Effects Of Gymnemic Acid Research Articles

Gymnemic Acid Stimulates In Vitro Splenic Lymphocyte Proliferation

Gymnemic acid is a mixture of triterpenoid saponins of oleanane class, isolated from Gymnema sylvestre Wild R.Br (family: Asclepidaceae), an herbal plant used in traditional medicine to treat diabetes. Effect of gymnemic acid (0.1-20 µg/mL) on in vitro mitogen (concanavalin A and lipopolysaccharide)-induced splenic lymphocyte proliferation was studied using rat as model. Significant (p < 0.05) stimulation of lymphoproliferation was observed in cultures treated with 10 and 20 µg/mL concentration of gymnemic acid in the absence or presence of mitogens. The present study suggests that gymnemic acid has immunomodulatory property, stimulating lymphoid components of immune system, and the traditional knowledge of anti-diabetic property of G. sylvestre is scientifically supplemented with its immunomodulatory properties.

Inhibitory effect of gymnemic acid on intestinal absorption of oleic acid in rats

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.Key words: gymnemic acid, oleic acid, glucose, intestinal absorption, rat.

Taste in Chimpanzee: I. The Summated Response to Sweeteners and the Effect of Gymnemic Acid

Taste in Chimpanzee: I. The Summated Response to Sweeteners and the Effect of Gymnemic Acid

Specificity and mechanisms of gymnemic acid antagonism (inhibition)

In her letter, Kennedy had several objections to our recent review of our conclusions about the effects of gymnemic acid (GA) on the mammalian sugar taste response (Jakinovich and Sugarman, 1988). Because our review focus was confined to the mammalian taste response, we will not address objections concerning insects or amino acids. In our response letter, we will only address the objections concerning the specificity and mechanism of GA antagonism (inhibition) of the mammalian sugar taste response

Effects of gymnemic acid on the chorda tympani proper nerve responses to sweet, sour, salty and bitter taste stimuli in the chimpanzee.

In man gymnemic acid is able to abolish the sweet taste. Also in man, the neural correlate of that effect is a disappearance of the response to sweet stimuli in the taste nerves, as indicated by the observations of Diamant et al. (1965). Although a variety of other mammals also show neural responses to sweet-tasting compounds, the corresponding effect of gymnemic acid has not been demonstrated. This study presents chorda tympani proper nerve recordings from the chimpanzee before and after gymnemic acid. On the chimpanzee tongue, application of 2 ml gymnemic acid (3-10 mg X ml-1 for 3-4 min) completely abolished the taste responses to 0.0035 M acesulfam-K, 0.0018 M aspartame, 0.015 M D-tryptophan, 0.02% monellin, and 0.02% thaumatin, reduced by 75% the response to 0.3 M sucrose, and by 50% that of 0.76 M xylitol. No decrease was recorded in the responses to 0.001 M quinine, 0.1 M NaCl, 0.02 and 0.04 M ascorbic acid, 0.02 and 0.04 M citric acid. The response to the sweeteners recovered with time and the recovery was complete or nearly complete after one and a half hours. It was also found that after application of 2 ml miraculin, 3 mg X ml-1 for 3 min to the tongue the neural response to acids was about 1.5 times as large as before. Gymnemic acid applied before miraculin prevented this enhancement and gymnemic acid after miraculin depressed the enhancement by miraculin of the response to citric and ascorbic acid.

Effects of gymnemic acid on sweet taste perception in primates

Application of gymnemic acid (GA) on the tongue depresses the taste of sucrose in man. This effect, as indicated by electrophysiological responses, has been found to be absent in three nonhuman primate species. In the present behavioral study the effect of GA on taste responses in 22 primate species, with two subspecies, and 12 human subjects has been investigated. In all the nonhuman primates studied, including the Pongidae which are closely related to man, GA did not suppress the response to sucrose, only in man did GA have a depressing effect

On the effects of gymnemic acid in the hamster and rat.

The gustatory activity of the chorda tympani proper nerve has been recorded before and after the application of gymnemic acid to the tongue of hamster and rat. Concentrations of pure gymnemic acid ranging from 1 mg/ml to 10 mg/ml have been used. In the hamster gymnemic acid suppressed the response to solutions of sucrose especially, but it also caused, at higher concentrations, a general suppression of the tast response. The depression caused in the response to sucrose was directly related to the strength of the gymnemic acid and inversely to that of the sucrose solution. In the rat a suppression of the response to saccharin was obtained but no suppression of the taste response to sucrose by gymnemic acid was observed.

ON THE GUSTATORY EFFECTS OF GYMNEMIC ACID AND MIRACULIN IN DOG, PIG AND RABBIT

The effects of gymnemic acid, 1 mg/ml, and miraculin, 1 mg/ml or in a tablet (Miralin™) on the taste response to sucrose, citric acid, NaCl and quinine have been studied in dog, pig and rabbit. In the dog gymnemic acid suppressed the response to sucrose for about 5 min in two out of three animals. It also affected the response to NaCl. Miraculin caused a slight short-lasting increase in the response to acid. No effects of the taste modifiers were observed in the pig. In the rabbit gymnemic acid did not suppress the response to sucrose while miraculin enhanced the response to citric acid in one out of three animals for a few minutes.

Effect of gymnemic acid on single taste hairs of the housefly, Musca domestica

The effect of a gymnemate salt extract (KGE) on the behavioral and neurophysiological taste responses of Musca domestica to sugar and salt were studied. After exposure of single taste hairs to KGE, the behavioral positive response to a just-suprathreshold sugar stimulus was abolished, and the neuronal firing pattern was modified in a form that ranged from a waxing and waning of impulse frequency to an abolishment of impulses. The neurophysiological response to a salt stimulus was similarly modified, although the waxing and waning of spike frequency was more rapid and firing returned to a near-control pattern sooner. Neurophysiological studies were replicated with two other fly genera. The results uniformly suggest a narcotic effect on the dendrites of taste neurons.

Reduction of sucrose preference in the hamster by gymnemic acid.

Abstract The effects of gymnemic acid (GA) treatment of the tongue of the hamster were studied in a brief exposure two-bottle preference test which paired 0.04 M sucrose with distilled water. Sucrose preference was significantly reduced following GA compared to preference following a control treatment. This behavioral effect occurs under conditions similar to those used electrophysiologically when GA reduces the recorded gustatory response magnitude to sucrose in the hamster. The merits of the hamster as a non-human model for the action of GA are discussed.

A note on the effects of gymnemic acid on taste perception

An investigation is presented on the effects of gymnemic acid—a substance known to raise the threshold for the taste of sweetness in humans—on saccharin vs. water and sucrose vs. water preferences in rats. Gymnemic acid eliminated the preference of saccharin over water, but failed to do so in the case of sucrose over water. The implications of the results arc discussed, and further work is suggested towards analysing the relative effects of oral and gastric factors on preference. It is also suggested that gymnemic acid might prove a useful tool in the investigation of hyperphagia.