Source, Etc

Olibanum or, as it is sometimes termed, frankincense (to be carefully distinguished from American frankincense) is a gum-resin obtained from Boswellia Carterii, Birdwood, and other species of Boswellia (N.O. Burseraceoe).

These plants are small trees that grow in southern Arabia and in Somaliland. Like the trees that yield myrrh they contain schizogenous ducts in the bark, in which an oleo-resin is secreted. The Somalis incise the bark and collect the gum-resin as soon as it has sufficiently dried. The drug is conveyed to Aden and thence to Bombay, whence it is exported to Europe.

Description

Olibanum occurs in small tears varying from 0.5 to 3 cm. in length and usually ovoid, pear-shaped, or club-shaped, but sometimes stalactitic in form, occasionally agglutinated into small masses. They are usually of a pale yellowish colour, frequently with a greenish, bluish, or reddish tinge, semi-translucent and covered with a dull white dust, the surface of the tear being dull even after the dust has been removed. They are brittle, breaking easily between the fingers; internally they are opalescent and translucent, the fractured surface being dull and waxy.

The drug has a fragrant, balsamic odour and an aromatic, slightly bitter taste, and soften to a plastic mass when chewed. Triturated with water it yields a whitish emulsion.

The student should observe

(a) The fragrant odour,

(b) The opalescent, waxy interior of the tears.

Constituents

Olibanum consists principally of resin (60 to 70 per cent.), gum (27 to 35 per cent.), and volatile oil (5 to 7 per cent.).

These constituents have been further investigated, with the following results (Halbey, 1898):

Soluble in alcohol, 72 per cent.

'Boswellic acid, free .

330

per cent.

,, „ combined

1.5

,,

, Olibanoresene

330

"

Volatile oil

7.0

"

Bitter principle

0.5

"

Insoluble in alcohol, 28 per cent.

Gum (arabic acid with Ca and Mg)

200

"

Bassorin ..

60

"

Vegetable Debris

20

"

According to this analysis the resin consists principally of a resin acid (boswellic acid) and an indifferent resin (olibano-resene) in about equal proportions. The gum consists mainly of arabin, with which is associated a little bassorin. The volatile oil is yellowish and fragrant; it contains pinene, dipentene, and phellandrene, but the aromatic constituent is not yet known.

Uses

Olibanum is used chiefly in the manufacture of incense and as an ingredient in plasters and fumigating pastilles.