Dr.

Saheli Pradhan Mitra

• Ensuring safety and quality of
produce in the food chain.
• Capturing new market
advantages by modifying supply
chain governance.
• Improving natural resources
use, workers health and
working conditions.
• Creating new market
opportunities for farmers and
exporters in developing
countries.
It is a scientific approach to healthy growth of
medicinal plant in large scale. The growth is
defined as progressive development of the
organs with respect to various factors.
Some of the advantages of cultivations are:
(1) Cultivation ensures quality and purity of
medicinal plants.
(2) It gives better healthy yield and therapeutic
effects.
(3) It minimizes biodiversity.
(4) It supplies the raw materials to the
industries throughout the year.
(5) It provides disease free plants.
(6) It increases industrialization and helps in
unemployment problem.
(a) Sexual method:
In this method plants are cultivated from the seeds and such plants are called
seedlings. This method is also known as seed propagation. Generally good quality
seeds of high germination rate should be used for cultivation. Seeds should be free
from other seeds and impurities. Examples: Mango, Lichi, Methi, Coriander, papaya,
tomato.

Advantages:
• It is an easy method to cultivate plants.
• It gives high yields.
• It gives more number of varieties.
• It is applicable for both monocot and dicot plants.

Disadvantages:
• Sometimes it takes more time to grow.
• Hybrid plant may not get.
• Healthy plants may not get from the same field.
• Asymmetric growth of the plants may occur.
(b) Asexual method:
Vegetative part of plant, such as steam or root, is placed in such an environment
that develops new plant. Examples: Jasmine, sugarcane, potato, banana, rose.

Advantages:
• It gives high yield.
• It develops hybrid plants.
• It gives fruits and flowers throughout the year.
• Quality of cultivated plant can improve.
• This method is more useful for monocot plants.

Disadvantages:
• It requires a skilled person.
• Initially temperature and soil nature have to be controlled.
• This method is time consuming.
Plant should be cultivated in conditions which are similar to the plant’s natural habitat.
Hence climate that is temperature, rainfall and length of day, plays an important role in the
growth of plants. Different crops require different climatic patterns. Most of the plants can
grow well in sunny, dry conditions.

Examples: In cloudy weather the amount of carbohydrates in leaves is decreased, since

photosynthesis is light-dependent. As carbohydrates serve as the initial starting material
for biosynthesis, their abundance affects secondary metabolites.

Changes in temperature may also influence plant growth by affecting the rate of chemical
reactions. Excessive temperature as well as frost also affects the growth, quality and
metabolism of the medicinal plants.

High temperature leads to death of the plants and low temperature infects the plants by
microorganisms. Alkaloids content become lower in Datura stramonium during cloudy/rainy
weather, volatile oils are produced more readily in warmer weather, yet very hot days lead
to a physical loss of oil; growing peppermint in shade rather than the sun. The contents of
alkaloids in Stramonium leaves lower in rainy and cloudy weather.
The effect of latitude is important in fat producing plants.

Tropical plants (palm oil, cocoa butter) contain mainly saturated fatty acids, while the
subtropical plants give a larger amounts of unsaturated acids. The olive, almond and
sesame oils are predominant in oleic acid. The plants of temperate zones (Cottonseed,
sunflower) also contain more unsaturated acids. Peanut and olive trees grown in the
subtropics have a higher unsaturated fat content.

Examples:
Cinchona succirubra grows well at low levels but alkaloids are not produced.

The bitter constituents of Gentiana lutea are increased with altitude.

The alkaloids of Aconitum napellus and Lobellia inflata and the oil content of Thyme and
Peppermint decrease with altitude.

Pyrethrum gives the best yields of flower-heads and pyrethrins at high altitudes on Equator
(East Africa).
Humidity refers to the amount of vapour that the air holds at a given time. It is usually
expressed as a percentage in relation to the maximum amount of water vapour that the air
will hold at current temperatures.

There are three main measurements of humidity: absolute, relative and specific.

Absolute humidity is the water content of air.

Relative humidity is the ratio of actual water
vapour content to the saturated water vapour
content at a given temperature and pressure
expressed in percentage (%). Specific humidity is a
ratio of the water vapour content of the mixture to
the total air content on a mass basis.

Humidity has a major impact upon the overall

performance and final yield of the plants grown
indoors.
Irrigation and
drainage should
be controlled and carried
out in accordance with the
needs of the individual
medicinal plant species
during its various
stages of growth. Water
used for irrigation purposes
should comply with local,
regional and/or national
quality standards in order to
ensure that the plants under
cultivation are neither over-
nor under-watered.
Solar radiation plays an important role as regulator and controller of growth and development.

Solar energy provides light required for seed germination, leaf expansion, growth of stem and shoot,
flowering, fruiting and thermal conditions necessary for the physiological functions of the plant.

Solar radiation also influences assimilation of nutrient and dry matter distribution. Plants require
solar radiation for photosynthesis and their growth rate is proportional to the amount received,
assuming that other environmental parameters are not limiting.

The intensity of light has much effect on the uptake of phosphorus and potassium. Oxygen intake
increases with the increase of light intensity.

Some species of plant produce more active constituents at night like Nicotiana tobacum; Ocimum
basilicum grown in glasshouses have less phenol and terpenoids in the leaves.

On the basis of reaction to the photoperiod, the plants are classified as short day, long day and
intermediate day plants. Short day plant: Tobacco; long day: grains, menthone, menthol; intermediate
day: cotton.
Reduction in the quantity of the crude drugs also depends on the pests and their attack. The huge
losses due to pest infestation tune to lakhs of rupees every year due to less medicinal values.

Pests are detrimental for the plants and thus controlling them during cultivation of medicinal plants
is essential. These pests include fungi, viruses, weeds, insects and rodents (non insect pests).
Example of fungal pests are Pythium spinosum (rhizome rot), Currularia prasadii (leaf blight),
Septoria digitalis (leaf spot), Cercospora rauwolfiae (leaf spot) etc.

Fungus on henbane lowers the alkaloid content. Some of the viruses like tobacco mosaic virus,
cucumber mosaic virus and tobacco ring spot virus attack the Digitalis plants.

Several insects can also cause problem in the growth of the plants, e.g., Diaphania nilgirica attack
Rauwolfia plant, Phytomyza atricornis attack Mentha plants etc.

Weeds are also considered as dreadful pests that are undesired plants. They can resist the growth of
the original plants. Some weeds also causes allergies e.g., hey fever caused by ragweed, asthma
cause by Parthenium etc. Non-insect pests like rats, monkeys, birds, snails, mites, crabs also spoil the
stored crude drugs
Mechanical method: During preliminary stages they can be controlled by hand picking, pruning,
burning and trapping.

Agricultural method: Advanced breeding techniques are capable of gene manipulation in different
stages of the plant growth to get disease free healthy plants. These methods include hybridization,
polyploidy, mutation and chemical races. To control weeds, ploughing should be deep as possible so
that up-rootation of the weeds is possible. Crop rotation also helps to minimize the attack of the
pests.

Biological control: This is very useful method by combating the pests with other living organisms.
Example, mexican brittle can control the parthenium by sucking the root sap of parthenium weeds;
Australian lady bug feeds on damaging insect called cottony cushion scale insect on citrus crop etc.

Chemical control: The use of chemical pesticides also helps to control the pests like insecticides,
fungicides, herbicides and rodenticides. When necessary, only approved pesticides and herbicides
should be applied at the minimum effective level, in accordance with the labelling and/or package
insert instructions of the individual product and the regulatory requirements that apply for the
grower and the end-user countries.
Genetic differences are responsible for morphological variety and biochemical diversity.
Information on genetic divergence is essential for sustained genetic improvement of a crop.
Genetic markers are used for the improvement of the crop production. They represent
genetic differences between individual organisms or species. Molecular markers are being
increasingly used for divergence studies and are known as genotypic markers. They do not
affect the phenotype of the trait of interest because they are located only near or linked to
genes controlling the trait.

Applications:
This method is
(1) Used for characterization and identification of cultivars, varieties and natural
populations;
(2) Used to understand the genetic variability of population;
(3) Provides protection of variety by fingerprinting;
(4) Determines the phylogenetic relationships between species and
(5) Assesses varietal uniformity.
It is also known as chemodemes.

They are regarded as a group of plants of a species which have identical morphological
characters but differ in their chemical nature. Hence chemodemes are considered as
chemically separate groups within species.

The chemical characters of chemodemes are hereditary. Genotype and phenotype are
together responsible for chemical races.

Applications:
Withania somnifera has three chemical races, Chemotype I and II contains same compounds
withaferin and chemotype III contain withanolides, where both these active constituents
have different medicinal action.

Chemical races have also been reported in Claviceps purpurea, Digitalis purpurea, Digitalis
lanata, Cinnamomum zeylanicum, Ocimum sanctum etc.
Labours:
All farms need either human labour or machinery to do the work. Some farm types use very
little labour, e.g. sheep farming. Others require a large labour force, e.g., rice farming in India.

Market:
This is the customer who buys farm produce. Farmers need to sell their crops and animals to
make a profit. Perishable crops such as soft fruits fetch a high price but need to be grown with a
short travelling distance of the market.

Finance:
Profits are used to pay the wages and to re-invest in the farm e.g., buying seeds, fertilizer,
machinery and animals. This is known as feedback within the farming system.

Transport:
Transportation is an economic factor of production of goods and services, implying that
relatively small changes can have substantial impacts in on costs, locations and performance. It
provides market accessibility by linking producers and consumers. Improvements in
transportation and communication favor a process of geographical specialization that increases
productivity and spatial interactions.
Site selection:
Medicinal plant materials derived from the same species can show significant differences
in quality when cultivated at different sites, owing to the influence of soil, climate and
other factors. These differences may relate to physical appearance or to variations in
their constituents, the biosynthesis of which may be affected by extrinsic environmental
conditions, including ecological and geographical variables and should be taken into
consideration.

Selection of plants:
The species or botanical variety selected for cultivation should be the same as that
specified in the national pharmacopoeia or recommended by other authoritative national
documents. In the absence of such national documents, the selection of species or
botanical varieties specified in the pharmacopoeia or other authoritative documents of
other countries should be considered. In the case of newly introduced medicinal plants,
the species or botanical variety selected for cultivation should be identified and
documented as the source material used or described in traditional medicine of the
original country.
The soil is a dynamic, complex, constantly-changing part of the earth's crust that extends from a
few centimetres deep in some places to several metres deep in others. It is a natural medium for
plant growth and is essential for the existence of living organisms including humans.

Typically, soil is a complex mixture of inorganic and organic materials. The inorganic materials,
that is, the mineral constituents of soil are derived from parent material (the soil forming rocks)
by fragmentation and weathering. The pore spaces formed between the mineral particles of soil
are filled with water and gases. The organic components of soil comprise organic wastes, dead
remains of plants and animals, and their decomposition products. Besides, a large variety of
algae, bacteria, fungi and many small and large animals are invariably present in a fertile soil.
Mechanical forces acting upon the rocks cause physical weathering. Temperature
fluctuations cause expansion and contraction of rock surface resulting in the
formation of cracks and fissures.

During cold weather, the water present in rock crevices gets frozen and the formation
of ice results in its expansion.

The force of expansion causes breaking up of rock. Broken rock fragments roll down
the slopes and break further into smaller pieces.

Hails, rainfall and fast flowing streams are important agents of physical weathering.
Wind is another agent of physical weathering particularly when it carries sand
particles which causes abrasion of rock surface, due to friction.

It is commonly seen that tree roots often penetrate through the rock crevices and in
course of time, with the radial growth of roots, the rocks get disintegrated.
The rocks while getting disintegrated may also undergo chemical change.

Water is an important agent in bringing about chemical changes due to dissolution or

reaction of one or more components of rock materials.

Presence of dissolved materials and warm temperature favor chemical weathering.

Some components of the rock may get dissolved and reprecipitated.

Some minerals like feldspar and mica readily combine with water through the process
of hydration and become soft and easily weatherable.

Another very important process of chemical weathering is through hydrolysis in which

water dissociates (particularly in the presence of carbon dioxide and organic acids) into
H+ and OH- ions which act on silicates like orthoclase to produce silicate clays.

Oxidation and reduction reactions and carbonation are other important means of
During the early stages of soil formation, organic matter in the soil is not very high, as the
vegetation and the soil fauna are not much developed. In such soils, algae, lichens, mosses, and
other small form of plants grow and contribute organic matter through their death and decay.

In due course of time, various types of plants, animals and microorganisms colonize such soils.
They also contribute organic matter to the soil, in the form of wastes or their dead remains. This
organic debris then breaks down into simpler products. This breakdown process, also known as
decomposition is brought about by different kinds of microorganisms such as bacteria, fungi,
and actinomycetes.

They break the organic substances into various compounds such as polysaccharides, proteins,
fats, lignin, waxes, resins and their derivatives. These compounds are further broken down into
simple products such as carbon dioxide, water and minerals. This latter process is called
mineralization.

The residual, incompletely decomposed organic matter left after mineralization is called humus
and the process of its formation as humification. Humus is an amorphous, colloidal and dark
substance that is the source of energy and nutrients for most soil microorganisms.
Humus is important, as it gives the soil a loose texture ensuring better aeration. Being colloidal in
nature, it has a great capacity for imbibing and retaining water and nutrients. Humus, greatly
improves the soil fertility.
Residual Soils
Residual soils are formed at the same site where the weathering of the parent rock has
taken place or soils formed in situ from the underlying rocks. These are also called
sedentary soils. In these soils the surface layers are most weathered but the degree of
weathering decreases with increasing depth, and the rock fragments become
progressively larger and mostly chemically unaltered until they finally integrate with
the underlying parent rock.
In India, the principal residual soil types are: the reddish soils of the Vindhyas and south
of it covering most of the Peninsular India; and the black soil of south-west India. The red
soils are poor in calcium, magnesium, phosphorus and nitrogen and colored red by the
presence of iron peroxide. The black soils, also called as black-cotton soils, are rich in
clay, well supplied with potash, calcium, magnesium and iron. These are well suited to
the cultivation of cotton and are characterized by the development of wide and deep
cracks during the summer season.
Transported Soils
These soils are formed from the weathered material which is transported and deposited
away from the site of origin. Depending upon the nature of the transporting agent, the
transported soils are called:

i) Colluvial,
ii) Alluvial,
iii) Glacial and
iv) Aeolian
During weathering, the rocks are broken
down into smaller particles. The weathered
material undergoes further number of
changes, which is a complex process, known
as pedogenesis or soil development.

Whereas in weathering, mostly physical and

chemical factors are involved, pedogenesis is
largely a biological phenomenon.
Soil profile is the sequence and nature of the horizons (layers) superimposed one above the other
and exposed in a pit-section dug through the soil mantle.
The smallest three-dimensional volume of a soil needed to give full representation of horizontal
variability of soil is termed a pedon.
A soil horizon is a layer which is parallel to
the soil surface and that has properties
produced by soil forming processes but
that are unlike those of adjoining layers. It
can be divided in five main horizons:

1. The ‘O’ Horizons

2. The ‘A’ Horizons
3. The ‘B’ Horizons
4. The ‘C’ Horizons
5. The ‘R’ Horizons
1. The ‘O’ Horizons
These are the organic horizons forming above the
surface of the mineral matrix, mainly composed of fresh
or partially decomposed organic matter. This horizon is
divided into following two sub-layers:

O1 (A00) region
This is the uppermost layer consisting of freshly fallen
dead organic matter as dead leaves, branches, flowers,
fruits, dead parts of animal etc. These do not show
evident break down.

O2 (A0) region
It is just below the O1 region, in which decomposition has
begun. Thus organic matter is found under different
stages of decomposition and microorganisms like
bacteria. Fungi, actinomycetes are frequently found.
Upper layers contain detritus in initial stage of
decomposition, in which material can be fairly
recognized, whereas the lower layers contain fairly
decomposed matter, the duff.
2. The ‘A’ Horizons

These are the mineral horizons formed either at or adjacent to the surface. These are rich in
organic matter and/or show downward loss (eluviation) of soluble salts, clay, iron or
aluminium, being consequently rich in silica or other resistant minerals. This is thus also
known as zone of eluviation- downward loss or leaching.

This horizon is divided into two sub-layers:

A1 region
It is dark and rich in organic matter. The amorphous, finely divided organic matter here
becomes mixed with the mineral matter, which is known as humus. This region having a
mixture of finely divided organic matter and the mineral matter is also called humic or
melanized region. In forest soils this region is less-deeper than those of the grasslands.

A2 region
This region is of light color in which the mineral particles of larger size as sand are more, with
little amount of organic matter. Chiefly in areas with heavy rainfall, the mineral elements and
organic chemicals are rapidly lost downwards in this region, making it light-colored. This is
also known as podsolic or eluvial zone or zone of leaching.
3. The ‘B’ Horizons

These are the mineral horizons forming below the surface in which
one or more of the following features can be present.
i. Enrichment wit inwashed clay (lessivation), iron, aluminium,
manganese or organic matter
ii. Residual enrichment with sesquioxides or silicate clays
iii. Sesquioxide coatings of mineral grains sufficient to give a more
intense color than horizons above or below.
iv. Alteration of the original rock material to give silicate clays or
oxides in conditions where above mentioned conditions do not
apply.

The ‘B’ horizon is dark-colored and coarse-textured due to the

presence of silica-rich clay organic compounds, hydrated oxides of
aluminium, iron etc. Since, the chemicals leached from A2 region,
become collected in tis horizon, it is also known as zone of illuviation
or illuvial zone. This zone is poorly developed in dry areas.

A1, A2 and B collectively are also known as mineral soil or solum.

4. The ‘C’ Horizons
These are the mineral horizons below the ‘B’ but exclusively true bedrock and without any
characteristics of ‘A’ or ‘B’ horizons. It consists of incompletely weathered, large masses of
rocks.

5. The ‘R’ Horizons

This is the parent, unweathered bedrock, upon which there is collective water.
Collection of Drugs
• The collection of medicinal plants from wild populations can give rise to additional
concerns related to global, regional and/or local over-harvesting and protection of
endangered species.

• After cultivation of the plants it is essential to collect the plant parts for the next step
of harvesting.

• Crude drugs are collected from wild or cultivated plants and hence proper selection
of the plant parts and their proper collection give the improved quality of the plants. It
even helps to increase the content of secondary metabolites in the plant parts.
Hence drugs should be collected when they contain maximum amount of
constituents in a highly scientific manner.
• Plant collections are important for:

1. Voucher specimens are the only verifiable record of the occurrence of a species in
time and space.
2. The taxonomy of species is continually evolving. With herbarium specimens,
species that have been subject to taxonomic change can be verified for an area
without the expense of additional field work.
3. Even common species are sometimes misidentified in the field; less-common
species can be easily misidentified (lack of distinguishing features, lack of
magnification, lack of time, large or difficult groups) or overlooked. Hence
specimens should be collected and identified in a lab with all the tools and
resources at hand.
4. The work of field professionals can be available to a wide audience through
depositing specimens in herbarium, as the specimens are available to many
researchers, in many fields, the world over for hundreds of years to come.
Harvesting
• Medicinal plants should be harvested during the optimal season or time period to
ensure the production of medicinal plant materials and is the most important step for
finished herbal products of the best possible quality.

• The time of harvest depends on the plant part to be used. The best time for harvest
(quality peak season/time of day) should be determined according to the quality and
quantity of biologically active constituents rather than the total vegetative yield of the
targeted medicinal plant parts.

• During harvest, care should be taken to ensure that no foreign matter, weeds or toxic
plants are mixed with the harvested medicinal plant materials.

• The most important objectives of harvesting are (1) An economic point which needs
focus with type of crude drug to be harvested (2) The Pharmacopoeial standards of
which it needs to achieve.
 Drying
Drying is the most common and fundamental method for post-harvest preservation of
medicinal plants because it allows for the quick conservation of the medicinal qualities of
the plant material in an uncomplicated manner. Drying is defined as decreasing moisture
content (MC) to preserve the product for extended shelf life.

Reason for Drying:

• To help in their preservation.
• To fix their constituents, by preventing reactions that may occur in presence of water.
• To prevent the growth of microorganisms such as bacteria and fungi.
• To facilitate their grinding.
• To reduce their size and weight.
• Insufficient drying favors spoilage by microorganisms and makes it possible for
enzymatic destruction.
Packaging and storage
• Once drying is complete, plants are packaged for transportation and further processing.

• Dried herbaceous plants are generally compressed into bales weighing from 60 to 100 kg
(13 to 220 pounds), which are then sewn into fabric bags or wrapped in plastic.

• Materials that cannot be baled, such as roots and bark, are placed in sacks. Smaller bags
may be used for dense materials such as dried fruits or seeds. Very fragile materials, such
as flowers, are packaged in crates.

• Dried plant materials tend to be hygroscopic (readily absorbing moisture) and must be
stored under controlled humidity. Highly hygroscopic materials are generally packed in
plastic. The crude drugs like roots, barks, large barks are packed in gunny bags.

• Storage is the main process to maintain the quality of the crude drugs and to protect the
drugs from the insect attack. Dried leaves are stored whole in airtight containers, such as
canning jars with tightly sealed lids.
 Processing
• The active principle of the plants provides the medicinal qualities or therapeutic efficacy.
Hence the active principles are required to separate from the plant constituents by means
of extraction.

• The basic principle of extraction is the solubility of the constituents in the respective
solvent. The phytoconstituents contained in every medicinal plant consist of a number of
compounds, which individually or in groups can have a specific action on the human body.

• Different methods are used to extract these phytoconstituents in a crude extract form in
which active principles are present, either sole or collectively.