Cellulose ■ Cellulose is a linear polymer, made of  (1-4) linked D-glucose (-glucan). ■ Cellulose is the chief polysaccharide of plant cell walls. ■ It constitutes 50% in wood, 50% in paper and 90% cotton hairs. ■ Complete acid hydrolysis of cellulose with hydrochloric acid gives  -D-glucose

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

2. B. Cellulose
■Cellulose is a linear polymer, made of β (1-4)
linked D-glucose (β-glucan).
■Cellulose is the chief polysaccharide of plant
cell walls.
■It constitutes 50% in wood, 50% in paper and
90% cotton hairs.
■Complete acid hydrolysis of cellulose with
hydrochloric acid gives → β-D-glucose

3. β-(1 4) linked D-glucose
O
OH
O
OH
CH2OH
O
OH
OH
CH2OH
O
O OH
OH
OH
CH2OH
OH
1
4
4
1
n
Cellulose

4. CoMMerCIal PreParatIon of
Cellulose
■Crude cellulose is obtained from wood or from
cottonseed hairs
■Different methods were used for the purification of
cellulose from the contaminant and to produce the
Crude cellulose.
■Sodium bisulfite or sodium hydroxide is principally
used to produce raw chemical pulps
(Crude cellulose), which is further purified by chlorine
bleaching.

5. Fractionation of crude cellulose
17 % NaOH
Alkali insoluble
α-Cellulose
(True cellulose)
Alkali soluble
Mixture of β and γ-celluloses
dilute acid
Acid-insoluble Acid-soluble
β-Cellulose γ-Cellulose

6. Heteropolysaccharides
A) Gums
■Plant gums are polysaccharides exuded from certain
plants as pathological products, e.g. gum arabic
and gum tragacanth.
■They are a heterogeneous group of acidic
substances, which swell in water to form viscous
or sticky solutions.
■Acid hydrolysis of gums → a complex mixture of
uronic acids, generally (D-glucuronic or
galacturonic) acid, together with D-galactose, L-
arabinose D-mannose, xylose, L-rhamnose and L-
fucose.

7. Gum Arabic Gum Tragacanth
Source Acacia senegal
Family Leguminosae.
Astragalus gummifer
Family Leguminosae.
Structure It consists mainly of
Arabin,
which is a mixture of the
calcium, magnesium and
potassium salts of arabic
acid
Tragacanthin
water-soluble fraction)
Bassorin
(water-insoluble fraction)
Acid
hydrolysis
Arabic acid → L-rhamnose,
D-galactose, L-arabinose,
glucuronic acid and
aldobionic acid
(a disaccharide formed of
galactose and glucuronic
acid
D-galactose, L-
arabinose, D-xylose and
L-fucose) and uronic
acids (mainly
galacturonic acid).
Gum Arabic (gum acacia) and Gum Tragacanth

8. Gum Arabic Gum Tragacanth
Properties water-soluble It swells into gelatinous
mass when placed in water
Chmical
test
*I2 solution → no color
*benzidine → blue color
)due to the presence of
oxidase enzymes(
*lead acetate → no ppt.
*Basic lead acetate →
flocculent ppt.
*I2 solution → blue spots
*benzidine → no color
)due to the absence of
oxidase enzymes(
*lead acetate → heavy ppt.
*Basic lead acetate →
no ppt.
Uses *Stabilizer in emulsions
*Suspending agent.
*Demulcent in various
cough, diarrhea and
throat preparations.
*Suspending agent.
*binder in pills and tablets
manufacture.
*Emulsifying agent for oils
and resins.
*demulcent and emollient.

9. Mucilages
They are normal products of metabolism formed within the cell
Classification of Mucilages
Polymers of D-mannans and D-galactans (galactomannans)
e.g. mucilages in Foenugreek seeds and Salep tubers
Neutral mucilages
Acidic mucilages
Polyuronides, consist mainly of D-galacturonic acid with the monosaccharides
D-galactose, xylose, arabinose and rhamnose, e.g. mucilages of Mustard and Linseed.
Sea weed mucilage
Sulfated polysaccharide ester
e.g. Agar
Alkali-soluble polysaccharides
e.g. Algin (sodium alginate).

10. Agar
Source: Agar is the dried colloidal concentrate of the
decoction of various red algae
Structure
Agar is formed of two main components
OOH
O
OH
OH
CH2OH
O
CH2
O
OH
OH6
1
4
3
Agarobiose
O
CH2OSO3H
OH
OH
OH
Sulfonated L-galactose unit
OH
Agaropectin
Agarose

11. Agarose Agaropectin
Galactose polymer,
consists of alternate
residues of D-galactose
and 3,6-anhydro-L-
galactose (agarobiose),
linked by β1,4 linkages.
it is free from sulfate.
a sulfonated polysaccharide
in which galactose and
galacturonic acid units are
partly esterified with sulfuric
acid. It is. It gives positive
test for sulfate on using
barium chloride.
Responsible for the gel
strength of agar
Responsible for the viscosity
of agar solutions
Uses: Preparation of bacteriological culture media,
as emulsifier, thickener for ice cream,
treatment of ulcers and chronic constipation.

12. Algin
Source: It is the polysaccharide obtained by alkaline
extraction of various species of brown algae.
Structure: Algin (sodium alginate) is the
(Na salt of alginic acid)
Alginic acid composed of D-mannuronic acid units
linked through β-1,4 linkages, in addition to a small
number of L-guluronic acid (oxidation product of
gulose) units.

13. O
OH
O
OH
COOH
O O
OHOH
COOH
O OH
OH
COOH
OH
1
4
4
1
n
Repeating units of mannuronic acid
O
OH
OH
COOH
H
OH
OH
OH
L-guluronic acid

14. Uses of algin
■Stabilizer, thickener, emulsifier,
deflocculating, jelling and slimming agent.
■It is used in dentistry, food and cosmetic
industries.
■It has important pharmaceutical applications
in formulation of creams, ointments, pastes,
jellies and tablets.

15. Pectic substances
■ Pectic substances are colloidal polyuronides of
high molecular weight.
■ They are mostly isolated from fruits as lemon and
orange pulps and their structures are changed during
ripening.

16. Structure
Pectins consist of three components:
Galacturonans: (α-1,4 D-galacturonic acid residues
esterified with methanol. The polymer chains are
interrupted by rhamnose units.
Arabinans: (α-1, 5-linked L-arabinofuranose units(.
Galactans: (β-1, 4-linked D-galactopyranose units(.

17. Types of pectic substances
Protopectin Pectin Pectinic acid Pectic acid
Precursor of
pectin, found in
the unripe fruits.
Produced from
protopectin during
ripening of the
fruits.
-Contains 10-12 %
methyl ester
-Partially
deesterified
pectin.
-Contains ~ 7%
methyl ester
-Completly
deesterified
pectin, found in
over-ripe fruits.
-Free from methyl
esters.
-Insoluble in
water.
-Transformed to
pectin by
heating
with water or
acid.
-Soluble in water.
-Precipitated by
alcohol or
metal ions, e.g.
iron or lead but
not calcium.
-Acidic solution
forms a gel in
presence of
sucrose
-Soluble in
water.
-Forms gel with
calcium ions
-Does not form
gel with
sucrose
-Soluble in water.
-Precipitated by
calcium ions.

18. Protopectin
Pectin
Pectic acid
protopectinase
Soluble pectin
pectinase
Galacturonic acid
(Deesterification and hydrolysis(
Pectin Pectic or pectinic acid
pectase enzyme
(Partial or complete deesterification(
pectinase
Galacturonic acid
Effect of pectic enzymes

19. Uses
■Pectin is topically applied as a paste in cases
of burns and ulcers.
■In treatment of diarrhea and dysentery.
■It is used as a gel and emulsion stabilizer and
in manufacture of jellies and jams.

20. Mucopolysaccharides
They are mixed polysaccharides containing sugar derivatives
mainly amino-sugars and uronic acids.
These disaccharide residues are polymerized by 1-4 bond to
give a linear macromolecule. Examples: chitin, Heparin,
hyaluronic acid and chondrointin sulphate.

21. Heparin: It is a complex polysaccharide which has an important
rule in the regulation of blood coagulation. It is used clinically as
an anticoagulant.
Occurrence: it occurs as granules in the mast cells and in the
wall of blood vessels especially in liver and lung. It also occurs in
connective tissue.
Heparin has a low molecular weight about 5000 - 20,000.
Composition: The major repeating structural component of
heparin is a glucuronic acid connected to glucosamine, with a
variable degree of sulphonation.

22. Biologically Active Carbohydrates

Carbohydrate-containing molecules are found on all cell
surfaces. Because of their inherent structural diversity, many
oligosaccharides are information carriers and recognition
molecules through linkages with other components such as
lipids and proteins.

Carbohydrates provide signals for protein targeting and serve
as receptors for binding toxins, viruses and hormones.

why natural or phytochemicals have biological activities ?
( similar as agonist or not as antagonist = blocker)

23. Antidiabetic agents (Glucosidase inhibitors)
Miglitol is an azosugar derivative isolated from cultures of various
species of Streptomyces and strains of genus Bacillus.
Acarbose (Glucobay®
)
is a complex oligosaccharide isolated from Actinoplanes.
It does not inhibit lactase and therefore, not expected to produce
lactose intolerance.

24. Antitumour agents
Antitumour agents of carbohydrate origin are limited. Only some non-toxic
antitumour polysaccharides derived from bacteria, fungi, and algae have
demonstrated good antitumour activity.
1- Lentinan (1-3)-β-D-glucans, which have an β- D-glucopyranosyl group
linked (1-6) to every 3rd
or 4th
residue of the main chain. Lentinan is a β-1,3-D-
glucan extracted from the shiitake mushroom Lentinus edodes (Lentinula
edodes). It appears to act as an immunostimulant and has been tried in the
treatment of malignant neoplasms and in HIV infection.
2- Schizophyllan (Sonifilan®
) is an extracellular product of the fungus
Schizophyllum commune. It has a (1-3)- β-D-glucan structure. It is an
immunostimmulant related to lentinan. It is useful in combination with other
antineoplastic treatments in the management of carcinomas of the lungs,
stomach, uterus and breasts.

25. Antibiotics
This class of useful and potential therapeutics has gained attention with the
appearance of complex nucleoside antibiotics, which exhibit a variety of
biological activities.
Of these are natural the thiosugars, aminoglycosides and macrolide
antibiotics produced by various species of bacteria and fungi.
Sialic acid and sialic acid analogues
Sialic acid terminated glycans (sialyloligo-saccharides), that are present on
cell surface glycoproteins and glycolipids, are involved
in many biological processes.
They participate in numerous carbohydrate-protein interactions.
These sialylated oligosaccharides serve as ligands for microbial toxins,
bacterial and viral adhesions and for mammalian lectins responsible for
cell-cell adhesion.
O
OH
COOH
OH
OH
OH
HO
H3COCHN
Sialic acid

26. 
This has resulted in a substantial increase in the reported
synthesis sialic acid analogues. Several sialic acid analogues
were developed as anti-inflammatory and inhibitors of flu
virus infections.
Anticoagulant agents

Examples of polysulfated polysaccharides used as
anticoagulant are Heparin, hyaluronic acid, dermatan sulfate
and heparin sulfate.

The use of dextran and dextran sulfate in the prophylaxis of
surgical and medical thromboembolism has a long tradition,
their action is due to physical effects.

27. Lactulose [4-(β-D-galactopyranosyl)-β-D-fructofuranose is
used in treatment of hepatic coma and chronic constipation.
Sucralfate is an aluminum hydroxide complex of sucrose
sulfate that is used in the therapy of duodenal ulcers.
O
OR
OR
OR
CH2OR
CH2OR
O
CH2OR
OR
ORO
R= SO3
-
[Al2(OHO)5]+
Sucralfate