Musk
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2008-07-05T02:53:27Z
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/* Nitro-musks */
[[Image:Moschustier.jpg|thumb|''Moschus moschiferus'', [[Siberian musk deer]]]]
{{About|the musk odor|the MuSK receptor|MuSK protein}}
'''Musk''' is the name originally given to a substance with a penetrating [[odor]] obtained from a [[gland]] of the male [[musk deer]], which is situated between its stomach and genitals. The substance has been used as a popular [[perfume]] [[fixative]] since [[Ancient history|ancient times]] and is one of the most expensive [[animal product]]s in the world. The name, originated from [[Sanskrit]] ''{{Unicode|muṣká}}'' meaning "testicle" (as in a 'single' testicle), has come to encompass a wide variety of substances with somewhat similar odors although many of them are quite different in their [[chemical structure]]s. They include glandular secretions from animals other than the musk deer, numerous plants emitting similar fragrances, and artificial substances with similar odors.<ref name=Merriam/>
Until the late 19th century, the natural musk were used extensively in [[perfume]]ry until economic and ethical reasons motivated the adoption of synthetic musk, which are used almost exclusively.<ref name=Rimkus>{{cite book | title = Synthetic Musk Fragrances in the Environment (Handbook of Environmental Chemistry) | first = Gerhard G. (Ed.)| last = Rimkus | coauthors = Cornelia Sommer | chapter = The Role of Musk and Musk Compounds in the Fragrance Industry |publisher = [[Springer Science+Business Media|Springer]] | year = 2004 | isbn = 3540437061 }}</ref> The [[organic compound]] primarily responsible for the characteristic odor of musk is [[muscone]].
Modern use of natural musk pods is limited to [[Traditional Chinese medicine]].
==Natural sources==
===Musk deer===
[[Image:Musk 1616.jpg|upright|thumb|"Musk-cat", woodcut from ''Hortus Sanitatis'', 1490]]
Musk was unknown in [[classical antiquity]] and reference to it does not appear until the 6th century, when the Greek explorer [[Cosmas Indicopleustes]] mentioned it as a product obtained from [[India]].<ref name=Groom>{{cite book | title = New Perfume Handbook | first = Nigel | last = Groom | pages = p. 219-220 | publisher = Springer | year = 1997 | isbn = 0751404039 }}</ref> Soon afterwards Arab and [[Byzantine]] perfume makers began to use it, and it acquired a reputation as an [[aphrodisiac]].<ref name=Groom/> Under the [[Abbasid Empire]] of Arabs it was highly regarded, and the [[caliph]]s of [[Baghdad]] used it lavishly. In the early 9th century, [[Al-Kindi]] included it in a large number of his perfume recipes and it became one of the important luxury items brought by Arabian ships from the East.<ref name=Groom/> The etymology of the name ''musk'', originating from [[Sanskrit]] ''{{Unicode|muṣká}}'' via [[Middle Persian]] ''{{Unicode|mušk}}'', [[Late Greek]] ''{{Unicode|μόσχος}}'' (''moschos''), [[Late Latin]] ''muscus'', [[Middle French]] ''musc'' and [[Middle English]] ''muske'',<ref name=Merriam>{{cite web | url = http://www.m-w.com/dictionary/musk | title = Merriam-Webster's Online Dictionary: ''musk'' | publisher = [[Merriam-Webster]] | accessdate = 2007-04-07 }}</ref><ref>{{cite book | first = Pierre |last = Chantraine | title = Dictionnaire étymologique de la langue grecque | publisher = Klincksieck |year= 1990 | pages = p. 715 | isbn = 2-252-03277-4}}</ref> hints at its trade route.
The musk deer belongs to the family ''[[Moschidae]]'' and lives in [[Pakistan]], [[India]], [[Tibet Autonomous Region|Tibet]], [[China]], [[Siberia]] and [[Mongolia]]. To obtain the musk, the deer is killed and its gland, also called "musk pod", is removed. It is dried either in the sun, on a hot stone, or by immersion in hot oil. Upon drying, the reddish-brown paste turns into a black [[granular material]] called "musk grain", which is used for alcoholic [[solution]]s. The aroma of the [[tincture]] becomes more intense during storage and gives a pleasant odor only after it is considerably [[diluted]]. No other natural substance has such a complex aroma associated with so many contradictory descriptions; however, it is usually described abstractly as animalic, earthy and woody<ref name=Rimkus/> or something akin to the odor of baby's skin.<ref name=Kraft/>
Good musk is of a dark purplish color, dry, smooth and unctuous to the touch, and bitter in taste. It dissolves in boiling water to the extent of about one-half; alcohol takes up one-third of the substance, and [[ether]] and [[chloroform]] dissolve still less. The grain of musk will distinctly scent millions of [[Cubic foot|cubic feet]] of air without any appreciable loss of weight, and its scent is not only more penetrating but more persistent than that of any other known substance. In addition to its odoriferous principle, it contains [[ammonia]], [[cholesterol]], fatty matter, a bitter [[resin|resinous]] substance, and other animal principles.
The best quality is [[Tonkin]] musk from Tibet and China, followed by [[Assam]] and [[Nepal]] musk, while Carbadine musk from Russian and Chinese Himalayan regions are considered inferior.<ref name=Kraft/> Obtaining one kilogram (2.2 lb) of musk grains requires between thirty and fifty deer, making musk tinctures highly expensive. At the beginning of the 19th century, Tonkin musk grains cost about twice their weight in [[gold]].<ref name=Kraft/>
Musk has been a key constituent in many perfumes since its discovery, being held to give a perfume long-lasting power as a fixative. Despite its high price, musk tinctures were used in perfumery until 1979, when musk deers were protected as an [[endangered species]] by the [[Convention on the International Trade in Endangered Species of Wild Flora and Fauna]] (CITES). Today the trade quantity of the natural musk is controlled by CITES but illegal [[poaching]] and trading continues.<ref name=Kraft>{{cite book | title = Chemistry and Technology of Flavours and Fragrances | first = David J. (Ed.)| last = Rowe | coauthors = Philip Kraft | chapter = Chapter 7. Aroma Chemicals IV: Musks | publisher = Blackwell | isbn = 084932372X | year = 2004}}</ref> An illegal shipment of {{convert|700|kg|sp=us}} of Chinese musk from the musk deer was seized in Japan in 1987, an amount corresponding to approximately 100,000 deer killed.<ref>{{cite book | title = Managing the Chinese Environment (Studies on Contemporary China) | chapter = Recent Trends in Forestry and Conservation of Biodiversity in China |first = Richard Louis (Ed.)| last = Edmonds | coauthors = James Harkness | pages= p. 191 | publisher = [[Oxford University Press]] | year = 2000 | isbn = 0198296355}}</ref>
===Other animals===
[[Image:Ondatra_zibethicus_FWS.jpg|thumb|right|''Ondatra zibethicus'', the [[muskrat]]]]
[[Muskrat]] (''Ondatra zibethicus''), a rodent native to [[North America]], has been known since the 17th century to secrete a glandular substance with a musky odor.<ref name=Groom/> A chemical means of extracting it was discovered in the 1940s, but it did not prove commercially worthwhile.<ref name=Groom/>
Glandular substances with musk-like odor are also obtained from the [[Musk Duck]] (''Biziura lobata'') of southern [[Australia]], the [[musk shrew]], the [[musk beetle]] (''Aromia moschata''), the [[musk turtle]], the [[alligator]] of [[Central America]], and from several other animals.
In [[crocodile]]s, there are two pairs of musk glands, one pair situated at the corner of the jaw and the other pair in the [[cloaca]].<ref>{{cite book | title = Elsevier's Dictionary of Herpetological and Related Terminology | first = D.C. |last = Wareham | publisher = [[Elsevier Science]] | year = 2005 | isbn =0444518630 | pages = p. 129}}</ref> Musk glands are also found in snakes.
===Plants===
Some plants such as ''[[Angelica archangelica]]'' or ''[[Abelmoschus moschatus]]'' produce musky smelling macrocyclic lactone compounds. These compounds are widely used in perfumery as substitutes for natural musk or to alter the smell of a mixture of other musks.
The plant sources include [[musk flower]] ([[Mimulus|''Mimulus moschatus'']]), the [[muskwood]] (''[[Olearia argophylla]]'') of the [[Guianas]] and [[West Indies]], and the seeds of ''[[Abelmoschus moschatus]]'' ([[musk seed]]s).
==Artificial compounds==
[[Image:Musk incense.jpg|thumb|Musk scented incense. Most modern musk-scented products consist primarily of synthetic musk.]]
Since obtaining the deer musk requires killing the [[Endangered species|endangered animal]], nearly all musk fragrance used in perfumery today is synthesis, or called "[[white musk]]". They can be divided into three major classes — aromatic nitro musks, polycyclic musk compounds, and macrocyclic musk compounds.<ref name=Rimkus/> The first two groups have broad uses in industry ranging from [[cosmetics]] to [[detergent]]s. However, the detection of the first two chemical groups in human and environmental samples as well as their carcinogenic properties initiated a public debate on the use of these compounds and a ban or reduction of their use in many regions of the world. As an alternative, macrocyclic musk compounds are expected to replace them since these compounds appear to be safer.<ref name=Rimkus/>
===Nitro-musks===
[[Image:Musk Ketone.svg|thumb|Musk Ketone, a nitro-musk]]
An artificial musk was obtained by [[Albert Baur]] in [[1888]] by condensing [[toluene]] with [[isobutyl bromide]] in the presence of [[aluminium chloride]], and nitrating the product. It was discovered accidentally as a result of Baur's attempts at producing a more effective form of [[trinitrotoluene]]. It appears that the odour depends upon the symmetry of the three nitro groups. Following the discovery of ''Musk Baur'', the first nitro-musk, many similar preparations have been made. Notable nitro-musks include
*Musk Baur (Tonquinol)
*Musk Ketone
*Musk Xylene
*Musk Ambrette
*Moskene
===Polycyclic musks===
[[Image:Galaxolide.svg|thumb|Galaxolide, a polycyclic musk]]
An artificial musk that contains more than one ring in its molecular structure. These musks became popular after [[World War II]] and slowly supplanted the nitro-musks in popularity due to the latter's toxicity and molecular instability.
The creation of this class of musks was largely prompted through the need for eliminating the [[Nitro compound|nitro]] functional group from nitro-musks due to their photochemical reactivity and their instability in alkaline medium. This shown to be possible through the discovery of Ambral, a non-nitro aromatic musk, which promoted research in the development of nitro-free musks. This lead to the eventual discovery of Phantolide, so name due to its commercialization by [[Givaudan]] without initial knowledge of it chemical structure (elucidated 4 years later). While poorer in smell strength, the performance and stability of this compound class in harsh detergents led to its common use, which spurred further development of other polycyclic musks including Galaxolide.<ref name=Kraft/>
However it was discovered in the 1990s that polycyclic musks are also potentially harmful in that they can disrupt [[Cell metabolism|cellular metabolism]]<ref name=LukenbackEpel>{{Citation | last = Luckenbach | first = Till | last2 = Epel | first2 = David | title = Nitromusk and Polycyclic Musk Compounds as Long-Term Inhibitors of
Cellular Xenobiotic Defense Systems Mediated by Multidrug Transporters | journal = Environmental Health Perspectives | volume = 113 | issue = 1 | pages = 17-24 | date = January 2005| year = 2005 }}.</ref>. Many of these musks were used in large quantities to scent laundry detergents. Commonly used polycyclic musks include
*Galaxolide (HHCB)
*Tonalide (Musk Plus, AHTN)
*Phantolide
*Celestolide (Crysolide)
*Traesolide
===Macrocyclic musks===
[[Image:Muscone.png|thumb|[[Muscone]], a macrocyclic musk]]
A class of artificial musk consisting of a single ring composed of more than 6 carbons (often 10-15). Of all artificial musks, these most resemble the primary odoriferous compound from Tonkin musk in its "large ringed" structure. While the macrocyclic musks extracted from plants consists of large ringed [[lactone]]s, all animal derived macrocyclic musks are [[ketone]]s.<ref name=Kraft/>
Although muscone, the primary macrocyclic compound of musk was long known, it was only in 1926 where [[Leopold Ruzicka]] was able first synthesized this compound in very small quantities. Despite this discovery and the discovery of other pathways for synthesis of macrocyclic musks, compound of this class were not commercially produced and commonly utilized until the late 1990s due to difficulties in their synthesis and consequently higher price.<ref name=Sell>{{cite book | title = The Chemistry of Fragrances | first = Sell| last = Charles (Ed.) | coauthors = Charles Sell | chapter = Chapter 4. Ingredients for the Modern Perfumery Industry| publisher = Royal Society of Chemistry Publishing | isbn = 978-0-85404-824-3 | year = 2005| edition=2nd}}</ref>
About half the human population are [[anosmic]]s (unable to smell) to macrocyclic musks, possibly due to its high [[molecular weight]]. Common macrocyclic musks include:
*Ethylene Brassilate
*Globalide (Habanolide)
*Ambrettolide
*Muscone
*Thibetolide (Exaltolide)
*Velvione
===Alicyclic musks===
[[Image:D-Helvetolide.svg|thumb|Helvetolide, an alicyclic musk]]
Alicyclic musks, otherwise known as cycloakyl ester or linear musks, are relatively novel class of musk compounds. The first compound of this class was introduced 1975 with Cyclomusk, though similar structure were noted earlier in citronellyl oxalate and Rosamusk<ref name=KraftBrain>{{Citation |last = Kraft |first=Philip |title = 'Brain Aided' Musk Design |journal=Chemistry & biodiversity |year=2004 | volume=1| number=12| pages=1957-1974 }}</ref>. Alicyclic musks are dramatically different in structure than previous musks (aromatic, polycyclic, macrocyclic) in that they are modified akyl esters<ref name=Eh>{{Citation |last = Eh |first=Marcus |title = New Alicyclic Musks: The Fourth Generation of Musk Odorants |journal=Chemistry & biodiversity |year=2004 | volume=1| number=12| pages=1975-1984 }}</ref>. Although they were discovered more than 10 years before, it was only in 1990 with the discovery and introduction of Helvetolide at [[Firmenich]] that a compound of this class was produced at a commercial scale<ref name=KraftBrain/>. Romandolide, a more ambrette and less fruity alicyclic musk compared to Helvetolide was introduced ten years later<ref name=Eh/>. Common musks of this class include:
*Cyclomusk
*Helvetolide
*Romandolide
==See also==
*[[Androstenol]]
==Notes==
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{{1911}}
[[Category:Animal glandular products]]
[[Category:Fragrances]]
[[Category:Perfume ingredients]]
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