Natural products are chemical compounds or substances produced naturally by living organisms. With the development of modern technology, more and more plant extracts have been found to be useful to medical practice. Natural products can be divided into two major classes, primary metabolites, which are required for an organism to survive, and secondary metabolites, which are not required for an organism to survive, but usually lend the organism some form of growth or survival advantage within its environment.

1. Sem.V, Paper-XII
ECONOMIC BOTANY
Unit 5: Natural Products
Dr. Seema A. Gaikwad
Dept. of Botany
Vidnyan Mahavidyalaya, Sangola

2. Unit 5: Natural Products
Natural products are chemical compounds or substances produced
naturally by living organisms. With the development of modern
technology, more and more plant extracts have been found to be useful
to medical practice. Natural products can be divided into two major
classes, primary metabolites, which are required for an organism to
survive, and secondary metabolites, which are not required for an
organism to survive, but usually lend the organism some form of
growth or survival advantage within its environment.
Plants provide many products for human use, such as firewood,
timber, fibers, medicines, dyes, pesticides, oils, and rubber etc.

3. A- Rubber
Introduction:
Rubber, also called India rubber, latex, Amazonian rubber, caucho as initially produced, consists
of polymers of the organic compound isoprene, with minor impurities of other organic
compounds. Thailand and Indonesia are two of the leading rubber producers. Types
of polyisoprene that are used as natural rubbers are classified as elastomers.
Currently, rubber is harvested mainly in the form of the latex from the rubber tree (Hevea
brasiliensis) or others. The latex is a sticky, milky and white colloid drawn off by making
incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex
then is refined into rubber that is ready for commercial processing. In major areas, latex is
allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into
dry forms for sale.
Natural rubber is used extensively in many applications and products, either alone or in
combination with other materials. In most of its useful forms, it has a large stretch ratio and high
resilience, and also is water-proof.

4. A- Rubber: Properties of Rubber
Properties of Rubber: Elastomer commonly known as rubber is a linear polymer which possesses elasticity
and good resistance to corrosive fluids. The properties of rubber depend upon the type of fillers and
adhesives used.
Rubber finds a wide field of application because of the following properties:
1. It is elastic; because of this property a rubber band can be stretched to 9 or 10 times its original length and
when the load is removed it regains its original length.
2. It is strong and tough. Because of this property it can be put to use even under abnormal conditions.
3. It is highly impermeable to both water and air and therefore, it can be used to retain water as in rubber
bottles, hoses etc.
4. It exhibits a great resistance to abrasion, tearing and cutting over a wide range of temperature—7 to
115°C.
5. It is a bad conductor of heat.
6. It can contain liquids and gases.
7. The synthetic rubber offers great resistance to acids, petroleum products etc.
9. Its properties such as hardness, strength, abrasion, resistance etc., can be modified to the desired extent by
compounding techniques.

5. A- Rubber: Properties of Rubber
10. At low temperature natural crude rubber becomes stiff and when it frozen, it attains fibrous structure.
11. Raw rubber when heated to 130°C becomes soft and plastic. The plasticity can be varied within certain
ranges by chemicals.
12. Durability: Most rubbers are highly durable, resisting damage and degradation from abrasive and tearing
forces, impact, low temperatures, and water. They also exhibit a relatively slow heat buildup rate.
13. Resilience, also known as rebound, is the ability of rubber to return to its original size and shape
following a temporary deformation, such as contact with a metal surface
14. Tear resistance is the resistance of an elastomer to the development of a cut or nick when tension is
applied. This property, also called tear strength
15. Abrasion resistance is the resistance of rubber to abrasion by scraping or rubbing. Abrasion-resistant
rubber is used in industrial applications including conveyor belts that move coal, and pumps that handle
slurries.
16. Rubber is water repellent and resistant to alkalis and weak acids. Rubber's elasticity, toughness,
impermeability, adhesiveness, and electrical resistance make it useful as an adhesive, a coating composition,
a fiber, a molding compound, and an electrical insulator.

6. Source (Hevea brasilensis)-morphological characters
Natural rubber is obtained from latex, a milky liquid present in either the latex vessels (ducts) or
in the cells of rubber-producing plants. Around 20,000 species of plants produce latex, but only
2,500 species have been found to contain rubber in their latex. Hevea brasiliensis, the most
commonly, rubber tree or rubber plant, It is a flowering plant belonging to
the family Euphorbiaceae. It is the most economically important member of the genus Hevea
because the milky latex extracted from the tree is the primary source of natural rubber.
H. brasiliensis is a tall deciduous tree growing to a height of up to 43 m (141 ft) in the
wild, but cultivated trees are usually much smaller because drawing off the latex restricts the
growth of the tree. The trunk is cylindrical and may have a swollen, bottle-shaped base. The bark
is some shade of brown, and the inner bark oozes latex when damaged. The leaves have three
leaflets and are spirally arranged. The inflorescence include separate male and female flowers.
The flowers are pungent, creamy-yellow and have no petals. The fruit is a capsule that contains
three large seeds; it opens explosively when ripe

7. Source (Hevea brasilensis)-morphological characters

8. Source (Hevea brasilensis) - Extraction method
Rubber tapping means to make a cut in the bark of the rubber tree to harvest the latex.
Tapping is difficult to do well. In tapping, cut the lactiferous vessels are little tubes that
produce latex. When a tree is 50 centimeters in circumference at a height, of 1 meter from the
ground, that is, 5 years after it has been put in the plantation, one can begin to tap the tree. The
trees must be tapped very early in the morning, so as to harvest as much latex as possible. If
make the cuts late in the day, latex harvest is less, one third less. But you must not tap the
trees every day. When a tree is 50 centimeters in circumference at a height, of 1 meter from
the ground, that is, 5 years after it has been put in the plantation, one can begin to tap the tree.
To start the tapping, take a metal ribbon attached to a wooden lath 1.10 meters long. This
metal ribbon is at an angle of 30 degrees to the horizontal. Roll the metal ribbon round the
tree. With an awl (an iron point), make a cut along the ribbon. The cut ends when you have
gone right round the tree. The beginning of the cut and the end of the cut are on the same
vertical line. With the awl make a vertical channel from the lower edge of the cut. The cut and
the channel must be deepened. This is done with a gouge, a tool that is used by pushing it so
as to remove bark.

9. Source (Hevea brasilensis) - Extraction method
Push the gouge several times
along the cut and the channel,
taking away a very little bark at a time.
You do this so as to cut the bark
as close as possible to the cambium,
but without damaging it. As the bark is about 6
millimeters thick, the cut must be 4.5 millimeters
deep.The vertical channel is 25 centimeters long.
At the lower end of this channel, put a gutter.
Below that, put a cup called a latex cup.
Tie it to the tree. The latex flows along the cut,
into the channel, and at last, through the gutter, it
drops into the cup.

10. Source (Hevea brasilensis) - Economic importance
Rubber plays a crucial role in the Indian economy. It provides the principal raw material for
manufacturing over 35000- 40000 varieties of products ranging from toy balloons to giant
size tires. Natural rubber is one of the most important polymers for human society. Rubbers
are used in everyday life
• It is used to make car tires, conveyor belts, used as adhesive to join any material, used to
make balloons, gloves, rubber bands which are extensively used by everyone in everyday
life.
• Used to create seals and padding for a variety of automobile parts. Seals of the
windshield and window are good examples
• Used to erasing pencil marks on paper
• Rubber is an excellent option for flooring in kitchens, gyms, factories, animal shelters,
playgrounds and many other commercial places. It provides slip free, waterproof surface
which protects against injury and fatigue. It is also easy to maintain and highly
economical

11. Source (Hevea brasilensis) - Economic importance
• In its latex form, rubber can be used as an adhesive or a protective coating
for many surfaces.
• It serves as a great insulator. That means it does not conduct electricity.
That is why the material used to cover wires is made of rubber, gloves and
shoes of some construction, manufacturing, engineering workers are made
from rubber.
• In its fibrous form, natural rubber forms elastic which is used to produce
tight-fitting and expandable clothing such as wetsuits and cycling shorts.
Rubber is even found in the soles of shoes which will provide protection.
• It is used in medical devices, surgical gloves, aircraft and car tires,
pacifiers, clothes, toys, swim toys, inner tubes, lifeboats, life jackets, nozzle
sprayers, air bags etc.

12. Source (Hevea brasilensis) - Economic importance
• Other household rubber items include boots, raincoats, pond liners,
mattresses and cushions, pillows, grips on garden tools, bathtub plugs,
doorstops, earplugs, hot water bottles, aquarium tubing, faucet
washers and rug backings
• Industrial rubber is widely used in outdoor applications as it has high
resistive power and can withstand extreme weather conditions. The
ozone, UV rays, heavy wind, and rain do not impact the material
made of rubber. It performs excellently in the outdoor environment.
• Natural rubber is used in engineering applications, like anti-vibration
mounts, drive couplings, springs, bearings, rubber bands, and
adhesives.

13. Source (Hevea brasilensis) - Economic importance
• Mostly from discarded tires, can also be recycled and made
into new products, whether it is in the form of large rolls or
flexible rubber parts.
• Recycling rubber can even produce new forms of fuel that
are comparable to petroleum-based fuels and coal.
Recycled rubber is friendly to the environment: as a
substance, it is safe; it keeps tires out of landfills, and is
made with the environment in mind
• As a resource, recycled rubber is magnificent.