Editing Terpenoid (section)

{{Short description|Class of aromatic organic chemicals found in plants}}
The '''terpenoids''', also known as '''isoprenoids''', are a class of naturally occurring [[organic compound|organic chemicals]] derived from the 5-carbon compound [[isoprene]] and its derivatives called [[terpene]]s, [[diterpene]]s, etc.  While sometimes used interchangeably with "terpenes", terpenoids contain additional [[functional group]]s, usually containing oxygen.<ref>{{cite book|url=https://goldbook.iupac.org/html/T/T06279.html|title=IUPAC Compendium of Chemical Terminology|first=International Union of Pure and Applied|last=Chemistry|publisher=IUPAC|doi=10.1351/goldbook.T06279}}</ref> When combined with the hydrocarbon terpenes, terpenoids comprise about 80,000 compounds.<ref>{{cite journal |doi=10.1021/acs.chemrev.7b00287|title=Structural and Chemical Biology of Terpenoid Cyclases |year=2017 |last1=Christianson |first1=David W. |journal=Chemical Reviews |volume=117 |issue=17 |pages=11570–11648 |pmid=28841019 |pmc=5599884 }}</ref> They are the largest class of plant [[secondary metabolites]], representing about 60% of known [[Natural Products|natural products]].<ref>{{cite book | last = Firn | first = Richard | name-list-style = vanc |title=Nature's Chemicals|date=2010|publisher=Oxford: Biology}}</ref>  Many terpenoids have substantial [[pharmacological]] bioactivity and are therefore of interest to medicinal chemists.<ref name="wink10">{{cite book |doi=10.1002/9781444320503.ch5|chapter=Biochemistry of Terpenoids: Monoterpenes, Sesquiterpenes and Diterpenes|title=Biochemistry of Plant Secondary Metabolism|year=2010|last1=Ashour|first1=Mohamed|last2=Wink|first2=Michael|last3=Gershenzon|first3=Jonathan|pages=258–303|isbn=9781444320503}}</ref>

Plant terpenoids are used for their aromatic qualities and play a role in traditional herbal remedies. Terpenoids contribute to the scent of [[eucalyptus]], the flavors of [[cinnamon]], [[cloves]], and [[ginger]], the yellow color in [[sunflower]]s, and the red color in [[tomato]]es.<ref>{{Cite magazine |url=http://www.newyorker.com/reporting/2009/09/28/090928fa_fact_specter?currentPage=all |magazine=The New Yorker |title=A Life of Its Own | first = Michael | last = Specter | name-list-style = vanc |date=September 28, 2009}}</ref> Well-known terpenoids include [[citral]], [[menthol]], [[camphor]], [[salvinorin A]] in the plant ''[[Salvia divinorum]]'', [[ginkgolide]] and [[bilobalide]] found in ''[[Ginkgo biloba]]'' and the [[Cannabinoid|cannabinoids]] found in cannabis. The provitamin [[beta carotene]] is a terpene derivative called a [[carotenoid]].

The [[steroid]]s and [[sterol]]s in animals are biologically produced from terpenoid precursors. Sometimes terpenoids are added to [[protein]]s, e.g., to enhance their attachment to the [[cell membrane]]; this is known as [[isoprenylation]]. Terpenoids play a role in plant defense as prophylaxis against pathogens and [[attractant]]s for the predators of herbivores.<ref>{{Cite journal |last1=Singh |first1=Bharat |last2=Sharma |first2=Ram A. |date=April 2015 |title=Plant terpenes: defense responses, phylogenetic analysis, regulation and clinical applications |journal=[[3 Biotech]] |volume=5 |issue=2 |pages=129–151 |doi=10.1007/s13205-014-0220-2 |issn=2190-572X |pmc=4362742 |pmid=28324581}}</ref>