Flavonoids are plant secondary metabolites that contain a 15-carbon skeleton structure. They are classified into two main classes: anthocyanins and anthoxanthins. Hesperidin is a flavonoid glycoside found abundantly in citrus fruits. It consists of the aglycone hesperitin bound to the disaccharide rutinose. Hesperidin is isolated from citrus peels and can account for up to 14% of the fresh weight of immature oranges. It has various physiological functions and properties including acting as an antioxidant and strengthening capillary blood vessels.

1. FLAVONOIDS
INTRODUCTON

2. 1
FLAVONOIDS
INTRODUCTON
The flavonoids compounds are regarded as c6-
c3-c6 compounds (15 carbon skeleton) . In which each
c6 moity is a benzene ring.the variation in the state of
oxidation of the connecting c3 moity determines the
properties and Class of such compound.
Flavonoids compounds usually occurs in the glycosides
. In which one or more of the phenolic-OH groups are
combined with sugar residue.
The –OH group are generally found In poritions 5and7
in ring A while ring B commonly carries hydroxyl or
Alcohoxyl compound.
These occurs in almost all part of the plant neumorous
physiological activites have been atrbuted to then few
of then act as cardiac stimulant.
While hespiridine appears to strength in weak capillary
blood vessel.
Highly hydroxylated flavnones act as diuretics and as
antioxidant to lipids.
STRUCTURE OF FLAVONOIDS
Flavonoids consist of aromatic ring A
condensed to heterocyclic ring C attached to second
TYPES OF
FLAVONOD
1.flavone
2.flavonol
3.flavonone
4.chalcones
5.xanthone
6.isoflavone

3. 2
aromatic ring B.The structure is known as flavonoid diphenyl propane skeleton.
Flavonoid diphenyl propane
CLASSIFICATION :
Flavonoids are divided into two classes:
1.ANTHO CYANINS
2.ANTHO XANTHINS
ANTHO CYANINS
These are glycosides of antho cyanins & are the most important classes of
water plant pigment responsible for varies beautiful colours such as purple , blue,
red to fruits , flowers & leaves.
ANTHO XANTHINS
Antho xanthins are yellow or colourless compound &include flavonols ,
flavanols , isoflavones , flavanones
O
A C
B

4. 3
FLAVONOLS:
O
O
OH
Myrcitin , quercefin , kaempferol
Apple , olive , orange , black tea are contains flavonols.
FLAVANOLS:
O
OH
Catechin , Epicatechin
Green tea contains flavanols

5. 4
FLAVOXINES:
O
O
Apigenin , luteolin , fisetin
Most present in olives.
ISOFLAVAXONES:
O
O
Genistien , daidzerin
Mostly presentin soyabean.

6. 5
FLAVANONE:
O
O
Hespridine , NaringIn ,Herpitin
Lemon, orange , grape fruits contains flavanone.
CHEMISTRY OF HESPERIDIN:
Hesperidin is an abundant and in expansive bi-product of citrus
ultimation and is major flavonoids in sweet orange and lemon.
In young immature orange is it can account for upto 14%fresh weight
of the fruit .it is usually found in associated with vitamin C.
OCCURANCE:
Hesperidin is isolated in the large amount from the discarded rings
of the ordinary orange citrul aurantium L , citrus sinessin L , citrus unshliu L and
other spcies of geness is citrus family retaceae .

7. 6
ISOLATION:
Reflex dried powdered orange peal with light petroleum ether for
1hours.filter the extract dry the more at room temperature .
Re-extract the powdered with methanol in a showlet apparatus with
3hours.con.c the extract under reduce pressure to get viscous mass hesperidin.
CHEMISTRY:
Hesperidin is a flavanone glycosides compressing of an Aglycone
hesperidin or methyl eriodictoyl and an attached disaccharide rutinose hesperidin
is therefore , β-7 rutinoside of hesperidin.
O
O
OH
H
OCH3
OH
O
GLU
RHA
Hesperidin [hesperitin – Rhamnoglucosides]
O
O
OH
OCH3
OH
3’,5,7,tri hydroxyl4’ methoxy flavanone

8. 7
O
OH
HO OH
O
O
HO
OH
CH3
OH
CH2
HO
Rutinose(o –α –L ,rhumnosyl(1 - 6) glucose )
The disaccharide units is composed of 1mole of ramnose and 1mole of
glucose.rutinose chemically O –α –L –rhumnosyl (1 – 6) glucose.the position of
the sugar in hesperidin . the was determine by partial hydrolysis with dilute acid ,
leading to the formation of L –rhamose and hesperitin 7-β-D glucosides. Which
could cleaved by enzyme β , D glucosides.
Hence in hesperidin glucose is attached to heaperdine. Chemically is
3’,5,7 tri hydroxyl 4’methoxy flavonone. Herperidin is thus 3’,5,7 tri hydroxyl 4’
methoxy flavonone [6,α,L rhamno pyranoriyl β , D gluco
pyranoriylide].hesperidin upon alkaline hydrolysis yield phuro gluclinol 4
hesperitic acid .
Upon acid hydrolysis hesperidin produced 1mole each of the Aglycone
hesperitin,D glucose,r.hamnose. hydrolysis with either dilute sulphuric acid in
glycol yield optically active mixture of plus or minus and hesperitin with can be
separated by fractional recrystallization.
Under carefully controlled contitions of hydrolysis the hesperidin yield the
optically active
L(-)hesperidine and this on ozonisation gives L-maloic acid indicating that (-)
hesperitine of the 2s configuration.