Tragacanth

Scientific Name(s):A wide variety of Astragalus species, but most commonly A. gummifer Labill., are used in commerce. Family: Fabaceae (beans).

Common Name(s): Goat's thorn , green dragon , gum dragon , gum tragacanth , gummi tragacanthae , hog gum , Syrian tragacanth , tragacanth 1 , 2 , 3

Uses

Tragacanth has been used as a demulcent in cough and cold preparations and to manage diarrhea. It also has been shown to moderate the blood sugar level, but this has not been demonstrated consistently. However, limited information is available.

Dosing

There is no recent clinical evidence to support specific dosage of tragacanth. The gum has GRAS status as a food additive.

Contraindications

Contraindications have not yet been determined.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Presently, tragacanth is not recognized as having any adverse effects when used up to 21 days.

Toxicology

Tragacanth is highly susceptible to bacterial contamination, and preparations contaminated with enterobacteria have been reported to have caused fetal deaths when administered intraperitoneally to pregnant mice. 1

Botany

The tragacanth species are low-growing, thorny shrubs that are native to the mountainous regions of the Middle East. 1 Gum tragacanth is obtained by tapping the branches and tap roots. The gum dries as it exudes and is collected rapidly. The word tragacanth is said to derive from the Greek meaning “goat's horn,” which may describe the appearance and texture of the crude gum. 1

History

Tragacanth has been used since ancient times as an emulsifier, thickening agent, and suspending agent. 1 , 4 Today it is used extensively in foods and dressings and to thicken ice cream.

Chemistry

Tragacanth contains from 20% to 30% of a water-soluble fraction called tragacanthin (composed of tragacanthic acid and arabinogalactan). It also contains from 60% to 70% of a water-insoluble fraction called bassorin. Tragacanthic acid is composed of D-galacturonic acid, D-xylose, L-fructose, D-galactose, and other sugars. Tragacanthin is composed of uronic acid and arabinose and dissolves in water to form a viscous colloidal solution (sol), while bassorin swells to form a thick gel. 1 , 2

Tragacanthin partially dissolves and partially swells in water yielding a viscous colloid. The maximal viscosity is attained only after 24 hours at room temperature or after heating for 8 hours at high temperatures. The viscosity of these solutions is generally considered to be the highest among the plant gums. 1 The solutions are stable to heat and under a wide range of pH levels.

Uses and Pharmacology

Tragacanth has been used as a demulcent in cough and cold preparations and to manage diarrhea. 2

Animal data

Research shows little or no information regarding the uses of this product.

Clinical data

As with other water-soluble gums, there is some preliminary evidence that concomitant ingestion of tragacanth with a high sugar load can moderate the blood sugar levels in patients with diabetes, 5 although this effect has not been demonstrated consistently 6 and requires much more detailed investigation. Although gum tragacanth swells to increase stool weight and decrease GI transit time, it appears to have no effect on serum cholesterol, triglyceride or phospholipid levels after a 21-day supplementation period as do other soluble fibers. 6 , 7

Tragacanth has been reported to inhibit the growth of cancer cells in vitro and in vivo. 1 , 2

Because of its mucilaginous adhesive properties, tragacanth is used as a component of some denture adhesives. 8

Dosage

There is no recent clinical evidence to support specific dosage of tragacanth. The gum has GRAS status as a food additive.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Tragacanth is Generally Recognized as Safe (GRAS) in the US for food use. 8 There is no indication that dietary supplementation for up to 21 days has any significant adverse effects in man. 5

Toxicology

A cross-sensitivity to the asthma-induced effects of quillaja bark has been observed for gum tragacanth. 9

Tragacanth is highly susceptible to bacterial degradation, and preparations contaminated with enterobacteria have been reported to have caused fetal deaths when administered intraperitoneally to pregnant mice. 1

Bibliography

1. Leung Ay. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics . New York, NY: J. Wiley and Sons, 1980.
2. Morton JF. Major Medicinal Plants . Springfield, IL: Charles C. Thomas, 1977.
3. Evans WC. Trease and Evans' Pharmacognosy . 13th ed. London: Balliere Tindall, 1989.
4. Nuttall FQ. Dietary fiber in the management of diabetes. Diabetes 1993;42:503.
5. Eastwood MA, et al. The effects of dietary gum tragacanth in man. Toxicol Lett 1984;21:73.
6. Eastwood MA, et al. The effect of polysaccharide composition and structure of dietary fibers on cecal fermentation and fecal excretion. Am J Clin Nut 1986;44:51.
7. Berg E. A clinical comparison of four denture adhesives. Int J Prosthodont. 1991;4:449.
8. Anderson DM. Evidence for the safety of gum tragacanth ( Asiatic Astragalus spp.) and modern criteria for the evaluation of food additive. Food Addit Contam 1989;6:1.
9. Raghuprasad PK, et al. Quillaja bark (soapbark)-induced asthma. J Allergy Clin Immunol 1980;65:285.
10. Onsol A, Farrar GE Jr, eds. The Dispensatory of the United States of America, 25th ed. Philadelphia: J.B. Lippincott, 1955:1442.

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