English: Black catechu, cutch tree, terra japonica

Hindi: Khair

Sanskrit: Khadira

Known previously as cacho or kat, this tree formed an important export product from India to China, Arabia and Persia in the 16th century. It was used for tanning and dyeing and the original khaki was dyed and shrunk with it. Japan introduced it to Europe in the 17th century and from there, it was included in the London Pharmacopoeia of 1721.

Habitat

A common tree found throughout India and on the eastern slopes of the Western Ghats and the sub-Himalayan tract up to a height of 1500 m. It is also cultivated elsewhere.

Botanical description

A deciduous tree with short hooked spines, reaching 9-12 m in height ). The leaves are bipinnately compound with 30-50 pairs of leaflets, a feather-like appearance and a pair of recurved thorns at the base of the rachis. The greyish-brown bark exfoliates in long narrow strips. The flowers are pale yellow, in cylindrical spikes, and the fruit consists of flattened, glabrous and oblong pods with a triangular 'beak' at the apex. The sapwood is yellowish-white but the heartwood is red. The gummy extract of the wood, known as black catechu (to differentiate it from pale catechu or gambir, from Uncaria gambier), cutch or kat, is dark brown and brittle and is made from the dried aqueous extract prepared from the heartwood by boiling with water. The extract is concentrated and cooled in moulds; the dried mass formed is then broken into irregular, shiny pieces.

Parts used

Heartwood extract, gum, flowering tops, leaves, young shoots, bark and fruits. Traditional and modern use The extract from the heartwood is used as an anodyne, astringent, bactericide, refrigerant, detergent, stimulant, styptic, masticatory, expectorant and antiphlogistic. It is also used in asthma, cough, bronchitis, colic, diarrhoea, dysentery, boils, in skin afflictions and sores and for stomatitis. The bark is used as an anthelmintic, antipyretic, antiinflammatory, in bronchitis, ulcers, psoriasis, anaemia and gum troubles and has been used internally to treat leprosy.

Ethnoveterinary usage

The sap is used for the treatment of wounds and diarrhoea in ruminants. Black catechu and extracts of the bark are used in veterinary folk medicine for broken horn.

Major chemical constituents
Tannins and flavonoids

The outermost bark, inner bark and sapwood contain similar constituents to the extract: 20-35% of catechutannic acid, 2-10% of acacatechin, quercetin and catechu-red.The heartwood contains kaempferol, dihydrokaempferol, taxifolin, isorhamnetin, (+)-afzelchin, a dimeric procyanidin, quercetin, (-)-epicatechin,5(-)-catechin, fisetin, quercetagetin and (+ )-cyanidanol.

Medicinal and pharmacological activities

Hepatoprotective activity: Cyanidanol, isolated from the heartwood, showed hepatoprotective activity. An ethyl acetate extract in male rats decreased CCI4-induced elevated enzyme levels in acute and chronic models of liver damage. The results indicated some form of repair of the structural integrity of the hepatocyte cell membrane or regeneration of damaged liver cells. Decreased levels of serum bilirubin after treatment with the extract in both acute and chronic liver damage indicated the efficacy of the extract in restoring normal functional status of the liver and the protective action of the extract was further substantiated by histopathological observations.

Antiinflammatory activity: Cyanidanol demonstrated antiinflammatory activities.

Antifungal activity: The plant extract showed I an inhibitory action on the growth of fungi such as Piricularia oryzae and Colletotrichum falcatum.

Effect on leukaemia: A semi-purified saline extract of the seeds of Acacia catechu was tested for agglutinating activity against whole leucocytes and mononuclear cells from patients with chronic myeloid leukaemia, acute myeloblastic leukaemia, acute lymphoblastic leukaemia, various lymphoproliferative or haematological disorders and on normal healthy subjects. The seed extract agglutinated white blood cells from patients with different types of leukaemia; however, it did not react with the peripheral blood cells of normal individuals. It has been suggested that the seed extract may yield leukaemia -specific lectins.

Hypoglycaemic activity: The seed extract exhibited hypoglycaemic action in albino rats.