Transcript Heteroglycans - An-Najah National University

Heteroglycans
Heteroglycans
• Are natural plants hydrocolloids containing
more than one kind of monosaccharide
units.
I. Gums
•
•
•
•
•
•
•
Natural products that yield with hydrolysis
more than one type of monosaccharide units
or their salts or their acids.
Salts: Mg, Ca, K salts.
Acids: called uronic acids.
Uronic acids:
Glucose
glucuronic acid
Galactose
galacturonic acid
Arabinose
Arabic acid
• Definition of Gums:
Translucent, amorphous substances which formed
on the stems or branches ( higher plants parts )
after injury.
• Gums forms:
1. exudates gums: formed in barks of the stems
and branches– to prevent dehydration
– to heal the cavities
2. seeds gum: formed in seeds embryo- to reserve
food
3. marine gum: component of the cell wall or
intracellular region - to reserve food
Examples on Gums
A. Tragacanth
gum:
A. Tragacanth gum:
•
•
1.
2.
3.
4.
5.
6.
7.
8.
9.
The dried gummy exudations obtained by incision from
the stems and branches of the Tragacanth trees.
Physicochemical properties:
Translucent.
Amorphous.
Solid substance.
White or pale yellow colour.
Odourless.
Mucilaginous taste.
Partly soluble in water: 30% water soluble.
Insoluble in organic solvents.
Has resistance to the hydrolysis by acids
Constituents
1. Bassorin 70%: water insoluble portion.
Bassorin ---Hydrolysis--- galactose+
Arabinose
2. Tragacanthin 30%: water soluble portion.
Tragacanthin yields with hydrolysis
demethoxylated bassorin.
3. Starch.
4. Proteins
Purity tests:
1. Aqueous gum solution + lead acetate
precipitation ( due the presence of protein )
2. Aqueous gum solution + I2
deep blue
colour in some places ( presence of starch )
3. Aqueous gum solution + FeCl3
no deep
blue or deep green colour ( absence of tannins )
4. Aqueous gum solution + resorcinol + HCl
no red or pink colour ( absence of ketoses )
Identification tests:
1. 30% soluble in water.
2. Aqueous gum solution + NaOH
yellow or brown colour
3. Gives positive reaction with Molisch’s
and Fehling’s solution test.
Uses
1.
2.
3.
4.
Demulcent.
Emollient.
Laxative ( bulk laxative ).
Pharmaceutical uses:
1.
2.
3.
4.
Suspending agent.
Emulsifying agent.
Stabilizer.
Thickener.
5. Cosmetics: hand creams and body lotions
( emollient and emulsifying agent )
B. Arabic gum : Acacia gum:
Arabic gum
• The dried gummy exudations obtained by
incision from the stems and branches of
Arabic gum trees (Acacia trees)
Physicochemical properties
1.
2.
3.
4.
5.
6.
7.
Translucent.
Amorphous.
White or pale yellow colour.
Odourless.
Mucilaginous taste.
Soluble in water.
Insoluble in organic solvents.
Constituents
1. Arabin: a mixture of Ca, Mg, K salts for
1. Arabic acid.
2. Glucuronic acid.
3. Galacturonic acid.
4. Rhamnurnic acid.
Arabin (hydrolysis)
Arabinose +Rhamnose +
Glucose+ Galactose
2.
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Enzymes:
Oxidase enzyme.
Peroxidase enzyme.
Pectinase enzyme.
Purity tests
1. Aqueous gum solution + lead acetate
no precipitation.
2. Aqueous gum solution + I2
no deep blue colour .
3. Aqueous gum solution + FeCl3
no deep blue or deep green .
4. Aqueous gum solution + resorcinol + HC l
no red or pink colour
Identification tests:
1. Aqueous gum solution pH
slightly acidic with
time more acidic
2. Aqueous gum solution + Borax ( Na2B4O7 )
translucent mass
3. Aqueous gum solution + Benzedene + H2O2
blue colour
4. Aqueous gum solution + alcohol + acetic acid
white precipitate
5. Gives positive reactions with Molisch’s and Fehling’s
solution tests.
Uses:
1. Demulcent: ( more than the other gums ) : required in
the following preparations:
• Anti-tussives.
• Anti-diarrheal preparations ( suspending, demulcent ).
• Throat problems.
2. Emollient.
3. Laxative ( bulk laxative ).
4. Pharmaceutical uses:
1. Suspending agent.
2. Emulsifying agent.
3. Tablet binder.
Drug:
• Allergenic extract® : Trupharm : vials 5 ml, 10 ml:
• Contains:
1. Tragacanth gum.
2. Arabic gum.
3. Dust.
4. Mould.
5. Insect.
6. Pollen grains.
Indications:
1. Immunotherapy.
2. Allergy test.
C-Guar gum:
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1.
2.
3.
4.
5.
6.
7.
8.
Guar gum is the powdered endosperm (embryo) of
guar seeds.
Physicochemical properties:
Translucent.
Amorphous.
Pale yellow.
Solid substance.
Odourless.
Mucilaginous taste.
Freely soluble in water (both cold and hot water).
Insoluble in organic solvents.
Constituents:
1. Proteins.
2. Guaran ( galactomannan ):
α-D-galactose + β-D-mannose
Guaran is the principal polysaccharide in guar gum
Purity tests:
1. Aqueous gum solution + lead acetate
positive
2. Aqueous gum solution + I2
negative
3. Aqueous gum solution + FeCl3
negative
4. Aqueous gum solution + resorcinol + HCl
negative
Identification
1. Aqueous gum solution + Borax
translucent mass ( gel )
2. Gives positive reactions with Molisch’s
and Fehling’s solution tests.
Uses:
1. Pharmaceutical uses:
a)Thickener.
b)Tablet binder.
c)Stabilizer.
d)Emulsifying.
2. Cosmetics: lotions and creams.
3. Laxative.
4. Food industry:
a. Ice creams.
b. Cheese.
c. Soup.
D- Locust bean gum: Carob gum :
The powdered endosperm obtained from carob seeds.
•
Physicochemical properties:
1. Translucent.
2. Amorphous.
3. Pale yellow.
4. Solid substance.
5. Odourless.
6. Mucilaginous taste.
7. Freely soluble in water ( both cold and hot water ).
8. Insoluble in organic solvents.
Constituents
Guaran ( galactomannan ).
Purity tests:
• Aqueous gum solution + lead acetate
negative
• Aqueous gum solution + I2
negative
• Aqueous gum solution + FeCl3
negative
• Aqueous gum solution + resorcinol + HCl
negative
Identification tests:
• Aqueous gum solution + Borax
translucent mass ( gel )
• Gives positive reactions with Molisch’s and
Fehling’s solution tests
Uses:
1. pharmaceutical uses: for external
preparations as
a) Thickener.
b) Stabilizer.
2. Cosmetics.
3. Has laxative effect (but not used as
laxative)
E- Karaya gum: Indian gum:
Sterculia gum:
The dried gummy exudations obtained
by incision from the stems and branches
of Sterculia trees.
• Physicochemical properties:
• Colourless time
yellow(10 days), pink
( weeks), brown (months) colour.
• Characteristic odour and taste ( acetic acid ).
• Slightly soluble in water.
• Insoluble in the organic solvents.
Constituents:
•
1.
2.
3.
4.
Mixture of:
Galactose.
Galacturonic acid.
Rhamnose.
Acetic acid.
Purity tests:
1. Aqueous gum solution + lead acetate
negative
2. Aqueous gum solution + I2
negative
3. Aqueous gum solution + FeCl3
negative
4. Aqueous gum solution + resorcinol + HCl
negative
Identification test:
1. Gives positive reactions with Molisch’s
and Fehling’s solution tests.
2. Aqueous Gum solution + HCl heating
Acetic acid + CuSO4
deep blue
Uses
1. pharmaceutical uses: (external uses)
a) Suspending.
b) Emulsifying.
2.
3.
4.
5.
Dental adhesive.
Cosmetics.
Industrial use.
Laxative.
F- Xanthan Gum
• is a polysaccharide with a β-D-glucose
backbone like cellulose, but every second
glucose unit is attached to a tri-saccharide
consisting of mannose, glucuronic acid, and
mannose. The mannose closest to the backbone
has an acetic acid ester on carbon 6, and the
mannose at the end of the trisaccharide is linked
through carbons 6 and 4 to the second carbon of
pyruvic acid.
• Xanthan Gum is produced by the bacterium
Xanthomonas campestris, which is found on
cruciferous vegetables such as cabbage and
cauliflower. The negatively charged carboxyl
groups on the side chains cause the molecules
to form very viscous fluids when mixed with
water.
beta-D-mannose
Alpha-D-mannose
Beta-D- glucuronic aid
The repeating unit of Xanthan Gum
uses
• Xanthan gum is used as a thickener for
sauces, to prevent ice crystal formation in
ice cream, and as a low-calorie substitute
for fat. Xanthan gum is frequently mixed
with guar gum because the viscosity of the
combination is greater than when either
one is used alone.
G- Glucomannan
Glucomannan is a dietary fiber obtained from
tubers of Amorphophallus konjac (Devil's
Tongue) cultivated in Asia. Glucomannan is
used as a hunger suppressant because it
produces a feeling of fullness by creating
very viscous solutions that retard absorption
of the nutrients in food. One gram of this
soluble polysaccharide can absorb up to 200
ml of water, so it is also used for absorbent
articles such as disposable diapers and
sanitary napkins.
• The polysaccharide consists of glucose
(G) and mannose (M) in a proportion of
5:8 joined by β1→4 linkages. The basic
polymeric repeating unit has the pattern:
GGMMGMMMMMGGM. Short side chains
of 11-16 monosaccharides occur at
intervals of 50-60 units of the main chain
attached by β1→3 linkages. Also, acetate
groups on carbon 6 occur at every 9-19
units of the main chain. Hydrolysis of the
acetate groups favors the formation of
intermolecular hydrogen bonds that are
responsible for the gelling action.
portion (GGMM) of the glucomannan repeating unit.
The second glucose has an acetate group.
II. Mucilages
Definition:
•
Natural plants product, heteroglycan complex
polysaccharide.
• Mucilage give with hydrolysis :
a. monosaccharide units.
b. Ca, Mg, K, Na salts of monosaccharides.
c. Monosaccharide acids.
d. Ca, Mg, K, Na salts of monosaccharide acids.
They founded in some plants part as food reservoir
or and as water reservoir ( hydrophilic
substances).
•
1.
2.
3.
4.
Examples for plants parts containing
mucilage :
Leaves: Buchu.
Roots and rhizomes: Cinnamon and
Marshmallow.
Seeds: Lin (flax), Mustard, Fenugreek.
Weeds: Marine plants ( Laminaria, Red
Algae ).
Examples on mucilage
1. Agar
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1.
2.
3.
Agar is
Natural product.
Dry powder.
Hydrophilic substance .
Obtained from:
Red Algae.
Gracilaria.
Golidium.
Extraction of mucilage:
( Isolation of Agar ) :
1. Fresh weeds washed with running water
for 24 hours.
2. Extracted with diluted HCl
Filtration.
3. Washed with diluted NaOH, then with
water ( for about 30 hours ).
4. Extract ( Agar+ water ) congealed in ice.
5. Water separated as ice.
6. Extract dried with hot air.
Physicochemical properties:
1.
2.
3.
4.
Yellowish white powder.
Odourless or with slight odour.
Mucilaginous taste.
Slowly soluble in water
viscous
mass
5. insoluble in the organic solvents.
Agar contains
1. Proteins.
2. Mixture of :
a)
b)
c)
d)
L-galactose.
D-galactose.
Galacturonic acid.
Sulphate ions .
Agarobiose is the repeating disaccharide unit in agar
Agar is a polymer of agarobiose, a disaccharide composed of
D-galactose and 3,6-anhydro-L-galactose
Purity tests:
• Aqueous Agar solution + lead acetate
precipitate
• Aqueous Agar solution + I2
negative
• Aqueous Agar solution + FeCl3
negative
• Aqueous Agar solution + resorcinol + HCl
negative
Identification chemical tests:
1. Positive reaction with Molisch’s and Fehling’s
solution test.
2. Aqueous agar solution + HCl conc.
SO4
+Bacl2
BaSO4 ( white precipitate ).
3. Aqueous agar solution + HCl conc.
SO4
+ KCl
K2SO4 ( yellow precipitate ).
4. Aqueous agar solution + water
Δ
then
cooling
gel.
Agar main uses:
1. pharmaceutical uses:
a) Suspending.
b) Emulsifying.
c) Gelating agent for suppositories.
2. Laxative ( bulk laxative ).
3.Food industry.
4. Highly refined agar is used as a medium
for culturing bacteria, cellular tissues,
and for DNA fingerprinting.
Carrageenan
• Carrageenan is a generic term for several
polysaccharides extracted from seaweed.
Carrageenan compounds differ from agar
in that they have sulfate groups (-OSO3-)
in place of some hydroxyl groups.
Carrageenan is also used for thickening,
suspending, and gelling food products.
Psyllium seeds: Plantago seeds :
Plantain seeds:
1.
2.
3.
4.
Small seeds.
Have grey or brown colour.
Mucilaginous taste and slightly bitter.
Odourless.
Plantago seeds contain:
1. Psyllium hydrophilic mucilloid (seeds husk):
a mixture of:
–
–
–
–
–
Rhamnose.
Arabinose.
Xylose.
Galactose.
Galacturonic acid.
2. Glycoside: aucubin ( diuretic, slightly bitter
taste ).
3. Protein.
3. Fixed oils.
Aucubin
• The structure of the Plantago seeds
includes a remarkable glycoside of the
monoterpene class (iridoid) called
Aucubin. This glycoside has been studied
and numerous scientific papers have been
written about this particular member of the
monoterpene family.
The general characteristics of the iridoid
monoterpene aucubin are as follows:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Sedative
Anesthetic
Analeptic
Anaseptic (Anti-viral)
Anti-toxic
Anti-Histaminic
Anti-Inflammatory
Anti-Rheumatic
Anti-Tumor (Anti-Blastic, Anti-Cancer, AntiCarcinogenic)
Diuretic
Expectorant
Hypotensive
Organoleptic (Odor, Taste)
• The anti-toxic, anti-inflammatory and
expectorant characteristics suggest why
the plant is useful in lung disorders, and as
inferences as to the effect of the Plantago
on smokers.
Uses:
1. Laxative (f.o + mucilage) lubricant and
bulk laxative.
2. Diuretic.
3. Demulcent.
4. Anti-inflammatory activity specially for
GIT and mouth mucus membrane
inflammations.
Drugs
Trade
Name
Producer
Dosage
forms
Ingredients
Agiocure®
Teva
granules
Psyllium seeds
Agiolax®
Teva
granules
Psyllium seeds +
Senna fruits (pods)
Metamucil®
Searle
Powder
Psyllium hydrophilic
mucilloid + dextrose
Mucivital®
Arko
pharma
Sachets
Psyllium hydrophilic
mucilloid sugar free
Algins (Alginic acid and Sodium
Alginate
•
Hydrophilic heteroglycan complex
polysaccharide, obtained from brown
weeds (Brown Algae) ( in USA and
Australia ).
• Extraction by using organic solvents
Alginic acid
• Extraction by using diluted NaOH
Sodium Alginate
• Algins = alginic acid + sodium alginate
•
•
•
•
•
Alginic acid: a mixture of : beta-DGlucuronic acid.
Mannuronic acid
Sodium alginate: a mixture of: beta-DSodium salts of glucuronic acid ( Naglucuronate ).
• Sodium salts of mannuronic acid ( Namannuronate.
Alginic acid
Physicochemical properties:
1. White cream powder.
2. Odourless.
3. Mucilaginous taste except alginic acid ( slightly
acidic ).
4. soluble in water.
5. Insoluble in the organic solvents.
Note:
• Alginic acid + water
doesn’t form
viscous mass.
• Na-alginate + water
form viscous mass
Uses:
1. pharmaceutical uses:
a) Suspending.
b) Emulsifying.
c) Stabilizer.
2. Cosmetics: gel.
3. Industrial uses.
4. Food industry.
This drug- used for treatment of Gastro esophageal Reflux Disease (GERD)
Trade
Name
Producer Dosage Ingredients
form
Powder. •Al(OH)3
Chewing •Mannitol
•Alginic acid
tablet
•Sodium bicarbonate
Gaviscon Ferring
Liquid
•Al(OH)3
•CaCO3
•Sodium alginate
•Sodium bicarbonate
• Note:
• Alginic acid + sodium bicarbonate saliva , water
sodium alginate
water
viscous mass.
III. Pectin
• Heteroglycan complex polysaccharide, present
in the cell wall of plants tissues which function
as intercellular cementing agent, obtained from:
• Citrus fruits.
• Apple pomace.
• Protopectin 90°C + HCl (pH=3.4-4), organic solvent pectin
• Note:
• Protopectin: water insoluble.
• Pectin: water soluble.
• Organic solvent used to precipitate pectin.
• Pectin
• Pectin is a polysaccharide that acts as a
cementing material in the cell walls of all
plant tissues. The white portion of the rind
of lemons and oranges contains
approximately 30% pectin. Pectin is an
important ingredient of fruit preserves,
jellies, and jams.
Physicochemical properties:
1.
2.
3.
4.
5.
Yellowish white powder.
Odourless.
Mucilaginous taste.
Soluble in water ( 1:20 ).
Insoluble in the organic solvents
Constituents:
• A mixture of :
1. Galactose. (alpha-D-galacturonic acidmethoxylated)alpha1,4-bond
galacturonan
2. Fructose. (traces)
3. Arabinose. ok
4. Xylose. traces
Pectin
α-1, 4-linkage
1.Pectin is a polymer of α-Galacturonic acid with a
variable number of methyl ester groups
2.The structure shown here has three methyl ester
forms (-COOCH3) for every two carboxyl groups
(-COOH )
Purity tests:
• Aqueous pectin solution + lead acetate
negative
• Aqueous pectin solution + I2
negative
• Aqueous pectin solution + FeCl3
negative
• Aqueous pectin solution + resorcinol + HCl
red to pink colour
Identification tests:
• Positive reaction with Molisch’s and
Fehling’s solution tests.
• Positive reaction with Selivanoff’s test.
Uses:
1. Treatment of diarrhea: absorbent anti-diarrheal agent.
Absorption of:
o Fluids.
o Bacteria.
o Toxins.
o Gases.
2. Haemostatic.
3. Emulsifying and gelling agent in the pharmaceutics and
cosmetics.
4. Thickening agent in food industry.
Note:
Pectin usually comes with kaolin.
• Kaolin:
• Absorbent anti-diarrheal agent obtained from:
• Sand stones.
• Rocks.
• Clay.
All contain Al2O3 + SiO2
• Uses:
• Treatment of diarrhea (the same way as pectin).
• Coat for irritated intestinal mucosa caused by
diarrhea.
There is 2 types of anti-diarrheal agents
according to their mechanism of action:
1. Absorbent anti-diarrheal agents :
– Pectin.
– Kaolin.
2. Anti-peristaltic agents:
• Loperamide: from opiate alkaloids, decrease
intestinal hyper motility.
• Furazolidine: decrease intestinal hyper motility.
Drugs
Trade
Producer Dosage
Name
form
Dairin P.G® GAMA
Tablets
Susp.
Furamix®
BJPC
Tab.
Susp.
K.S.stop®
Belpharm Susp.
Kapectin
forte®
Taro
Kaopectin® Vitamid
Susp.
Susp.
Ingredients
Furazolidine
Kaolin, Pectin
Furazolidine
Kaolin, Pectin
Loperamide
Kaolin, Pectin
Kaolin
Pectin
Kaolin, Pectin
References
1. Gonzáles Canga, A., et al., Glucomannan:
Properties and Therapeutic Applications, Nutr.
Hosp., 19(1) 45-50, 2004.
2. J. P. Roubroeks, R. Andersson, D. I.
Mastromauro, B. E. Christensen and P. Åman,
Molecular weight, structure and shape of oat
(1→3),(1→4)-b-D-glucan fractions obtained by
enzymatic degradation with (1→4)-b-D-glucan
4-glucanohydrolase from Trichoderma reesei,
Carbohydr. Polym. 46 (2006) 275-285.