Members of this family of 500 species of trees and shrubs in 16 genera are to be found in tropical regions.
The majority of species yield fragrant oleo-gum-resins following damage to the bark, many of which have been used medicinally, but which are now used principally in incense manufacture and perfumery. Boswellia Roxb. species yield frankincense; Bursera Jacq. and Canarium L. species yield elemi; Commiphora Jacq. species yield myrrh, bdellium, and other resins, Protium heptaphyllum Marchand yields Brazilian elemi.
The genus Amyris P.Browne has enjoyed a confused taxonomic history, having been classified in both the Burseraceae and in the family Rutaceae. It is now considered to belong to the latter family (Willis 1973), but certain species have been transfered to the genus Commiphora, which belongs to the Burseraceae. Thus, Yucatan elemi derived from Amyris plumieri DC. is a product of the family Rutaceae, whilst balm of Mecca is derived from Amyris opobalsamum L. which is now considered to be a synonym of Commiphora gileadensis (L.) C.Chr., fam. Burseraceae.
Tincture of myrrh is still used in Britain as an application for the treatment of mouth ulcers.
The timber from one or two species is also of commercial value.
In common with other volatile oil containing materials of natural origin, the oleo-gum-resins obtained from members of this family may have mild rubefacient properties and may be weakly allergenic. Some of the resin acids also present in the oleo-gum-resins are similar to abietic acid, a known contact allergen. Thus, cross-sensitivity to certain Pinus L. species, fam. Pinaceae, and their products is theoretically possible.
The timber is exported from West Africa, and is used in the manufacture of plywood, blockboard, packing cases, and other such items (Hausen 1981).
A few cases of skin irritation in woodworkers have been reported (Spitzer 1927, Subiza 1958, Hartmann & Schlegel 1980). Woods & Calnan (1976) reported a case of a joiner with dermatitis on the eyelids, backs of the hands, and forearms who reacted to patch tests with gaboon and with deal (possibly Pinus L. sp., fam. Pinaceae).
The wood dust can also produce conjunctivitis, nasal irritation, and respiratory symptoms (Subiza 1958, Gronomeyer & Fuchs 1967).
The genus is monotypic.
Frankincense, otherwise known as gum olibanum, is derived from this and other species of Boswellia. Confusion may arise from the use of the term common frankincense which is used to describe turpentine, an oleoresin from Pinus species (fam. Pinaceae) from which turpentine oil is produced (Todd 1967). Both frankincense and turpentine have certain volatile oil constituents in common. These include pinene and dipentene.
The use of olibanum in adhesive plasters (Greenberg & Lester 1954) and in perfumes (Schwartz et al. 1957) has caused dermatitis in sensitive individuals. Sixteen patients contact sensitive to balsam of Peru (from Myroxylon balsamum Harms, fam. Leguminosae) showed negative patch test reactions to olibanum (Hjorth 1961).
Olibanum gum applied to intact or abraded rabbit skin for 24 hours under occlusion was found to be moderately irritating. Closed patch tests with 8% olibanum in petrolatum was found to be non-irritant to human skin. A maximisation test using 8% olibanum in petrolatum was found to be non-sensitising in 25 volunteers (Opdyke 1978a). The fragrance raw material olibanum absolute, which is prepared by ethanol extraction of olibanum gum followed by evaporation of the ethanol, was found to be non-irritant, non-sensitising, and non-phototoxic in various tests on mice, swine, and human subjects (Opdyke 1978b).
This and several closely related species yield the fragrance raw material known as linaloe oil, oil of linaloe Mexican, or linaloe wood oil. It is prepared by steam distillation of the wood. Perfumes, colognes, and toilet waters containing oil of linaloe may produce dermatitis in hypersensitive individuals (Tulipan 1938). The sensitiser in the oil is said to be linalool (Klarmann 1958) — linalool has caused an outbreak of dermatitis among girls who were bottling perfume (Schwartz et al. 1957).
Opdyke (1979) reported that oil of linaloe, when applied undiluted to the skin of mice and swine, was non-irritant and non-phototoxic. However, it was moderately irritant when applied under occlusion for 24 hours on intact or abraded rabbit skin. Oil of linaloe 8% in petrolatum was found to be non-sensitising in 25 human volunteers subjected to a maximisation test, and also non-irritant in a 48 hour closed patch test.
This species furnishes the gum-resin American elemi which, when dried, is known as chibou, cachibou, or gomart resin. Manila elemi and elemi oil are derived from Canarium commune L., Canarium luzonicum A.Gray, or Canarium ovatum Engl. (see below).
The pathological resinous exudate from these species is known as Manila elemi. The fragrance raw material known as elemi oil is prepared by steam distillation of Manila elemi. Elemi oil, when applied for 24 hours under occlusion to intact or abraded rabbit skin, was found to be slightly irritant. It was found to be non-irritant when applied undiluted to the skin of mice or swine, and non-irritant when applied in a 48 hour closed patch test to human skin at a dilution of 4% in petrolatum. No sensitisation reactions could be produced in 25 human volunteers subjected to a maximisation test using 4% elemi oil in petrolatum (Opdyke 1976a).
The oleoresin from both species is rubefacient (Nadkarni 1976, Quisumbing 1951, Perry & Metzger 1980). The wood from Canarium commune has produced dermatitis in woodworkers (Brezina 1912).
Canarium luzonicum has an edible seed (Willis 1973).
The wood sap is reported to be poisonous when it enters a cut (Cleland 1943).
This species is a source of Manila elemi (see Canarium commune).
This and other species furnish some of the black dammar of commerce (Willis 1973). Sensitivity to dammar is noted under Agathis Salisb. (fam. Araucariaceae).
In some species, the branches are spine-tipped (Codd 1951). The following list is representative:
This plant is the source of Balm of Mecca (Genders 1972), which was a favourite beauty preparation in the Middle East. However, it could produce alarmingly violent reactions on the face, as described by Lady Mary Wortley Montagu in a letter she wrote on June 17, 1717 (Wharncliffe & Moy Thomas 1861):
" As to the balm of Mecca, I will certainly send you some; but it is not so easily got as you suppose it, and I cannot, in conscience, advise you to make use of it. I know not how it comes to have such universal applause. All the ladies of my acquaintance at London and Vienna, have begged me to send pots of it to them. I have had a present of a small quantity (which, I'll assure you, is very valuable) of the best sort, and with great joy applied it to my face, expecting some wonderful effect to my advantage. The next morning, the change indeed was wonderful; my face was swelled to a very extraordinary size, and all over as red as my Lady B.'s. It remained in this lamentable state three days, during which, you may be sure, I passed my time very ill. I believed it would never be otherways; and to add to my mortification, Mr W—— [Wortley] reproached my indiscretion without ceasing. However, my face is since in statu quo; nay, I am told by the ladies here, that it is much mended by the operation, which I confess I cannot perceive in my looking-glass. Indeed, if one were to form an opinion of this balm from their faces, one should think very well of it. They all make use of it, and have the loveliest bloom in the world. For my part, I never intend to endure the pain of it again; let my complexion take its natural course, and decay in its own due time. I have very little esteem for medicines of this nature; but do as you please, madam; only remember, before you use it, that your face will not be such as you will care to show in the drawing-room for some days after. "
Balsamodendrum gileadense was suspected of producing allergic effects (Bardel 1935).
Balm of Mecca may also be called Balm (or Balsam) of Gilead (see Remington et al. 1918, Grieve 1931). This is likely to be a source of confusion because a number of other plants and plant products may be referred to as balm of Gilead. For example, the shrubby Cedronella canariensis Willd. ex Webb (syns Cedronella triphylla Moench, Dracocephalum canariense L.; fam. Labiatae) is popularly known as balm of Gilead. Also, the oleoresin from Abies balsamea Mill., fam. Pinaceae, which is usually called Canada balsam, may also be known as balm of Gilead, as may the resinous matter coating the buds of certain Populus L. species (fam. Salicaceae). Stuart (1979) asserts that the balm of Gilead of commerce is now derived from Populus candicans Aiton, Populus balsamifera L. and possibly other Populus species, for example Populus tremuloides Michx.
These three species are the principal sources of myrrh. A fragrance raw material known as myrrh oil or oil of Heerabol-Myrrh is prepared by steam distillation of myrrh. Opdyke (1976b) reports that no irritation, sensitisation, nor phototoxicity could be demonstrated with either the undiluted or diluted (8% in petrolatum) oil using a variety of tests on mice, swine and human volunteers. Myrrh absolute, prepared by ethanol extraction of myrrh followed by evaporation, was also found not to have phototoxic properties (Forbes et al. 1977).
Hjorth (1961) found one patient out of 13 who were sensitive to balsam of Peru (from Myroxylon balsamum Harms, fam. Leguminosae) to give a positive patch test reaction to myrrh.
The Mikea hunter-gatherers of Madagascar use a preparation of the bark to treat wounds (Stiles 1998).
The oleo-gum-resin exudate, known as guggulu gum or Indian bdellium has been found to contain minor amounts of sesamin (Patil et al. 1972). Sesamin is involved in sesame oil (Sesamum indicum L., fam. Pedaliaceae) contact allergy.
The berry is said to produce a stinging sensation in the mouth, followed after some days by swelling and burning of the lips (Watt & Breyer-Brandwijk 1962).
The soft resin from this species, when mixed with the pigment from Bixa orellana L. (fam. Bixaceae) forms an ointment that is useful as a preventative measure against skin inflammation in woodworkers caused by irritant timbers (Freise 1936).