Editing Oregano (section)

=== Chemistry ===
Oregano contains [[polyphenol]]s, including numerous [[flavones]].<ref name="Dragland2003">{{cite journal |last1=Dragland |first1=Steinar |last2=Senoo |first2=Haruki |last3=Wake |first3=Kenjiro |last4=Holte |first4=Kari |last5=Blomhoff |first5=Rune |date=1 May 2003 |title=Several culinary and medicinal herbs are important sources of dietary antioxidants |url=http://jn.nutrition.org/cgi/pmidlookup?view=long&pmid=12730411 |journal=Journal of Nutrition |volume=133 |issue=5 |pages=1286–90 |doi=10.1093/jn/133.5.1286 |issn=0022-3166 |pmid=12730411 |doi-access=free}}</ref><ref>{{cite journal |last1=Tair |first1=Asma |last2=Weiss |first2=Erika-Krisztina |last3=Palade |first3=Laurentiu Mihai |last4=Loupassaki |first4=Sofia |last5=Makris |first5=Dimitris P. |last6=Ioannou |first6=Efstathia |last7=Roussis |first7=Vassilios |last8=Kefalas |first8=Panagiotis |year=2014 |title=Origanum species native to the island of Crete: in vitro antioxidant characteristics and liquid chromatography–mass spectrometry identification of major polyphenolic components |journal=[[Natural Product Research]] |volume=28 |issue=16 |pages=1284–7 |doi=10.1080/14786419.2014.896011 |pmid=24635145 |s2cid=42500633}}</ref>

The essential oil of oregano is composed primarily of [[monoterpenoid]]s and [[monoterpene]]s, with the relative concentration of each compound varying widely across geographic origin and other factors. Over 60 different compounds have been identified, with the primary ones being [[carvacrol]] and [[thymol]] ranging to over 80%, while lesser abundant compounds include {{nowrap|[[p-cymene|''p''-cymene]]}}, {{nowrap|[[γ-terpinene]]}}, caryophyllene, [[spathulenol]], [[germacrene D]], [[β-fenchyl alcohol]] and {{nowrap|[[δ-terpineol]]}}.<ref>{{cite journal |last1=Teixeira |first1=Bárbara |last2=Marques |first2=António |last3=Ramos |first3=Cristina |last4=Serrano |first4=Carmo |last5=Matos |first5=Olívia |last6=Neng |first6=Nuno R |last7=Nogueira |first7=José M F |last8=Saraiva |first8=Jorge Alexandre |last9=Nunes |first9=Maria Leonor |year=2013 |title=Chemical composition and bioactivity of different oregano (''Origanum vulgare'') extracts and essential oil |journal=[[Journal of the Science of Food and Agriculture]] |volume=93 |issue=11 |pages=2707–14 |bibcode=2013JSFA...93.2707T |doi=10.1002/jsfa.6089 |pmid=23553824}}</ref>

Drying of the plant material affects both quantity and distribution of volatile compounds, with methods using higher heat and longer drying times having greater negative impact. A sample of fresh whole plant material found to contain 33 g/kg dry weight (3.1 g/kg wet) decreased to below a third after warm-air convection drying. Much higher concentrations of volatile compounds are achieved towards the end of the growing season.<ref>{{cite journal |last1=Figiel |first1=Adam |last2=Szumny |first2=Antoni |last3=Gutiérrez-Ortíz |first3=Antonio |last4=Carbonell-Barrachina |first4=Ángel A. |year=2010 |title=Composition of oregano essential oil (Origanum vulgare) as affected by drying method |journal=[[Journal of Food Engineering]] |volume=98 |issue=2 |pages=240–7 |doi=10.1016/j.jfoodeng.2010.01.002}}</ref>