antidiabetic effects of this herb may be decreased when used in conjunction with phenothiazines, rifampin, thiazide diuretics, and thyroid hormones.
The antidiabetic action of gymnema may be enhanced when it is used with allopurinol, anabolic steroids, chloramphenicol, clofibrate, fenfluramine, MAOI, phenylbutazone, probenecid and phenyramidol.
The antidiabetic action of gymnema may be enhanced when used in conjunction with salicylates, sulfinpyrazone, sulfonamides, and tetracyclines.
The ability of gymnema to increase insulin production and secretion may be antagonized by heparin.
Safety Factors & Toxicity
Gymnema sylvestre has no known toxicity, except for a temporary anesthetizing effect on the tongue for the taste of sugar (and possibly bitter) if the leaves are chewed.
Preparation & Administration
Use three times daily
Exact dosage requirements for humans have not been determined. Suggest following manufacturers' instructions on packaging inserts.
Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.
References
Chopra, R., J. Bose & N. Chatterjee. Gymnema sylvestre in diabetes mellitus. Indian Journal of Medical Research, 16, 115-120, 1928.
Facts and Comparisons. The Lawrence Review of Natural Products. Aug, 1993.
Gharpurey, K.G. Gymnema sylvestre in the treatment of diabetes. Indian Medical Gazette, 61, 155, 1926.
Gupta, S.S. Effect of some ayurvedic anti-diabetic drugs on the body weight of rats treated with anterior pituitary extract. Journal of Indian Medical Association, 39, 10-13, 1962.
Gupta, S.S. Effects of gymnema sylvestre and pterocarpus marsupium on glucose tolerance in albino rats. Indian Journal of Medical Science, 17, 501-505, 1963.
Gupta & Seth. Experimental studies on pituitary diabetes Part II: Comparison of blood sugar level in normal and anterior pituitary extract-induced hyperglycemic rats. Indian J of Med Research, 50, 708-714, 1962.
Gupta, S.S. Experimental studies on pituitary diabetes Part II Comparison of blood sugar level in normal and anterior pituitary extract-induced hyperglycemic rats. Indian Journal of Medical Research, 51, 716-725, 1963.
Gupta, S.S. & M.C. Variyar. Experimental studies on pituitary diabetes; Part IV. Effect of gymnema sylvestre and coccinia indica against the hyperglycemic response of somatotropin and corticotropin hormones. Indian Journal of Medical Research, 52, 200-207, 1964.
Kans, J.F. Encyclopedia of Homeopathic Drugs. Lucknow Publishers, Lucknow. 2, 334-335, 1938.
Loubatieres, A. The mechanism of action of the hypoglycemic sulphonamides: A concept based on investigations in animals and in man. Diabetes, 6, 408-417, 1957.
Manjunatha & Veerabasappa. Studies on snake venom enzymes. Purification of ATPase, a toxic component of Naja Naja venom & its inhibition by potassium gymnemate. Indian J of Biochem. Biophys., 19(2), 152-154, 1982.
Mirsky. A., S. Gitelson & G. Perisutti. The effect of tolbutamide on the diabetic action of somatropin. Endocrinology, 64, 766-772, 1959.
Mhaskar, K.S. & J.F. Caius. A study of Indian medicinal plants. II. Gymnema sylvestre R.Br. Indian Medical Research Memoirs, supplement to the Indian Journal of Medical Research, 16, 1-49, 1930.
Mowrey, Daniel B., Ph.D. Exper. Psych., Brigham Young University. Director of Nebo Institute of Herbal Sciences. Director of Behavior Change Agent Training Institute. Director of Research, Nova Corp.
Nadakarni & Nadakarni. The Indian Materia Mecica: Anti-diabetes. Popular Book Depot, Bombay, India, II, p. 15, 23, 239, 536, 1954.
Power, F.B. & F. Tutin. Chemical examination of gymnema sylvestre. Pharmaceutical Journal, LXXIII (1904), cited by Mhaskar and Caius, 1930.
Prakash, A.O., S. Mathur & R. Mathur. Effect of feeding gymnema sylvestre leaves on blood glucose in beryllium nitrate treated rats. Journal of Ethnopharmacology, 18, 143-146, 1986.
Qayum, A., N. Ahmed, K.D. Ahmed & S.G. Khatiak. Pharmacological screening of medicinal plants. Journal of the Pakistan Medical Association, April, 103-105, 1982.
Rathi & Visnanathan. Studies on protein-bound polysaccharide components and glycosaminoglycans in experimental diabetes--effect of gymnema sylvestre R.Br. Indian J of Experimental Biology, 19(8), 715-721, 1981.
Shanmugasundaram, K.R., C. Panneereselvan, P. Samdudram & E.R.B. Shanmugasundaram. Enzyme changes and glucose utilisation in diabetic rabbits: the effect of gymnema sylvestre, R.Br. Jnal of Ethnopharmacology, 7, 205-234, 1983.
Shanmugasundaram, K.R. & C. Panneerselvam. The insulinotropic activity of gymnema sylvestre R.Br. An indian medical herb used in controlling diabetes mellitus. Pharmacological Research Communications, 13(5), 475-486, 1981.
Sinsheimer, J.E., G. Subba Rao, H.M. McIlheny, R.V. Smith, H.F. Maassab & K.W. Cochraw. Isolation and antiviral activity of gymnemic acids. Experentia, 24, 302-303, 1968.
Manjunatha, Srivastava, Venkatakrishna-Ghatt, Jhala, Nigam, Kumar & Verma. Oral gymnema sylvestre R.Br. leaf extracts inducing protracted longevity and hypoglycemia in alloxan diabetic rats: review and experimental study. Int. J. Crude Drug Research, 24(4), 171-176, 1986.
Vogt, M. Observations on some conditions affecting rate of hormonal output by adrenal cortex. Journal of Physiology, 103, 317-332, 1944.
Wahi, S.P. & K.X. Chunekar. Pharmacological studies of gymnema sylvestre R.Br. Journal Sci. Res. Banaras Hindu University, Varanasi, India, 15, 205-210, 1964.
Young, F.G. Growth hormone and experimental diabetes. Journal of Clinical Endocrinology, 11, 53-556, 1951.
| Signup Free Applied Health Journal |
||||
|
FREE Sample Issue Your email address is all we need to start you on a better path to health. We respect your privacy.
|
