This document provides an overview of carbohydrate chemistry. It begins by classifying carbohydrates as simple or complex, and as reducing or non-reducing. Monosaccharides, disaccharides, and polysaccharides are introduced. Glucose is discussed as a key monosaccharide, with its preparation from sucrose and starch. Structural features of glucose such as cyclic and linear forms are described. Sucrose, maltose, and lactose are presented as important disaccharides. Starch, glycogen, and cellulose are highlighted as significant polysaccharides. Stereoisomers including anomers are defined. The biological importance of carbohydrates as an energy source and in structural roles is summarized. Common carbohydrate chemical

1. CHEMISTRY OF NATURAL PRODUCT
TYPE
BY: JACOB THON BIOR
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2. Contents
 Introduction
 Classifications
 Preparation of carbohydrates
 Stereochemistry of carbohydrates
 Isomerism
 Biological important
 Chemical test
 References
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3. Introduction
• Complex carbohydrates represent an important energy
source for your body. They provide the sustained fuel
your body needs for exercise, daily living activities
and even rest.
• Complex carbohydrates are often single units
(monosaccharides), which are bound together.
• The oligosaccharides contain two to ten simple units of
sugar E.g. Disaccharide C12H22O11 with two sugars.
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4. • Polysaccharides (C6H10O5)n contain hundreds
and thousands of monosaccharides which are
related and link by glycosidic linkage. Complex
carbohydrates have fairly long-lasting energy.
• The different types of carbohydrates can be
classified on the basis of their behaviour in
hydrolysis.
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5. CARBOHYDRATES
• What are Carbohydrates?
Are polyhydroxy aldehydes or ketones or the
compounds which produce units of such type on hydrolysis”.
• Cn(H2O)n is the general formula for all carbohydrates. This
formula is only valid for simple sugars, which are made up of
the same amount of carbon and water.
• Cellulose, starch, and glycogen are among the compounds that
belong to this family.
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6. • Carbohydrate originate as product of photosynthesis
from the condensation of carbon dioxide and the
process require sunlight energy and chlorophyll
pigment.
• nCO2 + nH2O + Energy CnH2nOn + no2
• Carbohydrate is a group of organic compounds
occurring in living tissues and foods in the form of
starch, cellulose, and sugars.
• The ratio of oxygen and hydrogen in carbohydrates is
the same as in water i.e. 2:1. It is typically breaken
down in the animal body to release energy.
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7. CLASSIFICATIONS OF
CARBOHYDRATES
 Based on complexity:
• They are classified into :
• Simple carbohydrates- these are naturally occuring sugars
found in fruits (fructose) and table sugar (sucrose).
• Complex carbohydrates- these occur in grains products,
potatoes E.g. Starch
 Based on reducing properties:
• Reducing sugars- they have free aldehyde and ketones groups
and detected by Fehling reagent, Benedict’s solution and Barfoed
reagent by turning the solution red E.g. Glucose, fructose, lactose,
maltose and cellobiose.
• Non-reducing sugars- E.g. Sucrose, glycogen and inulin.
• They react they reagents without reducing their properties.
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8.  Based on number of sugar units:
• Monosaccharides- (Greek mono means one, sakcharon
means sugar), they contains one molecule of simple sugar E.g.
Aldose (glyceraldehydes) and Ketose sugar (dihydroacetone).
• Oligosaccharides- (Greek oligo means few), they contains 2-
10 molecules of simple sugars E.g. Disaccharides (C12H22O11 ) and
trisaccharides.
• Polysaccharides (C6H10O5)n -(Greek poly means many), they
contain more than ten molecules of simple sugars E.g. Starch and
cellulose.
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9. Monosaccharides
• Monosaccharide carbohydrates are those carbohydrates
that cannot be hydrolyzed further to give simpler units
of polyhydroxy aldehyde or ketone.
• If a monosaccharide contains an aldehyde group then it
is called aldose and on the other hand, if it contains a
keto group then it is called a ketose.
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10. PREPARATIONS OF
CARBOHYDRATES: GLUCOSE
• One of the most important monosaccharides is
glucose. The two commonly used methods for the
preparation of glucose are:
• Originate as products of photosynthesis by
condensation of water and carbon dioxide in present
of sunlight.
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11. nCO2 + nH2O + Energy CnH2nOn + no2
• From Sucrose: If sucrose is boiled with dilute acid in
an alcoholic solution then we obtain glucose and
fructose.
• From Starch: We can obtain glucose by hydrolysis
of starch and by boiling it with dilute H2SO4 at 393K
under elevated pressure.
• Glucose is also called aldohexose and dextrose and
is abundant on earth.
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12. GLUCOSE STRUCTURE
• Glucose is named as D (+)-glucose, D represents
the configuration whereas (+) represents
the dextrorotatory nature of the ring structure of
glucose can explain many properties of glucose
which cannot be figured by open-chain
structure.
• The two cyclic structures differ in the
configuration of the hydroxyl group at C1 called
anomeric carbon. Such isomers i.e. α and β form
are known as anomers.
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13. 13

14. Structures of Glucose and
Mannose
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15. DISACCHARIDE
• On hydrolysis, disaccharides yield two molecules of
either the same or different monosaccharides.
• The two monosaccharide units are joined by oxide
linkage which is formed by the loss of water molecule
and this linkage is called glycosidic linkage.
• Sucrose is one of the most common disaccharides
which on hydrolysis gives glucose and fructose.
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16. • Maltose and Lactose (also known as milk sugar) are
the other two important disaccharides.
• In maltose, there are two α-D-glucose and in lactose,
there are two β-D-glucose which are connected by an
oxide bond.
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17. Polysaccharides
• Polysaccharides contain long monosaccharide units
joined together by glycosidic linkage.
• Most of them act as food storage for E.g. Starch.
Starch is the main storage polysaccharide for plants.
• It is a polymer of α-glucose and consists of two
components-Amylose and Amylopectin.
• Cellulose is also one of the polysaccharides that are
mostly found in plants.
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18. • It is composed of β-D- glucose units joined by a
glycosidic linkage between C1 of one glucose unit
and C4 of the next glucose unit.
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19. Stereochemistry of Carbohydrate
• Most simple sugars have the same molecular formula
C6H12O6 but they are different? This difference is
called isomerism E.g.
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20. Stereochemistry of Carbohydrate
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21. • when sugars differ from one another in configuration
at only one chiral center they are called epimers E.g.
Glucose and mannose are epimers at C2 similarly
glucose and Galactose are epimers at C4.
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22. ISOMERISM
• Refers to when two molecules have the same
molecular formula and distinct arrangement of atoms.
• All simple sugars are chiral molecules as they contain
at least one chiral carbon atom.
• Types of isomerism:
Structural isomerism:
• They have same molecular formula but different
bonds orders. E.g. Glucose and Fructose.
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23. 23

24. ISOMERISM
Optical isomerism: these isomerism is in relation to
the ability to rotate the plane of polarized light.
• Dextrorotatory: rotates the planes of polarized
light in clockwise direction (+). E.g. D-glucose.
• Levorotatory: rotates the planes of polarized
light in anticlockwise direction (-). E.g. L-glucose.
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25. • Stereoisomerism: molecules having same molecular
formula but different orientation of atoms in space.
E.g. Enantiomers (both molecules are mirror images
of each other and contains chiral centres that are non-
super imposable E.g. d/l glucose) and Diasteriomers
(contain chiral centres that are non-super imposable
but are not mirror images of each other, they differ
from each other in configuration at only one chiral
centre E.g. D.glucose and D.galactose).
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26. Anomers
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27. BIOLOGICAL IMPORTANCE
• We know carbohydrates are an important part of any
human’s diet. Some common sources of carbohydrates are:
• Dairy Products – Yogurt, Milk, Ice cream
• Fruits – Fruit juice or Whole fruit
• Grains – Cereal, Bread, Wheat, Rice
• Legumes – Plant-based proteins, Beans
• Starchy Vegetables – Corn, Potatoes
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28. • The main function of carbohydrate is to provide
energy through metabolic pathways and cycles. This
energy is needed to carry out important processes in
our body such as breathing, maintaining the body
temperature, contraction and relaxation of heart
muscles and only source of energy for the brain.
• It has protein sparing function. Regular intake of
carbohydrates in the diet of individual prevents the
proteins from being used as source of energy.
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29. • Human body is able to defend itself against the
invading microbes and remove foreign matter( such as
dust and pollen) by the mucus in our nose and throat
due to the properties of carbohydrates.
• Certain types of carbohydrates (E.g. Inulin) encourage
the growth of healthy bacteria in the intestines for
digestion.
• Cells communicate with each other with help of
carbohydrates.
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30. • Sugars are also one of the three essential components
of both DNA and RNA.
• A less important function of carbohydrates is their use
as sweeteners. Sweeteners may be categorized into
nutritive sweeteners and alternative sweeteners.
Nutritive sweeteners impart flavour to food and they
are metabolized for energy. E.g. Sucrose, glucose,
fructose, lactose. Alternative sweeteners are hundred
times sweeter than sucrose but provide no energy.
E.g. Saccharin, cyclamate, aspartame, acesulfame
• It is the source of carbon in metabolic processes for
the synthesis of other compounds.
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31. • Some carbohydrates are dietary fibres like cellulose,
hemicellulose, pectin, gum, and mucilage. They pass
out undigested through the small intestine, thereby
making the elimination of waste easier.
• Glycan (carbohydrate polymer) serve as structural and
protective element in the cell walls of bacteria, plants
and connective tissues in animal.
• Starch is use as excipient in pharmaceutical products
such as cosmetics.
• In fermentation process, carbohydrates are essential to
make wine, cheese and beer. 31

32. Summary of Carbohydrate
Carbohydrate food sources
Monosaccharides
Glucose fruit juices, honey, corn syrup, maltose hydrolysis
Galactose lactose hydrolysis
Fructose fruit juices, honey and sucrose hydrolysis
Disaccharides
Maltose germinating grains, starch hydrolysis (glucose + glucose)
Lactose milk, yogurt, ice cream (glucose +galactose)
Sucrose sugar cane, sugar beets (glucose + fructose)
Polysaccharides
Amylose Rice, wheat, grains, cereals (unbranched polymer of glucose joined
by α-1,4- glycosidic bonds)
Amylopectin Rice wheat, gains, cereals (branched polymer of glucose joined by
α-1,4 & α-1,6- glycosidic bonds)
Glycogen liver, muscle (branch...)
Cellulose plant fiber, bean (unbranched polymer of glucose joined by ß-1,4-
glycosisic bonds)
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33. Chemical Test
• Starch’s test: shows a deep blue colour with
iodine and yellow colour with 5% KOH.
• Molisch’s test: solution treated with alpha-
naphthol and concentrated sulphuric acid-
purple colour is produce.
• Reducing sugar’s test: heat the solution &
add a mixture of Fehling reagent – brick red if
reducing sugar is present.
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34. • Benedict’s test: to the sample of carbohydrate
add Benedict’s solution and boil, the colour
turns from blue to green, yellow, orange, or
brick red, indicating the presence of different
types of carbohydrates.
• Tollen’s test: to the sample of carbohydrate
add Tollen’s solution, colour turns to shiny
silver mirror indicating presence of reducing
sugars.
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35. References
 Jain, J.L (2005) Fundamentals of biochemistry by S.Chand.
 Karen C. Timberlake (2012) Chemistry: Introduction to
General, Organic and Biological Chemistry 11th edition.
 Satyanarayan, U (2007) Biochemistry.
 Carbohydrate Chemistry for food Scientist, 3rd edition,
James N. BeMiller.
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36. THANK YOU
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