Heteroglycans

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Heteroglycans
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• Heteroglycans
• Are natural plants hydrocolloids containing more
  than one kind of monosaccharide units.

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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

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• 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

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Examples on Gums

• A. Tragacanth gum

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A. Tragacanth gum

• 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

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Constituents

• 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

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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 )

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Identification tests

1. 30 soluble in water.
2. Aqueous gum solution NaOH yellow
   or brown colour
3. Gives positive reaction with Molischs and
   Fehlings solution test.

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Uses

1. Demulcent.
2. Emollient.
3. Laxative ( bulk laxative ).
4. Pharmaceutical uses
5. Suspending agent.
6. Emulsifying agent.
7. Stabilizer.
8. Thickener.
9. Cosmetics hand creams and body lotions (
   emollient and emulsifying agent )

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B. Arabic gum Acacia gum
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Arabic gum

• The dried gummy exudations obtained by incision
  from the stems and branches of Arabic gum trees
  (Acacia trees)

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Physicochemical properties

1. Translucent.
2. Amorphous.
3. White or pale yellow colour.
4. Odourless.
5. Mucilaginous taste.
6. Soluble in water.
7. Insoluble in organic solvents.

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Constituents

• Arabin a mixture of Ca, Mg, K salts for
• Arabic acid.
• Glucuronic acid.
• Galacturonic acid.
• Rhamnurnic acid.
• Arabin (hydrolysis) Arabinose
  Rhamnose Glucose Galactose
• Enzymes
• Oxidase enzyme.
• Peroxidase enzyme.
• Pectinase enzyme.

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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

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Identification tests

• Aqueous gum solution pH slightly
  acidic with time more acidic
• Aqueous gum solution Borax ( Na2B4O7 )
  translucent mass
• Aqueous gum solution Benzedene H2O2
• blue colour
• 4. Aqueous gum solution alcohol acetic acid
  white precipitate
• 5. Gives positive reactions with Molischs and
  Fehlings solution tests.

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Uses

• 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
• Suspending agent.
• Emulsifying agent.
• Tablet binder.

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Drug

• Allergenic extract Trupharm vials 5 ml, 10
  ml
• Contains
• Tragacanth gum.
• Arabic gum.
• Dust.
• Mould.
• Insect.
• Pollen grains.
• Indications
• Immunotherapy.
• Allergy test.

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C-Guar gum

• 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.

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Constituents

• Proteins.
• Guaran ( galactomannan )
• a-D-galactose ß-D-mannose

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Guaran is the principal polysaccharide in guar
gum
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Purity tests

• Aqueous gum solution lead acetate
  positive
• Aqueous gum solution I2 negative
• Aqueous gum solution FeCl3
  negative
• Aqueous gum solution resorcinol HCl
  negative

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Identification

1. Aqueous gum solution Borax
   translucent mass ( gel )
2. Gives positive reactions with Molischs and
   Fehlings solution tests.

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Uses

• 1. Pharmaceutical uses
• Thickener.
• Tablet binder.
• Stabilizer.
• Emulsifying.
• 2. Cosmetics lotions and creams.
• 3. Laxative.
• 4. Food industry
• a. Ice creams.
• b. Cheese.
• c. Soup.

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D- Locust bean gum Carob gum

• The powdered endosperm obtained from carob 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.

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Constituents

• Guaran ( galactomannan ).

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Purity tests

• Aqueous gum solution lead acetate
  negative
• Aqueous gum solution I2 negative
• Aqueous gum solution FeCl3
  negative
• Aqueous gum solution resorcinol HCl
  negative

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Identification tests

• Aqueous gum solution Borax
  translucent mass ( gel )
• Gives positive reactions with Molischs and
  Fehlings solution tests

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Uses

• pharmaceutical uses for external preparations as
• Thickener.
• Stabilizer.
• Cosmetics.
• Has laxative effect (but not used as laxative)

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E- Karaya gum Indian gum Sterculia gum

• The dried gummy exudations obtained by incision
  from the stems and branches of Sterculia trees.

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• 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.

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Constituents

• Mixture of
• Galactose.
• Galacturonic acid.
• Rhamnose.
• Acetic acid.

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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

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Identification test

• Gives positive reactions with Molischs and
  Fehlings solution tests.
• Aqueous Gum solution HCl heating
• Acetic acid CuSO4 deep blue

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Uses

• pharmaceutical uses (external uses)
• Suspending.
• Emulsifying.
• Dental adhesive.
• Cosmetics.
• Industrial use.
• Laxative.

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F- Xanthan Gum

• is a polysaccharide with a ß-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.

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beta-D-mannose
Alpha-D-mannose
Beta-D- glucuronic aid
The repeating unit of Xanthan Gum
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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.

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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.

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• The polysaccharide consists of glucose (G) and
  mannose (M) in a proportion of 58 joined by ß1?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 ß1?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.

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portion (GGMM) of the glucomannan repeating
unit.The second glucose has an acetate group.
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II. Mucilages
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Definition

• Natural plants product, heteroglycan complex
  polysaccharide.
• Mucilage give with hydrolysis
• monosaccharide units.
• Ca, Mg, K, Na salts of monosaccharides.
• Monosaccharide acids.
• Ca, Mg, K, Na salts of monosaccharide acids.
• They founded in some plants part as food
  reservoir or and as water reservoir ( hydrophilic
  substances).

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• 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 ).

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Examples on mucilage

• 1. Agar

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• Agar is
• Natural product.
• Dry powder.
• Hydrophilic substance .
• Obtained from
• Red Algae.
• Gracilaria.
• Golidium.

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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.

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Physicochemical properties

1. Yellowish white powder.
2. Odourless or with slight odour.
3. Mucilaginous taste.
4. Slowly soluble in water viscous mass
5. insoluble in the organic solvents.

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Agar contains

• Proteins.
• Mixture of
• L-galactose.
• D-galactose.
• Galacturonic acid.
• Sulphate ions .

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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-galactos
e
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Purity tests

• Aqueous Agar solution lead acetate
  precipitate
• Aqueous Agar solution I2 negative
• Aqueous Agar solution FeCl3
  negative
• Aqueous Agar solution resorcinol HCl
  negative

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Identification chemical tests

• Positive reaction with Molischs and Fehlings
  solution test.
• Aqueous agar solution HCl conc.
  SO4 Bacl2 BaSO4 ( white precipitate
  ).
• Aqueous agar solution HCl conc.
  SO4 KCl K2SO4 ( yellow
  precipitate ).
• Aqueous agar solution water ? then
  cooling gel.

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Agar main uses

• pharmaceutical uses
• Suspending.
• Emulsifying.
• Gelating agent for suppositories.
• Laxative ( bulk laxative ).
• 3.Food industry.
• 4. Highly refined agar is used as a medium for
  culturing bacteria, cellular tissues, and for DNA
  fingerprinting.

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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.

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Psyllium seeds Plantago seeds Plantain seeds

1. Small seeds.
2. Have grey or brown colour.
3. Mucilaginous taste and slightly bitter.
4. Odourless.

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Plantago seeds contain

• 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.

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Aucubin
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• 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.

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• The general characteristics of the iridoid
  monoterpene aucubin are as follows
• Sedative
• Anesthetic
• Analeptic
• Anaseptic (Anti-viral)
• Anti-toxic
• Anti-Histaminic
• Anti-Inflammatory
• Anti-Rheumatic
• Anti-Tumor (Anti-Blastic, Anti-Cancer,
  Anti-Carcinogenic)
• Diuretic
• Expectorant
• Hypotensive
• Organoleptic (Odor, Taste)

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• 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.

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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.

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Drugs
Ingredients Dosage forms Prod-ucer Trade Name
Psyllium seeds granules Teva Agiocure
Psyllium seeds Senna fruits (pods) granules Teva Agiolax
Psyllium hydrophilic mucilloid dextrose Powder Searle Metamucil
Psyllium hydrophilic mucilloid sugar free Sachets Arko pharma Mucivital
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Algins (Alginic acid and Sodium Alginate

• Hydrophilic heteroglycan complex polysaccharide,
  obtained from brown weeds (Brown Algae) ( in USA
  and Australia ).

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• Extraction by using organic solvents
  Alginic acid
• Extraction by using diluted NaOH
  Sodium Alginate
• Algins alginic acid sodium alginate

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• Alginic acid a mixture of beta-D-
• Glucuronic acid.
• Mannuronic acid
• Sodium alginate a mixture of beta-D-
• Sodium salts of glucuronic acid ( Na-glucuronate
  ).
• Sodium salts of mannuronic acid ( Na-mannuronate.

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Alginic acid
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Physicochemical properties

• White cream powder.
• Odourless.
• Mucilaginous taste except alginic acid ( slightly
  acidic ).
• soluble in water.
• Insoluble in the organic solvents.
• Note
• Alginic acid water doesnt form
  viscous mass.
• Na-alginate water form viscous
  mass

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Uses

• pharmaceutical uses
• Suspending.
• Emulsifying.
• Stabilizer.
• Cosmetics gel.
• Industrial uses.
• Food industry.

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This drug- used for treatment of Gastro
esophageal Reflux Disease (GERD)
Ingredients Dosage form Producer Trade Name
Al(OH)3 Mannitol Alginic acid Sodium bicarbonate Al(OH)3 CaCO3 Sodium alginate Sodium bicarbonate Powder. Chewing tablet Liquid Ferring Gaviscon
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• Note
• Alginic acid sodium bicarbonate saliva ,
  water sodium alginate water
  viscous mass.

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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 90C HCl (pH3.4-4), organic
  solvent pectin
• Note
• Protopectin water insoluble.
• Pectin water soluble.
• Organic solvent used to precipitate pectin.

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• 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.

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Physicochemical properties

1. Yellowish white powder.
2. Odourless.
3. Mucilaginous taste.
4. Soluble in water ( 120 ).
5. Insoluble in the organic solvents

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Constituents

• A mixture of
• Galactose. (alpha-D-galacturonic acid-
  methoxylated)alpha1,4-bond galacturonan
• Fructose. (traces)
• Arabinose. ok
• Xylose. traces

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Pectin
a-1,4 -linkage
1.Pectin is a polymer of a-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 )
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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

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Identification tests

• Positive reaction with Molischs and Fehlings
  solution tests.
• Positive reaction with Selivanoffs test.

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Uses

• 1. Treatment of diarrhea absorbent
  anti-diarrheal agent.
• Absorption of
• Fluids.
• Bacteria.
• Toxins.
• Gases.
• 2. Haemostatic.
• 3. Emulsifying and gelling agent in the
  pharmaceutics and cosmetics.
• 4. Thickening agent in food industry.

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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.

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• 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.

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Drugs
Ingredients Dosage form Producer Trade Name
Furazolidine Kaolin, Pectin Tablets Susp. GAMA Dairin P.G
Furazolidine Kaolin, Pectin Tab. Susp. BJPC Furamix
Loperamide Kaolin, Pectin Susp. Belpharm K.S.stop
Kaolin Pectin Susp. Taro Kapectin forte
Kaolin, Pectin Susp. Vitamid Kaopectin
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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.