Polyphenols are one of the most important and certainly the most abundant among the phytochemicals present in the plant kingdom. Polyphenols are a large and complex group of chemical substances or phytochemicals or plant-derived foods, which contain more than one phenolic hydroxyl group. Natural compounds found mainly in fruits, vegetables, grains and beverages. Chemical composition of polyphenols. Polyphenols are compounds that contain a -OH group placed in a benzene ring. Naturally, they are a compound with structural phenolic properties, which can be associated with various organic acids and carbohydrates.

The main categories of polyphenols –

1. Phenolic acids and products

2. Flavonoids

3. Stilbenes

4. Lignans

1. Phenolic Acids and Derivatives

 Phenolic Acids are a non-flavonoid polyphenolic chemical. It is further divided into two main types – benzoic acid and cinnamic acid derivatives based on C1-C6 and C3-C6.It is found in a variety of plant foods; the seeds and skins of fruit and vegetable leaves contain very high concentrations.

Types and resources:

Hydroxybenzoic acid:

 Eg. Ellagic and gallic acid – with water-based tannins – are present in berries and nuts, tea

Hydroxycinnamic acid:

 Eg. Caffeic and ferulic acid.

• Caffeic acid – a precursor to lignin

• Caffeic and Quinic acid provide chlorogenic acid.

• Fruits, vegetables, coffee beans, grains and sunflower seeds appear.

• Other sources are coffee, blueberry, kiwis, plums, cherries, apples, red wine, and cereals: corn, whole grains, oats, and rice.

 Benefits of Phenolic acid

It is easily absorbed into the walls of your intestinal tract, and can be beneficial to health as they act as antioxidants that prevent cell damage due to excessive oxidation reactions.They can also promote anti-inflammatory properties in the body when used.

2. Flavonoids

They form the largest group of plant polyphenols.They are found in different colors of plants yellow, orange and red.They have a standard structure C6-C3-C6 where two C6 units are phenolic.Due to the hydroxylation pattern and variability in the chromane ring , flavonoids can continue to be subdivided into subgroups such as –


 Flavan-3-ols

 Flavanones

 Flavonols

 Flavones, Flavonols, Flavanones, Flavanonols

These small groups are very common and are found throughout plants.Flavones and their flavonols derived from 3-hydroxy, including glycosides, methoxides and other acetylled products in all three rings, make this the largest group among all polyphenols.The most common flavonol aglycones – Quercetin and Kaempferol

3. Stilbenes

 They are not as rich in flavonoids, lignans and phenolic acids.There are two stilbenes




 It is a non-flavonoid polyphenolic compound found in the skin of dark grapes and products made from such grapes, such as wine and grape juice.It belongs to the stilbene class of aromatic phytochemicals and occurs as free (cis or trans transations) aglycone (slightly soluble but active form) or as glycoside (called piceid, highly soluble form).It is transferred across the intestinal tract and the circulatory system such as glucuronide (glycoside) but can also be injected into aglycone form once it has reached the organs or body fluids where it is processed by β-glucuronidases.This compound is a well-known inhibitor of cyclooxygenase-1 and cyclooxygenase-2 , which are commonly shown in colon cancer.It also inhibits monoamine oxidase while enhancing Ab protease degradation and acts as an effective antioxidant.

4. Lignans

It is a small group of non-flavonoid polyphenols. It is widely distributed in plant kingdoms – standing in more than 55 plant families – acting as antioxidants and antibodies against germs and viruses. Lignans are  found in more than 60 families of vascular plants .Biological activity includes Antiviral, anticancer, cancer prevention, anti-inflammatory, antimicrobial, antioxidant, immunosuppressive, hepatoprotective, osteoporosis Prevention.

 Health benefits of polyphenols

1. It can lower blood sugar levels

Polyphenols can help lower blood sugar levels leading to a lower risk of type 2 diabetes. This is because polyphenols can prevent the decomposition of starch into light sugars, reducing the chances of high blood sugar after a meal.Polyphenols can also help to stimulate insulin secretion. A rich polyphenol diet can lower the blood sugar levels, high glucose tolerance, and increases insulin sensitivity which are important in reduction of type 2 diabetes.

 2. It can improve the functioning of heart

Polyphenols can improve heart health.This is mainly due to the antioxidant properties of polyphenols that help reduce chronic inflammation which is a risk factor for heart disease.Polyphenol supplementation lowers blood pressure and LDL (bad) cholesterol and increases HDL (good) cholesterol.

3. It can prevent blood clots

Polyphenols can reduce the risk of bleeding. Blood clots form when platelets circulate in the blood and begin to clot. This process is known as platelet aggregation and helps prevent excessive bleeding.Excessive platelet aggregation can cause blood clots, which can have serious health consequences, including deep vein thrombosis, stroke, and pulmonary embolism.

 4. It can protect against cancer

 Foods rich in polyphenols reduce the risk of cancer. Polyphenols have powerful antioxidant and anti-inflammatory effects, both of which can help prevent cancer.

5. It can promote healthy digestion

 Polyphenols can benefit digestion which increases the intestines of beneficial bacteria while protecting harmful ones. Polyphenol-rich tea extracts can promote beneficial bifidobacterial growth.Green tea polyphenol can help fight harmful germs, including C. Difficile, E.coli, Salmonella and improvement in symptoms of peptic ulcer disease (PUD) and inflammatory bowel disease (IBD).

 6. It can improve brain function

Polyphenol-rich foods can increase concentration and memory. Grape juice – rich in polyphenols – helps increase memory in older adults with mild mental retardation. Cocoa flavanols can increase blood flow to the brain and link these polyphenols to improve working memory and attention. The extraction of rich Gypsum polyphenols Biloba plants seems to increase memory, learning, and concentration. It also linked improved mental functioning and short-term memory loss.

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