Olibanum, or frankincense, a well appreciated perfume raw material, is a gum-resin produced by wild small trees growing in Arabia and Somaliland. This gum-resin results either from natural exudation or from unnatural incisions made in the bark of the tree. The gums from Arabia and Somalihind converge to Aden, the main trade place for olibanum; these gums usually result from two species of the genus Boswellia (fam. Burseraceae): Boswellia carterii Bird, (Arabia and Somaliland) and Boswellia frereana Bird. (Somaliland). Two commercial brands of olibanum exist: “Aden” and “Eritrea,” whose main constituents respectively are: α-pinene and octyl acetate. The crude gum-resin, extracted with benzene, gives a resinoid with an average yield of 60%; an essential oil can also be obtained from the gum-resin in a classical way (steam-distillation) in a 5% yield.
Chemical Composition
The chemical composition of resinoid, essential oil and various pyrolysates of olibanum has already been well studied. Two recent reviews describe the presence of 110 components in olibanum resinoid and oil, up to then reported in the literature (see references quoted in these reviews). To this number, thirty-three constituents characterized in various olibanum pyrolysates must be added as well as two components omitted in the precedent reviews: incensole-oxide I and isoincensole-oxide II.
Since then, three additional new constituents have been identified: two triterpenoids (lupeol III and epi-lupeol IV) in the resinoid and a diterpenoid (isocembrene V) in the oil. Moreover, twenty-one new constituents of pyrolytic products obtained from Incense “Aden” have been identified successively 18, 2 (VI, VII) and 1 (VIII).
