Herbs as raw materials

B.Pharmacy VI Semester
Herbal Drug Technology
Herbs as raw materials
Definition of herbs, herbal medicine, herbal medicinal product, herbal drug preparation
Source of herbs, Selection, identification and authentication of herbal materials,
Processing of herbal raw material
Prof. Rajesh Dholpuria (9461194611)
Seth G.L. Bihani S.D. College of Tech. Education, Sri Ganganagar

CONTENTS
 Herbs as raw materials:
 Definition of
 Herb
 Herbal medicine
 Herbal medicinal product
 Herbal drug preparation
 Source of Herbs
 Selection, identification and authentication of herbal
materials.
 Processing of herbal raw material

INTRODUCTION:
 Herbs have used in the traditional system of medicine
since time immemorial to alleviate human illness and for
the maintenance of general health.
 As per WHO, 80% of world population of the
developing countries still rely on the crude drugs and
folklore medicines for their primary health care needs.
 The interest of people in herbal medicines has increased
significantly in both developed and developing countries.
 There is a great demand for herbs, hence there is a need
to adopt systematic scientific methods for their selection,
cultivation, collection, processing and to ensure the quality,
purity, safety, potency and develop modern methods for
their quality control so that maximum benefit is obtained
from these herbal medicines

HERBS:
 It consists of entire plant or any part of the plant.
 The word herb is derived from the Latin word herba, which means
grass, green stalk or blades.
Depending upon the perspectives, the word herb has different
meanings.
 In commercial terms: Herbs gently refers the plants used for culinary
purposes.
 In horticulture: Herbs refers to herbaceous, describes the exterior of
plant
 In botany: Herbs refers to entire or aerial parts of small, annual or
biennial, non-woody plant.
 In taxonomy: Herbs refer to above ground/aerial parts such as leaf,
flower and stem.
In herbal medicines: Herbs refer to all types of plants (herbs, shrubs or
trees) used in various forms or preparations valued for their therapeutic
benefits

HERBAL MEDICINE:
It is also known as herbalism or phytomedicine.
These consist of medicinal plants or any parts of
medicinal plants, usually in unprocessed or crude
forms which have medicinal value.
They include different parts of plants like entire
aerial part, roots, rhizomes, stem, leaves, flower,
fruits, seeds, bark etc.
It includes modern standards of testing and
evaluation of herbs.
The constituents and their therapeutic activity may
be known or unknown.

WHO GUIDELINES FOR HERBAL MEDICINES:
1. Herbal medicines are finished labeled medicinal
product that contain active ingredients; aerial or
underground parts of plants or combination of plants,
either in crude or processed formulations.
2. Herbal medicines may include juices, gums, volatile
oils, fixed oils or other substances derived from plants.
3. Herbal medicines might possess excipients
4. Medicines possessing crude material mixed with
chemically distinct substances including isolated
phytoconstituents are not termed as herbal medicines.
5. The main objectives are:
a. Provisions for recommended general test methods.
b. General limits for contamination for herbal drugs.

HERBAL MEDICINAL PRODUCTS:
 Products produced exclusively from herbs and used in
medicinal purposes are called herbal medicinal
products.
 These are defined as any medicinal product, exclusively
containing one or more active ingredients of herbal
origin. In addition they may contain excipients.
 In India there are variety of herbal medicinal products
that are produced as well as exported to other countries,
which play an important contribution in country’s GDP
 It includes various herbal formulations like syrups,
mixtures and tablets and novel dosage forms like

HERBAL DRUG PREPARATIONS
 These are preparations derived from herbal drugs which
are prepared by various techniques like extraction,
infusion, decoction, maceration, distillation, expression,
fractionation, purification, concentration and
fermentation.
 Herbal drug preparation are available in market in the
form of powders, extracts, tinctures, fixed oils, volatile
oils, resins, gums, etc.
 They contain a mixture of various constituents. However
pure isolated compounds do not come under this category.
 Sometimes phytoconstituents are isolated and formulated
in appropriate dosage form in place of entire herb or parts.

SOURCE OF HERBS:
Herbs or medicinal plants can be obtained from three
sources viz:
A. Wild source
B. Cultivated source
C. By using modern scientific techniques like tissue
culture, polyploidy, mutation, hybridization, genetic
engineering, germplasm etc. on cultivated plants

A. WILD SOURCE:
The plants are obtained from wild source and grow
themselves without any type of care at unutilized land such
as forests, plains, river banks, etc.
The wild plants also have reasonable active constituents and
sometimes new variety is produced. These plants grow under
favorable conditions in natural habitat.
Advantages:
 Economical; No cost of land, caring, fertilizers, irrigation
etc.
 Less time consuming.

Disadvantages of wild plants:
 The quality of the plants cannot be predicted due to various
environmental changes.
 The plants will not be uniform in their growth and yielding
characteristics.
 The collection is uneconomical as these are widely distributed in
different locations.
 They are sparsely distributed, so chances of adulteration and
substitution are more.
 Modern scientific techniques cannot be applied to increase the
yield as well as quality.
 If the plants are obtained continuously from wild source for
prolonged period, may lead to depletion of raw material.
 They cannot fulfill the demand when required.
 Sometimes genetically different plants are developed.

B. CULTIVATED SOURCE
The plants are obtained from cultivated source.
These plants are grown with proper care by human. Care is taken toward
soil, climate, rainfall, irrigation, time of sowing and collection, altitude,
temperature, fertilizers, manures, pesticides, weeds etc.
Advantages of cultivated plants:
 The quality and purity of medicinal plants can be ensured.
 Better yield and therapeutic quality, and give more profit.
 It ensures regular supply of raw materials due to planned cultivation.
 Application of modern scientific techniques like tissue culture, genetic
engineering, hybridization, germplasm, mutation, polyploidy etc. are
possible.
 Cultivation of medicinal and aromatic plants leads to industrialization
and has given rise to several cottage and small scale industries.
 Rapid growth of phytopharmaceuticals, perfumery and allied
industries is possible due to cultivation of medicinal and aromatic

C. By using modern scientific techniques like tissue culture,
polyploidy, mutation, hybridization, genetic engineering,
germplasm etc. on cultivated plants
a. Plant tissue culture techniques as source of drugs:
 Plant tissue culture is in vitro cultivation of plant cell or tissue
under aseptic and controlled environmental conditions, in liquid or
on semisolid well-defined nutrient medium for the production of
primary and secondary metabolites or to regenerate plant.
 This technique affords alternative solution to problems arising due
to current rate of extinction and decimation of medicinal plants.
The whole process requires a well-equipped culture laboratory and
nutrient medium. This process involves various steps, viz. preparation
of nutrient medium containing inorganic and organic salts,
supplemented with vitamins, plant growth hormone(s) and amino acids
as well as sterilization of explant (source of plant tissue), glassware and
other accessories inoculation and incubation.

b. Polyploidy:
 An increase in number of chromosome in certain tissues or entire plant in
multiples of the basic or haploid number is known as polyploidy.
 Polyploidy in plants is caused by cell generations, physical agents like X-
rays, centrifugation, temperature, shock and chemical agent like colchicine.
Advantages:
 Polyploidy plant is usually healthier, stronger and larger than their diploid
counterpart.
 Polyploidy plant contains larger flowers, pollen grains and stomata.
 Phytoconstituents of some plants can be increased than counterpart diploid
plants. For example
Plants Constituents % in 2n % in 4n
Atropa belladonna Hyoscine 0.21 6.80
Artopine 0.03 6.80
Acorus calamus Volatile oil 2.10 6.40
Fenugreek seeds Diosgenin 0.60 0.63
Disadvantage:
 The effect of polyploidy is not generally predictable

c. Mutation:
Mutation is the change in nucleotide sequence of a gene. This give rise to
a new genetic trait or changed genotype.
A cell or organism which shows the effect of mutation is called mutant
and the agent which causes mutation is known as mutagenic agent
Artificial mutation: Mutation is induced artificially by exposing the plant
to abnormal environment such as radiations, temperature, and chemicals
Radiation mutation: induced by electromagnetic waves of short
wavelength (UV light, β-rays, γ-rays).
Chemical mutation: induced by chemical mutagens like nitrogen
mustard, formaldehyde, nitrous acid etc.
Advantages:
 Mutation increase the phytoconstituents of certain plants
 Chemical mutagens have a successful use in increasing morphine
content of Papaver somniferum
Radiation mutagen has increased the yield and diosgenin content of
Dioscorea bulbifera

d. Hybridization
 Hybridization is a natural or artificial method in which
there occur a union or crossing of two genetically
different plants. As a result, individual produced is known
as hybrid.
 Hybridization does not modify genetic contents of
organisms, however it produces new combination of
genes.
Advantages:
 Desirable characters of two different plants can be
obtained in a single hybrid plant.
 Phytoconstituents of some plants can be increased in
hybrid plant.

STEPS INVOLVED IN PROCESSING OF HERBAL
DRUGS
1. Selection of Herb
2. Identification and Authentication
3. Cultivation of herbs
4. Collection of herbs
5. Processing of herbal raw material

1. SELECTION OF HERBS:
 The species or botanical variety selected for cultivation
should be the same as specified in the official
Pharmacopoeia or official document.
 In case of newly introduced medicinal plants, the
variety selected for cultivation should be identified and
documented.

2. IDENTIFICATION & AUTHENTICATION
Botanical Identity: The species, subspecies, genus, variety etc
of the plant for cultivation should be verified from a qualified
botanist/Institute and recorded.
Specimens: In case of a new plant with medicinal properties
whose identity is not known, a specimen of the plant should be
submitted to a national herbarium for identification and
documented.
Seeds and other propagation materials: The suppliers of
seeds and other propagation materials should specify all the
necessary information relating to the identity, quality as well as
their breeding history.
The seeds and propagation material should be free from
contamination and disease in order to promote healthy plant.

3. CULTIVATION OF MEDICINAL PLANTS:
 Cultivation of medicinal plants requires intensive care and
management as various factors like environment, soil,
irrigation, pests etc. play a vital role. These factors vary
from one plant to another.
 Scientific documented methods should be followed. If no
data available, traditional methods should be adopted and
a systematic method should be developed through
research.
 Good agricultural practices (GAP) and conservation
agriculture (CA) improve, conserve and make more
efficient use of natural resources.

4. COLLECTION OF HERBS:
 The proper time of collection is important because the
nature and quantities of constituents vary greatly in some
species according to the season.
 The two basic factors which should be considered during
collection are:
oThe plant parts should be collected when the level of
active constituents are maximum and when the material
will dry to give the maximum quality and appearance.
oThe environmental conditions in which the plant give
maximum active constituents should be considered. The
different environmental factors to be considered are
light, humidity, altitude, rainfall, soil type etc.

General scheme for collection of different parts of the
plants is as follows:
 Roots and Rhizomes: Roots are collected in the
beginning of the spring season just before the flowering.
Rhizomes are collected during the reproductive phase ie
when they contain maximum amount of the reserve food
stores and active constituents. Eg. Liquoroice and
Rauwolfica.
 Leaves: leaves of the plants are collected before plant
reaches the flowering stage. Eg. Senna, Belladonna.
 Flowers: flowers are collected before pollination takes
place. They are collected when the weather is dry and
especially during morning hours. Eg. Clove, Saffron.

 Bark: the time period of collection differs from different plant
barks. Bark is collected during spring, early summer, winter or
in autumn. The age of the tree at the time of collection is also
important. There are three methods to collect bark as follows:
oFelling method: Trees are cut from the base and bark is
peeled out.
oUprooting method: entire tree is uprooted ie pulled out
along with its roots. And the bark is removed.
oCoppicing method: the plant is cut at a certain distance
from soil leaving behind a stump known as stool. The stool
give out new shoots which are cut off to collect their barks.
This method is highly economical and rapid. Eg.
Cinnamon and Cascara.

 Gums and Latex: these are obtained by making incisions
on the plant parts and are then collected immediately as
they are oozes out. Eg. Acacia, Opium.
 Fruits: fruits are collected from plants when they are
fully grown in size. They may collected in ripe or unripe
conditions.

WHO guidelines regarding collection of Medicinal Plants.
1. Medicinal plants should be reaped when they are at the
most ideal quality for the proposed utilization.
2. Damaged plants or plant parts should be avoided.
3. Medicinal plants should be collected under the most
ideal conditions keeping away from wet soil dew, rain or
high air humidity. In the case when the reaping happens in
wet conditions, possible adverse effects should be checked
because of expanded dampness level.
4. Cutters or harvesters must be maintained so that the
contamination from soil particles is reduced to a minimum
level.

5. The harvested medicinal plants should not come into
direct contact with the dirt. It must be immediately
gathered and transported in dry and clean conditions.
6. During reaping, care should be taken to ensure that no
dangerous weeds bled with the medicinal plants.
7. All containers/holders utilized during collection must be
clean and free of contamination from past harvests. At the
point when containers are not being used, they should be
kept in dry conditions, free of bugs and out of reach to
mice/rodents, domesticated animals and residential
creatures.

8. Mechanical harm and compacting of medicinal plants
that can bring undesirable quality changes must be
avoided. In this regard consideration must be paid towards
overloading of sacks and stacking up of sacks.
9. Newly collected medicinal plants must be conveyed as
fast as possible to the handling office with a specific end
goal to avoid contamination.
10. The collected product must be shielded from pest, mice
or rodents, domesticated animals and house hold creatures.
Any post control measures taken, must be recorded.

5. PROCESSING OF HERBAL RAW MATERIALS
Processing of herbal raw materials involves various stages
for which the crude drugs undergo after harvesting.
Processing is classified as primary and secondary processing
which are further subcategorized as follows:…
Primary processing Secondary processing
Garbling Cutting/sectioning
Washing Ageing/sweating
Boiling Banking/Roasting
Leaching Boiling/streaming
Drying Stir/frying
Fumigation

Drying:
Slight excessive moisture in the crude drug deteriorate the
quality of the drug and also increases its weight. Before
marketing a crude drug it is necessary to dry it properly
because:
 Drying removes sufficient moisture to ensure good
keeping qualities.
 Drying prevents molding, the action of enzymes, the
action of bacteria and chemical or other possible changes
in the crude drugs.
 Drying preserve the drug for a longer time and give better
pharmaceutical elegance.

 Drying fixes the constituents and facilitates grinding and
milling.
 Drying converts the drug into a more convenient form for
commercial handling.
 Drying improves the quality of the drug and make it
resistant to the growth of micro organisms.
 Proper and successful drying involves two principles;
ocontrol of temperature and
oregulation of air flow.

Methods of drying:
 Depending upon the type of chemical constituents,
suitable drying method can be chosen. There are two
methods of drying: Natural drying and Artificial drying.
oNatural drying (Sun drying): when the contents of
the drugs are quite stable to the temperature and
sunlight, the drugs can be dried directly in sunshine
eg. Gum acacia, seeds, small sized fruits.
Shade drying: When the natural color and volatile
principles of the drugs are to be retained, drugs are
dried in shade. Eg. Digitalis, clove, senna, peppermint,
leafy and flower drugs.

Artificial Drying: 3 methods
a.Tray Dryer (oven drying): this method is used for the
drugs which do not contain volatile oils and are quite stable
to heat or which need deactivation of enzymes.
In this process hot air of required temperature is circulated in
the oven. Eg. Roots and bark drugs.
b.Vacuum dryer; the drugs which are sensitive to high
temperature are dried by this method. Eg. Tannins, digitalis
leaves.
c.Spray dryer: few drugs which are sensitive to atmospheric
conditions and also to temperature of vacuum drying are
dried by this method. Eg. Papaya latex, pectin etc.

Special methods of drying:
 In certain drugs, some special methods are required to
attain specific standards. Eg. Fermentation is done in case
of cinnamon bark and gentian root.
 For fleshy and thick plant parts; slicing and cutting into
smaller pieces is done to enhance drying.
 The flowers are dried in shade to retain their color and
volatile oil contents.

Garbling (Dressing):
 Garbling consists of the removal of extraneous matter
such as other parts of same plant, dirt, sand, foreign
organic matter and added adulterants.
 This step is done to some extent during collection and
harvesting, but should also be carried out after the drug is
dried and before packaging. Garbling may be done by
hand picking or by mechanical means. Eg. Clove stalks
are removed from the clove.
 Rhizomes are separated from roots, rootlets and stem
bases.
 Small pieces of bark are removed the gum.

Packaging:
The packaging of drugs depend on the final disposition.
While packing of crude drugs the main points to be
considered are:
oThe morphological and chemical nature of drugs.
oIts ultimate use.
oEffect of climatic conditions during transportation and
storage.
oThe type of packaging should be choosen that provide
protection to the drug and gives economy of space.

Examples of packaging:
 Most of the leafy drugs are baled with power balers into a solid
compact mass and then packed into burlap or gunny cover.
 Aloe is packed in goat skin.
 Resins like colophony and balsams of tolu are packed in kerosene
tin.
 Volatile oil containing drugs are packed in well closed containers,
protected from sunlight to prevent loss of volatile oil and
oxidation.
 The drugs which are very sensitive to moisture and also costly
need special attention. Eg. Squill, Ergot and Digitalis.
 Squill becomes flexible, ergot becomes susceptible to microbial
growth and digitalis looses its potency if come in contact with
slight excess of moisture. So desiccating agents such as CaO/silica

Storage and Preservation:
 Proper storage and preservation are important factors in
maintaining high degree of quality.
 Compactly and hard packed bales, barks and resinous
drug reabsorb a little moisture but drugs that are not
compactly packed can absorb moisture upto 10% to 30%.
 Moisture in the drug:
oreduce the percentage of active constituents.
oIncrease the weight of the drug.
oFacilitate enzymatic activiey and fungal growth.
 Light adversely affect the colored drugs, make them
unattractive and cause undesirable changes in the
constituents.

 The oxygen of the air increases oxidation of the
constituents of the drugs especially when oxidases are
present. Therefore the warehouses should be cool, dark
and well ventilated.
 The insects also infest vegetative drugs. The simplest
method used for destruction of insects and prevention of
their attack is to expose the crude drugs at 650
C.
 Large lots of drugs are stored in ware houses and are
fumigated with methyl bromide.
 If drugs in small quantities are stored in tight containers,
insects attack can be controlled by adding few drops of
chloroform or carbon tetra chloride from time to time.

 Small lots of drugs may be stored in tight and light
resistant containers. The tin cans, covered metal bins or
amber glass containers are most satisfactory.
 Crude drugs should not be stored in open, wooden boxes
or drawers and never in paper bags. It not only hasten the
deterioration but their odors are communicated from one
drug to another, attacks by insects are facilitated and
destruction by mice and rats may occur.
 In the case of digitalis and ergot where low moisture
content must be maintained at all times, a suitable non-
liquefying, inert, dehydrating agent may be introduced
into the tight container.

 High temperature accelerate all chemical reactions. So
drugs must be stored at possible low temperature. The
ideal temperature is just above freezing, but since this is
impractical in most cases, the ware house or other storage
places should be kept as cool as possible.

1
Prof. Rajesh Dholpuria
HOD, Pharmacognosy Section
Seth G.L. Bihani S.D. College of Tech. Education
Sri Ganganagar-335001 (Raj.)
Mob.: 94611-94611
E.mail: rajeshdholpuria@gmail.com

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