important odorants from osmanthus flowers
Osmanthus fragrans (Oleaceae)
Osmanthus, also called 'sweet olive', is a bush of the olive family from the Far East. Its plenty of small flowers give off an overwhelmingly sweet fragrance with a fruity nuance, resembling that of ripe apricots. In China they are used for perfuming tea. Moreover, a so-called osmanthus absolute is obtained by extraction of the flowers. It is a valuable ingredient in the art of perfumery. Its major constituents are variations on the structure of ionone: beta-ionone (10 %) and beta-damascenone, theaspirane and theaspirone, megastigmadienone and -trienone, etc. Furthermore,
(+)-gamma-decalactone (4 %) is a character impact compound [3].
mint lactone, kusunol and epi-gamma-eudesmol
Bursera graveolens (Burseraceae)
Bursera graveolens, known in Spanish as palo santo ("holy wood") is a deciduous tree that inhabits the South American Gran Chaco region (northern Argentina, Paraguay, Bolivia and the Brazilian Mato Grosso), i.e. the tropical dry forest zone. It greens during the rainy season, but is leafless for most of the year. It is related to the olibanum or frankincense tree (genus Boswellia) and is said to be to South America what sandalwood is to Asia.
The wood has a sweet and pleasant odour and is used as an incense. Terpenoids like mint lactone and sesquiterpenoids like kusunol, (-)-10-epi-gamma-eudesmol and a number of agarofuran eudesmanes are responsible for the minty, herbal and woody nuances. Among the odour determining compounds in the smoke from the wood are phenols, vanillin, valencene, dehydromintlactone and cyclotene (3-methyl-2-cyclopenten-2-ol-1-one) [49] [50].
Etymology: Lat. graveolens, strongly odoriferous.
phenethyl methyl ether
pandanol
Pandanus odoratissimus (Pandanaceae) Kewda, Keora
As suggested by its Latin name, this member of the screw tree family has strongly fragrant flowers. It is a native of South East Asia and is much cultivated on the Indian East Coast, for example in the Ganjam district of the Orissa province. The trees are found growing along seashores, banks of rivers, ponds and canals. The male flowers have a pleasant fruity-rosy odour. They are commonly known as 'kewda' or 'keora' in Hindi. The volatiles are emitted by the tender white spathes covering the flowers (photo on the left, the photo in the middle shows the ripe fruits). The flowers are steam distilled to yield a 'kewda attar', a very popular flavour and fragrance ingredient in India.
The main component of the hydrodistilled oil is phenethyl methyl ether (pandanol) (38 %), together with
terpinen-4-ol (19 %), alpha-terpineol (8 %) and phenethyl alcohol (7 %) [79]. Phenethyl alcohol and its derivatives are common odorants in flowers (see Frangipanni, Rose).
The Danish pharmacist Steffen Arctander who made a great career as a fragrance chemist in USA (at Colgate, etc.) describes the smell of phenethyl methyl ether in this way: "It has a very powerful, diffusive and penetrating odour, warm-floral, but when undiluted rather 'gassy-pungent'. In dilution Jasmine-Tuberose-like, floral, sweet. In extreme dilution, the odour is even slightly rosy" (Arctander S. Perfume and flavor chemicals (aroma chemicals). Las Vegas, NV: Steffen Arctander's Publications; 1969).
Etymology: Malayan panadan, fragrant. The English term 'screw tree' is motivated by the arrangement of leaves typical of this genus.