Definition  Carbohydrates are polyhydroxy aldehydes, or ketones or substances that hydrolyze to yield polyhydroxy aldehydes and ketones.  They usually contain hydrogen and oxygen in the same ratio as in water (2:1). Thus the name carbohydrates indicates that these compounds are hydrates of carbon.  Carbohydrates have the general formula Cx(H2O)Y while X = Y e.g hexoses C6(H2O)6

1. PhytochemistryPhytochemistry
By
Dr. Mostafa MahMouD hegazy ( Ph.D.)
CarBohyDrates
intro.

2. Definition
 Carbohydrates are polyhydroxy aldehydes, or
ketones or substances that hydrolyze to yield polyhydroxy
aldehydes and ketones.
 They usually contain hydrogen and oxygen in the same
ratio as in water (2:1). Thus the name carbohydrates
indicates that these compounds are hydrates of carbon.
 Carbohydrates have the general formula
Cx(H2O)Y while X = Y e.g hexoses C6(H2O)6

3. 1- Non carbohydrates follow the rule: e.g. formaldehyde
(HCHO) and acetic acid (C2H4O2).
2- Carbohydrates do not maintain the ratio of H:O the same
as in water (based on their chemical and physical
properties), such as:
-Desoxy sugars e.g. rhamnose (C6H12O5), cymarose (C7H14O4)
and digitoxose (C6H12O4),
-Sugar alcohols e.g. sorbitol (C6H14O6),
-Sugar acids e.g. gluconic acid (C6H12O7)
-Amino sugars e.g. glucosamine (C6H13NO5).
Simple carbohydrates are also known as “sugars or
saccharides” (latin: saccharum = sugar). Most of the sugar
names end by -ose.

4. Function and importance:
1- Soure of energy and carbon e.g. glucose.
2- Form structural tissues in plants and microorganisms
(cellulose, lignin).
3- They also participate in Biological processes e.g.biological
transport, cell-cell recognition, activation of growth factors
and modulation of the immune system.
4- Basic materials of industrial products such as paper, fibers
and food sources such as sugars and flour.
5- Medicinal use e.g. glucosamine, sorbitol, dehydrated
sorbitol, mannitol, heparin, dextran, Hyaluronic acid,
Castanospermine etc.

5. II. ACCORDING TO THE NO. OF SUGAR RESIDUES PRESENT IN THE
MOLECULE:

6. Classifications of Monosaccharides
According to number
of carbon atom
According to type of
carbonyl group they contain
Glyceraldehyde
Erythrose, Threose
Trioses
Tetroses
Pentoses Xylose, Arabinose, Apiose
Hexoses Glucose, Galactose, Mannose, Fructose
Aldoses Ketoses
Fructose
Glucose
Galactose
Mannose

7. Classifications of Oligosaccharides
Disaccharides Trisaccharides Tetrasaccharides
According to the number of molecules
of simple sugars they yield on hydrolysis
Reducing Non reducing
SucroseLactose, Maltose
Raffinose
Stachyose

8. Classifications of Polysaccharides
polymers of more than
one type of monosaccharide
Homopolysaccharides Heteropolysaccharides
polymers of a single
monosaccharide
Starch
Cellulose
Dextrins
Dextran
Gums Mucilages
Agar Algin
Pectic substances

9. Physical Properties
of Carbohydrates

10. Physical Characters
1- Condition: Monosaccharides and most disaccharides are
white, crystalline in shape and with sharp melting points.
2- Taste: Most of the simple and low molecular weight sugars
have a sweet taste.
3- Solubility:
Monosaccharides are soluble in cold water and hot
alcohol.
Gums are soluble in water and insoluble in alcohol.
Inulin, starch, pectin, mucilages and glycogen are difficulty
soluble in cold water, but more soluble in hot water and
insoluble in alcohol.
4- Optical activity:

11. POLARIMETRY
 Measurement of optical activity in
chiral or asymmetric molecules
using plane polarized light
 Measurement uses an instrument
called a polarimeter
 Rotation is either (+) dextrorotatory
or (-) levorotatory

13. Mutarotation
 Interconversion between the α- and β- anomers
 Pure α-glucose has a specific rotation of + 112o
 Pure β-glucose has a specific rotation of + 18.7o
 When either form of glucose is allowed to stand in aqueous
solution, the specific rotation of the solution slowly
changes to + 52.7o
.
 Mutarotation is the change in optical rotation as an
equilibrium mixture of anomers forms.

14. ]α]°C
= D
]α]°C
= D
]α]°C
D
]α]°C ]α]°C
D
At equilibrium = +52.5°
C OHH
C HHO
C OHH
C OHH
CH2OH
OH
OH
OH
H
H
OHH
OH
CH2OH
H
OH
OH
H
OH
H
OHH
OH
CH2OH
H
α-D-(+)-glucopyranose
C
O H
β-D-(+)-glucopyranose
[α]D = + 112o
[α]D = + 18.7o
open-chain form of
D-(+)-glucopyranose
Mutarotation

15. StereochemiStry

16. Stereochemistry
C
C*
O
C*
C*
C*
CH2OH
H OH
HO H
H OH
H OH
H
C
C*
O
C*
C*
C*
CH2OH
HO H
H OH
HO H
HO H
H
D-glucoseL-glucose
Enantiomers Epimers
D-mannose D-galactose
Diastereomers
C
C*
O
C*
C*
C*
CH2OH
H OH
HO H
HO H
H OH
H
C
C*
O
C*
C*
C*
CH2OH
HO H
HO H
H OH
H OH
H
C
C*
O
C*
C*
C*
CH2OH
H OH
HO H
H OH
H OH
H
D-glucose D-mannose
C
C*
O
C*
C*
C*
CH2OH
HO H
HO H
H OH
H OH
H
Two sugars that differ in configuration at only one chiral center
Enantiomers
Diastereomers
Epimers
Mirror images
Pairs of isomers that have opposite configurations at one
or more chiral centers but are NOT mirror images

17. Dand L Notation
 D, L tells which of the two chiral isomers we are referring
to.
 If the –OH group on the next to the bottom carbon atom
points to the right , the isomer is a D-isomer
 if it points left, the isomer is L.
 The D form is usually the isomer found in nature.
 D and L designations are like (R) and (S) designations in
that they are not necessarily related to the optical rotations of
the sugars to which they are applied. Thus, one may
encounter sugars that are D (+) or D (-) and others that are L
(-) or L(+).

18. The pyranose and furanose structure
 Hexoses do not exist most of the time as straight
aldehyde or ketone but a lot of evidences indicated
the presence of a chain equilibrium between the
straight chain and the cyclic structure.
 Reaction between the aldehyde or the keto group
and the hydroxyl group at C-5 or C-4 resulted in the
hemiacetal formation and hence the cyclic structure
either pyranose (C1- C5) or furanose (C1- C4).

19. Cyclic Structures
Monosaccharides with 5-6 carbon atoms form
cyclic structures
 The hydroxyl group on C-5 reacts with the
aldehyde group or ketone group
O O
pyran
furan

20. Linearand ring forms of glucose

21. e.g.
(α) D-glucopyranose (exist as hemiacetal).
(β) D-glucopyranose (exist as hemiacetal).
(β) D-fructofuranose (exist as hemiketal).
O
OH
OH
OH
CH2OH
OH
O
OH
OH
OH
OH
CH2OH
CH2OH
OH
H
HOH2C
OH
OH
O
β-D Glucopyranoseα-D Glucopyranose β-D Fructofuranose

22. Haworth Structure forD-Glucose
 Write –OH groups on the right (C-2, C-4) Down
 Write –OH group on the left (C-3) UP
 The new –OH on C-1 has two possibilites:
down for α- anomer, up for β- anomer.
o
CH2OH
OH
OH
OH
OH
o
CH2OH
OH
OH
OH
OH
α
β
α-D-Glucose β-D-Glucose

24. Reactions of
Monosaccharides

25. I- Reactions similar to alcohols
1- Ether Formation: As alcohols, simple sugars form ethers
(methyl derivatives).
2- Ester Formation: Acetylation of monosaccharides is used
in structure elucidation of carbohydrates.
C
OH
HO
OH
O
CH2OH
H OH
C
OAc
AcO
OAc
O
CH2OAc
H OAc
Glucose Glucose pentaacetate
Acetic anhydride
pyridine
II- Reactions similar to carbonyl compounds
1-Glycoside formation (acetal formation ):
O
ROH ROH
OR
OH
OR
OR
+ H2O
Carbonyl compound Hemiacetal Acetal

26. 2-Oxidation reactions
Aldoses may be oxidized to 3 types of acids
■Aldonic acids:
Aldehyde group is converted to a carboxyl group
glucose → gluconic acid
■Uronic acids:
Aldehyde is left intact and primary alcohol at the
other end is oxidized to COOH
glucose → glucuronic acid
galactose → galacturonic acid
■Controlled oxidation.
1-By first protecting the -CHO group, followed by
oxidation of the -CH2OH group, or
2-in one step by the aid of a specific enzyme.

27. Br 2,
H 2
O
COOH
OHH
HHO
OHH
OHH
CH2OH
D-Gluconic acid
HNO
3
Oxidation at C-1
Oxidation at C-6
Glucuronic acid
D-glucose
OHH
HHO
OHH
OHH
CH2OH
CHO
OHH
HHO
OHH
OHH
COOH
C
O H
Oxidation at C-1and C-6
COOH
OHH
HHO
OHH
OHH
COOH
Glucaric acid
(Saccharic acid)
Controlled oxidation

28. Br2, H2O
COOH
OHH
OHH
CH2OH
Trihydroxy
butyric acid
HNO3
two monocarboxylic acid
D-Fructose
O
HHO
OHH
OHH
CH2OH
CH2OH
COOH
OHH
OHH
COOH
CH2OH
COOH
Glycolic acid
COOH
COOH
Succinic acid Oxalic acid
two dicarboxylic acid
Ox idation of Ketoses

29. 2-Reduction reactions
■Either done catalytically (hydrogen and a
catalyst) or enzymatically
■The resultant product is a polyol or sugar
alcohol (alditol)
■Glucose → Sorbitol (glucitol)
■Mannose → Mannitol
■Fructose → Mannitol + Sorbitol
■Galactose → Dulcitol

30. D-Galactose
NaBH4
D-Fructose
O
HHO
OHH
OHH
CH2OH
CH2OH
D-glucose
OHH
HHO
OHH
OHH
CH2OH
CHO
OHH
HHO
OHH
OHH
CH2OH
CH2OH
Glucitol
(Sorbitol)
MannitolD-Mannose
HHO
HHO
OHH
OHH
CH2OH
CHO
NaBH4
HHO
HHO
OHH
OHH
CH2OH
CH2OH
2
2
4
OHH
HHO
HHO
OHH
CH2OH
CHO
Dulcitol
OHH
HHO
HHO
OHH
CH2OH
CHO
4
NaBH4 NaBH4
Mannitol
Sorbitol

31. Sugar alcohols are very useful intermediates
Mannitol used as an
osmotic diuretic
Mannitol hexanitrate
Used as Vasodilator

32. ■Sorbitol used as mild laxative
■Sorbitol can be dehydrated
to 1,4,3,6-dianhydro-D-
sorbitol (isosorbide(
which is used in treatment
of angina

33. III- Specific reactions
1- Reaction with phenylhydrazine (Osazone formation): The carbonyl group
of an aldose reacts with phenylhydrazine to give a crystalline phenylosazone.
This reaction leads to loss of the stereocenter at C-2.
Therefore, C-2 epimers such as glucose and mannose will give the same
osazone as the ketohexose at C-2 i.e. fructose.
Osazones are used in identification of mono- and disaccharides.
H
O
OHH
CH2OH
H
NNHph
OH
CH2OH
H
H
NNHph
CH2OH
O
H
NNHph
CH2OH
NNHph
C
C
(CHOH)3
+ NH2 NHph
C
C
(CHOH)3
+ NH2NHph
C
C
(CHOH)3
NH2NHph +
C
C
(CHOH)3
Glucose dehydrogenation
(oxidation)
Glucosazone
Condensation
Condensation

34. 2-Action of mineral acids: Treatment with hot concentrated
mineral acid (HCl or H2SO4) leads to dehydration of sugars.
the color develops by coupling with phenolic compounds or
amines.
Examples:
-In Molisch’s test the phenol used is α-naphthol.
-In Bial’s test the phenol is orcinol.
-In the Aniline acetate paper test: the amine used is aniline.
H H
OH
H
CHO
OHOH
O
CHO
H
OH
H
H
OH
H
CHO
OH
O
CHO
C C
C
HO
C
- 3 H2O
H2SO4
Pentose Furfural
C C
C C
- 3 H2O
H2SO4
Hexose Hydroxymethylfurfural
HOH2C
HOH2C
O H
H 2

35. 3- Reaction with oxidising cations: All
monosaccharides and reducing disaccharides (i.e all
sugars containing free hemiacetal or hemiketal
groups( are readily oxidized by metal ions such as
Cu+2
(Fehling’s and Benedict’s reagents(, Bi+3
and Hg+2
in alkaline medium.
These reactions are used for identification and
quantification of reducing sugars.
4-Action of alkalis: Monosaccharides, in presence of
alkalis may undergo polymerization, epimerization,
and rearrangement with or without cleavage.

36. Monosaccharides
Pentoses
Xylose
Arabinose
Apiose
Hexoses
Aldoses Ketoses
FructoseGlucose
Galactose
Mannose
e.g.
e.g. e.g.
Deoxy sugars
e.g.
Rhamnose
Digitoxose

37. Monosaccharides
A) Pentoses
O
OH OH
OH
OH
O
OH OH
OH
OH
CHO
OHH
HHO
HHO
CH2OH
CHO
OHH
HHO
OHH
CH2OH
CHO
OHH
OH
CH2OHHOH2C
D-apiose
(Branched
sugar)
α- D-xylopyranoseα- L-arabinopyranose

38. Name α-L Arabinose
(Pectin sugar)
α -D-Xylose
)wood sugar)
D-Apiose
(branched
sugar)
Source -Gums,
-Pectic
Substances,
Accompanying
hemicelluloses
-Corncobs
-Bran,
-Straw
-Any woody
material
Obtained by
hydrolysis of the
flavone
glycoside, apiin,
which is present
in the leaves and
seeds of parsley

39. Chemical tests of Pentoses
Aniline acetate paper:
Pentoses → red stain with a paper moistened with
aniline acetate solution
Bial’s test:
Pentoses → green color with Bial's reagent
(Orcinol/ HCl).
Phloroglucin /HCl:
Pentoses → red color, which changes to a brownish
violet precipitate.

40. B) Hexoses (Aldohexoses)
CHO
OHH
HHO
OHH
OHH
CH2OH
O
OH OH
OH
OH
CH2OH
O
OH
OH
OH
CH2OH
OH
β-D-glucose
α-D-glucose
D-glucose
CHO
HHO
HHO
OHH
OHH
CH2OH
O
OH OH
HOOH
CH2OH
O
OH
HOOH
CH2OH
OH
β-D-Mannose
α-D-Mannose
D-Mannose
CHO
OHH
HHO
HHO
OHH
CH2OH
O
HO
OH
OH
OH
CH2OH
OHO
OH
OH
CH2OH
OH
β-D-galactose
α-D-galactose
D-galactose

41. α-D-Glucose
(dextrose, grape sugar, blood sugar)
CHO
C OHH
C HHO
C OHH
C OHH
CH2OH
OH
OH
OH
H
H
OHH
OH
CH2OH
H
OH
OH
H
OH
H
OHH
OH
CH2OH
H
α-glucopyranoside β-glucopyranoside
D-glucose

42. Preparation
D-Glucose is commercially prepared from starch by:
Aqueous starch suspension (15-20%)
* Autoclaving at 150 o
C, 30-35 mints (complete hydrolysis)
* Dilute acid (0.03 N HCl)
* Neutralized with sodium carbonate to pH 4 to 5
* Filter
Filtrat
* Decolorized with charcoal
* Concentrated under reduced pressure
* Crystallized.
Glucose

43. Uses:
1.Nutrient, given by mouth or injection.
2.As ingredient in dextrose injections and in
dextrose/saline injections.
3.Dextrose is used commercially in the
manufacture of candy, carbonated beverages, ice
cream, bakery products and in the canning
industry.

44. Liquid glucose
■This is a colorless, sweet, and water-miscible
syrupy liquid.
■It is prepared by partial acid hydrolysis of starch
using dilute HCl and heating for 20 mints.
■It consists of a mixture of glucose, maltose, dextrin
and water.
■Used as sweetening agent, as substitute for sucrose
and as an excipient in massing pills.

45. Ketohexoses
Fructose, D-fructose, levulose, β-D(-) fructofuranose
(fruit sugar)
Source:
It is found free in honey and in fruits juices,
or as constituent of polysaccharide e.g. inulin.
CH2OH
OH
H
HOH2C
OH
OH
O
β-D FructofuranoseD-Fructose
O
HHO
OHH
OHH
CH2OH
CH2OH

46. Preparation
■Fromglucose
by the action of NaOH (epimerization)
■Fromsucrose
after the inversion of aqueous solutions of
sucrose and subsequent separation of
fructose from glucose.
■FromInulin
(a polymer characteristic of certain Astraceae
Jurusalem artichoke, and chicory) by acid
hydrolysis.

47. Uses
Fructose is used as food for diabetics
(in emergencies of diabetic acidosis)
and in infant feeding formulae
(more easily digested than glucose).