PHYTOCHEMICALS are chemical compounds produced by plants, generally
to help them thrive or thwart competitors, predators, or pathogens.
The name comes from the Greek word phyton, meaning plant. Some
phytochemicals have been used as poisons and others as traditional
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 limiting or preventing anti-disease
claims concerning phytochemicals on food product labels.
* 1 Definition
* 2 History of uses
* 3 Functions
* 4 Consumer and industry guidance
* 5 Effects of food processing
* 6 See also
* 7 References
* 8 Further reading
* 9 External links
Plants are composed entirely of chemicals of various kinds.
Phytochemicals (from Greek phyto, meaning "plant") are chemicals
produced by plants through primary or secondary metabolism . They
generally have biological activity in the plant host and play a role
in plant growth or defense against competitors, pathogens, or
Phytochemicals generally are regarded as research compounds rather
than essential nutrients because proof of their possible health
effects has not been established yet. Phytochemicals under research
can be classified into major categories, such as carotenoids and
polyphenols , which include phenolic acids , flavonoids , and
stilbenes /lignans .
Flavonoids can be further divided into groups
based on their similar chemical structure, such as anthocyanins ,
flavones , flavanones , and isoflavones , and flavanols . Flavanols
further are classified as catechins , epicatechins , and
Phytochemists study phytochemicals by first extracting and isolating
compounds from the origin plant, followed by defining their structure
or testing in laboratory model systems, such as cell cultures , in
vitro experiments, or in vivo studies using laboratory animals .
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
HISTORY OF USES
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 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 . The tropane alkaloids of A.
belladonna were used as poisons, and early humans made poisonous
arrows from the plant. 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
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 .
As of 2017, the biological activities for most phytochemicals are
unknown or poorly understood, in isolation or as part of foods.
Phytochemicals with established roles in the body are classified as
essential nutrients .
The phytochemical category includes compounds recognized as essential
nutrients, which are naturally contained in plants and are required
for normal physiological functions , so must be obtained from the diet
Some phytochemicals are known phytotoxins that are toxic to humans;
for example aristolochic acid is carcinogenic at low doses. Some
phytochemicals are antinutrients that interfere with the absorption of
nutrients. Others, such as some polyphenols and flavonoids, may be
pro-oxidants in high ingested amounts.
Nondigestible dietary fibers from plant foods, often considered as a
phytochemical, are now generally regarded as a nutrient group having
approved health claims for reducing the risk of some types of cancer
and coronary heart disease .
Eating a diet high in fruits, vegetables, grains, legumes and
plant-based beverages has long-term health benefits, but there is no
evidence that taking dietary supplements of non-nutrient
phytochemicals extracted from plants similarly benefits health.
Phytochemical supplements are neither recommended by health
authorities for improving health nor approved by regulatory agencies
for health claims on product labels.
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, evidence that such effects result from specific,
non-nutrient phytochemicals is limited or absent. For example,
systematic reviews and/or meta-analyses indicate weak or no evidence
for phytochemicals from plant food consumption having an effect on
breast , lung , or bladder cancers. 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 .
Phytochemicals, such as polyphenols, have been specifically
discouraged from food labeling in Europe and the United States because
there is no evidence for a cause-and-effect relationship between
dietary polyphenols and inhibition or prevention of any disease.
Among carotenoids such as the tomato phytochemical, lycopene , the US
Food and Drug Administration
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.
EFFECTS OF FOOD PROCESSING
Phytochemicals in freshly harvested plant foods may be degraded by
processing techniques, including cooking. The main cause of
phytochemical loss from cooking is thermal decomposition .
A converse exists in the case of carotenoids , such as lycopene
present in tomatoes , which may remain stable or increase in content
from cooking due to liberation from cellular membranes in the cooked
food. Food processing techniques like mechanical processing can also
free carotenoids and other phytochemicals from the food matrix,
increasing dietary intake.
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 cyanogenic glycosides present in unprocessed cassava.
List of antioxidants in food
List of phytochemicals in food
* ^ Breslin, Andrew (2017). "The Chemical Composition of Green
Plants". Sciencing, Leaf Group Ltd.
* ^ A B C D E F Molyneux, RJ; Lee, ST; Gardner, DR; Panter, KE;
James, LF (2007). "Phytochemicals: the good, the bad and the ugly?".
Phytochemistry. 68 (22–24): 2973–85. PMID 17950388 . doi
* ^ Harborne, Jeffrey B.; Baxter, Herbert; Moss, Gerard P., eds.
(1999). "General Introduction".
Phytochemical dictionary a handbook of
bioactive compounds from plants (2nd ed.). London: Taylor & Francis.
p. vii. ISBN 9780203483756 .
* ^ A B C D "Phytochemicals". Micronutrient Information Center,
Linus Pauling Institute, Oregon State University, Corvallis, Oregon.
2017. Retrieved 12 February 2017.
* ^ A B C D E F Heneman, Karrie; Zidenberg-Cherr, Sheri (2008).
"Publication 8313: Phytochemicals" (PDF). University of California
* ^ "Carotenoids". Micronutrient Information Center, Linus Pauling
Institute, Oregon State University, Corvallis, Oregon. July 2016.
Retrieved 12 February 2017.
* ^ A B "Flavonoids". Micronutrient Information Center, Linus
Pauling Institute, Oregon State University, Corvallis, Oregon.
November 2015. Retrieved 12 February 2017.
* ^ Sneader, W. (2000). "The discovery of aspirin: A reappraisal" .
BMJ (Clinical research ed.). 321 (7276): 1591–1594. PMC 1119266 .
PMID 11124191 . doi :10.1136/bmj.321.7276.1591 .
* ^ Landau E (22 Dec 2010). "From a tree, a \'miracle\' called
aspirin". CNN. Retrieved 18 June 2014.
* ^ A B Michael (1998). Alkaloids : biochemistry, ecology, and
medicinal applications. New York: Plenum Press. p. 20. ISBN
* ^ Timbrell, John (2005). The poison paradox : chemicals as
friends and foes. Oxford: Oxford Univ. Pr. p. 2. ISBN 0-19-280495-2 .
* ^ A B C D "Why is it important to eat vegetables? Nutrients".
ChooseMyPlate.gov, USDA Center for
Nutrition Policy & Promotion, US
Department of Agriculture. 16 January 2016. Retrieved 12 February
* ^ "What is an essential nutrient?". NetBiochem Nutrition,
University of Utah
University of Utah .
* ^ Iwasaki, S (April 1998). "Natural organic compounds that affect
to microtubule functions.". Yakugaku zasshi : Journal of the
Pharmaceutical Society of Japan. 118 (4): 112–26. PMID 9564789 .
* ^ Bjeldanes, Leonard; Shibamoto, Takayuki (2009). Introduction to
Food Toxicology (2nd ed.). Burlington: Elsevier. p. 124. ISBN
* ^ Shaw, D (December 2010). "Toxicological risks of Chinese
herbs.". Planta medica. 76 (17): 2012–8. PMID 21077025 . doi
* ^ Oxford Dictionary of Biochemistry and Molecular Biology. Oxford
University Press, 2006. ISBN 0-19-852917-1 .
* ^ Halliwell, B (2007). "Dietary polyphenols: Good, bad, or
indifferent for your health?". Cardiovascular Research. 73 (2):
341–7. PMID 17141749 . doi :10.1016/j.cardiores.2006.10.004 .
* ^ "Fiber". Micronutrient Information Center, Linus Pauling
Institute, Oregon State University, Corvallis, Oregon. April 2012.
Retrieved 12 February 2017.
* ^ "Health claims: fiber-containing grain products, fruits, and
vegetables and cancer; Title 21: Food and Drugs, Subpart E, 101.76".
U.S. Food and Drug Administration. 5 January 2017. Retrieved 8 January
* ^ "Health claims: Soluble fiber from certain foods and risk of
coronary heart disease (CHD); Title 21: Food and Drugs, Subpart E,
101.81". U.S. Food and Drug Administration. 5 January 2017. Retrieved
8 January 2017.
* ^ "Common questions about diet and cancer". American Cancer
Society . 5 February 2016. Retrieved 8 January 2017.
* ^ A B EFSA Panel on Dietetic Products,
Nutrition and Allergies
(NDA)2, 3 European Food Safety Authority (EFSA), Parma, Italy (2010).
"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" (PDF). EFSA Journal. 8 (2): 1489. doi
:10.2903/j.efsa.2010.1489 . CS1 maint: Multiple names: authors list
* ^ "Code of Federal Regulations, Title 21, Part 101, Food
Labeleing, Subpart D, Specific Requirements for Nutrient Content
Claims, Section 101.54". US Food and Drug Administration. 1 April
2016. Retrieved 12 February 2017.
* ^ Aune, D; Chan, D. S.; Vieira, A. R.; Rosenblatt, D. A.; Vieira,
R; Greenwood, D. C.; Norat, T (2012). "Fruits, vegetables and breast
cancer risk: A systematic review and meta-analysis of prospective
Cancer Research and Treatment. 134 (2): 479–93.
PMID 22706630 . doi :10.1007/s10549-012-2118-1 .
* ^ Smith-Warner, S. A.; Spiegelman, D; Yaun, S. S.; Albanes, D;
Beeson, W. L.; Van Den Brandt, P. A.; Feskanich, D; Folsom, A. R.;
Fraser, G. E.; Freudenheim, J. L.; Giovannucci, E; Goldbohm, R. A.;
Graham, S; Kushi, L. H.; Miller, A. B.; Pietinen, P; Rohan, T. E.;
Speizer, F. E.; Willett, W. C.; Hunter, D. J. (2003). "Fruits,
vegetables and lung cancer: A pooled analysis of cohort studies".
International Journal of Cancer. 107 (6): 1001–11. PMID 14601062 .
doi :10.1002/ijc.11490 .
* ^ "Electronic Code of Federal Regulations, Title 21, Chapter I,
Subchapter B, Part 101.78. Health claims: fruits and vegetables and
cancer". US Government Printing Office. 9 February 2017. Retrieved 12
* ^ Gross P (1 March 2009), New Roles for Polyphenols. A 3-Part
Report on Current Regulations & the State of Science, Nutraceuticals
World, retrieved 12 February 2017
* ^ Schneeman BO (9 July 2015). "Qualified Health Claims: Letter
Regarding "Tomatoes and Prostate, Ovarian, Gastric and Pancreatic
Cancers (American Longevity Petition)" (Docket No. 2004Q-0201)".
Office of Nutritional Products, Labeling and Dietary Supplements,
Center for Food Safety and Applied Nutrition, US Food and Drug
Administration. Retrieved 12 February 2017.
* ^ Bongoni, R; Steenbekkers, L.P.A; Verkerk, R; van Boekel,
M.A.J.S; Dekker, M (2013). "Studying consumer behaviour related to the
quality of food: A case on vegetable preparation affecting sensory and
health attributes". Trends in Food Science & Technology. 33 (2):
139–145. doi :10.1016/j.tifs.2013.08.004 .
* ^ Bongoni, R; Verkerk, R; Steenbekkers, B; Dekker, M; Stieger
(2014). "Evaluation of Different Cooking Conditions on Broccoli
(Brassica oleracea var. italica) to Improve the Nutritional Value and
Consumer Acceptance". Plant foods for human nutrition. 69 (3):
228–234. PMID 24853375 . doi :10.1007/s11130-014-0420-2 .
* ^ A B C Palermo, M; Pellegrini, N; Fogliano, V (2014). "The
effect of cooking on the phytochemical content of vegetables". Journal
of the Science of Food and Agriculture. 94 (6): 1057–70. PMID
24227349 . doi :10.1002/jsfa.6478 .
* ^ Dewanto, V; Wu, X; Adom, KK; Liu, RH (2002). "Thermal
processing enhances the nutritional value of tomatoes by increasing
total antioxidant activity". Journal of Agricultural and Food
Chemistry. 50 (10): 3010–4. PMID 11982434 . doi :10.1021/jf0115589 .
* ^ Hotz, C; Gibson, R. S. (2007). "Traditional food-processing and
preparation practices to enhance the bioavailability of micronutrients
in plant-based diets". The Journal of Nutrition. 137 (4): 1097–100.
PMID 17374686 .
* ^ Contents: Roots, tubers, plantains and bananas in human
nutrition. Rome: FAO. 1990. Chapter 7:
* 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 .