2. No. TITLE PAGE
1. Soaps & Detergents 3
• Intro 4
• Soaps 5
- History of Soap 5
Manufacturing 6
- Preparation of Soap 7
Manufacturing
- Structure of Soap Molecule
• Detergents 8
- Preparation of Detergents 9-10
- Structure of Detergent 10
Molecule 11-12
- Cleansing of Soap & 13-14
Detergent 15-16
- Additives in Detergent
- Effectivesness of Soaps &
Detergents
2. Food Additives 17
• Uses of Food Additives 18
- Types of Additives & 18
Examples 19-21
- Functions of Food Additives 21-22
- Effects of Food Additives
• The Rationale for using Food 22-23
Additives
3. Medicines 24
• Sources & Uses of Traditional 25
Medicines
• Modern Medicines 26
3. - Functions of each type of 26-28
Modern Meds
• Side Effects of Traditional 29
Medicines
• Side Effects of Modern 29
Medicines
• Correct Ways of Using 30
Medicines
4. SOAPS &
DETERGENTS
INTRODUCTION
1. Cleansing agents are chemical substance used to remove
grease and dirt.
2. There are two type of cleansing agents :
a) Soaps
b) Detergents
3. Soaps are sodium or potassium salt of fatty acids that
contains 12 to 18 carbon atoms per molecule.
4. Soaps are cleansing agents made from animal fats or
vegetable oil by saponification.
Soap is a salt of a compound known as a fatty acid. A soap
molecule consists of a long hydrocarbon chain (composed of
carbons and hydrogens) with a carboxylic acid group on one
end which is ionic bonded to a metal ion, usually a sodium or
potassium. The hydrocarbon end is nonpolar and is soluble in
nonpolar substances (such as fats and oils), and the ionic end
(the salt of a carboxylic acid) is soluble in water. The structure
of a soap molecule is represented below:
O
||
CH3-CH2-CH2- CH2-CH2-CH2-CH2- CH2-CH2- CH2-CH2- CH2-
CH2- CH2-CH2- C-O− Na+
Non-polar hydrocarbon chain ionic end.
(Soluble in nonpolar substances) (Soluble in water)
5. Detergents are structurally similar to soaps, but differ in the
water-soluble portion. Three examples of detergents are
shown below.
sodium alkyl sulfate
sodium alkylbenzene sulfonate
SOAP
The History of Soap Manufacturing
1. Soap have been used for more than 3000 years. It was recorded that the
Babylonians were making soaps around 2800 B.C.
2. The ‘Purifying Oils’ were recorded on Hebrew tablets in 4000 B.C.
3. In ancients time, soap made from ashes of plants which contain sodium carbonate
and potassium carbonate. The ashes were boiled with lime (calcium oxide) to
produce caustic potash (potassium hydroxide). Caustic potash is then boiled with
the animal fats to produce soap.
a) Ash + Lime boiled Caustic Potash
(K2CO3) (CaO) (KOH)
6. b) Caustic Potash + Animal Fats boiled Soap
4. In 1861, the Belgian Chemist Ernest Solvay (1838-1922) discovered the process to
make soda (sodium carbonate) from common salt (sodium chloride) and calcium
carbonate.
5. This process is known as the Solvay Process which produces sodium carbonate
cheaply for industrial use. Sodium carbonate (often called soda or soda ash) is
used for making glass, soaps and detergents.
6. Michel Chevreul (1786-1889), a French chemist, was noted for his research in the
composition of animal fats is composed of fatty acids and glycerol. This discovery
contributed to the rapid development of the soap and candle industry.
Preparation of soap by saponification
1. Soap is a cleansing agents produced by the reaction between sodium hydroxide
and potassium hydroxide with animal fats or vegetable oils. This reaction is known
as saponification.
2. Fats and vegetable oils are large, naturally occurring ester molecules. When fats or
oils are boiled with concentrated alkalis, such as sodium hydroxide, saponification
occurs and the ester molecules are broken down into soap and glycerol.
Fats or vegetable oils + concentrated alkalis soap +glycerol
7. 3. Saponification is the alkaline hydrolysis of ester using alkali solutions. From the
chemist aspect, soaps are sodium salts or potassium salts of long chain
carboxylic acids (with 12 to 18 carbon atoms per molecule).
4. Some examples of soaps are shown below.
a) Sodium palmitate, C15H31COONa
b) Sodium oleate, C17H33COONa
c) Sodium stearate, C17H35COONa
Additives such as perfume, colouring matter and sometimes antiseptics are added
to soaps to enhance their marketability.
5. Glyceryl tristearates are naturally occurring esters commonly found in animal fats
and vegetable oils. When the ester is boiled with concentrated sodium hydroxide
solution, saponification (alkaline hydrolysis) occurs and mixture of sodium
stearate (soap) and glycerol is obtained.
CH2COOC17H35 CH2OH
CHCOOC17H35 + 3NaOH CHOH
(heating)
CH2COOC17H35 3C17H35COONa + CH2OH
Glyceryl tristearate Sodium stearate (soap) Glycerol
6. The soap produced can be precipitated by adding common salt (sodium chloride)
to the reaction mixture.
7. The sodium chloride added reduced the solubility of soap in water. As a result,
precipitation of soap occurs.
8. The properties of soap depend on :
a) The type of alkali used for saponification
8. b) The type of animal fats or vegetable oils used.
9. Soaps produced from sodium hydroxide are hard, whereas soaps produced from
potassium hydroxide are soft.
10. Animal fats (tallow) from cows and vegetable oils (such as palm oil or olive oil) ae
used for making soap.
The structure of soap molecule
1. When soap is dissolved in water, it will dissociate and produce sodium ions and
carboxylate ions (RCOO-). For example, sodium stearate dissolves in water to form
sodium ions and stearate ions.
C17H35COONa (s) + water C17H35COO- (aq)
sodium stearate stearate ions
+ Na + (aq)
2. The active substance in soap is the carboxylate ion, for example, stearate ion. The
stearate ion consist of two parts : the ‘head’ and the ‘tail’. The ‘head’ id negatively
charged and the ‘tail’ is a long hydrocarbon chain.
O
3. The ‘head’ contains the -C-O- ions which dissolves readily in water (hydrophilic)
but does not dissolve in oil. Conversely, the ‘tail’ contains a long hydrocarbon
chain which is insoluble in water (hydrophobic) but dissolves readily in oil.
4. Soaps made from palmitic acid are known as sodium palmitate. Figure 5.2 shows
the structure of the palmitate ion in soaps.
5. The figure 5.3 9a) shows the molecular model of palmitate ion and Figure 5.3 (b)
shows the simple representation of the structure of the palmitate ion.
9. (a) The molecular model of the palmitate ion.
(b) The diagrammatic representation of the soap ion.
DETERGENTS
1. Detergents are synthetic cleansing agents made from hydrocarbons obtained from
petroleum fractions. Thus, detergents are petrochemicals.
2. Detergents can be classified into three main types, depending on the charge on the
detergent ion.
a) Anionic detergents where the head of the detergent particle contains a
negatively charged ion.
Negatively
- + charged ion
Example: R – O – SO3 Na (Sodium alkyl sulphate)
b) Cationic detergents where the head of the detergent particle contains a
positively charged ion.
Positively
Example: R – N (CH3)3+BR- charged ion
c) Non ionic detergents
Example: R – O – CH2CH2OH
3. There are two types of anionic detergents :
a) Detergent molecule with a benzene ring such as sodium alkylbenzene
sulphonate.
10. Where R represents a
long hydrocarbon
chain.
We can represent the detergent ion, alkylbenzene sulphonate ion, more simply as :
b) Detergent molecule without a benzene ring such as sodium alkyl sulphate.
We can represent the detergent ion, alkyl sulphate ion as:
R – OSO3
Preparation of detergents
11. 1. The detergent, sodium alkyl sulphate can be prepared from alcohols with chain
lengths of 12 to 18 carbon atoms in two steps.
Steps 1: Reaction with concentrated sulphuric acid
Step 2: Neutralisation with sodium hydroxide solution.
2. An example of a long chain alcohol is didecan – 1 –ol, CH3(CH2)10CH2OH. The
detergent prepared from dodecan -1 –ol is called sodium dodecyl sulphate (IUPAC
name) or sodium lauryl sulphate (common name). CH3(CH2)10CH2O-SO3-Na+ .
3. Sodikum alkylbenzene sulphinates, were first used in 1940s. It can be prepared in
three steps. The starting materials for making this detergents in a long chain
alkene, RCH = CH2 , obtained from the cracking of petroleum.
a) Step 1 : Alkylation
12. Alkylation is the introduction of the alkyl group to an organic molecule.
b) Step 2 : Sulphonation
Alkylbenzene produced the react with concentrated sulphuric acid acid to
form alkylbenzene sulphonic acid.
Sulphonation is the introduction of the sulphonic acid group, -SO3H to an
organic molecule to form sulphonic acid.
c) Step 3 : Neutralisation
Alkylbenzene sulphonic acid produced reacted with sodium hydroxide to
form sodium alkylbenzene sulphonate, the detergent
The structure of detergent molecule
When a detergent is dissolved in water, it dissociates to form sodium ions (Na+) and
detergent ions. The detergent ions have the same basic structure as the soap ions, that is
consist of two parts :
a) The ‘ head’ is the sulphate group (-OSO3-), which is negatively charged and
hydrophilic (dissolves readily in water but not in oils and grease).
b) The ‘tail’ is the long hydrocarbon chain, which is neutral and hydrophobic
(dissolves readily in oils and grease, but not in water).
13. alkyl sulphate ion
Alkylbenzene sulphonate ion
The cleansing of soap and detergent
1. The cleansing action of soap or detergent depends on their chemical bonding and
structures.
a) The ionic ‘head’ (negatively charged) is soluble in water (hydrophilic) but
insoluble in oily layer.
b) The long hydrocarbon ‘tail’ (neutral) is insoluble in water (hydrophobic) but
soluble in oily layer.
2. Oil cannot be washed away from clothing with water because oil (a covalent
molecult0 is insoluble in water.
3. Lifting greasy dirt from the surface cloth. When soap or detergent is added to the
dirty surface of a piece of cloth covered with a layer of oil or grease.
a) The negatively charged ‘head’ (hydrophilic) of soap ions or detergent ions
dissolves in water.
b) The hydrocarbon ‘tail’ (hydrophobic) of soap or detergent ions dissolves in
the layer of grease.
14. 4. I the water is agitated slightly, the grease begins to be lifted off the surface. This
cause by the forces of attraction between the water molecules and the negatively
charged heads.
The cleansing action of soap
5. On further agitation during washing, the greasy dirt is lifted from the surface.
15. 6. Emulsifying dirt in water
a) Soaps and detergents can act as emulsifying agents to emulsify oils and
grease.
b) The process of emulsification breaks large drops of grease into smaller
droplets that floats in water. The greasy droplets repel on another because
they carry the same charge. As a result, the grease is suspended in the
solution.
c) When the cloth is rinsed with the water, the droplet will be carried away.
d) The cleaning process become more efficient in the water containing the
soap or detergent solution is stirred
16. Additives in detergents
1. Modern detergents used for washing clothes usually contains a few types of
additives to :
a) Increase their cleaning power.
b) Make them attractive and saleable.
2. Only about 20% of the substances in a detergent are cle4ansing agents (sodium
alkyl sulphate or sodium alkylbenzene sulphonate). The other substances are
additives. The examples of addictives and their functions are described as follows:
3. Builders : Sodium tripolyphosphate (Na5P3O10)
a) Sodium tripolyphospathe is usd to soften hard water. In the presence of
sodium tripolyphosphate, Ca2+ ions and Mg2+ ions are removed.
b) Sodium tripolyphosphate increases the pH value of water. In this way,
muddy dirt can be removed.
4. Whitening / bleaching agents : sodium perborate
a) Bleaches (bleaching agents) remove coloured stains by oxidation process.
When coloured stanis are oxidized, the colour will disappear.
17. b) The whitening (bleaching) agents commonly used in detergent are sodium
perborate (NaH2BO43H2O). Sodium perborate decomposes in hot water to
release oxygen (an oxidising agent) which is responsible for the whitening
(bleaching) action.
c) Unlike chlorine, oxygen does not bleach the colour of dyes are not
damaging to fabrics. When properly used, the perborate bleaches make
fabrics whiter than chlorine bleaches and the colourful dyes of the fabrics
do not fade when dirty stains are removed.
d) Besides sodium perborate, sodium hypochlorite, (NaCIO) can also be used
as bleaches in detergents. The IUPAC name of sodium hypochlorite is
sodium chlorate (I).
e) Sodium hypochlorite releases chlorine that bleaches with dirty stains.
However, high concentrations of chlorine can be quite damaging to fabrics.
These bleaches do not work well on synthetic fabrics (polyster fabrics),
often causing a yellowing rather than the desire whitening. Also chlorine
causes the dyes on fabrics to fade.
5. Biological enzymes : Amylase, lipase, and protease
a) Protein stains such blood, milk, and tomato sauce cannot be removed by
the ordinary detergents because these types of stains are insoluble in
water.
b) Biological enzymes in detergents can break down fat and protein
molecules in food stains. The fatty acids, glycerol and amino acids
produced are soluble in water and are removed during washing.
6. Brighteners
a) Figure below shows the action of brighteners. The brighteners absorb the
invisible ultra-violet and re-radiate it as blue light.
18. b) Brighteners make fabrics appear whiter and brighter because the blue light
can hide any yellowing on the fabrics. Blue light added to the yellow light
reflected on old fabrics make them look white.
7. Drying agents ; Sodium sulphate and sodium silicate
Anhydrous sodium sulphate and sodium silicate (Na2S2O3) are used as drying
agents to ensure that the detergent in powdered firm is always in a dry condition.
8. Stabilisers
a) The functions of stabilizers is to prevents the formation of foam.
b) In an automatic washing machine, excessive foam can stop the pump
working. So, washing powders for automatic washing machine are made
using detergents that are good at removing and emulsifying grease, but do
not produced foam.
9. Perfumes
Perfumes are added to make clothes smell fresh and clean.
19. The effectiveness of soaps and
detergents as cleansing agents
Advantages of soaps
1. Soaps are effective cleansing agents in soft water, that is water does not contain
Mg2+ and Ca2+ ions.
2. Soaps do not cause pollution problems to the environment. This is because soaps
are made from chemical found in animals and plants. This means that soaps are
biodegradable, that is they can be composed by the action of bacteria.
Disadvantages of soaps
1. Soaps are ineffective in hard water, that is, water that contains magnesium and
calcium salts.
2. In hard water, soaps will react with Mg2+ and thus, soaps do not lather in hard
water.
3. Scum is grey solid that is insoluble in water. It consists of magnesium stearate and
calcium stearate.
4. Soaps are not also effective in acidic water, for example rainwater containing
dissolves acids. H+ ions from acids will react with soap ions to produce carboxylic
acids molecular size that are insoluble in water.
5. Stearic acids and other carboxylic acids do not act as cleansing agents because
they exist mainly as molecules and do not anionic hydrophilic ends (’head’) that
dissolves in water.
Advantages of detergents
1. Detergents are cleansing agents that are effective in soft water as well as hard
water. This is because detergents do not form scum with Mg + and Ca2+ ions found
in hard water.
2. The detergents ions (R –O – SO3- and R – SO3- )react with Mg+ and Ca2+ ions in hard
water. However, the magnesium salts and calcium salts which are formed are
soluble in water. Hence, the scum is not formed and the detergents are still active
in hard water and lathers easily.
3. Detergents are synthetic cleansing agents. This means that the structure of the
hydrocarbon chain can be modified to produce detergents with specific properties.
Nowadays, different types of detergents have been synthesised for specific uses
such as shampoos and dish cleaner.
4. Furthermore, detergents are also effective in acidic water because H+ ion is acidic
water do not combined with detergents ions.
20. Disadvantages of detergents
1. Most detergents have branched hydrocarbon chains and are non-biodegradable,
that is, they cannot decomposed by bacteria. As a result, non-biodegradable
detergents cause water pollution.
2. Phosphates in detergents act as fertilizers and promote the growth of water plants
and algae. When the plants die and decay, they will used up the oxygen dissolves
in water. This will decrease the oxygen content in water and kill fishes and other
aquatic lives.
3. Detergents produce a lot of foam in water. The layer of foam that covers the water
surface will prevents oxygen from dissolving in water. This condition will cause
fish and other aquatic life ti die from oxygen starvation.
4. Additives such as sodium hydrochlorite (bleaching agents) releases chlorine gas
in water that is acidic. Chlorine gas is highly toxic and kills aquatic life.
21.
22. FOOD ADDITIVES
USES OF FOOD
ADDITIVES
Types of additives and examples
1. Food preservative have been used since ancient times. Ancient civilization used
salt to preserve meat and fish, herbs and spices to improve the flavor of food.
2. Food additives are chemicals that are added to food in small quantities for specific
purposes such as protection against bacterial attack or restoring the colour of
food destroyed during food processing.
23. 3. Food additives are used :
a) To retard food spoilage and to preserve food (longer shelf life).
b) To make food taste better or smell better.
c) To add colouring to food so that the food looks fresher, more interesting
or more appealing.
4. There are two main groups of food additives :
a) Preservatives and antioxidants to protect food from being spoiled by
bacterial attact or atmospheric oxidation. In this way, the food can be kept
longer.
b) Flavouring agents, stabilizers, thickening agents (thickeners), and dyes
(colouring agents) to enhance the taste, smell and appearance of the food.
5. Table below show a list of different types of food additives, their functions and
examples of each types.
Type of food additive Examples of food additive
Preservatives Sodium nitrite ; sodium nitrate ; benzoic acid ; sodium benzoate ;
sulphur dioxide ; sodium sulphite ; sorbic acid ; sodium sorbate
Antioxidants Ascorbic acid (vitamin C) ; BHA (butylated hydroxyanisole) ; BHT
(butylated hydrixitoluene) ; citric acid ; sodim citrate
Flavouring agents Monosodium glutamate (MSG) ; aspartame
Stabilisers and Gelatin ; acacia gum (agar)
thickening agents
Dyes (colouring Azo compounds ; tripheny compounds
agents)
Functions of food additives
Preservatives
1. Preservatives are chemicals that are added to food to retard or to prevent the
growth of microorganism such as bacteria, mould or fungus, so that the food can
be stored for a long time.
24. 2. In ancient times, food additives from natural sources such as salt, sugar and
vinegar were used to preserve food and to make the food taste better.
3. Nowadays, synthetic preservatives are used, table below shows the types of
preservatives commonly used. Many of the preservatives are organic acids and
salts of organic acids.
Preservative Molecular formula Uses
Sodium nitrite NaNO2 To preserve meat, cheese and dried fish.
Sodium nitrate NaNO3 To prevent food poisoning in canned
foods.
To maintain the natural colour of meat
and to make them look fresh
Benzoic acid C6H5COOH To preserve sauce (olyster, tomato or
Sodium benzoate C6H5COONa chilli), fruit juice, jam and margarine
Sulphur dioxide SO2 Used as bleaches and antioxidants to
Sodium sulphite Na2SO3 prevent browning in fruit juices.
Maintain the colour and freshness of
vegetables.
To prevents the growth of yeast
Antioxidants
1. Antioxidants are chemicals that are added to foods to prevent the oxidation of fats
and oils by oxygen in the air.
2. Foods containing fats or oils are oxidized and become rancid when exposed to air.
3. When the fats and oils are oxidized, rancid product are formed. This makes the
food unpalatable. The rancid product are volatile organic compound with foul
odours (for example , butanoic acid, C3H7COOH).
4. Antioxidants are added to fats, oils, cakes, sausages, biscuits and fried foods to
slow down the oxidation process so that these foods do not become rancid.
25. Flavouring agents
1. There are two types of flavouring agents : artificial flavours and flavour enhancer.
They are added to foods to make them taste better.
2. Flavour enhancer have little or no taste of their own. They are chemicals that are
added to food to bring out the flavours or to enhance the taste of food.
3. An example of a flavour enhancer is monosodium glutamate (MSG). MSG is used to
enhance the flavours of other foods.
4. Artificial flavour includes sweeteners and other flavours such as peppermint or
vanilla. Aspartame and saccharin are examples of artificial sweeteners.
5. Both aspartame and saccharin can be used as a substitute for sugar to enhance the
sweetness in food and drink. However, the used of saccharin is banned in many
countries because it is carcinogenic. Aspartame has largely replaced saccharin as
the artificial sweetener or choice.
6. Many esters have fruity odours and tastes and are used as artificial flavours. Table
below shows some examples of esters that are used in making drinks.
Ester Benzyl Octyl Ethyl
ethanoate ethanoate butanoate
Flavour Strawberry Orange Pineapple
Stabilisers and thickening agents
1. Stabilisers and thickening agents improve the texture and the blending of foods.
2. Stabilisers are chemicals that are used to enable oil and water in the food to mix
together properly in order to form an emulsion of oil and water. Examples of
stabilizers are gelatin and acacia gum.
3. Stabilisers are added to improve the texture of foods. For examples, stabilisers are
added to ice-cream and peanut butter to keep them smooth and creamy.
26. 4. In the presence of stabilisers, the emulsion of oil does not separate from water.
This means that the stabilisers improves the stability of some foods such as ice-
cream and salad dressings (mayonnaise).
5. Without stabilisers, ice crystals would form in ice-cream, particles of chocolate
would settle out of chocolate milk, oil and vinegar in salad dressing will separate
as soon as mixing is stopped.
6. Thickening agents are chemicals that are added to foods to thicken the liquid and
to prevent the foods from becoming liquid. Thickening agents (also called
thickeners) absorb water and thicken the liquid in foods to produce a jelly-like
structure.
7. Most thickening agents are natural carbohydrates. Gelatin and pectin are added to
help jams and jellies to set.
Dyes
1. Dyes (colouring agents) are chemicals that are added to foods to give them colour
so as to improve their appearance.
2. Some foods are naturally coloured, but the colour is lost during food processing.
The foods industry uses synthetic food colours to :
a) Restore the colour of food lost during food processing.
b) Enhance natural colours, so as to increase the attractiveness of foods.
c) Give colour to foods that do not have colour.
3. Some dyes are naturally plant pigments while others are synthetically prepared.
The synthetic colours used in foods are azo and triphenyl compounds. Both these
compounds are organic compounds.
4. The synthetic dyes , brilliant blue, is an example of triphenyl compound. The
synthetic dye, tartrazine and sunset yellow are examples of azo compounds.
5. Azo compounds are organic compounds containing the diazo group, - N = N -, and
are usually yellow , red, brown, black in colour. Triphenyl compounds are organic
compounds containing three phenyl groups, -C6H5, and are usually green. Blue or
purple in colour.
Effect of food additives on health
27. 1. The types of food additives allowed and the quantity permitted
are controlled by the 1983 Food Act and the 1985 Food
Regulation.
2. The permissible quantity depends on the type of food and the
food additives. For example, benzoic acid added must not
exceed 800 mg per kg in cordial drinks, whereas sodium nitrite
must not exceed 100 mg per kg in meat product.
3. The excessive intake of food additives for a prolonged period
of time will ruin our health. The side effects arising from taking
food additives are allergy, cancer, brain damage and
hyperactivity.
4. Allergy
a) Food additives such as sodium sulphite (preservative),
BHA and BHT (antioxidants), MSG (flavouring) and some
food colours (e.g, Yellow No. 5) can cause allergic
reactions in some people.
b) The symptoms of MSG allergy are giddiness, chest pain
and difficulty in breathing. This condition is called the
‘Chinese restaurant syndrome’
c) The presence of sodium nitrate or sodium nitrite in food
can cause ‘blue baby’ syndrome that is fatal for babies.
This syndrome is due to the lack of oxygen in the blood.
Hence, the use of nitrate and nitrite is allowed in baby
foods.
5. Cancer
a) Chemicals that cause cancer are called carcinogens.
Sodium nitrite (a preservative) is a potent carcinogen.
b) The nitrite react with the amines in food to produce
nitrosamine which can cause cancer.
6. Brain damage
28. Excessive intake of nitrites for a prolonged period of time can
cause brain damage. In this condition, the supply of oxygen to
the brain is disrupted and this cause brain damage.
7. Hyperactivity
a) Food additives such as tartrazine can cause
hyperactivity.
b) Children who are hyperactivity become very active, find
it difficult to relax or sleep and are very restless.
The rationale for using food additives
Advantages
1. To prevent food spoilage
a) Oxidation and microorganism (bacteria, fungi) are the
main causes in the decomposition of food. In hot climate,
meat and fish rot easily. The use of preservatives is an
effective way to prevent food spoilage and to ensure that
foods can be supplied throughout the year.
b) If preservative are not used, food spoilage might
drastically reduce the food supply, making foods to cost
more.
c) Few deaths are associates with the use of food additives.
However, many people die due to food poisoning caused
by bacterial toxins.
2. To improve nutritional value
During food processing, vitamins and minerals may be
destroyed. Thus, additives that improve nutrition can be
added. These additives include vitamin B, C and D, and
minerals such as iron. The addition of these additives increase
the nutritional value of foods.
3. For medical reasons
a) Aspartame and sorbitol are used to make foods and
drinks sweet without using sugar. These food additives
29. are particularly useful as artificial sweeteners for
diabetic patients.
b) Artificial sweeteners give the sweet taste but without
adding calories to the food. Thus, they can be used to
reduce obesity.
c) Potassium iodide is added to table salt to reduce the
incidence of goitre.
d) Vitamin C is added to friut juices to prevent scurvy.
Vitamin D is added to margarine to prevent rickets.
Disadvantages
1. Eating food additives such as preservatives, antioxidants and
flavour enhancers is excess quantities over a long period of
time is detrimental to health.
2. Some food additives are used to make foods look more
appealing. These additives have little nutritional value. Eating
such foods increases the risk of health hazard.
3. Some foods are fortified with excess amounts of nutrients,
such as vitamins A and D, or of trace elements, such as copper
and zinc. Eating foods with excessive amounts of nutrients can
ruin our health.
30.
31. MEDICINES
Sources and uses of traditional
medicines
1. A medicine is a substance used to prevent or cure diseases or
to reduce pain and suffering due to illnesses.
2. Traditional medicines are medicines derived from natural
sources such as plants and animals without being processed
chemically.
3. Since ancients, mankind had used various types of plants and
roots, animals and animal part to cure diseases.
32. 4. Medicines obtained from plants are known as herbal
medicines. The sources and uses of some herbal medicines are
shown in table below :
Plant Part of the plant Uses
used
Garlic Corm For preventing flu
attack
For reducing high
blood pressure
Ginger Rhizome For treating stomach
(horizontal pain due to wind in the
underground stem) stomach
and leaves For supplying heat
energy to keep the
body warm
For preventing flu
attack
Aloe vera Leaves For preventing itchy
skin
For treating burns
(scalding) on the skin
Lemon (lime) Fruits For treating boils or
abscesses on the skin
For preventing flu
attack
For treating skin
diseases
Quinine Bark of Chinchona For treating malaria
tree For preventing muscle
cramps
Ginseng Roots As a tonic to improve
the overall health of
human beings
For increasing energy,
endurance and
reducing fatigue
Lemon grass Stem/leaves Has antibacterial and
antifungal properties
For treating cough
Tongkat Ali Roots As a tonic for after a
birth and general
health
33. Modern medicines
1. Before the 20th century, most medicines were extracted from
plants (herbal medicines). Since 1900. Thousands of modern
drugs have been synthesised from organic compound.
2. Modern medicines can be classified as follows based on their
effects on the human body.
3. Some examples of modern medicines are analgesics,
antibiotics, psychotherapeutic drugs.
4. Modern drugs have a trade name and a generic name. For
example, the analgesic aspirin (generic name) is sold under
different brand names such as Caprin and Disprin. Similarly,
paracetamol (generic name) is sold under the trade name of
Panadol.
5. Modern medicines usually contain a mixture of active
ingredients prepared in different forms, such as capsules, pills,
solutions or suspensions. For example, Alka-Seltzer (used as
an antacid) contains sodium bicarbonate (NaHCO3), citric acid
and aspirin. It is the sodium bicarbonate then neutralizes the
excess stomach acid.
Fucntion of each type of modern drug
Analgesics
1. Analgesics are medicines that relieve pain. Examples of
analgesics are aspirin, paraccetamol, and codeine. Analgesics
are sometimes called painkillers.
2. Aspirin and paracetamol are mild painkillers whereas codeine
is powerful painkillers.
3. Analgesics relive pain but do not cure the disease.
4. Aspirin : pain relief and anti-inflammatory action
a) The IUPAC name of aspirin is acetyl aslicylec acid. Aspirin
contains two functional groups, a carboxylic acid group
and the ester group. Thus, aspirin is aicidc in nature.
b) Uses of aspirin
Aspirin reduces fever and inflammable as well as relives
pain. Aspirin is used to :
(i) Reduce fever
34. (ii) Relieve headaches, muscle aches and joint aches
(iii) Treat arthritis, a disease caused by inflammation of
the joints
(iv) Act as an anticoagulant. It prevents the clotting of
blood and reduce the risk of the heart attack and
strokes.
5. Paracetamol
a) Paracetamol have the following structural formula. Thus,
unlike aspirin, paracetamol is neutral in nature.
b) Paracetamol is similar to aspirin in its effects (that is,
reduces fever and relieves pain) but it does not reduce
inflammation.
c) Paracetamol also reduces or relieves flu symptoms such
as fever, bone aches and runny nose.
6. Codeine
a) Codeine is an organic compound that contains the
elements of carbon, hydrogen, oxygen and nitrogen.
b) Codeine is an analgesics and is used to relive mirror to
moderate pain. Codeine is more powerful than morphine.
Codeine and morphine are narcotic drugs
c) Codeine is also used in cough mixtures for suppressing
coughs.
Antibiotics : antibacterial medicine
1. Antibiotics are chemicals that destroy or prevent the growth of
infectious microorganism.
2. Two examples of antibiotics are penicillin and streptomycin.
3. Antibiotics are used to treat diseases caused by bacteria.
4. Antibiotics are not effective against diseases caused by viral
infections such as influenza, measles, or small pox.
5. Penicillin
35. a) Penicillin is derived from the mould Penicillium notatum.
b) Penicillin are used to treat diseases, caused by bacteria,
such as pneumonia, gonorrhea and syphilis.
c) Penicillin is only effective on certain bacteria. For
example, it cannot be used to treat tuberculosis.
6. Streptomycin is the antibiotic that is effective in treating
tuberculosis.
Psychotherapeutic medicines
1. Psychotherapeutic medicines are a group of drugs for treating
mental or emotional illnesses.
2. Psychotherapeutic drugs can be divided into a few groups as
shown in table below :
Types of Example
psychotherapeutic
drugs
a) Stimulants Caffeine,
amphetamine
b) Antidepres Prozac
sant
c) Antipsycho Chloropromazin
tic agents
3. Stimulants
a) Stimulants are naturally occurring or synthetic drugs that
stimulate (excite) the activity of the brain and central
nervous system.
b) Adrenaline is a stimulant that the body produces when it
needs to prepare for demanding or energetic activities.
36. c) Stimulants make a person more alert, more energetic,
less tired and more cheerful.
d) Examples of stimulants are caffeine and amphetamines.
Caffeine is a week, naturally occurring stimulant and is
found on coffee, tea and Cola drinks.
e) Amphetamines are strong synthetic stimulants and
increase alertness and physical ability.
f) Amphetamines increase the heart and respiration rates,
as well as the blood pressure. As a result, it causes the
body to postpone the need of sleep and can reverse,
partially and temporarily, the symptoms of fatigue.
4. Antidepressants
a) Depression is a chronic illness. Most cases of depression
are caused by a chemical imbalance in the brain.
b) People experiencing depression feel hopeless. They
experience a loss of interest in everyday activities such
as work or hobbies.
c) There is a strong correlation between the amounts of
special chemicals (called neurotransmitters) in the brain
and a person’s mood. If these chemicals get too low, the
person may feel depressed.
d) Antidepressants are medicines that increase the brain’s
level of neurotransmitters, thus improving mood.
e) Antidepressants make a person feel calm and sleepy.
5. Antipsychotic medicines
a) Psychosis is the serious mental illness in which people
lose touch with reality. People with psychosis may,
Hear voice and see things that are not really there
(hallucinations)
Have belief that are not based on reality (delusions)
37. b) In psychiatry, there are a number of disorders that are
classified under ‘ psuchosis’, such as schizophrenias
(madness), psychotic depression, mania and so on.
c) Psychotic patients have extreme mood swings. Their
mood changes rapidly from high spirit to deep
depression.
d) Antipsychotic medicines do not cure symptoms to help
the person live a more normal life.
Side effects of traditional medicines
1. It is generally believed that traditional medicines have little
side effects compared to modern medicines. In fact, traditional
medicines are sometimes used to counteract the side effects of
some modern medicines.
2. However, taking high doses of quinine for a prolonged period
may cause hearing loss. German health officials recently
reported 40 cases of liver damage which were linked to the
herbal medicine containing kava-kava.
3. While the use of traditional medicine is rising globally, health
experts have insufficient data about how it affects patients.
4. The World Health Organisation( WHO) hopes to set up a global
monitoring system to monitor the adverse side effects of
traditional medicines.
Side effects of modern medicines
Type of modern
Side effects
drug
Can cause bleeding in the stomach because
aspirin is vey acidic.
Aspirin
Can cause allergic reactions, skin rashes and
asthmatic attacks
Amphetamines People who abuse amphetamines are excitable
38. and talkative.
Psychologically additive and can cause heart
attack.
Can cause anxiety, sleeplessness, aggressive
behavior and decrease appetite.
Can cause enlarged pupils, heavy perspiration and
trembling hands.
Codeine Can cause addiction.
Can cause allergic reactions.
Penicillin
Can cause death for people who are allergic to it.
Can cause nausea, vomiting, dizziness, rashes and
Streptomycin fever.
Can cause loss of hearing following long-term use.
Stimulants Can cause addiction.
Can cause addiction.
Antidepressants Can cause headaches, grogginess and loss of
appetite.
Can cause dry mouth, blurred vision, urinary
retention, constipation.
Antipsychotic
Can cause tremor and restlessness.
drugs
Sedation (make people calmer, or to make people
sleepy)
Correct ways of using medicines
In taking any medicine, we should know why the medicine is prescribed, how the
medicine should be used, what special precautions should be followed, what special
diet should be followed, what are the side effects, and what storage conditions are
needed. In addition, we should note the following points :
1. Self-medication
Do not prescribe medicines for yourself (self-medication) or for
other people. Discuss with your doctor and listen to him
concerning the medicine to be taken.
2. Follow the instructions given
Follow the instructions given by your doctor or pharmacist
concerning the dosage and method of taking the medicine.
39. 3. Medicines for adult and children
Medicines for adult should not be given to children and vice
versa.
4. Side effects
Visit the doctor immediately if there are symptoms of allergy
or other effects of the drugs.
5. Expiry date
Like foods, medicines also have expiry date. Do not take
medicines after their expiry dates.
