Arjuna

ARJUNA

Synonyms

Arjun bark, arjun.

Biological Source

Arjuna consists of dried stem bark of the plant known as Terminalia arjuna Rob, belonging to family Combretaceae.

Geographical Source

The tree is common in Indian peninsula. It is grown by the side of streams and very common in Chotta Nagpur region.

Cultivation and Collection

Arjuna is found as naturally growing plant in the dense forests. It is very common in Baitul in Madhya Pradesh and also in Dehradun. Arjuna can be successfully raised by sowing seeds or by means of stumps. The seeds take about 21 days for germination. It needs moist fertile alluvial loam and rainfall in the range of 75 to 190 cm. It grows satisfactorily up to 45°C. The bark is also collected from wild growing plants, and it is reported that yield per tree varies from 9 to 55 kg.

Morphology

Microscopy

Transverse section of fresh bark shows cork composed of uniformly arranged several layers of small, tangentially elongated cells. Below cork is a region of cortex, composed of thin-walled, more or less brick-shaped parenchymatous cells containing cluster crystals of calcium oxalate. A few groups of sclerenchymatous pericyclic fibres are scattered in the cortex. Secondary phloem consists of phloem parenchyma composed of thin-walled, polygonal cells with wavy walls containing cluster crystals of calcium oxalate and pigmented cells. Phloem fibres, composed of sclerenchymatous cells, occur in groups and are scattered in the form of patches in parenchyma. Narrow and almost straight medullary rays are also present.

Chemical Constituents

The dry bark from the stem contains about 20 to 24% of tannin, whereas that of the bark obtained from the lower branches is up to 15 to 18%. The tannins present in arjuna bark are of mixed type consisting of both hydrolysable and condensed tannins. The tannins are reported to be present are (+) catechol, (+) gallocatechol, epicatechol, epigallocatechol, and ellgic acid. The flavonoids such as arjunolone, arjunone, and baicalein have been reported from the stem bark. The triterpenoid compounds arjune-tin, arjungenin, arjunglucoside I and II, and terminoic acid have also been reported from the bark. The root contains number of triterpenoids such as arjunoside I and II, terminic acid, oleanolic acid, arjunic acid, arjunolic acid, etc. The fruits also contain 7 to 20% of tannins. A pentacyclic triterpenic glycoside arjunoglucoside III has been reported from the fruits along with hentriacontane, myristyl oleate and arachidic stearate.

Chemical Test

Ethereal extract of arjuna shows pinkish fluorence under ultra-violet light.

Uses

Arjuna bark is used as a diuretic and astringent. The diuretic properties can be attributed to the triterpenoids present in fruits. It causes decrease in blood pressure and heart rate. It is used in the treatment of various heart diseases in indigenous systems of medicines. The bark was extensively used in the past by the local tanneries for tanning animal hides. It yields a very firm leather of a colour which is similar babool tanned leather.

Adulterants

The dried bark of the plant Terminalia tomentosa is used as an adulterant for the drug. However, it can be distinguished from arjuna bark by fluorescence test. Ethereal extract of arjuna gives pink fluorescence, whereas T. tomentosa gives pale blue.

Marketed Products

It is one of the ingredients of the preparations known as Abana, Geriforte, Liv 52, Mentat (Himalaya Drug Company), Arjun Ghrita, Arjun churna (Baidyanath Company), and Madhudoshantak (Jamuna Pharma).