{{Short description|Group of naturally occurring hydrocarbons}} {{chembox | Name = Germacrenes | ImageFile = Germacrene A chemical structure.png | ImageSize = 100px | ImageCaption = (–)-Germacrene A | IUPACName = (1''E'',5''E'',8''S'')-1,5-dimethyl-8-(prop-1-en-2-yl)cyclodeca-1,5-diene | OtherNames = {{unbulleted list|(−)-Germacrene A|(''E'',''E'')-Germacra-3,9,11-triene|(1''E'',5''E'',8''S'')-1,5-dimethyl-8-(1-methylethenyl)-1,5-cyclodecadiene|(''S''-(''E'',''E''))-1,5-dimethyl-8-(1-methylethenyl)-1,5-cyclodecadiene}} |Section1={{Chembox Identifiers | index1_label = A | index2_label = B | index3_label = C | index4_label = D | index5_label = E | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID1 = 29776407 | ChemSpiderID2 = 4444852 | ChemSpiderID3 = | ChemSpiderID4 = 28288426 | ChemSpiderID5 = | PubChem1 = 9548705 | PubChem2 = 5281519 | PubChem3 = 25244915 | PubChem4 = 5373727 | PubChem5 = 10632030 | KEGG1 = C16141 | KEGG2 = C09672 | KEGG3 = C19747 | ChEBI1 = 36517 | ChEBI2 = 5337 | ChEBI3 = 61478 | ChEBI4 = 49045 | Beilstein = 6500908 (A) 1864177 (D) | ChEMBL2 = 448125 | InChI1=1S/C15H24/c1-12(2)15-10-8-13(3)6-5-7-14(4)9-11-15/h6,9,15H,1,5,7-8,10-11H2,2-4H3/b13-6+,14-9+/t15-/m1/s1 | InChIKey1 = XMRKUJJDDKYUHV-DFSVIBJJSA-N | SMILES = C/C/1=C\CC/C(=C/C[C@H](CC1)C(C)C)/C | SMILES1 = C/C/1=C\CC/C(=C/C[C@@H](CC1)C(=C)C)/C | SMILES2 = C/C/1=C\CC/C(=C/CC(=C(C)C)CC1)/C | SMILES3 = C/C/1=C\CC/C(=C/C=C(\CC1)/C(C)C)/C | SMILES5 = CC\1CC/C=C(/CCC(/C=C1)C(=C)C)\C | InChI = 1/C15H26/c1-12(2)15-10-8-13(3)6-5-7-14(4)9-11-15/h6,9,12,15H,5,7-8,10-11H2,1-4H3/b13-6+,14-9+/t15-/m0/s1 | InChIKey = YDLBHMSVYMFOMI-SDFJSLCBBV | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChI = 1S/C15H26/c1-12(2)15-10-8-13(3)6-5-7-14(4)9-11-15/h6,9,12,15H,5,7-8,10-11H2,1-4H3/b13-6+,14-9+/t15-/m0/s1 | InChI4=1S/C15H24/c1-12(2)15-10-8-13(3)6-5-7-14(4)9-11-15/h7-8,10,12,15H,3,5-6,9,11H2,1-2,4H3/b10-8-,14-7- | InChIKey4 = GAIBLDCXCZKKJE-BZXLUOIMSA-N | InChI5=1S/C15H24/c1-12(2)15-10-8-13(3)6-5-7-14(4)9-11-15/h6,9,11,14-15H,1,5,7-8,10H2,2-4H3/b11-9+,13-6+ | InChIKey5 = OAOGSSAAVUPEKA-BMCYRRRCSA-N | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = YDLBHMSVYMFOMI-SDFJSLCBSA-N | CASNo_Ref = {{cascite|correct|CAS}} | CASNo1 = 28387-44-2 | CASNo2 = 15423-57-1 | CASNo3 = 34323-15-4 | CASNo4 = 37839-63-7 }} |Section2={{Chembox Properties | Formula = C<sub>15</sub>H<sub>24</sub> | MolarMass = 204.35 g/mol | Appearance = | Density = 0.793 g/mL | MeltingPt = | BoilingPtC = 236.4 | Solubility = }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}
'''Germacrenes''' are a group of naturally occurring volatile organic hydrocarbons of the sesquiterpene and cycloalkene class. They are typically produced in plants and have antimicrobial and insecticidal properties, though they also play a role as insect pheromones. Two prominent molecules are germacrene A and germacrene D.
== Structures == Germacrene has five structural isomers.<ref name=Adio>{{cite journal |last=Adio |first=A. M. |title=Germacrenes A–E and related compounds: thermal, photochemical and acid induced transannular cyclizations |journal=Tetrahedron |year=2009 |volume=65 |issue=8 |pages=1533–1552 |doi=10.1016/j.tet.2008.11.050}}</ref>
{| cellspacing="20px" align="center" style="text-align:center" |+ ''Germacrene isomers'' | 100px|Germacrene A | 100px|Germacrene B | 100px|Germacrene C | 100px|Germacrene D | 100px|Germacrene E |- Align="center" | (–)-Germacrene A || Germacrene B || Germacrene C || Germacrene D || Germacrene E |} Germacrene A is chiral and both the (–)-(''S'') and (+)-(''R'') forms are found naturally.<ref name=Adio/> Germacrene D is also known in both enantiomeric forms.<ref>{{cite journal |last1=Arimura |first1=G.-I. |last2=Huber |first2=D. P. W. |last3=Bohlmann |first3=J. |title=Forest tent caterpillars (''Malacosoma disstria'') induce local and systemic diurnal emissions of terpenoid volatiles in hybrid poplar (''Populus trichocarpa × deltoides''): cDNA cloning, functional characterization, and patterns of gene expression of (−)-germacrene D synthase, ''PtdTPS1'' |journal=The Plant Journal |year=2004 |volume=37 |issue=4 |pages=603–616|doi=10.1111/j.1365-313X.2003.01987.x |pmid=14756770 |doi-access=free }}</ref>
== Natural occurrences == The essential oils of deadnettles (genus ''Lamium''),<ref>{{ cite journal |last1=Flamini |first1=G. |last2=Cioni |first2=P. L. |last3=Morelli |first3=I. | title = Composition of the essential oils and ''in vivo'' emission of volatiles of four ''Lamium'' species from Italy: ''L. purpureum'', ''L. hybridum'', ''L. bifidum'' and ''L. amplexicaule''| journal = Food Chemistry | year = 2005 | volume = 91 | issue = 1 | pages = 63–68 | doi = 10.1016/j.foodchem.2004.05.047 }}</ref> hedgenettles (genus ''Stachys''),<ref>{{cite journal |first1=K. |last1=Morteza-Semnani |first2=M. |last2=Akbarzadeh |first3=Sh. |last3=Changizi |title=Essential oils composition of ''Stachys byzantina'', ''S. inflata'', ''S. lavandulifolia'' and ''S. laxa'' from Iran |journal=Flavour and Fragrance Journal |date=2005-11-01 |volume=21 |issue=2 |pages=300–303 |doi=10.1002/ffj.1594}}</ref> and ''Clausena anisata'' are characterized by their high contents of germacrene D. Germacrene B is a major component of patchouli oil.<ref name="HasegawaTajima1992">{{cite journal|last1=Hasegawa|first1=Yoshihiro|last2=Tajima|first2=Katsuhiko|last3=Toi|first3=Nao|last4=Sugimura|first4=Yukio|title=An additional constituent occurring in the oil from a patchouli cultivar|journal=Flavour and Fragrance Journal|volume=7|issue=6|year=1992|pages=333–335|issn=0882-5734|doi=10.1002/ffj.2730070608}}</ref>
==Metabolism in plants== The germacrenes are precursors to sesquiterpene lactones.<ref>{{cite journal|title=What Made Sesquiterpene Lactones Reach Cancer Clinical Trials?|author1=Ghantous, Akram |author2=Gali-Muhtasib, Hala |author3=Vuorela, Heikki |author4=Saliba, Najat A. |author5=Darwiche, Nadine |journal=Drug Discovery Today|year=2010|volume=15|issue=15–16 |pages=668–678|doi=10.1016/0305-1978(86)90101-8|pmid=20541036 }}</ref> For example, the enzyme germacrene A hydroxylase in chicory converts (+)-germacrene A to a carboxylic acid which is the starting material for costunolide synthase, which converts it to costunolide:<ref name=Franssen>{{cite journal | vauthors = de Kraker JW, Franssen MC, Dalm MC, de Groot A, Bouwmeester HJ | title = Biosynthesis of germacrene A carboxylic acid in chicory roots. Demonstration of a cytochrome P450 (+)-germacrene a hydroxylase and NADP+-dependent sesquiterpenoid dehydrogenase(s) involved in sesquiterpene lactone biosynthesis | journal = Plant Physiology | volume = 125 | issue = 4 | pages = 1930–40 | date = April 2001 | pmid = 11299372 | pmc = 88848 | doi = 10.1104/pp.125.4.1930 }}</ref><ref>{{cite journal |vauthors = de Kraker JW, Franssen MC, Joerink M, de Groot A, Bouwmeester HJ |title = Biosynthesis of costunolide, dihydrocostunolide, and leucodin. Demonstration of cytochrome p450-catalyzed formation of the lactone ring present in sesquiterpene lactones of chicory |journal = Plant Physiology |volume = 129 |issue = 1 |pages = 257–68 |date = May 2002 |pmid = 12011356 |pmc = 155889 |doi = 10.1104/pp.010957 }}</ref>
{{chemrxn|width=65%| {{chemrxn/cpd|qid=Q27104477|caption=(+)-germacrene A }} {{chemrxn/arw|uppercaption=Oxidase }} {{chemrxn/cpd|qid=Q27131000|caption=(+)-germacrene A acid }} {{chemrxn/arw|uppercaption=Synthase }} {{chemrxn/cpd|costunolide }} }}
== References == {{reflist}}
== Further reading == === Germacrene A === {{refbegin|25em}} * {{cite journal |last1=Deguerry |first1=F. |last2=Pastore |first2=L. |last3=Wu |first3=S. |last4=Clark |first4=A. |last5=Chappell |first5=J. |last6=Schalk |first6=M. |title=The diverse sesquiterpene profile of patchouli, ''Pogostemon cablin'', is correlated with a limited number of sesquiterpene synthases |journal=Archives of Biochemistry and Biophysics |date=2006-10-15 |volume=454 |issue=2 |pages=123–136|doi=10.1016/j.abb.2006.08.006 |pmid=16970904 }} * {{cite journal |last1=Omura |first1=H. |last2=Honda |first2=K. |last3=Feeny |first3=P. |title=From terpenoids to aliphatic acids: further evidence for late-instar switch in osmeterial defense as a characteristic trait of swallowtail butterflies in the tribe Papilionini |journal=Journal of Chemical Ecology |date=2006-09-01 |volume=32 |issue=9 |pages=1999–2012|doi=10.1007/s10886-006-9124-x |pmid=16902823 |bibcode=2006JCEco..32.1999O |s2cid=25242966 }} * {{cite journal |last1=Forcat |first1=S. |last2=Allemann |first2=R. K. |title=Stabilisation of transition states prior to and following eudesmane cation in aristolochene synthase |journal=Organic and Biomolecular Chemistry |date=2006-07-07 |volume=4 |issue=13 |pages=2563–2567|doi=10.1039/b604147g |pmid=16791319 }} * {{cite journal |last1=Bertea |first1=C. M. |last2=Voster |first2=A. |last3=Verstappen |first3=F. W. |last4=Maffei |first4=M. |last5=Beekwilder |first5=J. |last6=Bouwmeester |first6=H. J. |title=Isoprenoid biosynthesis in ''Artemisia annua'': cloning and heterologous expression of a germacrene A synthase from a glandular trichome cDNA library |journal=Archives of Biochemistry and Biophysics |date=2006-04-15 |volume=448 |issue=1–2 |pages=3–12|doi=10.1016/j.abb.2006.02.026 |pmid=16579958 }} * {{cite journal |last1=Lou |first1=Y |last2=Baldwin |first2=I. T. |title=Silencing of a germin-like gene in ''Nicotiana attenuata'' improves performance of native herbivores |journal=Plant Physiology |date=2006-03-01 |volume=140 |issue=3 |pages=1126–1136|doi=10.1104/pp.105.073700 |pmid=16461381 |pmc=1400569 }} * {{cite journal |last1=Chang |first1=Y.-J. |last2=Jin |first2=J. |last3=Nam |first3=H.-Y. |last4=Kim |first4=S.-U. |title=Point mutation of (+)-germacrene A synthase from ''Ixeris dentata'' |journal=Biotechnology Letters |date=2005-03-01 |volume=27 |issue=5 |pages=285–288|doi=10.1007/s10529-005-0681-9 |pmid=15834787 |s2cid=21959582 }} {{refend}}
=== Germacrene D === {{refbegin|25em}} * {{cite journal |last1=Rivero Cruz |first1=B. |last2=Rivero Cruz |first2=I |last3=Rodríguez |first3=J. M. |last4=Cerda García-Rojas |first4=C. M. |last5=Mata |first5=R. |title=Qualitative and quantitative analysis of the active components of the essential oil from '''Brickellia veronicaefolia'' by nuclear magnetic resonance spectroscopy |journal=Journal of Natural Products |date=2006-08-01 |volume=69 |issue=8 |pages=1172–1176|doi=10.1021/np060180b |pmid=16933870 |bibcode=2006JNAtP..69.1172R }} * {{cite journal |last1=Yang |first1=F.-Q. |last2=Li |first2=S.-P. |last3=Chen |first3=Y. |last4=Lao |first4=S.-C. |last5=Wang |first5=Y.-T. |last6=Dong |first6=T.-T. |last7=Tsim |first7=K.-W. |title=Identification and quantitation of eleven sesquiterpenes in three species of Curcuma rhizomes by pressurized liquid extraction and gas chromatography-mass spectrometry |journal=Journal of Pharmaceutical and Biomedical Analysis |date=2005-09-15 |volume=39 |issue=3–4 |pages=552–558|doi=10.1016/j.jpba.2005.05.001 |pmid=15946818 }} * {{cite journal |last1=Umlauf |first1=D. |last2=Zapp |first2=J. |last3=Becker |first3=H. |last4=Adam |first4=K. P. |title=Biosynthesis of the irregular monoterpene artemisia ketone, the sesquiterpene germacrene D and other isoprenoids in ''Tanacetum vulgare'' L. (Asteraceae) |journal=Phytochemistry |date=2004-09-01 |volume=65 |issue=17 |pages=2463–2470|doi=10.1016/j.phytochem.2004.08.019 |pmid=15381410 |bibcode=2004PChem..65.2463U }} * {{cite journal |last1=Agnihotri |first1=V. K. |last2=Thappa |first2=R. K. |last3=Meena |first3=B. |last4=Kapahi |first4=B. K. |last5=Saxena |first5=R. K. |last6=Qazi |first6=G. N. |last7=Agarwal |first7=S. G. |title=Essential oil composition of aerial parts of ''Angelica glauca'' growing wild in North-West Himalaya (India) |journal=Phytochemistry |date=2004-08-01 |volume=65 |issue=16 |pages=2411–2413|doi=10.1016/j.phytochem.2004.07.004 |pmid=15381015 |bibcode=2004PChem..65.2411A }} * {{cite journal |last1=Raal |first1=A. |last2=Paaver |first2=U. |last3=Arak |first3=E. |last4=Orav |first4=A. |title=Content and composition of the essential oil of ''Thymus serpyllum'' L. growing wild in Estonia |journal=Medicina (Kaunas) |year=2004 |volume=40 |issue=8 |pages=795–800|pmid=15300002 }} * {{cite journal |last1=He |first1=X. |last2=Cane |first2=D. E. |title=Mechanism and stereochemistry of the germacradienol/germacrene D synthase of ''Streptomyces coelicolor'' A3(2) |journal=Journal of the American Chemical Society |date=2004-03-10 |volume=126 |issue=9 |pages=2678–2679|doi=10.1021/ja039929k |pmid=14995166 |bibcode=2004JAChS.126.2678H }} {{refend}}
Category:Alkene derivatives Category:Sesquiterpenes Category:Cycloalkenes B