Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poisons 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 claims about phytochemicals on food product or nutrition labels.

Definition
Phytochemicals are chemicals of plant origin. 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 predators.

Phytochemicals are generally 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, stilbenes or lignans. Flavonoids can be further divided into groups based on their similar chemical structure, such as anthocyanins, flavones, flavanones, isoflavones, and flavanols. Flavanols are further classified as catechins, epicatechins, and proanthocyanidins. In total, between 50,000 and 130,000 phytochemicals have been discovered.

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 in vitro studies using cell lines 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 biological activity.

History of uses

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 Atropa 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 Augustus. Other uses include perfumes, such as the sequiterpene santolols, from sandalwood.

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.

, 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.

Functions
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 in humans.

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.

Non-digestible 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 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.

See also

 Allelopathy
 List of antioxidants in food
 List of phytochemicals in food
 Nutrition
 Secondary metabolites

References

Further reading

 Higdon, J. An Evidence – Based Approach to Dietary Phytochemicals. 2007. Thieme. .
 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. .

External links

Dr. Duke's Phytochemical and Ethnobotanical Databases – United States Department of Agriculture

 
Dietary antioxidants
Nutrients
Nutrition
Polyphenols
Carotenoids
피토케미컬() 또는 식물 화학물질(植物化學物質)은 식물에서 자연적으로 만들어지는 모든 화학물질 즉 유기화합물을 통틀어 말한다(phyto는 그리스어로 "식물"을 의미한다). 천연물의 주요 성분이며, 일부는 블루베리의 보라색과 같이 식물의 색소, 마늘의 냄새와 같은 식물의 관능성 등과 관련되어 있다. 카로티노이드 또는 플라보노이드 등과 같이 피토케미컬은 다양한 생리 활성 기능BRM,Biological response modifiers)을 가지고 있어 생물학적으로 중요성을 가지지만, 필수 영양소는 아니다. elifesciences의 천연물에 관한 연구 'The LOTUS initiative for open management in natural products research'에 의하면, 현재까지 약 5만 ~ 13만여 종의 피토케미켈이 발견되었다.

생리학적 의미에서의 피토케미컬 
피토케미컬은 세포의 기능 또는 메커니즘과 관련한 구체적인 지식 없이 수천년 전부터 약물로 사용되어 왔다. 예를 들어, 히포크라테스는 버드나무 잎을 해열제로 처방하였다고 한다. 항염증 및 통증 완화 기능이 있는 살리신은 처음에 버드나무의 껍질에서 추출되었고, 이 후 인공적으로 생산되어 처방전 없이 살 수 있는 약물인 아스피린의 주성분이 되었다.

발효성 식이섬유와 같은 특정 피토케미컬은 미국 식품의약청(FDA)에 의해 제한된 건강정보에 한해서 허용된다.

일부 생리학적 특성을 지닌 피토케미컬들은 복잡한 유기 분자이기보다 성분이라고 할 수 있다. 예를 들어, 과일과 채소에 풍부한 셀레늄은 갑상선 호르몬 물질대사와 면역 기능을 포함하는 주요 대사 경로와 관련된 식이 미네랄이다. 특히, 이것은 필수적인 영양소이며, 효소의 생체 내의 항산화 작용을 하는 글루타티온 합성의 공동 인자이다.

임상 실험 및 효능 표기 상황 
현재 피토케미컬을 기반으로 한 식이 보충제는 구매할 수 있다. 하지만 미국 암 협회는, "(현재)사용가능한 과학적 증거는 피토케미컬 식이 보충제를 섭취하는 것이 장기적으로 사람들이 과일, 채소, 콩, 그리고 곡물 등을 섭취하는 것만큼 건강에 좋다는 주장을 지지하지 않는다"고 말했다.

가공 식품 및 식물성 화학 물질 
갓 수확한 식물성 식품에 포함된 피토케미컬은 요리와 같은 가공과정에서 기능이 저하될 수 있다. 요리 과정에서 피토케미컬의 기능이 저하되는 주요 원인은 열 분해이다.

반대로 라이코펜과 같이 토마토에 포함된 카로티노이드의 경우 요리할 경우 안정적으로 유지되거나 세포막으로부터 빠져나와 증가한다. 기계적 가공 과정과 같은 식품 가공 기술은 카로티노이드와 다른 피토케미컬들을 풍부하게 해주고 영양 흡수율을 높여준다.

식물의 씨앗
일반적으로 열매 깊숙한 속에 위치하며 동물의 섭취를 목적으로 한, 당분을 함유하는 열매의 특성과는 다르게 식물의 씨앗은 동물의 섭취로부터 배설, 토양의 균이나 바이러스에서도 보존되어 싹이 발아될 수 있도록 진화하였다. 장미과 벚나무속의 일부 열매에서처럼 몇몇 열매의 씨앗은 시안배당체 성분을 함유함으로써 이러한 메커니즘을 보다 잘 완수하도록 진하했다. 이러한 생리활성물질(BRM,Biological response modifiers)의 예로는 아미그달린(amygdalin), 솔라닌(Solanine), 쿠쿠르비타신(cucurbitacins) 등과 같은 피토케미컬(phytochemical)이 알려져있다.

생리활성물질
피토케미컬은 식물의 입장에서 보면  자연적으로 가지고 있는 자체적인 생리활성물질(BRM)로서의 의미도 가지며 이러한 맥락에서  활동일 주기(活動日週記)를 주관하는 태양 빛과 온도같은 외부환경과 서로 연관되는 내부적인 생화학물질로서 하루를 주기로 하여 나타나는 식물의 광합성이나 달맞이꽃, 나팔꽃의 개화등의 변화 현상은 그 주요한 예이다.

먹이사슬
식물은 생태계  먹이 그물(food web)의 주요한 하위 근간에 위치한다는 점에서  시각적인 정보메커니즘에서의 색소나 후각적 정보메커니즘에서의 향기 등처럼 생화학적으로 매우 풍부한 분자수준의 발현 메커니즘을 보유하고 진화해왔다. 식물 색소의 주요한 피토케미컬(phytochemical)로는 안토시아닌(anthocyanin)등이 알려져있으며 냄새 및 향기에 관여하는 피토케미컬(phytochemical)로는 테르펜(terpene), 쿠마린(Coumarin), 락톤(lactone) 등이 알려져있다.

환경오염
많은 과학자들이 환경오염 특히 토양 및 수질오염 그리고 인위적인 비료 또는 살충제등의 남용등에서 농작물의 재배는 심각할 수 있는 피토케미컬의 변형 또는 중금속같은 오염물질 성분의 함유을 지적하고 있다. 이는 최상위 포식자로서 인간의 자연에 대한 올바른 환경관념과 행동을 필연적으로 촉구한다고 볼 수 있다.

같이 보기 
 페로몬
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각주 

[참고](식품의약품안전처-식물 열매나 씨앗 섭취시 주의하세요!)https://www.mfds.go.kr/brd/m_99/view.do?seq=34386&srchFr=&srchTo=&srchWord=&srchTp=&itm_seq_1=0&itm_seq_2=0&multi_itm_seq=0&company_cd=&company_nm=&page=1
[참고](2012.09.10 10:00 사이언스타임즈,씨앗, 잘못 섭취하면 독 된다)https://www.sciencetimes.co.kr/news/%EC%94%A8%EC%95%97-%EC%9E%98%EB%AA%BB-%EC%84%AD%EC%B7%A8%ED%95%98%EB%A9%B4-%EB%8F%85-%EB%90%9C%EB%8B%A4/

추가 자료 
 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.
 "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): 139–45. doi:10.1016/j.tifs.2013.08.004
 "Carotenoids and human health". Pharmacological Research 55 (3): 207–16. doi:10.1016/j.phrs.2007.01.012PMID 17349800
 "Potential Synergy of Phytochemicals in Cancer Prevention: Mechanism of Action" J Nutr 134 (12): 3479S–85

외부 링크 
 화학 데이터베이 –미국 농무부
 식물성 화학 물질에 LPI –linus pauling 박사 연구소에서 Oregon State University

 
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