{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 419851613 | ImageFile = Ambrein.svg | ImageSize = 160 | IUPACName = (1''R'',2''R'',4a''S'',8a''S'')-1-<nowiki/>{(3''E'')-6-[(1''S'')-2,2-dimethyl-6-methylidenecyclohexyl]-4-methylhex-3-en-1-yl}-2,5,5,8a-tetramethyldecahydronaphthalen-2-ol | OtherNames = Ambrein |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 10000763 | ChEBI_Ref = {{ebicite|changed|EBI}} | ChEBI = 78306 | InChI = 1/C30H52O/c1-22(15-16-24-23(2)13-10-18-27(24,3)4)12-9-14-26-29(7)20-11-19-28(5,6)25(29)17-21-30(26,8)31/h12,24-26,31H,2,9-11,13-21H2,1,3-8H3/b22-12+/t24-,25?,26-,29+,30-/m1/s1 | InChIKey = BIADSXOKHZFLSN-CQDHYIGWBE | SMILES1 = O[C@@]1(CCC3[C@]([C@H]1CC\C=C(/C)CC[C@@H]2C(=C)\CCCC2(C)C)(C)CCCC3(C)C)C | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C30H52O/c1-22(15-16-24-23(2)13-10-18-27(24,3)4)12-9-14-26-29(7)20-11-19-28(5,6)25(29)17-21-30(26,8)31/h12,24-26,31H,2,9-11,13-21H2,1,3-8H3/b22-12+/t24-,25?,26-,29+,30-/m1/s1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = BIADSXOKHZFLSN-CQDHYIGWSA-N | CASNo_Ref = {{cascite|correct|??}} | CASNo = 473-03-0 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 1N9JB373FJ | PubChem = 11826112 | SMILES = C/C(=C\CC[C@@H]1[C@]2(CCCC(C2CC[C@@]1(C)O)(C)C)C)/CC[C@@H]3C(=C)CCCC3(C)C }} |Section2={{Chembox Properties | C = 30 | H = 52 | O = 1 | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }} '''Ambrein''' is a triterpene alcohol that is the chief constituent of ambergris, a secretion from the digestive system of the sperm whale. It has been suggested as the possible active component producing the supposed aphrodisiac effects of ambergris.<ref>{{cite journal | vauthors = Sandroni P | title = Aphrodisiacs past and present: a historical review | journal = Clinical Autonomic Research | volume = 11 | issue = 5 | pages = 303–7 | date = October 2001 | pmid = 11758796 | doi = 10.1007/BF02332975 | s2cid = 40455528 }}</ref> Although ambrein itself is odorless, it serves as the biological precursor for aromatic derivatives such as ambroxide and is thought to possess fixative properties for other odorants.

It has been shown to act as an analgesic<ref>{{cite journal | vauthors = Taha SA | title = Studies on the mode of action of ambrein as a new antinociceptive compound | journal = Japanese Journal of Pharmacology | volume = 60 | issue = 2 | pages = 67–71 | date = October 1992 | pmid = 1479744 | doi = 10.1254/jjp.60.67 | doi-access = free }}</ref> and has been proven to increase sexual behavior in rats,<ref>{{cite journal | vauthors = Taha SA, Islam MW, Ageel AM | title = Effect of ambrein, a major constituent of ambergris, on masculine sexual behavior in rats | journal = Archives Internationales de Pharmacodynamie et de Therapie | volume = 329 | issue = 2 | pages = 283–94 | year = 1995 | pmid = 8540767 }}</ref> providing some support for its traditional aphrodisiac use.

Apart from its supposed aphrodisiac effects, ambrein has been shown to decrease spontaneous contractions of smooth muscles in rats, guinea pigs, and rabbits. It reduces these contractions by serving as an antagonist and interfering with Ca<sup>2+</sup> ions from outside the cell.<ref>{{cite journal | vauthors = Taha SA, Raza M, El-Khawad IE | title = Effect of ambrein on smooth muscle responses to various agonists | journal = Journal of Ethnopharmacology | volume = 60 | issue = 1 | pages = 19–26 | date = February 1998 | pmid = 9533428 | doi = 10.1016/s0378-8741(97)00126-8 }}</ref>

The aroma is described as (characteristically) ambergris, labdanum, amber, woody.<ref>{{cite web |title=ambrein|url=https://scentsandflavors.com/database/9dbb5642-b55b-4e17-bc0a-87b0d6afa454 |website=Scents and Flavors |publisher=Scents and Flavors |access-date=26 March 2026}}</ref>

==Discovery== In 1946, Ruzicka and Lardon "established that the fragrance of ambergris is based on the triterpene (named) ambrein".<ref name=ruzicka46>{{cite journal |doi=10.1002/hlca.19460290414|title=Zur Kenntnis der Triterpene. (105. Mitteilung) Über das Ambreïn, einen Bestandteil des grauen Ambra|year=1946|last1=Ruzicka|first1=L.|last2=Lardon|first2=F.|journal=Helvetica Chimica Acta|volume=29|issue=4|pages=912–921 |bibcode=1946HChAc..29..912R }}</ref><ref name="frs">{{cite journal | last1 = Prelog | first1 = Vladimir | author-link1 = Vladimir Prelog| last2 = Jeger | first2 = Oskar | doi = 10.1098/rsbm.1980.0013 | title = Leopold Ruzicka (13 September 1887 &ndash; 26 September 1976) | journal = Biogr. Mem. Fellows R. Soc. | volume = 26 | pages = 411–501 | year = 1980 | doi-access = free }}</ref><ref name="hillier19">{{cite journal |doi=10.1530/JOE-19-0084|title=Terpenes, hormones and life: Isoprene rule revisited|year=2019|last1=Hillier|first1=Stephen G.|last2=Lathe|first2=Richard|journal=Journal of Endocrinology|volume=242|issue=2|pages=R9–R22|pmid=31051473|doi-access=free}}</ref>

== Biosynthesis == Ambrein is synthesized from the common triterpenoid precursor squalene. The squalene-hopene cyclase (SHC) catalyzes the cyclization of squalene into the monocyclic 3-deoxyachilleol A. Tetraprenyl-beta-curcumene synthase (BmeTC) converts 3-deoxyachilleol A into the tricyclic ambrein.<ref>{{Cite journal| vauthors = Di K, Qinggele C, Fanglong Z, Ting L, Wenyu L |title=Heterologous biosynthesis of triterpenoid ambrein in engineered Escherichia coli|journal=Biotechnology Letters|volume=40|issue=2|pages= 399–404 |date=February 2018 |doi= 10.1007/s10529-017-2483-2 |pmid=29204767|s2cid=3267910| issn= 1573-6776}}</ref>

thumb|Biosynthetic pathway of Ambrein

== References == {{reflist}}{{Whaling}} Category:Perfume ingredients Category:Whale products Category:Animal glandular products Category:Triterpenes Category:Decalins Category:Tertiary alcohols