The Essential Oils of the Burseraceae

The Chemical Composition of Boswellia occulta Oleogum Resin Essential Oils

“…Although both are generally considered by botanical taxonomists to be conspecific (B. sacra), others have considered the African populations to be B. carteri and the Arabian populations to be B. sacra. 1,11 There seem to be 2 chemotypes of B. frereana from Somaliland (unpublished results from our laboratory). One chemotype is rich in α-pinene and α-thujene, and the other chemotype is dominated by α-thujene and p-cymene.…”

“…The Boswellia genus is made up of around 20 species; however, this number is in dispute. 1 Boswellia species are well known for producing frankincense, an aromatic oleogum resin. Frankincense has been used in traditional medicine and cultural and religious ceremonies for thousands of years.…”

“…More recently, essential oils derived from frankincense resins have become popular in complementary and alternative medicine and in aromatherapy and have shown notable biological activities. 1 Boswellia sacra Flueck., native to southern Oman, Yemen, Somaliland, and Somalia, yields an oleogum resin essential oil made up largely of α-pinene, α-thujene, limonene, sabinene, myrcene, β-caryophyllene, and p-cymene. 1 Although generally considered botanically synonymous, the African populations of B. sacra have often in the literature been considered a separate species, B. carteri Birdw., and essential oils from these resins are also rich in α-pinene, limonene, myrcene, α-thujene, p-cymene, and β-caryophyllene.…”

“…1 Boswellia sacra Flueck., native to southern Oman, Yemen, Somaliland, and Somalia, yields an oleogum resin essential oil made up largely of α-pinene, α-thujene, limonene, sabinene, myrcene, β-caryophyllene, and p-cymene. 1 Although generally considered botanically synonymous, the African populations of B. sacra have often in the literature been considered a separate species, B. carteri Birdw., and essential oils from these resins are also rich in α-pinene, limonene, myrcene, α-thujene, p-cymene, and β-caryophyllene. 1 Boswellia frereana Birdw., endemic to Somalia, also yields an oleogum resin essential oil dominated by α-pinene with lesser amounts of p-cymene, α-thujene, sabinene, and β-caryophyllene.…”

“…The essential oil is composed largely of octyl acetate with smaller amounts of octanol. 1 Recently, a new species of Boswellia, B. occulta Thulin, DeCarlo & S. P. Johnson, has been described 2 and identified as the source of a methoxyalkane-rich oleogum resin essential oil which has been contaminating commercial B. carteri essential oils; as the Somali harvesters consider B. occulta and B. carteri to be the same tree, they frequently mix the resins of the 2 species. 3 Methoxyalkanes in the frankincense resin coming from Somaliland are of considerable interest to the aromatics industry, which initially suspected them to be synthetic contaminants 4 (pers.…”