Do you have the info on that? The studies I've looked at seem to point to it increasing insulin secretion or possibly mimicking insulin IIRC. I hadn't heard about blocking carb absorption...
Certainly. Gymnema is FIRST AND FOREMOST a carbohydrate blocker. All other effects are pretty much secondary.
The ability to lower glucose levels in blood is caused by the delay in absorption of glucose in the intestines into the blood. Gymnemic molecules are molecular similar to glucose molecules. Gymnema molecules (specifically from the peptide Gurmarin) fill tongue receptor locations; curbing sugar cravings (inhibiting sweet taste sensation). This results in people actually taking in less sugar/carbohydrates which obviously leads to lower blood glucose levels. Gymnemic molecules fill the receptor location in absorptive external layers of the intestine; preventing sugar molecule absorption. This is the cause of the “low blood sugar levels”
Source
Division of Veterinary Pharmacology, Nippon Veterinary and Animal Science University, Musashino-shi, Tokyo, Japan.
Abstract
The leaves of Gymnema inodorum (GI) have been known to be effective for some diseases including diabetes mellitus, rheumatic arthritis and gout. The crude saponin mixtures extracted from GI leaves inhibited glucose absorption in the isolated intestinal tract and suppressed the increased blood glucose in rats. In this study, we examined the relationship between chemical structure and pharmacological activity of the four components from GI leave extracts (GiA-1, GiA-2, GiA-5 and GiA-7). These components were the derivatives of (3beta,4alpha,16beta)-16,23,28-trihydroxyolean-12-en-3-yl-beta-D-glucopyranosiduroic acid. GiA-2, GiA-5 and GiA-7 that have suppressive effects on the high K+-induced contraction, an increase in deltaPD and the increased blood glucose level in the glucose tolerance test have -H at the 21st position and -CH2OH at 4beta of aglycon. On the other hand, GiA-1 that does not have any effects on the three parameters mentioned above has -H at the 21st position and -CH3 at 4beta of aglycon. In conclusion, it is suggested that the inhibitory effect of triterpenoids in Gymnema leaves on glucose absorption from the intestinal tract relies on -CH2OH at 4beta.
Inhibitory effect of gymnemic acid on intestinal absorption of oleic acid in rats.
Wang LF, Luo H, Miyoshi M, Imoto T, Hiji Y, Sasaki T.
Source
Third Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago, Japan.
Abstract
Gymnemic acid, a mixture of triterpene glycosides extracted from the leaves of Gymnema sylvestre, is known to inhibit the intestinal absorption of glucose in human and rats. This work examined the effect of gymnemic acid on oleic acid absorption by the method of intestinal perfusion in rats. The results showed the following. (i) Gymnemic acid potently inhibited the absorption of oleic acid in intestine. (ii) This inhibition was dose dependent and reversible. (iii) The extent of inhibition and the recovery progress were extremely similar to that of glucose absorption. (iv) Taurocholate did not affect the inhibitory effect of gymnemic acid on oleic acid absorption, but lowering its concentration facilitated the recovery from the inhibition. (v) The absorption of oleic acid was not affected by other glycosides such as phloridzin, stevioside, and glycyrrhizin. These new findings are important for understanding the roles of gymnemic acid in therapy of diabetes mellitus and obesity.
Suppression of glucose absorption by extracts from the leaves of Gymnema inodorum.
Shimizu K, Ozeki M, Tanaka K, Itoh K, Nakajyo S, Urakawa N, Atsuchi M.
Source
Division of Veterinary Pharmacology, Nippon Veterinary and Animal Science University, Tokyo, Japan.
Abstract
Gymnema sylvestre (GS) is one of the Asclepiad strains that grows in South-east Asia. Their therapeutic effects for treating diabetes mellitus, rheumatic arthritis and gout have been well known for a long time. However, the problem is that GS suppresses sweetness and tastes bitter. For this study, we chose Gymnema inodorum (GI) instead of GS, since it has an advantage that it does not suppress sweetness nor is it bitter in taste. In this paper, effects of glucose availability of some saponin fractions (F-I to F-IV) extracted from GI leaves, which were obtained by high-performance liquid chromatography were studied on a high K(+)-induced contraction of guinea-pig intestinal smooth muscle, O2 consumption on guinea-pig ileum, glucose-evoked transmural potential difference (delta PD) of guinea-pig everted intestine and blood glucose level in glucose tolerance tests on rats. The extracts of GI leaves suppressed the intestinal smooth muscle contraction, decreased the O2 consumption, inhibited the glucose evoked-transmural potential, and prevented the blood glucose level. Our studies suggest that the component of GI inhibits the increase in the blood glucose level by interfering with the intestinal glucose absorption process.
