View source for Phytochemical

{{Short description|Chemical compounds produced by plants}}
[[File:Berries.jpg|thumb|Red, blue, and purple colors of berries derive mainly from [[polyphenol]] phytochemicals called [[anthocyanin]]s]]
[[File:Kürbisse 3082-1.jpg|thumb|''[[Cucurbita]]'' fruits, including [[squash (plant)|squash]] and [[pumpkin]], typically have high content of the phytochemical [[pigment]]s called [[carotenoid]]s]]

'''Phytochemicals''' are [[chemical compound]]s produced by [[plant]]s, generally to help them resist fungi, bacteria and [[plant virus]] infections, and also consumption by insects and other animals. The name comes {{ety|gre|''[[wikt:φυτόν|φυτόν]]'' (phyton)|plant}}. Some phytochemicals have been used as [[poison]]s and others as [[traditional medicine]].

As a term, ''phytochemicals'' is generally used to describe plant compounds that are under research with unestablished effects on health, and are not scientifically defined as [[essential nutrients]]. Regulatory agencies governing food labeling in Europe and the United States have provided guidance for industry to limit or prevent [[health claim]]s about phytochemicals on food [[Nutrition facts label|product or nutrition labels]].

==Definition==
Phytochemicals are chemicals of [[plant]] origin.<ref>{{cite web|last1=Breslin|first1=Andrew|title=The Chemical Composition of Green Plants|url=http://sciencing.com/chemical-composition-green-plants-8336363.html|publisher=Sciencing, Leaf Group Ltd.|date=2017}}</ref> Phytochemicals (from Greek ''phyto'', meaning "plant") are chemicals produced by plants through primary or secondary [[metabolism]].<ref name=Molyneux/><ref name=Harborne>{{cite book|editor1-last=Harborne|editor1-first=Jeffrey B.|editor2-last=Baxter|editor2-first=Herbert|editor3-last=Moss|editor3-first=Gerard P.|title=Phytochemical dictionary a handbook of bioactive compounds from plants|date=1999|publisher=Taylor & Francis|location=London|isbn=9780203483756|page=vii|edition=2nd|chapter-url=https://books.google.com/books?id=VCITWqQS_6MC&q=vast+array|chapter=General Introduction}}</ref> They generally have [[biological activity]] in the plant host and play a role in plant growth or defense against competitors, pathogens, or predators.<ref name=Molyneux>{{cite journal|last1=Molyneux|first1=RJ|last2=Lee|first2=ST|last3=Gardner|first3=DR|last4=Panter|first4=KE|last5=James|first5=LF|title=Phytochemicals: the good, the bad and the ugly?|journal=Phytochemistry|date=2007|volume=68|issue=22–24|pages=2973–85|doi=10.1016/j.phytochem.2007.09.004|pmid=17950388|url=https://naldc.nal.usda.gov/download/13290/PDF}}</ref>

Phytochemicals are generally regarded as research compounds rather than [[essential nutrients]] because proof of their possible health effects has not been established yet.<ref name="lpi">{{cite web|url=http://lpi.oregonstate.edu/infocenter/phytochemicals.html|title=Phytochemicals|publisher=Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, Oregon|date=2017|access-date=12 February 2017}}</ref><ref name=Heneman/> Phytochemicals under research can be classified into major categories, such as [[carotenoids]]<ref name="lpi-carot">{{cite web|url=http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/carotenoids|title=Carotenoids|publisher=Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, Oregon|date=July 2016|access-date=12 February 2017}}</ref> and [[polyphenols]], which include [[phenolic acids]], [[flavonoids]], [[stilbenes]] or [[lignans]].<ref name=Heneman/> Flavonoids can be further divided into groups based on their similar chemical structure, such as [[anthocyanins]], [[flavones]], [[flavanones]], [[isoflavones]], and [[flavanols]].<ref name=Heneman/><ref name="lpi-flav">{{cite web|url=http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/flavonoids|title=Flavonoids|publisher=Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, Oregon|date=November 2015|access-date=12 February 2017}}</ref> Flavanols are further classified as [[catechins]], [[epicatechins]], and [[proanthocyanidins]].<ref name=Heneman>{{cite web|last1=Heneman|first1=Karrie|last2=Zidenberg-Cherr|first2=Sheri|title=Publication 8313: Phytochemicals|url=http://anrcatalog.ucanr.edu/pdf/8313.pdf|publisher=University of California Cooperative Extension|date=2008}}</ref><ref name=lpi-flav/> In total, between 50,000<ref>{{cite journal|display-authors=3 |last1=Afendi |first1=Farit Mochamad |last2=Okada |first2=Taketo |last3=Yamazaki |first3=Mami |last4=Hirai-Morita |first4=Aki |last5=Nakamura |first5=Yukiko |last6=Nakamura |first6=Kensuke |last7=Ikeda |first7=Shun |last8=Takahashi |first8=Hiroki |last9=Altaf-Ul-Amin |first9=Md. |last10=Darusman |first10=Latifah K. |last11=Saito |first11=Kazuki |last12=Kanaya |first12=Shigehiko |title=KNApSAcK Family Databases: Integrated Metabolite–Plant Species Databases for Multifaceted Plant Research |journal=Plant and Cell Physiology |date=February 2012 |volume=53 |issue=2 |pages=e1–e1 |doi=10.1093/pcp/pcr165}}</ref> and 130,000<ref>{{cite journal |display-authors=3|last1=Rutz |first1=Adriano |last2=Sorokina |first2=Maria |last3=Galgonek |first3=Jakub |last4=Mietchen |first4=Daniel |last5=Willighagen |first5=Egon |last6=Gaudry |first6=Arnaud |last7=Graham |first7=James G |last8=Stephan |first8=Ralf |last9=Page |first9=Roderic |last10=Vondrášek |first10=Jiří |last11=Steinbeck |first11=Christoph |last12=Pauli |first12=Guido F |last13=Wolfender |first13=Jean-Luc |last14=Bisson |first14=Jonathan |last15=Allard |first15=Pierre-Marie |title=The LOTUS initiative for open knowledge management in natural products research |journal=eLife |date=26 May 2022 |volume=11 |pages=e70780 |doi=10.7554/eLife.70780}}</ref> phytochemicals have been discovered.

[[Food chemistry|Phytochemists]] study phytochemicals by first [[extract]]ing and isolating compounds from the origin plant, followed by defining their structure or testing in laboratory model systems, such as ''[[in vitro]]'' studies using [[cell cultures|cell lines]] or ''[[in vivo]]'' studies using [[animal testing|laboratory animals]].<ref name=Molyneux/> Challenges in that field include isolating specific compounds and determining their structures, which are often complex, and identifying what specific phytochemical is primarily responsible for any given biological activity.<ref name=Molyneux/><ref name=Webb>{{Citation | author1=Webb, L. J. (Leonard James) | author-link= Leonard Webb (academic) | title=An Australian phytochemical survey : Alkaloids in Queensland flowering plants | publication-date=1950 | publisher=Brisbane | url=https://trove.nla.gov.au/work/31787527 | access-date=25 March 2022}}</ref><ref>{{Citation | author1=Price, J. R. | author2=Lamberton, J. A. | author3=Culvenor, C.C.J | title=The Australian Phytochemical Survey: historical aspects of the CSIRO search for new drugs in Australian plants. Historical Records of Australian Science, 9(4), 335–356 | publication-date=1992 | publisher= Australian Academy of Science | url=https://www.publish.csiro.au/HR/HR9930940335 | pages=335, 336}}</ref>

==History of uses==
[[Image:Atropa belladonna Prague 2011 2.jpg|thumb|Berries of ''Atropa belladonna'', also called ''deadly nightshade'']]

Without specific knowledge of their cellular actions or mechanisms, phytochemicals have been used as [[poison]] and in [[traditional medicine]]. For example, [[salicin]], having [[anti-inflammatory]] and [[analgesic|pain-relieving]] properties, was originally extracted from the bark of the white [[willow tree]] and later synthetically produced to become the common, [[over-the-counter]] drug, [[aspirin]].<ref>{{Cite journal 
| last1 = Sneader | first1 = W. 
| title = The discovery of aspirin: A reappraisal 
| journal = BMJ (Clinical Research Ed.) 
| volume = 321 
| issue = 7276 
| pages = 1591–1594 
| year = 2000 
| pmid = 11124191 
| pmc = 1119266
 | doi=10.1136/bmj.321.7276.1591
}}</ref><ref>{{cite web|url=http://www.cnn.com/2010/HEALTH/12/22/aspirin.history/|title=From a tree, a 'miracle' called aspirin|author=Landau E|publisher=CNN|date=22 Dec 2010|access-date=18 June 2014}}</ref> The tropane alkaloids of ''[[Atropa belladonna]]'' were used as poisons, and early humans made [[Arrow poison|poisonous arrows]] from the plant.<ref name=Michael1998>{{Cite book| last = Michael| year = 1998| title = Alkaloids : biochemistry, ecology, and medicinal applications| pages = 20| url = https://books.google.com/books?id=bMCzyrAtrvYC&q=hallucinogenic++Atropa+belladonna&pg=PA20| isbn = 978-0-306-45465-3| publisher = Plenum Press| location = New York}}</ref> In [[Ancient Rome]], it was used as a poison by [[Agrippina the Younger]], wife of Emperor [[Claudius]] on advice of [[Locusta]], a lady specialized in poisons, and [[Livia]], who is rumored to have used it to kill her husband Emperor [[Augustus]].<ref name=Michael1998/><ref name=Timbrell2005>{{Cite book| last = Timbrell | first = John| year = 2005| title = The poison paradox : chemicals as friends and foes| pages = [https://archive.org/details/poisonparadoxche0000timb/page/2 2]| url = https://archive.org/details/poisonparadoxche0000timb| url-access = registration | quote = poisons used by the wife of Claudius. | isbn = 978-0-19-280495-2| publisher = Oxford Univ. Pr.| location = Oxford}}</ref> Other uses include [[perfume]]s, such as the [[Sesquiterpene|sequiterpene]] [[alpha-Santalol|santolol]]s, from [[Sandalwood oil|sandalwood]].{{sfn|Ellena|2022|pp=12-15}}

The [[English yew]] tree was long known to be extremely and immediately toxic to animals that grazed on its leaves or children who ate its berries; however, in 1971, [[paclitaxel]] was isolated from it, subsequently becoming an important [[cancer drug]].<ref name=Molyneux/>

As of 2017, the biological activities for most phytochemicals are unknown or poorly understood, in isolation or as part of foods.<ref name=Molyneux/><ref name=Heneman/> Phytochemicals with established roles in the body are classified as [[essential nutrients]].<ref name=lpi/><ref name=cmp/>

==Functions==
The phytochemical category includes compounds recognized as essential nutrients, which are naturally contained in plants and are required for normal [[physiology|physiological functions]], so must be obtained from the [[Diet (nutrition)|diet]] in humans.<ref name="cmp">{{cite web|url=https://www.choosemyplate.gov/vegetables-nutrients-health|title=Why is it important to eat vegetables? Nutrients|publisher=ChooseMyPlate.gov, USDA Center for Nutrition Policy & Promotion, US Department of Agriculture|date=16 January 2016|access-date=12 February 2017}}</ref><ref>{{cite web | url = http://library.med.utah.edu/NetBiochem/nutrition/lect1/2_1.html | title = What is an essential nutrient? | publisher = NetBiochem Nutrition, [[University of Utah]]}}</ref>

Some phytochemicals are known [[phytotoxins]] that are toxic to humans;<ref>{{cite journal|last1=Iwasaki|first1=S|title=Natural organic compounds that affect to microtubule functions.|journal=Yakugaku Zasshi |date=April 1998|volume=118|issue=4|pages=112–26|doi=10.1248/yakushi1947.118.4_111|pmid=9564789|doi-access=free}}</ref><ref>{{cite book|last1=Bjeldanes|first1=Leonard|last2=Shibamoto|first2=Takayuki|title=Introduction to Food Toxicology|date=2009|publisher=Elsevier|location=Burlington|isbn=9780080921532|page=124|edition=2nd|url=https://books.google.com/books?id=Lq4iw2UtDacC&pg=PA124}}</ref> for example [[aristolochic acid]] is carcinogenic at low doses.<ref name=Shaw2010>{{cite journal|last1=Shaw|first1=D|title=Toxicological risks of Chinese herbs.|journal=Planta Medica|date=December 2010|volume=76|issue=17|pages=2012–8|doi=10.1055/s-0030-1250533|pmid=21077025|doi-access=free}}</ref> Some phytochemicals are [[antinutrients]] that interfere with the absorption of nutrients.<ref>''[https://books.google.com/books?id=XpUjsqD7lFUC&pg=PA47 Oxford Dictionary of Biochemistry and Molecular Biology]''. Oxford University Press, 2006. {{ISBN|0-19-852917-1}}.</ref> Others, such as some polyphenols and flavonoids, may be [[pro-oxidant]]s in high ingested amounts.<ref name="halliwell">{{cite journal|pmid=17141749|year=2007|last1=Halliwell|first1=B|title=Dietary polyphenols: Good, bad, or indifferent for your health?|journal=Cardiovascular Research|volume=73|issue=2|pages=341–7|doi=10.1016/j.cardiores.2006.10.004|doi-access=free}}</ref>

Non-[[digestion|digestible]] [[dietary fiber]]s from plant foods, often considered as a phytochemical,<ref name="lpi-fiber">{{cite web|url=http://lpi.oregonstate.edu/mic/other-nutrients/fiber|title=Fiber|publisher=Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, Oregon|date=April 2012|access-date=12 February 2017}}</ref> are now generally regarded as a nutrient group having approved [[health claim]]s for reducing the risk of some types of [[cancer]]<ref name="FDA1">{{cite web|url=http://www.ecfr.gov/cgi-bin/text-idx?SID=c7e427855f12554dbc292b4c8a7545a0&mc=true&node=pt21.2.101&rgn=div5#se21.2.101_176|title=Health claims: fiber-containing grain products, fruits, and vegetables and cancer; Title 21: Food and Drugs, Subpart E, 101.76|publisher=U.S. Food and Drug Administration|date=5 January 2017|access-date=8 January 2017}}</ref> and [[coronary heart disease]].<ref name="FDA2">{{cite web|url=http://www.ecfr.gov/cgi-bin/text-idx?SID=c7e427855f12554dbc292b4c8a7545a0&mc=true&node=pt21.2.101&rgn=div5#se21.2.101_181|title=Health claims: Soluble fiber from certain foods and risk of coronary heart disease (CHD); Title 21: Food and Drugs, Subpart E, 101.81|publisher=U.S. Food and Drug Administration|date=5 January 2017|access-date=8 January 2017}}</ref>

Eating a diet high in fruits, vegetables, grains, legumes and plant-based beverages has long-term health benefits,<ref name=cmp/> but there is no evidence that taking [[dietary supplements]] of non-nutrient phytochemicals extracted from plants similarly benefits health.<ref name=lpi/> Phytochemical supplements are neither recommended by health authorities for improving health<ref name=Heneman/><ref name="acs">{{cite web|url=http://www.cancer.org/healthy/eathealthygetactive/acsguidelinesonnutritionphysicalactivityforcancerprevention/acs-guidelines-on-nutrition-and-physical-activity-for-cancer-prevention-common-questions|title=Common questions about diet and cancer|date=5 February 2016|publisher=[[American Cancer Society]]|access-date=8 January 2017}}</ref> nor approved by regulatory agencies for health claims on product labels.<ref name="EFSA">{{cite journal|author=EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3 European Food Safety Authority (EFSA), Parma, Italy|title=Scientific Opinion on the substantiation of health claims related to various food(s)/food constituent(s) and protection of cells from premature aging, antioxidant activity, antioxidant content and antioxidant properties, and protection of DNA, proteins and lipids from oxidative damage pursuant to Article 13(1) of Regulation (EC) No 1924/20061|journal= EFSA Journal|year= 2010|volume= 8|issue=2|page=1489|doi=10.2903/j.efsa.2010.1489|doi-access=free}}</ref><ref name="fda-101.54">{{cite web|url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.54|title=Code of Federal Regulations, Title 21, Part 101, Food Labeleing, Subpart D, Specific Requirements for Nutrient Content Claims, Section 101.54|publisher= US Food and Drug Administration|date=1 April 2016|access-date=12 February 2017}}</ref>

==Consumer and industry guidance==

While health authorities encourage consumers to eat diets rich in fruit, vegetables, [[whole grains]], [[legumes]], and nuts to improve and maintain health,<ref name=cmp/> evidence that such effects result from specific, non-nutrient phytochemicals is limited or absent.<ref name=lpi/> For example, [[systematic review]]s and/or [[meta-analysis|meta-analyses]] indicate weak or no evidence for phytochemicals from plant food consumption having an effect on [[breast cancer|breast]], [[lung cancer|lung]], or [[bladder cancer|bladder]] cancers.<ref name=Aune2012review>{{cite journal|pmid=22706630|year=2012|last1=Aune|first1=D|title=Fruits, vegetables and breast cancer risk: A systematic review and meta-analysis of prospective studies|journal=Breast Cancer Research and Treatment|volume=134|issue=2|pages=479–93|last2=Chan|first2=D. S.|last3=Vieira|first3=A. R.|last4=Rosenblatt|first4=D. A.|last5=Vieira|first5=R|last6=Greenwood|first6=D. C.|last7=Norat|first7=T|doi=10.1007/s10549-012-2118-1|s2cid=6984786|url=http://eprints.whiterose.ac.uk/75579/15/Combine.pdf}}</ref><ref>{{cite journal|pmid=14601062|year=2003|last1=Smith-Warner|first1=S. A.|title=Fruits, vegetables and lung cancer: A pooled analysis of cohort studies|journal=International Journal of Cancer|volume=107|issue=6|pages=1001–11|last2=Spiegelman|first2=D|last3=Yaun|first3=S. S.|last4=Albanes|first4=D|last5=Beeson|first5=W. L.|last6=Van Den Brandt|first6=P. A.|last7=Feskanich|first7=D|last8=Folsom|first8=A. R.|last9=Fraser|first9=G. E.|last10=Freudenheim|first10=J. L.|last11=Giovannucci|first11=E|last12=Goldbohm|first12=R. A.|last13=Graham|first13=S|last14=Kushi|first14=L. H.|last15=Miller|first15=A. B.|last16=Pietinen|first16=P|last17=Rohan|first17=T. E.|last18=Speizer|first18=F. E.|last19=Willett|first19=W. C.|last20=Hunter|first20=D. J.|doi=10.1002/ijc.11490|s2cid=28381529|url=https://cris.maastrichtuniversity.nl/portal/en/publications/fruits-vegetables-and-lung-cancer-a-pooled-analysis-of-cohort-studies(e5a7f16c-9f94-461e-9454-f35522b553f5).html}}</ref> Further, in the United States, regulations exist to limit the language on product labels for how plant food consumption may affect cancers, excluding mention of any phytochemical except for those with established health benefits against cancer, such as [[dietary fiber]], [[vitamin A]], and [[vitamin C]].<ref>{{cite web|url=http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&SID=4bf49f997b04dcacdfbd637db9aa5839&ty=HTML&h=L&mc=true&n=pt21.2.101&r=PART#se21.2.101_178|title=Electronic Code of Federal Regulations, Title 21, Chapter I, Subchapter B, Part 101.78. Health claims: fruits and vegetables and cancer|publisher=US Government Printing Office|date=9 February 2017|access-date=12 February 2017}}</ref>

Phytochemicals, such as polyphenols, have been specifically discouraged from food labeling in Europe and the United States because there is no evidence for a [[causality|cause-and-effect]] relationship between dietary polyphenols and inhibition or prevention of any disease.<ref name=EFSA/><ref>{{citation |title= New Roles for Polyphenols. A 3-Part Report on Current Regulations & the State of Science |author= Gross P|date=1 March 2009 |publisher= Nutraceuticals World |url= http://www.nutraceuticalsworld.com/issues/2009-03/view_features/new-roles-for-polyphenols/|access-date=12 February 2017}}</ref>

Among carotenoids such as the [[tomato]] phytochemical, [[lycopene]], the US [[Food and Drug Administration]] found insufficient evidence for its effects on any of several cancer types, resulting in limited language for how products containing lycopene can be described on labels.<ref name="fda-lycopene">{{cite web|url=https://www.fda.gov/Food/IngredientsPackagingLabeling/LabelingNutrition/ucm072760.htm|title=Qualified Health Claims: Letter Regarding "Tomatoes and Prostate, Ovarian, Gastric and Pancreatic Cancers (American Longevity Petition)" (Docket No. 2004Q-0201)|publisher=Office of Nutritional Products, Labeling and Dietary Supplements, Center for Food Safety and Applied Nutrition, US Food and Drug Administration |author=Schneeman BO|date=9 July 2015|access-date=12 February 2017}}</ref>

==Effects of food processing==

Phytochemicals in freshly harvested plant foods may be degraded by processing techniques, including cooking.<ref name="palermo">{{Cite journal
 | pmid = 24227349
| year = 2014
| last1 = Palermo
| first1 = M
| title = The effect of cooking on the phytochemical content of vegetables
| journal = Journal of the Science of Food and Agriculture
| volume = 94
| issue = 6
| pages = 1057–70
| last2 = Pellegrini
| first2 = N
| last3 = Fogliano
| first3 = V
| doi = 10.1002/jsfa.6478
| hdl = 11381/2677278
| hdl-access = free
}}</ref> The main cause of phytochemical loss from cooking is [[thermal decomposition]].<ref name=palermo/>

A converse exists in the case of [[carotenoids]], such as [[lycopene]] present in [[tomato]]es, which may remain stable or increase in content from cooking due to liberation from cellular membranes in the cooked food.<ref>{{cite journal |pmid=11982434 |year=2002 |last1=Dewanto |first1=V |last2=Wu |last3=Adom |last4=Liu |title=Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity |volume=50 |issue=10 |pages=3010–4 |journal=Journal of Agricultural and Food Chemistry |doi=10.1021/jf0115589 |first2=X |first3=KK |first4=RH}}</ref> [[Food processing]] techniques like mechanical processing can also free carotenoids and other phytochemicals from the food matrix, increasing dietary intake.<ref name=palermo/><ref>{{Cite journal
| pmid = 17374686
| year = 2007
| last1 = Hotz
| first1 = C
| title = Traditional food-processing and preparation practices to enhance the bioavailability of micronutrients in plant-based diets
| journal = The Journal of Nutrition
| volume = 137
| issue = 4
| pages = 1097–100
| last2 = Gibson
| first2 = R. S.
| doi = 10.1093/jn/137.4.1097
| doi-access = free
}}</ref>

In some cases, processing of food is necessary to remove phytotoxins or antinutrients; for example societies that use [[cassava]] as a staple have traditional practices that involve some processing (soaking, cooking, fermentation, etc.), which are necessary to avoid getting sick from [[Glycoside#Cyanogenic glycosides|cyanogenic glycosides]] present in unprocessed cassava.<ref>{{cite book|title=Contents: Roots, tubers, plantains and bananas in human nutrition|date=1990|publisher=FAO|location=Rome|url=http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents}} [http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity Chapter 7: Cassava toxicity]</ref>

==See also==
<!-- Please keep entries in alphabetical order & add a short description [[WP:SEEALSO]] -->
{{div col|small=yes|colwidth=20em}}
* [[Allelopathy]]
* [[List of antioxidants in food]]
* [[List of phytochemicals in food]]
* [[Nutrition]]
* [[Secondary metabolites]]
{{div col end}}
<!-- please keep entries in alphabetical order -->

== References ==
{{Reflist}}

==Further reading==
*{{Cite book |last=Ellena |first=Jean-Claude |url=https://books.google.com/books?id=yrZNEAAAQBAJ |title=Atlas of Perfumed Botany |trans-title=Atlas de botanique parfumée|date=2022 |translator=Erik Butler|origyear=2020 Flammarion, Paris|publisher=[[MIT Press]] |location=[[Cambridge, Massachusetts|Cambridge]]|isbn=978-0-262-04673-2 }}
* Higdon, J. ''An Evidence – Based Approach to Dietary Phytochemicals''. 2007. Thieme. {{ISBN|978-1-58890-408-9}}.
* Rosa, L.A. de la / Alvarez-Parrilla, E. / González-Aguilar, G.A. (eds.) ''Fruit and Vegetable Phytochemicals: Chemistry, Nutritional Value and Stability''. 2010. Wiley-Blackwell. {{ISBN|978-0-8138-0320-3}}.

==External links==
*{{Commons category-inline|Phytochemicals}}
*[https://phytochem.nal.usda.gov/phytochem/search Dr. Duke's Phytochemical and Ethnobotanical Databases] – United States Department of Agriculture

{{Phytochemical}}

{{二次利用|date=13 December 2022}}
[[Category:Phytochemicals| ]]
[[Category:Dietary antioxidants]]
[[Category:Nutrients]]
[[Category:Nutrition]]
[[Category:Polyphenols]]
[[Category:Carotenoids]]