Author: James J. Gormley
Source: Better Nutrition, October 1997
Herbal Approaches to Diabetes and Hyperglycemia
Ayurvedic botanicals often succeed where conventional medicine fails. Helping improve indicators associated with hyperglycemia and diabetes is one such area. Three herbals important in this effort are plants which seem to grow most happily when climbing: Gymnema sylvestre, Momordica charantia, and Tinospora cordifolia.
Before any discussion of herbal approaches to hyperglycemia and diabetes can happen, insulin should be defined. According to Stedman’s Medical Dictionary, insulin is “a peptide hormone […] secreted by” masses of cells in the pancreas (islets of Langerhans). Insulin promotes glucose utilization and metabolism of proteins and fats in the body.
Gymnema sylvestre. With extracts and decoctions of leaves used traditionally for their antiseptic, diuretic, and laxative benefits as early as the firs-century, A.D., G. sylvestre had already acquired a reputation for its glucose-lowering abilities. In fact, its Hindi name is Gurmar, which means “destroyer of sugar.”
Today, a powder made from the dried leaves of this botanical is used as part of an effective herbal arsenal against diabetes mellitus. As early as 1930, K.S. Mhaskar and J.F. Caius were reporting their initial results on research they conducted between 1924 through 1929. Their studies pointed to the tremendous promise implicit in their findings relating to G. sylvestre and the lowering of excessive blood-sugar levels.
Unfortunately, with the coming of insulin and a flood of synthetic hypoglycemic drugs, the excitement about herbal medicines for diabetes was largely (although only temporarily) eclipsed by mainstream-pharmaceutical companies.
Modern research. We can trace contemporary research into G. sylvestre by looking at studies published between 1981 and 1990 by E.R.B. Shanmugasundaram, and K. Radha Shanmugasundaram, and others. In a report that appeared in the Journal of Ethnopharmacology in 1990, a water-soluble extract of the leaves of this herb was given to 27 patients with insulin-dependent diabetes mellitus (IDDM) on insulin therapy. Compared with control patients, insulin requirements came down as the body’s own (endogenous) insulin utilization was improved, possibly through “revitalisation” of pancreatic “beta” cells in insulin-dependent subjects.
Beneficial effects on non-insulin-dependent patients (with mild-to-moderate hyperglycemia) were demonstrated in 1981 by the same researchers. In other words, more than just helping metabolize circulating excess sugars, compounds in the leaves appear to modulate the release of insulin from their source – the pancreas.
Momordica charantia. Also referred to as bitter melon, this edible fruit “has been used in the traditional medicine systems of China, India, Africa, and the southeastern U.S. (where it has been naturalized)” according to an HerbClip from the Texas-based American Botanical Council dated January 6, 1995. “Clinical trials have shown the fruit extract to have hypoglycemic, antidiabetic effects.”
True enough. In fact, a 1994 experimental study by Iclal Cakici, and colleagues, which also appeared in the Journal of Ethnopharmacology, found that “M. charantia fruits are capable of producing hypoglycemia [in hyperglycemic animals].”
Not unlike G. sylvestre, its effects may be due to the activity of an insulin-like compound in the plant and, also, from its ability to stimulate pancreatic beta-cells to secrete insulin – rather than by directly affecting intestinal glucose absorption.
Tinospora cordifolia. This climbing shrub also has compounds that combat diabetes.
In a preclinical study conducted by K. Raghunathan and P.V. Sharma in 1969, the ability of T. cordifolia to reduce experimentally brought-on hyperglycemia was investigated.
Based on positive results in preventing elevation of blood-sugar levels, these authors suggested that compounds in this shrub appear to: a) prevent excess release of sugars stored in the liver (liver glycogen); b) prevent excess breakdown (catabolism) of sugars stored in muscle (muscle glycogen), thereby preventing excess conversion of lactic acid to blood sugar in the liver; and c) improve glucose utilization related to muscle-glycogen release and lactic acid/blood sugar conversion, a process normally compromised in diabetic subjects.
What these frankly exciting results tell us is two-fold: 1) that the web of signalling and activation/inactivation relationships involving insulin, blood glucose, stored glycogen, the pancreas, and the liver is very delicate; and 2) select Ayurvedic botanicals appear to help these mechanisms work better, thereby decreasing our reliance on synthetic hypoglycemic drugs and on insulin, in some cases.