This document presents a detailed review of the pharmacological activity of flavonoids. It begins with an introduction to flavonoids and their classification. It then discusses various pharmacological activities of flavonoids including their anticancer, anti-depressant, anti-inflammatory, anti-bacterial, anti-diabetic, anti-hypertensive, and anti-ulcer activities. The mechanisms of these activities are also described. Later, the document discusses the functions and applications of flavonoids in areas like neurodegenerative diseases and chemoprevention. It concludes that flavonoids exhibit beneficial biological effects like antioxidant and anti-inflammatory properties.

1. Presented by
Ms. Rajanigandha. R. Jori
M Pharm
( Pharmacology )
DETAIL REVIEW OF PHARMACOLOGICAL
ACTIVITY OF FLAVONOIDS

2. CONTENTS
 INRODUCTION
 CLASSIFICATION
 PHARMACOLOGICAL ACTIVITY OF
FLAVONOIDS
 FUNCTION AN APPLICATION OF FLAVONOIDS
 CONCLUSION
 REFERENCES

3. INTRODUCTION
 Flavonoids are phenolic substances widely distributed in all vascular plants.
 Secondary plant metabolism and accumulate in specific group of plant organs
such as leaves, fruits, roots, and stems
 Low molecular weight compound ,bioactive polyphenols which play an
essential role in photosynthesizing cell.
 “functional ingredients” and “health promoting biomolecules” in recent
literature due to their potential role in promoting health and preventing chronic
degenerative diseases.
 Played significant roles in successful medical treatments in ancient as well as
modern times.

4. CLASSIFICATION
Flavonoids are classified as follows :
 Flavones
 Flavonols
 Isoflavones
 Chalcones
 Anthocyanins
 Flavones : widely present in leaves, flowers and fruits as glucosides such as
Luteolin, apigenin and tangeritin ,double bond between positions 2 and 3 and a
ketone in position 4 of the C ring.
Ex. Celery, parsley, red peppers, chamomile, mint and ginkgo biloba
 Flavonols : Flavonols are flavonoids with a ketone group. Flavonols occur
abundantly in a variety of fruits and vegetables such as kaempferol, quercetin,
myricetin and fisetin.
Ex. Onions, kale, lettuce, tomatoes, apples, grapes and berries

5.  Isoflavones : Large and very distinctive sub-group of flavonoids ,distributed in
limited distribution in the plant kingdom.
Ex. soyabeans and other leguminous plants
 Chalcones : Subclass of flavonoids , there is absence of ‘ring C’. Hence, they can
also be referred to as open-chain flavonoids. Examples of chalcones are
phloridzin, arbutin, phloretin and chalconaringenin
Ex. tomatoes, pears, strawberries, bearberries and wheat products
 Anthocyanins : Pigments responsible for colours in plants, flowers and fruits.
Cyanidin, delphinidin, malvidin, pelargonidin and peonidin are the most
commonly studied anthocyanins.
Ex. cranberries, black currants, red grapes, merlot grapes, raspberries,
strawberries, blueberries, bilberries and blackberries.

6. PHARMACOLOGICALACTIVITY OF
FLAVONOIDS
• Flavonoids of tea obstruct epidermal growth factor and platelet derived growth
factor mediated signal relay pathways.
• Malignant cells affect various events such as angiogenesis. Tyrosine kinase is
mediator of signal transduction process which causes cell proliferation,
migration, differentiation and apoptosis.
• This tyrosine kinase is inhibited by flavonoids quercetin and genistein
Anticancer Activity :

8. Anti-Depressant activity :
 Depression is one of the most prevalent psychiatric disorders, and is characterized by a
decrease in an individual’s ability to experience pleasure.
 Quercetin shows a protective effect against reserpine induced dysfunctions.
 Flavonoids, quercetin and rutin , act against dysfunctions induced by reserpine by
scavenging upon reserpine generated oxygen derived free radicals.
 Other flavonoids including fisetin, quercetin, naringenin, nobiletin (a dietary flavonoid),
luteolin and kaempferitrin also have reported antidepressant activity .

9. Different mechanisms of flavonoids :

10. Anti-Inflammatory :
Inflammation is a complex biological response of body tissues to harmful stimuli, such
as pathogen infection, damaged cells, tissue injury, and chemical irritation.
• This process is followed by recruitment of inflammatory cells, the release of ROS, RNS,
and proinflammatory cytokines to eliminate foreign pathogens and repair injured
tissues.
• Hesperidin, Luteolin and Quercetin are known to possess such type of anti-
inflammatory property. They mainly affect the enzyme systems involved in the
generation of inflammatory processes and inhibit phospho-di-esterases involved in cell
activation.
• Apigenin, quercetin and luteolin inhibit COX-2 at very high concentrations and inhibit
production.
• Some flavonoids like myricetin, kaemferol, quercetin and morin act by inhibiting lipo-
oxygenase.

11. Anti-Bacterial :
 An Antibacterial agent is the one which interrupts the propagation and growth of
bacteria.
 Apigenin-7-O- triglycoside, apigenin, luteolin-7-O-neohesperidoside, lucenin-2,
saponarine and vitexin are some of the flavonoids have been proved to possess
inhibitory effect against various bacteria.
 Shown to have antibacterial effect against several bacteria including Enterobacter
cloaceae and Pseudomonas aeruginosa.
 Golnar extract (Punica granatum L.var.) has played a successful role in preventing
food poisoning as it shows antibacterial action against both gram positive and gram
negative food poisoning causing bacterias.
MOA :
The mode of antimicrobial action may be related to their ability to inactivate microbial
adhesins, enzymes, cell envelope transport proteins, and so forth.

12. Anti-Diabetic activity :
 Diabetes mellitus is a metabolic disorder indicated by condition such as
hyperglycaemia .

13.  It scale down diabetes mellitus either by avoiding glucose absorption or
by improving glucose tolerance.
 Reduced diabetes mellitus via several mechanisms like reduction in
glucose absorption and by inhibiting the activity of α-glucosidase in the
small intestine.
 Diosmin stimulates the production of insulin from β-cells of pancreas.
 Rutin, ellagic acid, boswellic acid and quercetin shows higher activity.
They act by increasing the peripheral utilization of glucose and by
obstructing the glucose transporter function in intestine.

14. Anti-Hypertensive activity :
 The fall in blood pressure has been accomplished by various flavonoids via their
effects on functions of epithelium.
 Different classes of flavonoids such as flavanones (naringin and hesperidin), flavanols
(epicatechin) and flavones (luteolin, chrysin), all have exhibited vasodilatory effect.
NITRIC OXIDE SYNTHASE ACTIVITY :
 Nitric oxide is produced by various cell of the body including macrophages and
endothelial cells. Dilation of blood vessels in the body is maintained by nitric oxide
which is released by the action of nitric oxide synthase
 Like Naringin, hesperidin, quercetin and epicatechin have augmented nitric oxide
synthase activity and bioavailability in the endothelium which enhanced endothelial
function.

15. Anti-Ulcer activity :
 Peptic ulcer occurs in that part of the gastrointestinal tract which is exposed to
gastric acid and pepsin.
 The probable anti-ulcer effect of hesperidin has been due to its antioxidant and
mucoprotective effect.
 Free radicals play major role in formation of stomach ulcers. Hesperidin allows
the regeneration of ulcerated tissue and prevented hemorrhagic injury of gastric
mucosa.
 Quercetin has been found to have antiulcer activity in animals.
 It acts by inhibiting the enzyme histidine decarboxylase and thus reduce the
formation of histamine in the gastric mucosa, which stimulates the parietal cells
and pepsinogen responsible for the secretion of hydrochloric acid and pepsin
respectively.

16. Functions and applications of flavonoids :
 Carry out a number of protective functions in the human body
 Interfere with nucleic acid or proteins, show antimicrobial or insecticidal and
pharmacological properties.
 Broad spectrum of health promoting effects.
 Citrus flavanones such as hesperidin, hesperetin and naringenin cross blood–brain
barrier and show an effective role in the intervention for neurodegenerative
diseases.
 Anti-inflammatory activity using flavonoids from the leaves of the plant
Spilanthes paniculata has.
 Flavonoids such as tannins, stilbenes, curcuminoids, coumarins, lignans,
quinones and other flavonoids have chemopreventive properties and also
contribute to induce apoptosis by arresting the cell cycle

17. CONCLUSION :
 We conclude that flavonoids are naturally occurring compounds present in plants
and shows different pharmacological activities such as anti-parkinson, anti-
ulcer, anti-depressant, anti-bacterial, anti-hypertensive, anti-diabetic, anti-
inflammatory and anti-cancer, anti viral.
 Prevention and cure of diseases by using phytochemicals compounds especially
flavonoids are well known. Flavonoids are such phytochemicals exhibit many
biological properties which are beneficial for human health. They interact with a
great number of cellular targets such as anti-oxidant, free-radical scavenger
activities .

18. REFERENCES :
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 4. Cushnie TPT and Lamb AJ: Antimicrobial activity of flavonoids.
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biology. Advances in Enzymology and Related Areas of Molecular Biology
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