It is indigenous to Iran, Greece, Turkey, Iraq and Syria. In India, Garhwal, Kumaon & Central Punjab are the areas where few species of tragacanth are found. North Syria and Iran supply Persian tragacanth. Smyrna tragacanth is exported from Smyrna port in Asiatic turkey.
Most of the shrubs from which tragacanth is collected grow at an altitude of 1000-3000 m. The shrubs are thorny. The mode of formation of tragacanth is entirely different from that of acacia, the gum exuding out immediately after an injury.
Most of the drug comes from Persian source only. Tragacanth gum is formed as a result of transformation of the cells of pith and medullary rays into gummy substance. Incisions are more on various parts of the stem and fluid which oozes out is collected after drying. Tragacanth is found in irregular flattened flakes with ribbon like appearance depending upon the incisions made on the plant. It is collected from April to November every year.
Colour: the flakes are white or pale yellowish-white.
Shape: tragacanth occurs in the form of thin, flattened ribbon like flakes, more or less curved.
Size: flakes are approximately 25x12x2 mm in size.
The gum is horny, translucent with transverse and longitudinal ridges. Fracture of the drug is short.
It is partly soluble is water in which it swells to homogeneous, adhesive and gelatinous mass. It is insoluble in alcohol.
Tragacanth contains two fractions of which one is soluble in water. The water-soluble portion of the tragacanth is known as tragacanth, constituting about 8 to 10% of the gum. Water-insoluble portion is known as bassorin (60-70%). Tragacanth contains about 15% of methoxy group which swells in water. It is constituents of the gum responsible for its high viscosity. Normally, 1.0% solution of tragacanth has a viscosity of not less than 250 centipoises The products of hydrolysis of tragacanth are galacturonic acid, D-galactopyranse, L-arabino-rhamnose and D-xylopranose.
Foreign organic matter: not now than 1.0%
Sulphated Ash: not more than 4.0%
Moisture content: not more than 15.0%
- When solution of tragacanth is boiled with few drops of 10% aqueous ferric chloride solution, deep yellow precipitation is formed.
- A stringy precipitate is formed by dissolving tragacanth and precipitated copper oxide in concentrated ammonium hydroxide.
- When it is warned with sodium hydroxide solution, Canary yellow colour is developed. With strong iodine solution, it gives green colour.
It is used as a demulcent and as an emollient in cosmetic tragacanth is used as a thickening, suspending and as an emulsifying agent. It is used along with acacia as a suspending agent. Mucilage of tragacanth is used as a binding agent in the tablets and also as an excipient in the pills. Tragacanth power is used as an adhesive. It is also used in lotions for external use and also in spermicidal jellies, as a stabilizer for ice creams in 0.2%-0.3% concentration and also in sauces.