Olibanum. Boswellia carteri, Boswellia frereana.
Olibanum. Thus. Oliban, Encens, Fr. Weihrauch, G.—Olibanum, the frankincense of the ancients, was erroneously ascribed by Linnaeus to Juniperus phoenicea L. (J. lycia L.). There are two varieties of olibanum, one coming to Europe from the Mediterranean, and the other directly from Calcutta. These varieties were formerly considered distinct, but recent researches indicate their common origin. In 1843 Captain Kempthorne, of the East India Company's navy, saw the olibanum tree growing upon the mountains, on the African coast, between Bunder Maryah and Cape Guardafui. According to his statement, it grows on the bare marble rocks composing the hills of that region, with very brittle soil or the slightest fissure to support it, adhering by means of a substance thrown out from the base of the stem. This rises forty feet, and sends forth near the summit short branches, covered with a bright green, singular foliage. The juice, which exudes through incisions made into the inner bark, has at first the color and consistence of milk, but hardens on exposure. (P. J., iv, 37.) Sir William J. Hooker says that the African olibanum is derived from Boswellia papyrifera Hochst., one of the Burseraceae; but thinks it highly probable that it is furnished by more than one species which has since proven to be the case. (P.-J., 1859, 217.) Birdwood asserts (Tr. Linn. Soc.; xxvii) that no olibanum is obtained in India, all coming from a coast district of Arabia (the same district as that described by Theophrastus), and being the product of a new species of Boswellia, B. Carterii Birdwood. It is very likely that several species of Boswellia furnish the olibanum of commerce— viz., B. Carterii Birdw. (furnishes what is known as Luban Bedowi, or Luban Sheheri), and B. Frereana Birdw. (furnishes Luban Meyeti or Luban Matti). It appears that the resin of B. papyrifera Hochst. is not gathered at all. The product of B. serrata Roxb. (known as Salaigugul) is not sent into general commerce, but is employed medicinally only in India.
The Arabian or African frankincense is in the form of yellowish tears, and irregular, reddish lumps or fragments. The tears are generally small, oblong or roundish, not very brittle, with a dull and waxy fracture, softening in the mouth. and bearing much resemblance to mastic, from which. however, they differ in their want of transparency. The reddish masses soften in the hand, have a stronger taste and odor than the tears, and are often mixed with fragments of bark and small crystals of calcium carbonate which are visible under the microscope.
The Indian frankincense, or olibanum, consists chiefly of yellowish, somewhat translucent, roundish tears, larger than those of the African, and generally covered with a whitish powder produced by friction. It has a balsamic resinous odor, and an acrid, bitterish, somewhat aromatic taste. When chewed it softens in the mouth, adheres to the teeth, and partially dissolves in the saliva, which it renders milky. It burns with a brilliant flame and a fragrant odor. Triturated with water, it forms a milky, imperfect solution. Alcohol dissolves nearly three-fourths of it, and the tincture is transparent. Tschirch (Harze und Harzbehälter, 1900, p. 253) has made a thorough study of olibanum and determined all of its constituents with care. Alcohol extracts 72 per cent., consisting of resins 65 per cent. and volatile oil 6 per cent.; water soluble gum, 20 per cent.; bassorin, 6-8 per cent.; plant residue, 2-4 per cent. The resins were composed of boswellic acid, C32H52O4, a resin acid of which well crystallized salts were obtained, and olibanoresin, C14H22O, a neutral resin.
In the essential oil Wallach identified l-pinene and dipentene, while the chemists of Schimmel & Co. found in addition phellandrene.
W. F. Daniell has described an odorous product, used as frankincense in Sierra Leone, and obtained from a large tree, growing in the mountainous districts of that region. The tree has been described by J. J. Bennett in P. J., 1854, 251, as Daniella thurifera (Fam. Leguminosae). According to Daniell, the juice exudes through openings made by an insect, and, concreting in connection with the woody particles resulting from the boring of the insect, falls at length to the ground, where it is collected by the negroes. (See A. J, P., xxvii, 338.)
Olibanum is stimulant like the other gum-resins, but is now very seldom used internally. According to Delioux, of Toulon, however, it affords a cheap, efficient substitute for the balsams of Tolu and Peru. It appears to act more favorably when combined with a little soap. Delioux has also obtained advantage from the inhalation of its fumes, when heated, in chronic bronchitis and laryngitis. (B. G. T., Fev. 28, 1861.) It is chiefly employed for fumigation and in unofficial plasters. Dose, fifteen grains (1.0 Gm.), which may be increased to a drachm (3.9 Gm.) or more.
Canadian olibanum is reported by Karl Dieterich to be an American substitute for olibanum, which comes into the drug market from Hamburg. Its melting point is 77-78° C. (170.6°-172.4° F.). Thus occupies a place about midway between Canadian olibanum or gum thus. It is a valuable American pine resin, which, however, contains no gum and therefore is not a gum resin. (Ph. Zhalle, 1912, 652-654.)