Synonyms: Gambier, Catechu
Biological source: It is an aqueous extract prepared from the leaves and young shoots of Uncaria gambier Roxburgh.
Family: Rubiaceae.
Geographical source: It is a climbing shrub native to Malay Archipelago and largely cultivated on islands of Singapore and Sumatra. This drug was used in India for the chewing purpose with Piper betle (betel) leaf.
Description:
Form: Cubes, rectangular blocks or irregular broken pieces.
Colour: Dark reddish brown.
Odour: None.
Taste: First bitter and astringent afterwards sweetish.
The surfaces of cubes are even with minute cavities, slightly concave, breaks easily and are friable.
Chemical Constituent:
The drug mainly contains (+)-catechin (7-33%), catechutannic acid (22-50%). Other constituents are catechu red, quercitin and gambier fluorescin, a fluorescent substance.
Chemical Test:
1. 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.
2. When drug is treated with vanillin and hydrochloric acid, it produces pink or red colour due to the presence of catechin.
3. Add sodium hydroxide to the alcoholic extract of drug and add few drops of petroleum ether in it, stirr the solution and kept it aside for some time. Green fluorescence observed in layer of petroleum ether.
Uses:
It is used medicinally as an astringent in the treatment of diarrhoea and a local astringent in the form of lozenges. It is also used for tanning and dyeing purposes.
Adulterants:
The starch, astringent extracts and mineral matters like clay, ferric hydroxide etc has been added as an adulterant