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polyphenols 300 x 220

Chemical structures of Ginkgo biloba natural substances (leaf, fruits)



PolyphenolsPolyphenols are a large group of natural substances found in plants and characterized by the presence of more than one phenol unit per molecule. Polyphenols are generally divided into lignans, coumarins, stilbenes, flavonoids, neoflavonoids, isoflavonoids, quinones, hydrolysable and condensed tannins.


Sources of polyphenols in our diet are mainly fruits, vegetables, cereals, olive, legumes, chocolate, and beverages as tea, coffee and wine. During the last years, the research on the health effects of polyphenols exploded.


Polyphenols are the most abundant antioxidants in our diet, and as such protect cell constituents against oxidative damage. Oxidative damage is often linked with degenerative diseases as cancer, osteoporosis, diabetes, cardiovascular (atherosclerosis) and neurodegenerative diseases.


Flavonoids are important antioxidant polyphenols : anthocyanins (responsible for most of the red and blue colours in fruits, vegetables and also flowers), flavanols as epigallocatechin gallate (EGCG) in green tea, isoflavones as daidzein from soy milk, flavonols as quercetin (apples, onions, ginkgo).


Resveratrol (mainly in grape skin) is a stilbene with strong antioxidant properties.


Many polyphenols are also classified as phytoestrogens because they share some other important properties such as estrogenic activity. Phytoestrogens are nonsteroidal plant metabolites that bind to estrogen receptors. Although phytoestrogens have only a weak estrogenic activity compared with the natural sex hormone β-estradiol, the huge quantities in the diet or in food supplements can induce significant estrogenic properties.


The most important phytoestrogens belong to the isoflavones (mainly in soy-products, but also in beans and peanuts), coumestans (flavonoids) (soy-products, but also in alfalfa, Brussels sprouts and spinach), lignans (cereals as sesam and lin seed) or flavanones (flavanoids) found in hops and hence also in beer.


Phytoestrogens, mainly isoflavones, are intensively studied for their positive beneficial properties as reducing post-menopausal symptoms, cancer protection (prostate), osteoporosis. Evidence for these positive effects comes from epidemiological studies in Asian countries as Japan and China, which have high soy consumption.


However, their possible deleterious effects in breast cancer is heavenly discussed. Although in our western countries, the intake of phytoestrogens through the normal diet is well below the level required to achieve a biological response, the use of a growing number of food supplements containing phytoestrogens (following the controversies regarding hormone replacement therapy) warrants some caution for some categories in the population. Phytoestrogens can also be classified as endocrine disruptors.Polyphenols

NORMS AND LEGISLATION (maximum level allowed in food) :

There are no legal limits for these natural products. When used as food supplements, it is compulsory to notify it to the FPS Public Health.


CODA-CERVA has a lot of experience in the chemical analysis of anthocyanins. More recently we developed methods for the analysis of Ginkgo biloba flavonoids, ginkgolides and bilobalide (project FOODINTER).
Within Foodinter we also develop analysis methods for soy isoflavones.



Alfons Callebaut



- Sergent T, Dupont I, Van Der Heiden E, Scippo ML, Pussemier L, Larondelle Y, Schneider YJ.
CYP1A1 and CYP3A4 modulation by dietary flavonoids in human intestinal Caco-2 cells.
Toxicol Lett. 2009, 191(2-3),216-22


- N. Terahara, A. Callebaut, R. Ohba, T. Nagata, M. Ohnishi-Kameyama and M. Suzuki
PHYTOCHEMISTRY 58 (1) 493-500 (2001)
Acylated anthocyanidin 3-sophoroside-5-glucosides from Ajuga reptans flowers and the corresponding cell cultures.


- A. Callebaut, N. Terahara and M. Decleire
PLANT SCIENCE 118, 109-118 (1996)
Anthocyanin acyltransferases in cell cultures of Ajuga reptans.
- N. Terahara, A. Callebaut, R. Ohba, T. Nagata, M. Ohnishi-Kameyama and M. Suzuki
PHYTOCHEMISTRY 42 (1) 199-203 (1996)
Triacylated anthocyanins from Ajuga reptans flowers and cell cultures.


- A. Callebaut, M. Decleire and K. Vandermeiren
in "BIOTECHNOLOGY IN AGRICULTURE AND FORESTRY, VOLUME 24 : MEDICI¬NAL AND AROMATIC PLANTS V", 1-22 (1993). Editor : Y.P.S. Bajaj. Spinger Verlag Berlin Heidelberg.
Ajuga reptans (Bugle) : In Vitro Production of Anthocyanins