Synonyms: Gambier, Catechu
Biological source: It is an aqueous extract prepared from the leaves and young shoots of Uncaria gambier Roxburgh.
Geographical source: It is a climbing shrub native to the Malay Archipelago and largely cultivated on islands of Singapore and Sumatra. This drug was used in India for chewing purposes with Piper betle (betel) leaf.
Cultivation and Collection of Pale Catechu
The plantation is done in damp soil and at an altitude of 500 ft above sea level. The nursery-raised seedlings of about 9 months are planted at about 3-meter distances in between. When the plant reaches a height of about 2 meters coppicing has been done. From about eight years after plantation to the twenty years age of the plant, the yield is at its maximum. The shoots are cut down with a broad-bladed knife and put in a special type of vessel known as ‘Cauldron’ which is made of hardwood with an iron bottom. The leaves and young shoots are boiled in ‘Cauldron’ for about three hours with continuous stirring of the content. The decoction is evaporated till it becomes thick and pasty with a yellowish-green colour. The contents are transferred into wooden tubs and allow cooling. After about ten minutes the semi crystallized magma is poured into wooden trays to settle down. It is cut into cubes with a wooden knife while the preparation is still moist and sun-dried. Much amount of Gambier is filled into kerosene tins to solidify to obtain large blocks which are marketed. The cube shape of Gambier is preferred for pharmaceutical purposes.
Description of Pale Catechu
- Form: Cubes, rectangular blocks, or irregular broken pieces.
- Colour: Dark reddish-brown.
- Odour: None.
- Taste: First bitter and astringent afterward sweetish.
The surfaces of cubes are even with minute cavities, slightly concave, break easily, and are friable.
Chemical Constituent: The drug mainly contains (+)-catechin (7-33%), catechu tannin acid (22-50%). Other constituents are catechu red, quercitin, and gambier fluorescein, a fluorescent substance.
Chemical Test of Pale Catechu
- Dip a matchstick in the test solution, dry it and moist it with concentrated hydrochloric acid. Then warm the stick near flame. The colour of the wood changes to pink due to the formation of phloroglucinol.
- When the drug is treated with vanillin and hydrochloric acid, it produces pink or red colour due to the presence of catechin.
- Add sodium hydroxide to the alcoholic extract of the drug and add a few drops of petroleum ether in it, stir the solution, and kept it aside for some time. Green fluorescence was observed in a layer of petroleum ether.
Uses of Pale Catechu
It is used medicinally as an astringent in the treatment of diarrhea and a local astringent in the form of lozenges. It is also used for tanning and dyeing purposes.
The starch, astringent extracts, and mineral matters like clay, ferric hydroxide, etc have been added as an adulterant.
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