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Herbs as raw materials.ppt by Dr.U.Srinivasa, Professor and Head, Srinivas College of Pharmacy, Mangalore
1. HERBS AS RAW MATERIALS
Dr. U.Srinivasa, Professor and Head
Srinivasa college of pharmacy,
Mangalore – 574143
Email – drsrinivaspharmacy@rediffmail.com
2. WHAT IS HERB
In Pharmacognosy
Herb is a drug composed usually of
the tender parts of the plant axis.
(the stem + leaves +flowers + fruits)
3. A MEDICINAL HERB
It is different from botanic term “herb": It refers to
a plant or plant part valued for its medicinal,
aromatic or savory qualities. Herb plants produce
and contain a variety of chemical substances that
act upon the body.
Herbal medicine = Botanical medicines =
Harbalism = Phytomedicine
It is the useof herbs for theirtherapeutic or
medicinal value.
4. DIFFERENCE BETWEEN HERBAL AND
CONVENTIONAL MEDICINES
Conventional medicine
Contains one active principle in high
concentration
Is simple with single indication
HerbaI medicine
Contains several active principles in low
concentrations.
Is complex promoted for several divergent uses.
5. HERBAL MATERIALS
Herbal materials include, in addition to herbs,
fresh juices, gums, fixed oils, essential oils,
resins and dry powders of herbs.
In some countries, these materials may be
processed by various local procedures, such as
steaming, roasting or or other plant materials
6. HERBAL PREPARATIONS
Herbal preparations are the basis for finished
herbal products and may include comminuted or
powdered herbal materials, or extracts, tinctures and
fatty oils of herbal materials.
They are produced by extraction, fractionation,
purification, concentration or other physical or
biological processes.
They also include preparations made with natural
vehicle or heating herbal materials in alcoholic
beverages and/or honey, or in other materials.
7. Finished herbal products
Finished herbal products consist of one or more
herbal preparations made from one or more herbs
(i.e. from different herbal preparations made of the
same plant as well as herbal preparations from
different plants.
Products containing different plant materials are
called “mixture herbal products”. Finished herbal
products and mixture herbal products may contain
excipients in addition to the active ingredients.
8. HERBAL MEDICINE
The definition of herbal medicine is the use of
plants to prevent and treat an illness, or to achieve
good health, as well as the drugs and tinctures that
are used.
An example of herbal medicine is using a tincture
made from ginger to relieve an upset stomach.
Also called Herbalism, Phytomedicine or
Phytotherapy.
9. HERBAL MEDICINAL PRODUCTS
Herbal medicinal products are medicinal
products where the active ingredient consists
exclusively of herbal substances or herbal
preparations.
Natural remedies are medicinal products where
the active ingredient is of natural origin and
consists of an animal part, a bacterial culture, a
mineral or a salt.
It includes various herbal formulations like
tablets, syrups, capsules, semisolid dosage
forms etc
10. HERBAL DRUG PREPARATIONS
Herbal preparations are the basis for finished
herbal products and may include comminuted or
powdered herbal materials, or extracts, tinctures
and fatty oils of herbal materials.
They are produced by extraction, fractionation,
purification, concentration or other physical or
biological processes
11. STEPS INVOLVED IN THE SELECTION, IDENTIFICATION
AND PROCESSING OF HERBAL MATERIALS
1. Selection of herbs
2. Identification and Authentication
3. Cultivation of herbs
4. Collection of herbs
5. Processing of herbal raw material
12. SELECTION OF HERBS :
The species or botanical variety selected for
cultivation should be same as specified in the
official pharmacopeia or natural documents.
In case of newly introduced medicinal plants,
the variety selected for cultivation should be
identified and documented.
13. IDENTIFICATION AND AUTHENTICATION
OF HERBAL DRUGS
BOTANICAL IDENTIFICATION :
The species, subspecies, genus, variety etc of
the plant for cultivation should be verified from a
qualified botanist or institute and recorded.
SPECIMENS :
In case of new plant with medicinal properties
whose identity is not known, a specimen of the
plant should be submitted to a regional or
national herbarium for identification and
documentation.
14. SEEDS AND OTHER PROPAGATION
MATERIALS :
The suppliers of the seeds and other
propagation materials should specify all the
necessary information relating to the identity,
quality as well as breeding history,
The seeds and propagation material should be
free from contamination and diseases in order to
promote healthy plant growth.
15. CULTIVATION OF MEDICINAL PLANTS :
Cultivation of medicinal plants requires
intensive case and management as various
factors such as 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.
16. Good agricultural practices in cultivation
(GACP) and conservation agriculture (CA)
which aims to improve and make more efficient
use of natural resources
17. COLLECTION OF HERBS :
For collection of medicinal plants , a proper time
should be selected .
Herbs are selected for collection at a stage
when they yield maximum amount of chemical
constituents.
Skilled labour should be employed as they are
trained to identify and select the herbs at a
proper stage.
18. The age of the plant also plays a vital factor
for their selection,
Diseased plants should be rejected.
Season of collection should be given due
consideration while selecting the plants for
collection.
19. PROCESSING OF HERBAL RAW MATERIALS :
Processing of herbal raw materials involves
various stages from which the crude drugs
undergo after harvesting.
It can be classified into primary and secondary
processing which are further sub categorized to
PRIMARY PROCESSING –
1. Garbling
2. Washing
3. Blanching
4. Leaching
5. Drying
21. Garbling ( Sorting )
This process helps in ensuring the purity and
cleanliness of the harvested material.
Dirt like soil, dust, impurities like insects, dead
tissues and residual non medicinal plants are
separated from the raw material.
The process depends on the part of the plant
to be prepared.
22. The process may involve procedures such as
removing dirt and foreign substances,
discarding damaged parts, peeling of barks,
sieving, removal of hairs from roots, removal
of seeds from fruits etc
This may be done by mechanical means but in
some cases it is usually performed manually
by hands.
23. Washing
After garbling the herbal raw material should be
cleaned well to remove the traces of remaining
soil, dirt and other impurities from the surface.
The roots, rhizomes and tubers are washed
with clean water.
24. Blanching
After washing, certain herbal raw materials
need to undergo blanching (Parboiling)
process in which they are put in boiling water
for a short period.
This may help in improving the storage life of
the raw material and prevent insect / mold
(Fungi) contamination.
25. Leaching
Some impurities can be removed by subjecting
the plant material under running water known
as leaching.
However the duration of leaching should be
controlled to prevent the loss of chemical
constituents present in the drug.
26. Drying
In some cases the plant material should be
thoroughly dried after washing in order to
prevent the deterioration and degradation of
active constituents.
They must be dried as soon as possible to
remove moisture and reduce the damage due
to microbial or mold (Fungi) infestation.
27. Drying also prevents the activation of certain
enzymes which may otherwise degrade the
active ingredients and also facilitate grinding
and milling of the raw material
Methods of drying :
1. Natural drying –
Sun drying and Shade drying
2. Artificial drying
28. Natural drying –
Sun drying –
Most of herbal raw material can be dried in
open air under direct sunshine provided the
climate is suitable.
The duration of drying process depends on the
physical structure of the plant material and
weather conditions.
29. The plant material should be spread out in
thin layers, care should be taken to prevent
contamination by dust, impurities.
While drying the plant material should also be
protected from insects, birds, rodents, pests
and other domestic animals
30. Shade drying :
Some medicinal plants cannot be directly
exposed to sunlight, hence need to be dried
under shade.
This drying process is slow but helps in
minimizing loss of colour, volatile oils and
aromatic components from being evaporated.
31. Artificial drying :
Drying by artificial heat is more rapid than open
air drying and is necessary in rainy season and
regions where is high humidity.
The temperature and equipment's used for
drying depends on the physical and chemical
nature of the drug and its constituents.
32. Various equipment's such as tray dryers,
spray dryers, vacuum dryers are used
Over heating may lead to excessive loss of
volatile components as well as decomposition
of chemical constituents.
The temperature should be kept below 600c
wherever possible
34. Cutting/sectioning and communition :
After thoroughly drying , the herbal materials are
processed by cutting and sectioning into smaller
sizes which are convenient for storage as well as
extraction.
Various sizes can be obtained depending on the
part of the herb and extraction methods used.
It may be small particles, coarse powder or fine
powder.
35. Aging/sweating :
Aging refers to storing the raw material for a
specified time after harvesting.
It is generally done under sun or in shade for
up to a year.
During the process of aging excessive water is
evaporated and enzymatic reactions may occur
to alter the chemical composition of herbal
material.
36. Example –
Cascara bark should be aged for at least one
year prior to use in medicinal preparations to
reduce its irritant effects
37. Sweating :
Sweating is done by subjecting the herbal
materials at a temperature between 450c to
650c with high humidity for a period ranging
from one week to few months.
The sweating process is considered a
hydrolytic and oxidative process in which
some of the chemical ingredients of the herbs
are hydrolyzed or oxidized.
38. Example – Vanilla beans are subjected to
sweating between woolen blankets for about
2 months during which they lose up to 80% of
weight and develop a characteristic desirable
color and odour
39. Baking /roasting :
It is a process of drug heating where the herbal
material is heated in ovens.
The temperature of heating and duration of
baking or roasting vary from one herbal
material to another until the drug develops a
specific colour.
Example – Nutmeg is roasted till they turn to
yellowish brown colour
40. Boiling/steaming:
In the boiling process the drug is cooked in
water or any other liquid solvent such as
vinegar, wine, milk or animal urine.
Example- Acorus calamus rhizome is boiled in
cows urine to enhance its anticonvulsant
activity
41. Steaming:
In the steaming process the herbal material is
kept in contact with steam using a steamer
resulting in development of moist texture.
Example – Roots of Polyganum multiforum
are steamed in the presence of black bean
decoction to enhance its tonic effects.
42. Stir frying :
It is process in which the herbal materials are
put in a pot of frying pan and continuously
stirred for specific period under heat until the
external color changes, charred or even
carbonized.
To facilitate uniform heating, the drug material
can be admixed with sand, talc or clay.
Example – Liquorice roots and rhizomes are
stir fried with honey.
43. Fumigation :
Sometimes the harvested raw materials are
subjected to fumes.
Fumigation with sulphur dioxide is commonly
employed for some medicinal herbs for the
purpose of preserving, color, improved
appearance , bleaching and preventing the
growth of insects and molds(Fungi).
44. Extraction of herbal materials :
Extraction is a process of separation in which
the chemical constituents present in plant and
tissues are removed by using selective
solvents which is called as menstrum.
Methods of extraction –
1. Infusion
2. Decoction
3. Fluid extract
4. Tinctures
5. Powder extract
