Τι είναι οι πολυφαινόλες; Τροφές πλούσιες σε πολυφαινόλες – Πολυφαινόλες στο ελαιόλαδο – Οφέλη για την υγεία

What are the Polyphenols? Polyphenols rich foods – Polyphenols in olive oil – Health benefits of the Polyphenols

Polyphenolic compounds - polyphenolic acid - polyphenolic flavonoids - polyphenolic antioxidants in olive oil

Polyphenols: Chemical Composition

Πολυφαινόλες are organic compounds characterized by the presence of multiple phenol units in their chemical structure. Phenol itself is a benzene ring with a hydroxyl (-OH) group attached. Polyphenols are defined by having more than one phenol unit, and their structure determines their function, biological activity, and classification. They are synthesized through two main pathways in plants: the shikimate pathway (shikimic acid pathway) and the phenylpropanoid pathway.

General Chemical Features

Phenolic Structure: Polyphenols are based on aromatic rings bonded to hydroxyl groups.
Functional Groups: Besides hydroxyl groups, polyphenols often contain other functional groups like methoxy (-OCH₃) and carboxyl (-COOH) groups, which influence their solubility and biological activity.
Molecular Weight: Polyphenols range from small molecules like phenolic acids to large, complex polymers like tannins.

Classification of Polyphenols by Structure

Polyphenols are broadly divided into the following categories:

Flavonoids
Core Structure: C6-C3-C6 (two aromatic rings connected by a three-carbon bridge).
Subclasses: Flavonoids are further categorized based on the oxidation and substitution pattern of their central ring:
Flavonols (e.g., quercetin, kaempferol)
Flavones (e.g., luteolin, apigenin)
Isoflavones (e.g., genistein, daidzein)
Flavan-3-ols (e.g., catechins, epicatechins)
Anthocyanins (e.g., cyanidin, malvidin).
Sources: Found in fruits, vegetables, tea, and wine.

Phenolic Acids
Core Structure: Based on benzoic acid or cinnamic acid derivatives.
Examples: Gallic acid, caffeic acid, ferulic acid, and p-coumaric acid.
Sources: Present in coffee, berries, and whole grains.

Stilbenes
Core Structure: C6-C2-C6 (two aromatic rings connected by a two-carbon ethylene bridge).
Example: Resveratrol.
Sources: Grapes, wine, and peanuts.

Λιγνάνες
Core Structure: Derived from the dimerization of two phenylpropanoid units.
Examples: Secoisolariciresinol and matairesinol.
Sources: Seeds (especially flaxseeds), grains, and vegetables.

Tannins
Core Structure: Large polymeric molecules made up of flavonoid or phenolic acid monomers.
Types:
Hydrolyzable tannins: Based on gallic acid or ellagic acid.
Condensed tannins: Polymers of flavan-3-ols.
Sources: Found in tea, wine, and some fruits.

Key Chemical Properties

Hydroxylation: The number and position of hydroxyl groups influence antioxidant activity.
Conjugation: Polyphenols often exist as glycosides, bound to sugar molecules, which affects their solubility and bioavailability.
Polymerization: Larger polyphenols (like tannins) have enhanced ability to bind proteins and other macromolecules.

Functional Role of Chemical Composition

Antioxidant Activity: The phenolic hydroxyl groups donate hydrogen atoms to neutralize free radicals.
Chelation: Polyphenols can bind metal ions, reducing metal-catalyzed oxidation.
Interaction with Biomolecules: The ability to interact with proteins and lipids influences their roles in health and metabolism.

In summary, the chemical composition of polyphenols—marked by their phenolic structure, hydroxylation patterns, and functional group diversity—determines their biological roles and health benefits. Their wide variety and complexity make them crucial for both plant defense and human nutrition.

Understanding Polyphenols:

Polyphenols are Nature’s Protective Compounds

Πολυφαινόλες are a diverse group of naturally occurring compounds found in plants, celebrated for their powerful antioxidant properties and numerous οφέλη για την υγεία. They are secondary metabolites produced by plants to defend against ultraviolet radiation, pathogens, και herbivores.

For humans, consuming foods rich in polyphenols has been linked to improved health and disease prevention.

Types of Polyphenols

Polyphenols are categorized into four main groups based on their chemical structure:

Flavonoids: The largest category, including compounds like quercetin, catechins, and anthocyanins. Flavonoids are abundant in fruits, vegetables, tea, and red wine.
Phenolic Acids: Found in coffee, berries, and certain grains, these compounds, such as caffeic acid and ferulic acid, exhibit strong antioxidant properties.
Stilbenes: A smaller group, with resveratrol being a well-known member. It is commonly found in red wine and grapes.
Λιγνάνες: Present in seeds, particularly flaxseeds, and whole grains, lignans are known for their estrogen-like effects.

Food Sources of Polyphenols

Polyphenols are abundant in a variety of plant-based foods. Key sources include:

Fruits: Apples, berries, grapes, cherries, and citrus fruits.
Vegetables: Spinach, onions, and broccoli.
Beverages: Tea, coffee, and red wine.
Legumes and Nuts: Soybeans, lentils, almonds, and walnuts.
Herbs and Spices: Turmeric, cloves, and rosemary.
Ελαιόλαδο: Εξτρα παρθένο ελαιόλαδο is a particularly rich source of polyphenols, contributing to its health benefits.

Health Benefits of Polyphenols

ο antioxidant activity of polyphenols helps neutralize harmful free radicals in the body, reducing oxidative stress—a factor linked to chronic diseases like cancer, cardiovascular disease, and neurodegenerative disorders. Here are some key benefits:

Heart Health: Polyphenols improve endothelial function, lower blood pressure, and reduce LDL cholesterol oxidation.
Brain Health: Compounds like flavonoids may enhance cognitive function and reduce the risk of Alzheimer’s disease.
Anti-Inflammatory Effects: Polyphenols modulate inflammatory pathways, alleviating symptoms of conditions such as arthritis.
Πρόληψη Καρκίνου: Their role in protecting DNA from damage and inhibiting tumor growth is under extensive study.

Bioavailability and Absorption

Not all polyphenols are equally bioavailable. Factors like food preparation, gut microbiota, and individual metabolism influence their absorption. Fermented foods and beverages often improve polyphenol bioavailability.

Challenges and Research

While the health benefits of polyphenols are well-documented, challenges remain in fully understanding their mechanisms. Research continues to explore optimal intake levels, interactions with other nutrients, and long-term effects on health.

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Polyphenols are vital for maintaining health and preventing disease. A diet rich in polyphenol-containing foods supports overall well-being, making polyphenols essential for a balanced, health-promoting lifestyle. Incorporating a variety of fruits, vegetables, nuts, and high-quality olive oil can ensure you reap the benefits of these powerful plant compounds.

Polyphenols in Olive Oil (EVVO – Extra virgin Olive Oil) :

Antioxidant Chemical Compounds in Extra Virgin Olive Oil and Table Olives

Chemical structures of polyphenols identified in olive oil extracts

Polyphenol Rich Olive Oil – The Health Benefits by type of Polyphenolic Compounds

"The purpose of food is to get olive oil into your mouth”. That’s one of Dr. Gundry’s favorite sayings. Why is he so obsessed with olive oil? Find out in this video why Olive Oil and the Polyphenols it contains, is one of the best things for your health.

Antioxidants in Greek Virgin Olive Oils

Table 2. Individual phenolic compounds reported in Greek virgin olive oils.

( source: https://www.mdpi.com/2076-3921/3/2/387 )

Table 2. Individual phenolic compounds reported in Greek virgin olive oils

Analytical Technique	Cultivar	N	Compounds
HPLC	NS	24	Hydroxytyrosol, tyrosol
HPLC various detectors	NS	Not provided	Hydroxytyrosol, tyrosol, vanillic acid, p-hydroxybenzoic acid, syringic acid, o-coumaric, p-coumaric acid, gallic acid, homovanillic acid, ferulic acid
HPLC	NS Cloudy and filtered oils	6	Hydroxytyrosol, tyrosol
HPLC	Κορωνέικη	8	Hydroxytyrosol, tyrosol, oleuropein aglycon, dialdehydic form of elenolic acid linked to OH-tyrosol, dialdehydic form of elenolic acid linked to tyrosol, tyrosol derivative, caffeic acid, vanillic acid
LC-SPE-NMR	Κορωνέικη Kolovi	2 2	Hydroxytyrosol, tyrosol, hydroxytyrosol acetate, tyrosol acetate, a large number of secoiridoid derivatives including elenolic acid, vanillic acid, vanillin, p-coumaric acid, pinoresinol, 1-acetoxypinoresinol, apigenin, luteolin
³¹P-NMR	Κορωνέικη Mastoeidis	2 2	Total and free hydroxytyrosol and tyrosol *, vanillin, vanillic acid, homovanillic acid, (+)-pinoresinol, (+)-1-acetoxypinoresinol, syringaresinol, luteolin, apigenin
¹H-NMR, ³¹P-NMR and HPLC	Koroneiki, Kolovi, Mastoeidis *	111	Total and free hydroxytyrosol and tyrosol, (+)-pinoresinol, (+) 1-acetoxypinoresinol, luteolin, apigenin
¹H-NMR, ³¹P-NMR	Κορωνέικη	131	Total and free hydroxytyrosol and tyrosol, p-coumaric acid, homovanillic alcohol, (+)-pinoresinol, (+)-1-acetoxypinoresinol, syringaresinol, luteolin, apigenin
¹H-NMR, ³¹P-NMR	Κορωνέικη	4	Total hydroxytyrosol and tyrosol, oleuropein aldehydic form, ligstroside aglycon, oleuropein and ligstroside aldehydic form, decarboxymethyl oleuropein and ligstroside dialdehydic form, p-coumaric acid, vanillin, vanillic acid, homovanillic alcohol, (+)-pinoresinol, (+)-1-acetoxypinoresinol, syringaresinol, apigenin
¹H-NMR, ³¹P-NMR	Adramitini, Koroneiki, Throumbolia, Mastoeidis	221	Total and free hydroxytyrosol and tyrosol, p-coumaric acid, homovanillic alcohol, (+)-pinoresinol, (+)-1-acetoxypinoresinol, syringaresinol, luteolin, apigenin
HPLC	Koroneiki irrigated vs. not irrigated	6	Total hydroxytyrosol and tyrosol, p-coumaric acid, homovanillic alcohol, (+)-pinoresinol, (+)-1-acetoxypinoresinol, syringaresinol, luteolin, apigenin
HPLC	Koroneiki 2- vs. 3-phase decanters	9	Total hydroxytyrosol and tyrosol, oleuropein aglycon, dialdehydic form of elenolic acid linked to OH-tyrosol, dialdehydic form of elenolic acid linked to tyrosol, tyrosol derivative
HPLC/MSD	Mastoeidis	3	Tyrosol, vanillic acid, luteolin, apigenin
¹H-NMR	13 cultivars n **	158	Oleocanthal, oleacein
LC-MS	Κορωνέικη Λιανολιά	20 20	Hydroxytyrosol, tyrosol, oleacein aglycon, aldehydic form of oleuropein aglycon, oleocanthal aglycon, aldehydic form of ligstroside aglycon, p-coumaric acid, ferulic acid, vanillic acid, 1-acetoxypinoresinol, apigenin, luteolin
HPLC-GCMS	Λιανολιά	Not provided	Hydroxytyrosol, tyrosol, and derivatives
HPLC	Κορωνέικη	20	Total hydroxytyrosol and tyrosol
HPLC-Orbitrap-HRMS/MS	Κορωνέικη	Not provided	Identified 25 compounds, Quantitated: total hydroxytyrosol, total tyrosol, oleuropein aldehydic form, oleuropein aglycon, oleuropein and ligstroside aldehydic form, oleocanthal, oleacein
HPLC	Throumbolia, Koroneiki 3 ripening stages	6	Total hydroxytyrosol and tyrosol, oleuropein aglycon, dialdehydic form of elenolic acid linked to hydroxytyrosol, dialdehydic form of elenolic acid linked to tyrosol
GC-MS, TMS derivatives	Κορωνέικη	1	Free hydroxytyrosol and tyrosol, p-coumaric acid, vanillin, vanillic acid, p-hydroxybenzoic acid, ferulic acid, p-hydroxyphenylacetic acid, homovannilic alcohol, kaempferol
GC-MS, TMS derivatives	Κορωνέικη	1	Free hydroxytyrosol and tyrosol, caffeic acid, p-coumaric acid, vanillin, vanillic acid, p-hydroxybenzoic acid, ferulic acid, p-hydroxyphenylacetic acid, syringic acid, cinnamic acid, homovannilic alcohol, protocatechuic acid, kaempferol
GC-MS, TMS derivatives	Koroneiki 2 crop years organic vs. conventional	32	Free hydroxytyrosol and tyrosol, caffeic acid, p-coumaric acid, vanillic acid, ferulic acid, p-hydroxybenzoic acid, syringic acid, cinnamic acid, homovannilic alcohol, protocatechuic acid
GC-MS, TMS derivatives	Koroneiki 3 ripening stages	3	Free hydroxytyrosol and tyrosol, caffeic acid, p-coumaric acid, vanillic acid, p-hydroxybenzoic acid, ferulic acid, cinnamic acid, homovannilic alcohol, kaempferol, naringenin, genistein

NS: not specified; total hydroxytyrosol and total tyrosol: the sum of free and esterified forms of both phenyl alcohols; *: Mastoeidis cultivar is also referred as “Athinolia” or “Tsounati”; **: Adramytini, Agouromanaki, Athinolia, Chalkidiki, Conservolia, Kolovi, Koroneiki, Koutsourolia, Lianolia, Manaki, Megaritiki, Throuba, Sylvestris; TMS: trimethylsilyl.