CARBOHYDRATES

What are the classifications of carbohydrates based on sugar units?

• Monosaccharides (1 sugar unit)

• Disaccharides (2 sugar units)

• Oligosaccharides (3-10 sugar units)

• Polysaccharides (>10 sugar units)

What are monosaccharides also known as?

Simple sugars.

How are monosaccharides classified based on the number of carbon atoms?

• Dioses (2C): Hydroxyacetaldehyde

• Trioses (3C): Glyceraldehyde, Dihydroxyacetone

• Tetroses (4C): Erythrose, Erythrulose

• Pentoses (5C): Arabinose, Xylose, Xylulose, Ribose, Ribulose

• Hexoses (6C): Glucose, Fructose, Galactose, Mannose

• Heptoses (7C): Heptulose

• Octoses (8C): D-glycero-D-mannoctulose

• Nonoses (9C): Sialic acid

What are the most important hexoses?

Glucose (Dextrose), Fructose, Galactose, Mannose.

What is another name for glucose?

Dextrose.

What are the alternative names for glucose?

Blood sugar, grape sugar, and physiologic sugar.

What are the uses of glucose?

• Source of ATP

• Sweetening agent

  • GLUCOSE

  • DEXTROSE EXCIPIENT

What is liquid glucose used for?

As a sweetening agent.

What is another name for fructose?

Fruit sugar.

Where is fructose commonly isolated from?

Sweet fruits, honey, or mel.

What are the uses of fructose?

• Source of nutrients (DM)

• Sweetening agent

What happens when galactose reacts with HNO₃?

It forms mucic acid crystals.

What is the C4 epimer of D-glucose?

Galactose.

What is the C2 epimer of D-glucose?

Mannose.

What are the oxidation products of glucose?

Plant acids.

What is citric acid derived from?

Lemon juice (Citrus limon, Rutaceae).

Who isolated citric acid?

Scheel.

What is the use of citric acid in pharmaceuticals?

As an acidulant in effervescent formulations.

What is tartaric acid a byproduct of?

The wine industry.

What is the pharmaceutical use of tartaric acid?

It is used as an acidulant in effervescent formulations.

What is the use of lactic acid in infant nutrition?

It serves as an acidulant in infant feeding formulas.

What compound forms when fumaric acid reacts with ferrous?

Ferrous fumarate.

What is the pharmaceutical use of ferrous fumarate?

It is used as a hematinic (iron supplement).

From which natural source is malic acid obtained?

Cherry juice (Prunus cerasus, Rosaceae).

What is the pharmaceutical use of malic acid?

It is used as a flavorant.

What is the product of reduction of D-glucose?

D-glucitol, also known as sorbitol.

From which plant source is sorbitol obtained?

The berries of Mountain Ash (Sorbus aucuparia, Rosaceae).

How does the sweetness of sorbitol compare to sucrose?

It is half as sweet as sucrose.

What is the pharmaceutical use of sorbitol?

It is used as a humectant.

What is the product of reduction of mannose?

Mannitol

From which plant is mannitol obtained?

The leaves of Manna Ash (Fraxinus ornus, Oleaceae).

What are the pharmaceutical uses of mannitol?

• Osmotic diuretic (used for cerebral edema)

• Osmotic cathartic (for constipation)

• Diluent in chewable tablets

Name three examples of pentoses.

Arabinose, Xylose, and Xylulose.

What is the natural source of pentoses?

Gum Arabic or Acacia Gum.

What is xylose commonly known as?

Wood sugar.

How is xylose isolated?

By boiling corn cobs and straw with dilute acids.

What is the pharmaceutical use of pentoses?

They are used as diagnostic aids.

What are the two most important pentoses found in nucleic acids?

Ribose and deoxyribose.

What test is used to detect pentoses using orcinol?

Bial’s Test.

What is the principle of Bial’s Test?

Pentoses react with orcinol to form a blue color.

What test detects pentoses using benzidine?

Tauber’s Test.

What is the result of Tauber’s Test when pentoses are present?

A cherry red color.

What reagent is used in Tollen’s Test for pentoses?

Phloroglucinol.

What is the principle behind Tollen’s Test?

Pentoses react with phloroglucinol, forming furfural derivatives with a characteristic red color.

How are disaccharides formed?

By dehydration reaction.

What two monosaccharides form sucrose?

Glucose and fructose.

What type of bond is present in sucrose?

Alpha-1,2 glycosidic bond.
AKA - Table sugar.

What are the natural sources of sucrose?

• Sugar cane (Saccharum officinarum, Poaceae)

• Sugar beets (Beta vulgaris, Amaranthaceae)

• Sugar maple (Acer saccharum, Aceraceae)

What are the pharmaceutical and industrial uses of sucrose?

• Demulcent

• Preservative

• Sweetening agent

• Manufacture of syrups

What two monosaccharides form maltose?

Glucose and glucose.

What type of bond is present in maltose?

Alpha-1,4 glycosidic bond.

What is another name for maltose?

Malt sugar.

What are the sources of maltose?

• Partial breakdown of starch

• Germination of barley (Hordeum vulgare, Poaceae)

What is the pharmaceutical use of maltose?

It is an ingredient in energy drinks.

What two monosaccharides form lactose?

Galactose and glucose.

What type of bond is present in lactose?

Beta-1,4 glycosidic bond.

What is another name for lactose?

Milk sugar.

What is the source of lactose?

It is isolated from cow’s milk (Bos taurus, Bovidae).

What are the steps in isolating lactose from milk?

1. Let cow’s milk stand.

2. Fat globules rise to the top, forming cream.

3. Cream is churned to form butter.

4. The remaining liquid is buttermilk.

5. Separate the cream layer to get skimmed milk.

6. Treat skimmed milk with rennin (a milk-coagulating enzyme).

7. Skimmed milk separates into two layers:

   • Upper layer: Coagulum (Cheese)

   • Lower layer: Whey (Lactose is isolated from whey).

What are the pharmaceutical uses of lactose?

Tablet diluent (commonly used in chewable tablets with mannitol).

• Ingredient in infant’s milk.

• Food for Lactobacilli (beneficial gut bacteria).

What is lactulose composed of?

It is a semi-synthetic disaccharide composed of galactose and fructose.

How is lactulose produced?

It is produced by the alkaline rearrangement of lactose.

What is the main pharmaceutical use of lactulose?

It is used as a cathartic (laxative).

What is the mechanism of action of lactulose as a cathartic?

It is converted by colonic microbes into lactic acid and acetic acid, which irritate the colon and stimulate bowel movement.

How does lactulose help in preventing portal systemic encephalopathy (PSE)?

The acidified stool traps ammonia from the blood, reducing its levels in patients with liver disease.

What is the principle of Fehling’s test?

Cupric ions (Cu²⁺) are reduced to cuprous oxide (Cu⁺), leading to a color change from blue to brick red.

What is the sequestrant used in Fehling’s test?

Sodium potassium tartrate (Rochelle salt).

What is the principle of Benedict’s test?

Reducing sugars react with cupric sulfate, reducing it to cuprous oxide, forming a yellow to brick red precipitate upon heating.

How is Benedict’s test used in medical diagnosis?

It is used to detect reducing sugars in urine, which can indicate diabetes mellitus.

What is the sequestrant used in Benedict’s test?

Sodium carbonate.

What is the principle of Tollen’s Silver Mirror Test?

Ammoniacal silver nitrate (Tollen’s reagent) is reduced by sugars with an aldehyde group, forming a silver mirror.

What is the chemical reaction in Tollen’s test?

Ag⁺ → Ag⁰ (Colorless to Silver Mirror).

What is the principle of Barfoed’s Test?

Cupric ions (Cu²⁺) are reduced to cuprous oxide (Cu⁺), producing a brick red precipitate.

How can Barfoed’s test distinguish between monosaccharides and disaccharides?

• Monosaccharides react within 2-3 minutes.

• Disaccharides react in more than 10 minutes.

What are oligosaccharides?

They are carbohydrates composed of 3-10 sugar units.

What are some examples of oligosaccharides?

• Gentianose (Glu-Glu-Fru)

• Raffinose (Gal-Glu-Fru)

• Maltotriose (Glu-Glu-Glu)

• Melezitose (Glu-Fru-Glu)

• Stachyose (Gal-Gal-Glu-Fru)

What are polysaccharides?

They are long chains of sugar molecules with more than 10 sugar units.

What are homoglycans?

They are polysaccharides composed of the same type of sugar units.

Give examples of homoglycans and their sugar units.

• Starch → Glucose units

• Inulin → Fructose units

What are heteroglycans?

They are polysaccharides composed of different types of sugar units.

What are some examples of heteroglycans?

Gums and mucilages such as carrageenan.

What sugar units make up carrageenan?

• Galactose

• Glucose

• Fructose

• Arabinose

: What is the most common source of starch?

• Corn (Zea mays, Poaceae)

• Potato (Solanum tuberosum, Solanaceae)

• Wheat (Triticum aestivum, Poaceae)

• Rice (Oryza sativa, Poaceae)

• Cassava (Manihot esculenta, Euphorbiaceae)

What are the two main components of starch?

Amylose and Amylopectin

What are the characteristics of amylose?

• Composed of 250-300 glucose units

• Linear (Helical) starch

• Water-soluble

• Forms a blue color with iodine

What are the characteristics of amylopectin?

• Composed of >1,000 glucose units

• Branched starch

• Water-insoluble

• Forms a violet color with iodine

What is pregelatinized starch?

It is chemically or mechanically processed to rupture starch granules.

What is the pharmaceutical use of pregelatinized starch?

It is used as a tablet binder.

What is sodium starch glycolate used for?

It is used as a disintegrant in tablets

What is Hetastarch 6% used for?

It is a plasma expander used in IV therapy.

What is the antidote for iodine poisoning?

Starch acts as an antidote for iodine poisoning.

What is inulin?

It is a fructosan that yields only fructose units upon hydrolysis.

What is the medical use of inulin?

It is used as a diagnostic aid for renal dysfunction.

What are some natural sources of inulin?

• Chicory (Blue Dandelion Root) (Cichorium intybus, Asteraceae)

• Cone Flower (Echinacea angustifolia, Asteraceae)

What is the traditional use of Echinacea angustifolia?

It is used to treat common colds and flu.

What is dextran?

It is a microbial product synthesized by Leuconostoc mesenteroides.

What enzyme produces dextran?

Dextran sucrase (transglycosylase).

What is the pharmaceutical use of dextran?

It is used as a 6% plasma expander.

What is cellulose?

It is a polysaccharide composed of glucose units forming plant cell walls.

What is a common natural source of cellulose?

Cotton (Gossypium hirsutum, Malvaceae).