PHARMACOGNOSY

Chapter :- Carbohydrate

Que. Write a note on Isabgol.

Ans:-

 Synonym - Psyllium Husk

 Biological Source – Isabgol consist of dried seeds and husk of plantago ovata Forsk.
 Family – Plantaginaceae.
 Goegraphical Source- Mainly cultivated in India, Pakistan, Iran, and USA
 Morphology- Seeds are small, boat shaped
Husk- White, Fibrous, and Mucilaginous in texture
 Chemical Constituent-
Mucilage 20-30% Responsible for water absorption and gel formation.
Cellulose & Hemicellulose- Contributes to bulk forming laxative properties.
Fixed Oils- Provide anti-inflammatory effect.
Alkaloids & Glycosides - Contributes to minor medicinal properties.
 Pharmacological Action-
(i) Laxative Action – Swells in water, forming a gel that aids in stool passage.
(ii) Hypocholesterolemic Effect – Binds bile acids, reducing cholesterol absorption.
(iii) Hypoglycemic Effect – Delay glucoses absorption, aiding in diabetes management
 Uses in Medicine –
i. Constipation- Bulk laxative for smooth bowel stool
ii. Diarrhea & IBS- Regulates stool consistency.
iii. Hypercholesterolemia- Lowers LDL cholesterol levels
iv. Diabetes Management- Helps control postprandial blood sugar spikes.
 Side effects & Precaution –
(i) Can cause bloating, gas or chocking if not taken with enough water
(ii) May interfere drug absorption
(iii) Contraindication in bowel obstruction and difficulty swallowing.
Que. Write source, constituents, chemical test and medical use of Tragacanth.

Ans:-

 Biological Source: Tragacanth is a natural gum obtained from the exudate of the stems and
branches of Astragalus gummifer and other species of Astragalus (Family: Fabaceae).
 Geographical Source: It is mainly found in Iran, Turkey, Iraq, Syria, and Greece, with Iran
being the largest producer.
 Chemical Constituents:
I. Tragacanthin (Water-soluble part, ~30%) – Forms a viscous colloidal
solution.
II. Bassorin (Water-insoluble part, ~60–70%) – Swells in water but does
not dissolve.
III. Arabinogalactans & Xylogalacturonic Acid – Contribute to the gum’s
viscosity.
IV. Starch, Cellulose, and Minerals – Present in small amounts.
 Chemical Tests for Identification:

1. Ruthenium Red Test

Procedure: Add ruthenium red solution to the gum.

Positive Result: Pink or red coloration indicates the presence of mucilage.

2. Swelling Test

Procedure: Place a small amount of gum in water and observe.

Positive Result: Significant swelling indicates the presence of tragacanth mucilage.

3. Molisch’s Test (For Carbohydrates)

Procedure: Add α-naphthol and sulfuric acid to the sample.

Positive Result: Purple ring formation confirms carbohydrate presence

 Medicinal Uses of Tragacanth:

1. Emulsifying & Suspending Agent – Used in pharmaceutical suspensions and emulsions.

2. Demulcent & Soothing Agent – Protects mucous membranes, used in cough syrups and lozenges.

3. Laxative – Acts as a bulk-forming laxative for constipation.

4. Binding Agent – Used in tablet formulations to improve cohesion.

5. Dietary Fiber – Helps in weight management and digestion.

Que. Discuss Method of preparation of starch from various source.

Ans: -

Starch is a carbohydrate polymer obtained from various plant sources such as maize (corn), potatoes, rice,
and wheat. The extraction method varies depending on the source, but the general process involves milling,
separation, washing, and drying.

1. Preparation of Starch from Maize (Corn Starch)

Steps:
 Steeping: Corn kernels are soaked in warm water (50°C) with 0.1% sulfur dioxide for
24–48 hours to soften the grains.
 Grinding: The softened kernels are coarsely ground to release the germ.
 Germ Separation: The germ is separated by centrifugation and removed for oil
extraction.
 Fiber Removal: The ground material is passed through sieves to remove fiber.
 Starch Separation: The remaining slurry undergoes centrifugation to separate starch
from protein (gluten).
 Washing & Drying: The starch is washed multiple times, dried in hot air, and powdered
for storage.

Yield: ~60% starch from corn.

2. Preparation of Starch from Potato (Potato Starch)

Steps:

 Cleaning & Peeling: Potatoes are washed and peeled to remove dirt and impurities.
 Grinding: The peeled potatoes are crushed to release starch granules
 Slurry Formation: Water is added to the crushed material to form a slurry.
 Separation: The slurry is passed through fine sieves to remove fibers and residual solids.
 Settling & Decantation: The starch settles at the bottom, and the supernatant is decanted.
 Drying: The wet starch is dried at 40–50°C, ground into a fine powder, and stored.

Yield: ~18–20% starch from potatoes.

 3. Preparation of Starch from Rice (Rice Starch)

Steps:

 Soaking: Rice grains are soaked in an alkaline solution (0.25% NaOH) for 24 hours.
 Grinding: The softened grains are ground to form a fine slurry.
 Sieving: The slurry is passed through fine sieves to remove husk and fibers.
 Centrifugation: The starch is separated from the protein and impurities by centrifugation.
 Neutralization & Washing: The starch is washed with water and neutralized with mild acid if needed.
 Drying: The purified starch is dried, ground, and packed.

Yield: ~70–80% starch from rice.

4. Preparation of Starch from Wheat (Wheat Starch)

Steps:

 Dough Formation: Wheat flour is mixed with water to form a dough.

 Washing: The dough is washed with water to separate gluten from starch.
 Starch Separation: The starch milk (starch suspension) is collected and allowed to settle.
 Centrifugation: The settled starch is centrifuged to remove excess water.
 Drying & Grinding: The wet starch is dried at a controlled temperature and powdered.

Yield: ~60–70% starch from wheat.

Que. Demonstrate the pharmacognostic study of Acacia.

Ans:-

 Biological Source:
 Acacia gum is a dried exudate obtained from the stems and branches of Acacia senegal and other
species of Acacia (Family: Fabaceae).

 Geographical Source:
It is primarily obtained from Sudan, Nigeria, Senegal, India, Pakistan, and Arabia. Sudan is the
largest producer.

 Morphological Characteristics:

Color: Pale yellow to brown

Odor: Odorless.

Taste: Bland, mucilaginous.

Shape: Usually irregular tears, rounded nodules, or fragments.

Solubility: Soluble in water, forming a viscous solution; insoluble in alcohol.

 Microscopic Characteristics
 Fragments of acacia cells with thickened walls.
 Presence of mucilage (stains pink with ruthenium red).
 Crystalline calcium oxalate deposits may be seen.

 Chemical Constituents
 Arabinogalactan Complex (Gum Acacia) (~85%) – Mixture of calcium, magnesium, and potassium
salts of polysaccharides.
 Enzymes (Oxidases, Peroxidases, and Pectinases) – Influence the viscosity of the gum.
 Tannins and Minerals (Calcium, Magnesium, and Potassium).

 Chemical Tests for Identification

 Ruthenium Red Test

Procedure: Add ruthenium red solution to the sample.

Positive Result: Pink or red color indicates mucilage presence.

 Molisch’s Test (Carbohydrate Test)

Procedure: Add α-naphthol and sulfuric acid.

Positive Result: Purple ring formation confirms carbohydrate presence.

 Lead Acetate Test

 Procedure: Add lead acetate solution to gum solution.

Positive Result: White precipitate forms, confirming the presence of gum.

 Pharmacological Actions

Demulcent – Soothes irritated mucous membranes.

Emulsifying Agent – Used in suspensions and emulsions.

Expectorant – Helps in cough formulations.

Prebiotic – Promotes gut health.

 Uses

1. Used in Pharmaceuticals – As a suspending agent in syrups and emulsions.

2. Cough Syrups & Lozenges – Acts as a demulcent to relieve throat irritation.

3. In Cosmetics – Used in lotions and creams as a stabilizer.

4. Food Industry – Used as a thickener in candies, beverages, and ice creams.

Que. Write in detail about any two carbohydrate containing drugs.

Ans:-

1. Starch

 Biological Source:

Starch is a polysaccharide obtained from the seeds, tubers, or roots of various plants, mainly from Zea mays
(Maize Starch) – Family: Poaceae

 Geographical Source:

Starch is produced in India, China, USA, Russia, and Brazil.

 Chemical Constituents:

Amylose (20–30%) – Linear polymer of α-D-glucose linked by α-(1→4) bonds.

Amylopectin (70–80%) – Branched polymer of α-D-glucose with α-(1→4) and α-(1→6) bonds.

Water & Small Amounts of Proteins and Lipids.

  Identification Tests:

1. Iodine Test

Procedure: Add iodine solution to starch suspension.

Positive Result: Blue-black color (disappears upon heating and reappears on cooling).

2. Microscopic Test

Observed under the microscope using iodine stain.

Different sources show different starch granule shapes and sizes.

 Pharmacological Actions:

Demulcent – Protects irritated mucous membranes.

Adsorbent – Used as a protective agent in diarrhea.

Binder & Disintegrant – Used in tablet formulations

 Medicinal & Pharmaceutical Uses:

1. Used as a pharmaceutical excipient – Tablet binder, disintegrant, and diluent.

2. Dietary carbohydrate – Source of energy

3. Used in dusting powders – Acts as a protective and absorbent agent.

4. Food industry – Thickening agent in sauces, soups, and bakery products.

2. Honey

 Biological Source:

Honey is a natural sugary secretion produced by bees (Apis mellifera, Family: Apidae) from nectar collected
from flowers.

 Geographical Source:

Major producers include India, China, USA, Ukraine, and Argentina.

  Chemical Constituents:

Sugars (~80%)

Fructose (38–40%)

Glucose (30–35%)

Sucrose (~5%)

Maltose and other oligosaccharides

Water (15–18%)

Enzymes (Invertase, Diastase, Glucose Oxidase)

Vitamins & Minerals (Iron, Calcium, Magnesium, B-complex vitamins)

Flavonoids & Phenolic Compounds (Antioxidants)

 Identification Tests:

1. Fiehe’s Test (For Adulteration with Artificial Honey)

Procedure: Add resorcinol + HCl to honey.

Positive Result: Red color appears in adulterated honey.

2. Molisch’s Test (For Carbohydrates)

Procedure: Add α-naphthol and sulfuric acid.

Positive Result: Purple ring at the interface.

 Pharmacological Actions:

Demulcent & Soothing Agent – Used in cough syrups and throat lozenges.

Antibacterial & Wound Healing – Used in burn and ulcer dressings.

Prebiotic Effect – Supports gut health by promoting good bacteria.

Energy Booster – Rapidly absorbed sugar source for instant energy.

 Medicinal & Pharmaceutical Uses:

1. Used in cough syrups as a soothing agent.

2. Topical wound dressing in burns and ulcers due to its antibacterial properties.

3. As a vehicle for herbal formulations in Ayurvedic and Unani medicines.

4. Used as a preservative in traditional medicines.

Que. Classify carbohydrate with example.

Ans:-

Carbohydrates are organic compounds composed of carbon (C), hydrogen (H), and oxygen (O) in the general
formula (CH₂O) n. They are classified based on their structure and complexity into the following categories:

1. Monosaccharides (Simple Sugars)

These are the simplest form of carbohydrates that cannot be hydrolyzed into smaller units.

They contain 3–7 carbon atoms and are classified based on the number of carbons.

Examples:

Triose (3C): Glyceraldehyde, Dihydroxyacetone

Tetrose (4C): Erythrose, Threose

Pentose (5C): Ribose, Deoxyribose, Xylose, Arabinose

Hexose (6C): Glucose, Fructose, Galactose, Mannose

Heptose (7C): Sedoheptulose

2. Disaccharides (Oligosaccharides – 2 Sugar Units)

Formed by the condensation of two monosaccharides with the elimination of water.

Examples:

Sucrose (Glucose + Fructose) – Table sugar

Lactose (Glucose + Galactose) – Milk sugar

Maltose (Glucose + Glucose) – Found in barley

Trehalose (Glucose + Glucose) – Found in mushrooms

3.Oligosaccharides (3–10 Sugar Units)

These contain 3 to 10 monosaccharide units linked by glycosidic bonds.

Examples:

Raffinose (Galactose + Glucose + Fructose) – Found in beans and cabbage

Stachyose (Galactose + Galactose + Glucose + Fructose) – Found in legumes

4. Polysaccharides (Complex Carbohydrates, >10 Sugar Units)

Long chains of monosaccharide units joined by glycosidic bonds.

They are classified into homopolysaccharides and heteropolysaccharides.

A. Homopolysaccharides (Same Monomer Units)

Starch (Glucose units) – Found in plants (Rice, Wheat, Potatoes, Corn)

Glycogen (Glucose units) – Animal storage polysaccharide in liver & muscles

Cellulose (Glucose units) – Structural polysaccharide in plant cell walls

Inulin (Fructose units) – Found in onions, garlic, and chicory root

B. Heteropolysaccharides (Different Monomer Units)

Hyaluronic Acid (Glucuronic acid + N-acetylglucosamine) – Found in connective tissues

Chondroitin Sulfate (Glucuronic acid + N-acetylgalactosamine) – Found in cartilage

Agar (Galactose + Sulfated Polysaccharides) – Found in seaweed, used in culture media.

Que. Write Biological source, chemical constituents, chemical test and uses of Agar.

Ans:- Agar in Pharmacognosy

 Biological Source:
Agar is a phycocolloid obtained from the cell walls of red algae belonging to the genera:

Gelidium amansii (Family: Gelidiaceae)

Gracilaria verrucosa (Family: Gracilariaceae)

 Geographical Source:

Agar is primarily obtained from Japan, China, India, Sri Lanka, the USA, and the Philippines.

 Chemical Constituents:

Agar is a heteropolysaccharide composed of:

Agarose (~70%) – A linear polymer of alternating D-galactose and 3,6-anhydro-L-galactose.

Agaropectin (~30%) – Contains sulfate esters, pyruvic acid, and galactose units.

Minerals (Calcium, Magnesium, and Potassium).

 Chemical Tests for Identification:

1. Solubility Test

In hot water: Agar swells and dissolves, forming a gel upon cooling.

In cold water: Agar is insoluble but swells.

2. Iodine Test (For Carbohydrates)

Procedure: Add iodine solution to an aqueous agar solution.

Positive Result: No blue or red color (Differentiates agar from starch and tragacanth)

3. Molisch’s Test (For Carbohydrates)

Procedure: Add α-naphthol and sulfuric acid to the sample.

Positive Result: Purple ring formation confirms carbohydrate presence.

 Uses of Agar:

Pharmaceutical Uses:

Used as a suspending agent in pharmaceutical formulations.

Bulk laxative – Helps relieve constipation by adding bulk to stool.

Used in tablet formulations as a binder and disintegrant.

Microbiological Uses:- Used in culture media for bacterial and fungal growth (e.g., Nutrient Agar, MacConkey
Agar).

Food Industry Uses:- Used as a gelling agent in jellies, puddings, and ice creams.

Vegetarian substitute for gelatin in confectionery products.

Cosmetic & Industrial Uses:-

Used in cosmetics for creams and lotions as a thickener.

Used in textile and paper industries as a sizing agent.

Que. Give two identification test for carbohydrates.

Ans:-

1. Molisch’s Test (For Carbohydrates)

 Principle: Molisch's test is a general test for carbohydrates that detects the presence of
any sugar (monosaccharides, disaccharides, oligosaccharides, and polysaccharides).

 Procedure:

1. Add a few drops of Molisch's reagent (α-naphthol solution in ethanol) to the carbohydrate solution.

2. Add concentrated sulfuric acid carefully along the sides of the test tube.

3. A red or purple ring forms at the junction of the two liquids.

Positive Result: A purple or red ring forms at the interface of the two liquids, indicating the presence of
carbohydrates.

2. Benedict’s Test (For Reducing Sugars)

  Principle: Benedict's test is used to detect reducing sugars, which have a free aldehyde or ketone
group capable of reducing copper(II) ions to copper(I) oxide.
 Procedure:

1. Add Benedict’s reagent (a blue solution of copper(II) sulfate) to the carbohydrate solution.

2. Heat the mixture in a boiling water bath for 5–10 minutes.

3. Observe the color change.

Positive Result: The presence of reducing sugars results in a color change from blue to green, yellow, orange,
or red, depending on the amount of reducing sugar present.

Que. Distinguish agar and acasia pharmacognostically.

Feature Agar Acasia

1. Source Extracted from red algae. Extracted from the sap of acasia
tree.
2. Composition Polysaccharides mainly Complex polysaccharide
composed of agarose and composed of arabinose,
agaropectin galactose, rhamnose and
glucuronic acid.
3. Solubility Insoluble in cold water, dissolve Highly soluble in both hot and
in hot water cold water
4. Texture & Properties Form a firm, gel-like structure Form a viscous solution but does
when cooled not gel
5. Uses Microbiological culture medium

Que. Compare starch and honey

Aans:-

1. Composition & Structure

Starch: A complex carbohydrate (polysaccharide) made of long chains of glucose molecules. It consists of
amylose (linear) and amylopectin (branched).

Honey: A mixture of simple sugars (monosaccharides), mainly fructose (~40%) and glucose (~30%), along with
water and trace compounds (enzymes, antioxidants, etc.).

2. Source

Starch: Found in plants (e.g., potatoes, rice, wheat, corn). It serves as an energy storage molecule.

Honey: Produced by bees from flower nectar. It serves as an immediate energy source for bees.
3. Digestion & Absorption

Starch: Needs to be broken down into glucose by enzymes (e.g., amylase) before absorption in the small
intestine.

Honey: Contains pre-digested sugars, which are quickly absorbed into the bloodstream, providing a fast
energy boost.

4. Taste & Sweetness

Starch: Tasteless in its raw form but can develop a slightly sweet taste when broken down.

Honey: Naturally sweet due to fructose, which is sweeter than glucose.

5. Uses

Starch: Used as a thickener (soups, sauces), in food processing (bread, pasta), and industrial applications
(glue, paper).

Honey: Used as a sweetener, natural remedy (antibacterial properties), and in skincare.

6. Energy Release

Starch: Provides slow-releasing energy (complex carbs take time to digest).

Honey: Provides quick energy due to its simple sugars.

7. Health Impact

Starch: Whole-food sources (e.g., whole grains) are healthy, but refined starches (e.g., white bread) can spike
blood sugar.

Honey: Has antioxidants and antimicrobial properties but is still high in sugar and should be consumed in
moderation.

8. Physical State

Starch: Usually a powder or granules

Honey: A thick, viscous liquid

Que. Compare Acacia and tragacanth.

Ans:-

Properties Acacia Tragacanth

1. Biological Source Obtained from the stem and Dried gummy exudate from stem
branches of acacia tree, primarily of astragalus species, mainly
Acacia Senegal and acacia astragalus gummifer
arabica.
2. Chemical components. Mainly arabinogalactan, a Consist of two factors :
complex polysaccharides. Contain 1. Tragacanthin [Water
calcium, magnesium, potassium soluble mucilage]
salt and enzyme 2. Bassorin [swells in water
but does not dissolve]
3. Appearance Yellowish white tear or granules White or pale yellow irregular
ribbon like flakes.
4. Solubility Soluble in cold water, forming a Swell in water to form a gel but
viscous solution does not completely dissolve
5. Taste Bland or slightly sweet Tasteless
6. Odor Odorless Odorless
7. Use 1. Binder in tablet 1. Thickening and
formation. suspending agent in
2. Emulsifier in syrups and emulsion.
pharmaceutical and food 2. Bulk laxative due to high
industries. water absorbing
3. Demulcent capacity.