Opoponax

Origin

Commiphora guidottii is a tree or shrub native to Somalia and Ethiopia. In Somali the tree is known as hadi, and the resin is called hebbakhade, habaghadi or habak hadi. The tree grows in association with gypsum-producing areas and in open bushland.

In Ethiopia the tree occurs in the Ogaden region in the east, and in Somalia it is widely known in the Bari, Bakool, Galguduud, Gedo, Mudug and Nugal regions. It belongs to the family Burseraceae, and Commiphora sessiliflora Vollesen is a synonym of it.

It has been mistakenly believed that the opopanax of perfumery comes from Commiphora erythraea, owing to historical misidentification. The oleo-gum-resin of hagar ad, from Commiphora holtziana or C. erythraea, is sometimes sold under the name of opopanax, in part because of its similar scent.

Botanical sources

The oil and resinoid are obtained from the resin of Commiphora erythraea var. glabrescens or of closely related species such as C. guidottii and C. kataf, trees growing in Somalia. In the strict sense C. erythraea is narrowly distributed along the coast of the Red Sea, while the broader concept of the species takes in Commiphora holtziana, which is widespread in East Africa. C. guidottii is an accepted species name, whereas C. erythraea is treated as a synonym of C. kataf.

The oleogum resin of C. erythraea is called opopanax, bisabol myrrh or perfumed bdellium, and the species is found mostly in northeastern Africa, in Somalia, Eritrea and Kenya. C. kataf is found mainly in Kenya, and its resin is called African opopanax. Its furanosesquiterpenoid composition is similar to that of C. erythraea, but its myrrhone content is markedly higher, the highest of all samples investigated.

Composition

The crude resin contains 50 to 80% of a water-soluble gum, 15 to 40% of an alcohol-soluble resin and 5 to 9% of essential oil. Sesquiterpene hydrocarbons such as α-santalene, (E)-α-bergamotene and (Z)-α-bisabolene make up the main constituents of the oil. Bisabolene (C₁₅H₂₄) and a mixture of alcohols are also named among its main constituents.

The essential oil of Commiphora erythraea contained mainly curzerene, β-elemene, β-bourbonene and (Z)-α-bisabolene, and was deficient in furanoeudesma-1,3-diene. The resin of C. erythraea contains moderate amounts of the furanosesquiterpenoids curzerenone (1.7 μg/mg) and myrrhone (0.6 μg/mg). The absence of furanoeudesma-1,3-diene allows a distinction from C. myrrha. This is of particular interest, as C. erythraea is frequently used as an adulterant of C. myrrha.

In C. erythraea, (Z)-α-bisabolene contributes especially to the typical odor of opopanax.

Properties and identification

The oil tends to resinify on exposure to air. It dissolves in ten volumes of 90% ethanol, although the solutions are occasionally turbid. Its acid number is at most 4 and its saponification number lies between 4 and 20.

Opopanax tears in benzene do not react, whereas myrrh tears give a violet color in the presence of bromine vapors, so adulteration is readily detectable.

Not the true opopanax

The term opopanax traditionally refers to the medicinal gum resin of Opopanax species, which belong to the family Apiaceae. In perfumery, opopanax refers to the gum resin of an unrelated species, Commiphora guidottii. To tell the perfumery material from the true opopanax, it is often spelled opoponax and sometimes called the opopanax of perfumery.

The genus Opopanax, of the family Apiaceae, has four species: O. chironium, O. hispidus, O. persicus and O. siifolius. The crude resin of O. chironium was offered as regular, tear-shaped lumps of a brilliant red color, rather soft, shiny and easily ground. The name opopanax is also given to Vachellia farnesiana, a species of the family Fabaceae.

Place among the Commiphora resins

The genus Commiphora, of the family Burseraceae, has more than 200 species, mainly in northeastern Africa, southern Arabia and India. Myrrh-like resins from other Commiphora species are known as bdellium, balsam and opopanax (bisabol).

Status and research

Commiphora guidottii has been assessed as vulnerable on the IUCN Red List. It is threatened by over-harvesting for charcoal, by excessive extraction of its resin and by regional climate change. The species is very rare in Ethiopia. Essential oil from its oleo-gum-resin has been researched for its use in topical treatment of wounds.

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Related: Benzoin · Copal · Elemi · Frankincense · Incense · Labdanum · Myrrh · Myrrh Oil