Production of Medicinal Plants in Asia

Keith Chapman Narong Chomchalow
FAO Regional Office for Asia and the Pacific Office of the President
Bangkok Assumption University
Thailand Bangkok
Thailand
Keywords: biodiversity, conservation, cultivation, threatened species, wildcrafting

Abstract
Medicinal plants have played a significant role in many ancient traditional
systems of medication in Asia such as the Ayurvedic and Unanic systems of India,
the Chinese traditional medicine, as well as their derivatives in most Asian countries.
At present, medicinal plants still play an important role in both developed and
developing countries in Asia. In addition, they also generate income to the people of
many Asian countries who earn a living from selling collected materials from the
wild or through their own cultivation.
Asia is unique among geographical regions of the world since it possesses (I)
high biological diversity, (ii) high cultural diversity, (iii) diverse ancient civilizations,
and (iv) abundant raw material for modern drug manufacturing.
Collecting naturally-occurring medicinal plants has taken place in Asia since
prehistoric time. At present, such activity, although limited in amount in most
countries, is still carried on with the objectives of using them in traditional medicine
or for processing into pharmaceutical products. Such activity generates income to
the native people, provides raw material at a low cost, and access to material not
available through cultivation. However, collection also creates problems in genetic
erosion, especially with uncontrolled collection, and thus unsustainability.
Cultivation of medicinal plants in Asia is characterized by the following
criteria: (i) subsistence cropping systems, (ii) scattered farming areas, (iii) poor
quality, and (iv) lack of integration. The advantages of commercial cultivation of
medicinal plants include: (i) helping to conserve endangered species in their natural
habitat, (ii) permitting production of uniform materials, (iii) providing good income
to the farmers, (iv) providing opportunities for value-addition through processing,
(v) providing a better environment through utilizing waste and unproductive lands,
and (vi) providing continuity of supply.
As compared to other economic crops, medicinal plants have received much
less attention in genetic and cultural improvements. Only a few countries in the
Region are now cultivating improved cultivars, while the rest still depend on wild
material collected for cultivation. Their cultivation techniques are quite primitive,
resulting in poor yield and quality of the materials. Several constraints are
envisaged, e.g. biotic (unimproved cultivars, long life cycle, susceptability to pests
and diseases), abiotic (low soil fertility, flood and drought, improper light intensity
and duration, extremes of temperatures, and physical injuries or damage),
technological (lack of good agronomic practices, lack of technology and technology
transfer, and lack of facilities) and socio-economic (competition with other economic
crops and modern drugs; lack of market channels, a domestic pharmaceutical
industry, and organized cultivation; and no price support/incentive provided).
In spite of the above constraints, medicinal plants continue to play a significant
role in the welfare of people in Asia. Due to higher demand of raw material for
industrial processing, coupled with the loss of natural habitats of most medicinal
plants, large-scale cultivation of promising species has recently been attempted in
several countries.
Proc. WOCMAP III, Vol. 5: Quality, Efficacy, Safety, Processing & Trade in MAPs
Eds. E. Brovelli, S. Chansakaow, D. Farias, T. Hongratanaworakit,
M. Botero Omary, S. Vejabhikul, L.E. Craker and Z.E. Gardner
Acta Hort. 679, ISHS 2005
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INTRODUCTION
Medicinal plants are those that possess certain chemicals that are active in treating
and preventing specific ailments and diseases. Such chemicals can be extracted for the
manufacture of pharmaceutical products.
Medicinal plants have played a significant role in various ancient traditional
systems of medication such as the Ayurvedic and Unanic systems of India, the Chinese
traditional medicine, and their derivatives in many Asian countries. At present, medicinal
plants still play an important role in developing countries in Asia, both in preventive and
curative treatments, despite advances in modern western medicine. They also generate
income to the people of many Asian countries who earn a living from selling collected
materials from the forest, or who cultivate them on their lands.
The development of modern medicine since the turn of the century, supplemented
with the introduction of modern drugs produced by pharmaceutical companies, have dealt
a strong blow to traditional medicine which was accused as being inefficient, laborious in
preparation and, most important of all, unavailable due to scarcity of raw material. This is
exacerbated by the lack of traditional doctors who cannot earn a living without basic
materials (i.e. medicinal plants) and demand (i.e. customers).
The high cost of modern drugs (most of which have to be imported from the
West), their unavailability in remote areas, and, most important of all, the serious side
effects of certain drugs, have all made the pendulum of medical treatment swing back to
the side of traditional medicine in recent years. The importance and value of traditional
and indigenous herbal medicine were the subject of WHO’s campaign during the 70’s
which led to an appeal to all member countries to do their utmost to preserve their
national heritage in the form of ethno-medicine and ethno-pharmacology and to reinclude
the use of known and tested medicinal plants and derivatives into their primary
health care in rural areas, as well as an alternative when modern medicine was not
available. Moreover, since a large portion of drugs produced by pharmaceutical industry
are derived from medicinal plants, the demand for these raw materials is steadily rising.
Such demand is met by obtaining naturally-occurring plants through indiscriminate
collecting, or by cultivating them.
ASIA: THE LAND OF MEDICINAL PLANTS
Asia is unique among geographical regions of the world since it possesses the
following tropical ranging from tundra to deserts and rainforests characters:
High Biological Diversity
Due to its widely diversified ecological conditions, particularly in the tropical rain
forests, it has a biological diversity that is the greatest of all regions of the world. This
high diversity of the Region is reflected by the number of species of plants and animals,
including medicinal plants.
High Cultural Diversity
Not only is Asia rich in biological diversity, it is also quite rich in cultural
diversity. Since the dawn of human history, biodiversity and humanity have become
inextricably linked. Areas of high biological diversity are among the most culturally
disparate, with large numbers of distinct communities inhabiting adjacent areas, each with
their own language, culture, and system of traditional medicine. The last category
depends on the availability of medicinal plants easily found within the community. A
wealth of traditional knowledge about medicinal plants to cure illness has been
accumulated over a long period and has been handed down from generation to generation
until the present time.
Ancient Civilizations
Parallel with cultural diversity that took place in isolated areas in the jungles of
tropical Asia was the existence of ancient civilizations in East and South Asia. Unlike the
47
ruins of many empires of other regions, the Chinese and the Indian were quite successful,
prosperous, and, above all, healthy. A simple argument for their being healthy is the
number of people presently living in the two most populous countries of the world.
Indonesia, which is the fourth most populous country, can also claim to have “healthy”
people as well as ancient civilization. All these ancient peoples had made extensive use of
medicinal plants to cure their ailments based on the systems of traditional medicine. From
China and India, systems of traditional medicine spread to all other Asian countries. They
were later modified to become systems of their own in most Asian countries.
Abundant Raw Materials for Modern Drugs
Asia has been well known in the modern world as the storehouse of raw materials
for western pharmaceutical manufacturers. Up to the recent past, the majority of these
raw materials were easily obtainable from collecting naturally occurring plants. Along
with cheap raw materials, accumulated traditional knowledge of native peoples of the use
of medicinal plants was also “exported” freely for further development and exploitation
by western pharmaceutical companies.
MEDICINAL PLANTS PRODUCED IN ASIA
Having a long history of being utilized by Asian people, the number of species of
medicinal plants known to the people of Asia is enormous. This makes listing of all
medicinal plants found in Asia difficult and impracticable. Thus, in order to provide a
meaningful list of medicinal plants in Asia, it is best to provide the list of promising
species and group them into two categories, namely those which are collected from the
wild and those which are cultivated.
Medicinal Plants that are Collected from the Wild
It has been estimated that four out of five medicinal plants utilized by man are
collected from the wild (Srivastana et al., 1995). The list of medicinal plants that are
collected from the wild is presented in Table 1 while the details are given in Chapter 4.
Medicinal Plants that are Cultivated
Due to higher demand of raw materials for the manufacture of drugs as well as to
meet other requirements such as standard quality, reliable supply, reasonable price, etc.,
many medicinal plants are now being cultivated. The list of medicinal plants that are
cultivated is shown in Table 2 while the details are given in Chapter 5.
Countries of Production of Major Medicinal Plants in Asia
Although most countries in Asia are capable of acquiring medicinal plants for
their traditional uses, very few are capable of producing them in commercial quantity.
These are China, India, Indonesia, and Nepal. There are also a few countries that are able
to produce medicinal plants on a commercial scale, but the quantity produced is still quite
low, and mainly utilized domestically. The list of countries of production of major
medicinal plants in Asia is shown in Table 3.
COLLECTING NATURALLY-OCCURRING MEDICINAL PLANTS
The Present Status
Collecting naturally occurring medicinal plants has taken place since pre-historic
times. As the result of population explosion and the resulting forest clearing for food
production, most Asian countries, which until recently collected medicinal plants from
the wild, have almost completely halted such practices as they are quite scarce or nonexistent.
A few countries that are able to maintain high degrees of natural forest cover are
the ones that keep on collecting medicinal plants from the wild. These countries include
Nepal, Bhutan, Lao PDR, and to a certain extent, Bangladesh, China, India, Indonesia,
and Pakistan (Table 1).
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Objectives of Collecting
1. For Use in Traditional Medicine. For native people who live in remote areas, as well
as the poor people who cannot afford to buy expensive western drugs, traditional systems
of medication such as the Ayurvedic, Unanic, Jamu, etc., are the only means to cure
illness. Such systems depend almost exclusively on medicinal plants. Of the amount
utilized in the preparation of traditional medicine, about 90% are collected from the
forests.
2. For Processing into Pharmaceutical Products. Due to the scarcity of medicinal
plants occurring naturally in the wild, the cost involved in transportation, the variability
of collected material, and the non-constant supply, very few countries are able to keep on
such a practice. The country in which this practice is made on a large scale is Nepal, due
to her favorable conditions. Previously, raw materials were collected for export (through
her southern neighbor India) for processing into pharmaceutical products, often by
western countries. However, with the establishment of a state enterprise, Herbs
Production and Processing Co. Ltd. (HPPCL), together with the installation of processing
units in remote mountainous areas, much collected raw material is now being processed
domestically.
Advantages of Collecting Naturally Occurring Medicinal Plants
1. Generating Income of Native People. In the hilly and mountainous region of Nepal,
collecting naturally occurring medicinal plants has supplemented the meager incomes
derived from subsistence farming (Rawal, 1996). This is further fostered by the
establishment of distillation units by the local people in these areas. These small
enterprises have uplifted the income of the local people through collecting material from
the wild, gaining value addition from local processing, and saving on high cost of
transport bulky material on rugged terrain to be sold in the city.
2. Providing Raw Material at Low Cost. In countries where naturally-occurring
medicinal plants are available in large quantity, collecting provides raw material for
pharmaceutical factories at low costs, particularly where cheap labor is also available.
3. Access of Material Not Available through Cultivation. Traditional medicine requires
a large number of medicinal plants, many of which are available only from the wild.
Collecting this type of medicinal plants is important to traditional doctors who depend on
the supply of such material.
Disadvantages of Collecting Naturally Occurring Medicinal Plants
1. Genetic Erosion. With the increasing popularization of ‘alternative medicine’ (to
modern allopathic medicine), large quantities of medicinal plants are being collected. The
amount collected varies from country to country, and from one species to another. If the
collected materials are used in traditional medicine, the amount is small and collected by
the ‘expert’ who knows what he wants. A traditional doctor depends on sustainable
supply of the materials; thus he only collects what he needs and leaves the remainder to
resume their growth for his future harvesting. On the other hand, if materials are collected
by commercial collectors for export to pharmaceutical companies, they are collected
‘vigorously’ and in large quantities, damaging not only the ones collected, but also their
neighboring plants. It often happens that these materials are greedily collected down to
the last specimens of the species. Many species of medicinal plants in the Himalayan
forests are now in danger of extinction. Mahesh Uniyal of Indian Press Service in Dehra
Dun, India, described a case of Taxus baccata, which grows at 1600 m above sea level.
This species has disappeared from large parts of India and Nepal. This is because the thin
spiked leaves of the plants yield toxol, an anti-cancer drug, thus inducing hill people to
collect the plant to sell through the middlemen (at US$3.50 per kg) to city-based
exporting firms (Uniyal, 1993).
Where materials are collected for a domestic industry, as demonstrated in the case
of HPPCL of Nepal, the situation is not that serious. In fact, the villagers who collect
materials for sale to the middlemen realize the fact that these materials are their own
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resources, thus awareness of their conservation is quite obvious.
2. Uncontrollable Quality and Quantity. As would be expected, both quality and
quantity of materials collected from the wild cannot be controlled. Often the materials are
mixtures of various kinds of medicinal plants that may look alike but, in fact, they are not.
The quantity collected depends on luck and seasonal conditions.
3. Unsustainability. As forests in most Asian countries are disappearing at a fast rate, the
supply of medicinal plants that grow in the forests is obviously unsustainable.
Measures to Conserve Naturally Occurring Medicinal Plants
Realizing the fact that naturally occurring medicinal plants are threatened, several
measures have been undertaken by various approaches or agencies. These are:
1. Systematic and Reasonable Collecting. Sustainable collecting can be achieved if it is
done properly. This is demonstrated in Nepal where a mutual benefit to the collector and
local processor results in proper harvesting techniques as well as appropriate methods of
post-harvest treatment (Rawal, 1996). Such practices provide an incentive to the
collectors for conservation of species for future collection.
2. Reduction of Pressure on Collecting. Cultivation, whether on small-scale, backyard
garden, subsistence farming, or large-scale, can reduce the pressure on collecting
naturally occurring medicinal plants in the wild.
3. National Legislation. A few countries in Asia have formulated legislation to conserve
medicinal plants. For example:
• Administrative regulation for “Protection of Wild Medicinal Plant Resources” was put
into effect in China since 1987 (Chen, 1996).
• The Ministry of Environmental Affairs of Sri Lanka formulated an “Action Plan for
Conservation of Biodiversity”, and conservation of medicinal plants has been
included as a project to be taken along with it (Arambewela, 1996).
• In 1993, the Government of India banned export of all wild medicinal plants (Uniyal,
1993).
4. International Regulations. It is a common practice of international conferences to
develop a “Declaration” or “Resolution”, within which measures to conserve medicinal
plants are included, e.g.
• Resolution of the so-called, “Washington Convention – 1973” includes a statement,
“The trade and use of some of the medicinal plants collected from wild sources are
restricted” (Hussain, 1996).
• In 1988, an international congress organized by WHO, IUCN and WWF issued the
“Chiang Mai Declaration” having a motto “Saving Lives by Saving Plants” - which
exhorted government and the public to pay attention to the potential inherent in
medicinal plants (Henle, 1996).
CULTIVATION OF MEDICINAL PLANTS IN ASIA
Characteristics of Medicinal Plant Cultivation
As medicinal plants are relatively new crops for cultivation, very few farmers in
the Region are presently engaged in their cultivation. However, it may be that such
cultivation will receive greater attention from farmers in the near future. At present,
cultivation of medicinal plants is characterized by the following traits:
1. Subsistence Cropping Systems. Medicinal plants are presently grown by smallholders
in subsistence cropping systems. This includes the use of primitive cultivars
grown in mixed cropping, i.e. together with other economic crops. The yield as well as
the quantity is quite low.
2. Scattered Farming Areas. With few exceptions, most areas growing to medicinal
plants are widely scattered in producing countries. This results in difficulty in collecting
harvested raw materials by the middlemen.
3. Poor Quality. This is due to various factors including the use of unimproved varieties,
poor cultural techniques, and poor post-harvest handling.
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4. Lack of Integration. In certain areas, medicinal plants are grown as commercial crops.
Yet in such cases, they are normally grown as intercrops, especially among food crops
that are considered primary crops as they bring income and basic foods to the farmers.
There is no systematic integration between primary crops and medicinal plants, except for
China. Even in China, where total production of medicinal plants is quite high the
proportion (mostly operated by industrial enterprises) in which medicinal plants are
grown monoculturally is very small. This contrasts with many other economic crops that
are mostly grown as monocrops.
Advantages of Commercial Cultivation of Medicinal Plants
As the supply of medicinal plants collected from the wild is decreasing due to
prevailing forest destruction and their demand is rising due to global population increases,
commercial cultivation of medicinal plants may become increasingly popular among
farmers of developing countries in Asia. The advantages of such cultivation are as
follows:
1. Help Conserving Endangered Species in Their Natural Habitat. Many species of
medicinal plants are listed as endangered species due to indiscriminate collecting for sale
to pharmaceutical industry. Cultivation of these species would help conserve them by
relieving some of the collecting pressure on them.
2. Permit Production of Uniform Material. Commercial cultivation of selected clones
or improved varieties of medicinal plants should result in production of uniform material.
Such material, in turn, will lead to consistent standard products of high quality, a prerequisite
for successful pharmaceutical industrial use.
3. Provide Good Income to the Farmers. Medicinal plants are high-value crops; thus
they should bring higher income to the growers, particularly if improved, high-yielding
clones or varieties are used as planting material.
4. Provide Opportunities for Value-Addition through Processing. Technology of
processing medicinal plants is now available in many developing countries in Asia.
Commercial cultivation would provide raw material for further processing, many steps of
which could be done in the locality where cultivation takes place.
5. Provide a Better Environment through Utilizing Waste and Unproductive Lands.
As medicinal plants yield high income to the growers, costly inputs can be used for their
cultivation. This allows the utilization of waste and unproductive lands that would
otherwise remain idle, if low value food crops are grown.
6. Provide Continuity of Supply. Cultivation engenders much less risk to the supply of
raw material. Thus, manufacturers can set production targets well in advance, with a high
probability of securing the needed raw material from cultivated plants.
Genetic Improvement
As compared to other economic crops such as food crops, vegetables, oilseed
crops, etc., medicinal plants have received much less attention in terms of genetic
improvement. This is evident in the number of named cultivars used in commercial
cultivation, which is surprisingly low. Lack of improved cultivars is due to the lack of
germplasm conservation, facilities, breeders and a lack of demand for large-scale
cultivation of medicinal plants.
There are several approaches to obtaining improved cultivars of medicinal plants:
1. Introduction from Other Countries. This is a common approach attempted by
several institutes in various countries, since it is the easiest and least time-and-effort
consuming. Moreover, introduced varieties normally yield marketable standard products.
2. Selection from already Existing Variants. Selection of the desired genotypes can be
made from existing variants contained in the germplasm collection. A variety of psyllium,
‘Gujarat Isabgol-1’, now grown commercially in India is a good example of how a variety
was developed from a single-plant selection for high tiller and spike numbers, together
with high seed yield/plant and synchronized seed maturity (Gupta, 1993). The variety is
reported to produce a grain yield of 1 t/ha in sandy soil of average fertility in western
51
India. Similarly, a selection, RS-1 of Rauvolfia serpentina, obtained from a germplasm
collection, produces high root yield and contains a stable amount of reserpine, serpentine
and ajmalicine (Gupta, 1993).
3. Conventional Breeding. Necessary steps for conventional breeding include: (a)
acquisition of genetic variability to be used as parental material. This may be obtained
from germplasm collection or through induced mutation, (b) evaluation of material for
desirable characters, (c) recombination through hybridization that may have to run
through several generations of selfing or backcrossing, and (d) selection of desired
genotypes .
Unlike food crops or other crops whose major objective in their breeding
programs is high yield of the biomass, the main objective of medicinal plant breeding is
for high quality of the major important constituents. Of course, yields of each component
and total biomass are also of considerable importance. Other characters that are aimed at
are the ease in extraction of active compounds, uniformity of the compounds and their
products, early maturity (especially of rhizome-bearing crops), resistance to pests,
diseases and environmental stresses.
Due to the lack of breeders and other facilities, not much breeding work on
medicinal plants has been conducted in most Asian countries except for India. Table 4
shows the results of breeding work on medicinal plants in India. A few cases of
successful breeding of medicinal plants are cited below:
The Indian Institute of Horticultural Research in Bangalore, India, has contributed
to upgrading the yield of crude drugs and enhancing the contents of the active principle in
Solanum viarum by breeding two varieties, ‘Arka Sanjeevini’ and ‘Arka Mahima’. The
latter, an autotetraploid, free of spines, nitrogen-responsive and with higher solasodine
content, has been developed (IIHR, 1993).
4. Biotechnological Approaches. Recent advances in biotechnological research have
been applied to genetically improve medicinal plants for commercial exploitation. These
are used as a means of:
Increasing Genetic Variability. Methods used are anther or haploid culture, and cell
suspension culture.
Culturing and Selecting Desirable Genotypes. These involve cell suspension culture and
rapid multiplication of variant cell lines of desirable genotypes.
Rescuing Embryos of Selected Genotypes. This is to overcome incompatibility resulting
from interspecific crosses.
Rapid Multiplication of Clones of Selected Genotypes. Through in vitro
micropropagation, selected genotypes can be multiplied rapidly as uniform clones.
Transferring Genes from Distant Parents. Through protoplast fusion/somatic
hybridization, transfer of genes from distant parents which cannot be transferred through
sexual means as the result of incompatibility is possible.
Specific Gene Transfer. This technique is used to introduce new characters encoded by
such genes directly into existing crops, thus retaining all the beneficial properties, and to
avoid reassortment of genes that occurs in traditional breeding.
Although many of the techniques have not yet been successfully applied to
improve medicinal plants, some have already been made quite successfully. For example,
Krumbiegel and Schieder (1981) were able to obtain 13 somatic hybrids selected from
interspecific hybridization of Atropa belladona x A. innoxia.
Cultural Improvement
Next to genetic improvement, cultural improvement contributes significantly to
the success of commercial cultivation of any economic crops including medicinal plants.
Several methods have been made to improve the cultivation of medicinal plants. These
are:
1. Good Agro-technological Practices (GAP). It has been demonstrated in a number of
species of medicinal plants that improved cultivars alone cannot produce high yield and
desirable quality of the products. It has to be accompanied by GAP such as proper soil
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preparation and fertilizer application, the use of good planting material, plant spacing,
control of weeds, insects and diseases, proper time and technique of harvesting all the
way to proper post-harvest treatment. In addition, knowledge of biosynthetic pathways
that lead to the production of physiologically important constituents which make these
crops economically valuable is of great importance. Likewise, knowledge of
physiological response of genotype to the environment will help in the understanding of
the crop’s behavior, especially with respect to enhanced fertilizer responsiveness, water
and light requirement, etc. These will also help in the reduction of crop duration in the
field, increase the amount of desirable secondary metabolite, and even reduction of any
undesirable constituents (Franz, 1993).
2. Cropping Systems. In order to obtain maximum benefits of existing space, season, soil
moisture and nutrients, several cropping systems involving medicinal plants have been
employed. These include:
Intercropping. Several cash crops, e.g. vegetable, legumes, cereals, root crops, etc. can be
grown together with medicinal plants, with several advantages, e.g. reduction of weed,
extra income, from the same area. This practice is particularly recommended for
medicinal plants with lengthy periods of growth, e.g. rauwolfia, periwinkle, dioscorea,
turmeric, ginger, etc.
Crop Rotation. This practice not only reduces incidence of weed growth but also of seedborn
diseases. Normally, leguminous crops which provide nitrogen through their ability
to fix atmospheric nitrogen are often used in crop rotation programs with medicinal crops.
Indian farmers who grow psyllium, opium poppy and other medicinal crops are using
cluster beans or cowpea as a rotation crop.
3. Selection of Suitable Sites. The ideal sites for cultivating medicinal plants are those
with suitable soil and climatic conditions, which vary from crop to crop. As a “rule of
thumb”, fertile soil with high organic matter is preferable.
CONSTRAINTS IN PRODUCTION OF MEDICINAL PLANTS
In large-scale cultivation of medicinal plants, the following constraints are
normally encountered.
Biotic Constraints
These are constraints associated with living things, particularly medicinal plants
themselves and their pests or other living things closely associated with medicinal plants.
1. Genetic Makeup. Most commercially cultivated medicinal plants are either primitive
cultivars or those taken from the wild for cultivation. Thus, the yield and quality are often
quite low. The lack of breeding institute, coupling with genetic erosion and genetic
wipeout of germplasm, makes the task of plant breeders very difficult if not impossible.
There is also the lack of exploration of medicinal plant germplasm, which results in very
small germplasm collections in the (seed) genebanks or field genebanks. Although
numerous medicinal-plant gardens have been established, for example, in Thailand
(Swangpol, 1995), they are mainly for exhibition purposes, and not for the specific
purpose of germplasm enhancement, since, in most cases, there is no genetic diversity in
the collection.
2. Long Life Cycle. Many of our medicinal plants possess a long life cycle which often
makes commercial cultivation costly and impractical. This is particularly true in the case
of plants whose useful parts are underground organs like roots, tubers and rhizomes such
as rauwolfia, ginseng, periwinkle, dioscorea, etc. Dioscorea which is grown for its tubers
rich in diosgenin, a steroid used as contraceptive drug, will attain a maximum content of
diosgenin only after 5 to 6 years of growth.
Certain medicinal plants are trees with a very long life cycle, e.g. Cinchona.
Others possess active compounds in the bark or stem which need to be stripped off, or
cutting down the trees, resulting in the loss of plants, or taking a long time for the next
harvest time to arrive.
3. Susceptibility to Pests and Diseases. When grown commercially as a monocrop or
53
estate crop, many species of medicinal plants are quite susceptible to pests and diseases,
particularly those plants having a narrow genetic base as the result of vegetative
propagation through rapid multiplication by way of in vitro culture.
Abiotic Constraints
These are constraints associated with non-living factors including soil factors and
mineral nutrition, water, light, temperature, other physical injuries or damage. Details of
these constraints are given below:
1. Low Soil Fertility. Being secondary crop, medicinal plants are often grown in soils of
low fertility. This results in poor yield and, sometimes, poor quality. Fertilizer application
can help improve the situation, but the cost involved may be prohibitive, with certain
species.
2. Flood and Drought. Too much or too little water available for the growth of medicinal
plants may result in stunted growth or even death.
3. Improper Light Intensity and Duration. Many medicinal plants are shade-lovers as
they are grow naturally underneath big trees in the forest. When grown in plantation
monoculturally without shade of big trees, their growth is severely affected. The opposite
occurs when a light-lover plant is grown as an intercrop underneath the canopy of big
trees.
The photoperiod can severely affect the quality of medicinal plants. A short-day
plant cannot do well long-day conditions, and vice versa. This applies to plants in which
the flowers are harvested for the medicine. Under an unsuitable light regime, no flower
will develop, resulting in no yield of desired product.
4. Extremes of Temperatures. Plants survive well in an optimum range of temperatures.
Too low or too high temperatures are detrimental to the growth of medicinal plants. This
is why plants introduced from the temperate zone often cannot do well in tropical Asia,
unless grown at high altitudes.
5. Physical Injuries or Damage. Strong winds or storms, earthquakes, other man-made
injuries or damage may cause severe loss of yield., from medicinal plants.
Technological Constraints
These are constraints associated with technological aspects of production,
including:
1. Lack of GAP. Many farmers who grow medicinal plants suffer from the lack of knowhow
in production technology, starting from sowing seeds, transplanting seedlings, caring
for a plant throughout its life cycle, harvesting, all the way to proper post-harvest
treatment. This last operation often causes much deterioration in quality of the produce.
Lack of Technology. Due to the lack of research and development, no technology for
medicinal plant cultivation has been developed.
Lack of Technology Transfer. Due to the lack of efficient extension services, essential
technology are not being transferred (even when these are available).
Lack of Facilities. In most developing countries in Asia, facilities for R&D, and services
for medicinal plants are not available. This includes, inter alia, facilities to access the
quality of produce, processing facilities (especially in remote areas), and the masses to
mass-produce planting material rapidly.
Socio-economic Constraints
1. Competition with Other Economic Crops. Many farmers would consider medicinal
plants as secondary crops. Unless they compete with other economic crops in terms of
income to the farmers, they will not even consider growing them, since most species of
medicinal plants give low yield, are more laborious in various steps of cultivation and
harvesting, and produce low income. Moreover, as the farmers do not have previous
experience in growing medicinal plants, they prefer growing other traditional crops.
2. Lack of Marketing Channels. Unlike other economic crops, there is often a lack of
marketing channels for medicinal plants in most countries. Also, there is no guarantee of
54
a market demand for greater supply.
3. Competition with Modern (Allopathic) Drugs. Most people still depend on modern
drugs since they are efficient, selective in action (despite side effects), accessible almost
everywhere, convenient in taking. All these lower the priority for medicinal plant
utilization.
4. Lack of Domestic Pharmaceutical Industry. With few exceptions, most developing
countries in Asia do not have access to a pharmaceutical industry. Thus, there is no
guarantee of sustained demand for medicinal plants.
5. Lack of Organized Cultivation. To be successful, medicinal plant cultivation requires
well organized contractual systems of production similar to those practiced in Europe.
6. No Price Support/Incentive Provided. Unlike a few other economic crops, in most
countries medicinal plants do not benefit from support/incentive from the government or
the private sector.
CONCLUSIONS
Medicinal plants are man’s best friend in time of need. Man has made use of them
from time immemorial. As technology and development become more advanced, the need
for them is much greater and the chance to collect them from the forest is receding. Rural
property and constant demand for cultivated land are threatening the forests which are the
homes of incalculable numbers of species of invaluable medicinal plants. The only
possible solution to save this precious inheritance of mankind is to cultivate them
systematically. This approach will also provide socio-economic benefits to the rural
people as well as satisfy the need of urban people who want to go “back-to-nature” and
use medicinal plants.
Medicinal plants continue to play a significant role in the welfare of people in
Asia as they have for the past several millennia. Due to higher demand of raw material for
industrial processing, coupled with the loss of natural habitats of most medicinal plants
which were once naturally occurring plentifully in the wild, large-scale cultivation of
promising species has been attempted in several countries while collecting for industrial
processing still continues in certain countries. The latter approach is likely to come to an
end sooner or later due to over-exploitation, unless the campaign to conserve biodiversity
puts a stop to it.
Medicinal plants have been mostly brought into cultivation only recently. They
have not been subjected to intensive breeding programs. Thus, the yield and quality are
quite low. In order to start any breeding program, germplasm collection and conservation
are most essential. As most natural habitats of medicinal plants are on the verge of being
destroyed, there is an urgent need to collect and conserve valuable germplasm of
medicinal plants before they are extinct.
At the same time, many more breeding programs should be initiated. These
programmes should be supplemented with R&D on agro-technology in order to obtain
maximal yield and quality of the source of raw materials for pharmaceutical products.
Most Asian countries have claimed the existence of an enormous number of
medicinal plants grown in their territories. Such figures are quite impressive but are
irrelevant in terms of research and development. It is impossible to invest a large sum of
money to work on all species listed. Priorities need to be established and the number
should be reduced to a manageable one as far as longer term R&D is concerned.
However, screening of many wild species for medicinal compounds should continue
before many of them become extinct via forest destruction, overcropping, overgrazing
and desertification.
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Tables
Table 1. List of medicinal plants collected from the wild in Asia.
Species Common name Family Part used Country of collection
Aesculus indica Indian horse chestnut Sapindaceae seed PAK
Alocasia macrorrhiza Shott giant taro Araceae rhizome LAO, VIE
Alstonia scholaris Dita bark Apocynaceae cortex LAO, VIE
Amomum Cardamom Zingiberaceae fruit LAO, VIE
Amorphophallus rivieri Konjac Araceae tuber LAO, VIE
Artemisia maritima Wormseed Compositae aerial parts PAK, VIE
Artocarpus lakoocha Monkey jack Moraceae lignin LAO, VIE
Blumea balsamifera -- Compositae leave LAO, VIE
Catharanthus roseus Periwinkle Apocynaceae root & leaf LAO, VIE
Cassia alata Ringworm bush Leguminosae leave PHI, VIE
Cinchona ledgeriana Cinchona Rubiaceae bark LAO, VIE
Coscinium usitatum -- Menispermaceae creeper LAO, VIE
Costus speciosus -- Zingiberaceae rhizome LAO, VIE
Dioscorea deltoidea Steroidal yam Dioscoraceae tuber PAK, VIE
Drymaria fortunei -- Caryophyllaceae rhizome LAO, VIE
Embelia ribes -- Euphorbiaceae fruit LAO, VIE
Ephedra gerardiana -- Gnetaceae berry PAK
Glycyrrhiza glabra Licorice Leguminosae root & rhizome PAK, CPR
Kaempferia galanga Galangal Zingiberaceae rhizome LAO, VIE
Lagerstroemia speciosa "Banaba" Lythraceae leaf & bark PHI, VIE
Leonurus heterophyllus -- Labiatae herb LAO, VIE
Moringa oleifera Drumstick tree Moringaceae seed PHI, VIE
Rauvolfia serpentina Rauwolfia Apocynaceae root IND, NEP, LAO, THA, VIE
Schefflera elliptica -- Araliaceae bark LAO, VIE
Smilax glabra -- Liliaceae rhizome LAO, VIE
Stephania rotunda -- Minispermaceae tuber LAO, VIE
Sterculia lygnophora -- Steculiaceae fruit LAO
Styrax tonkinensis Styracaceae resin LAO, VIE
Swietenia macrophylla Mexican mahogany tree Meliaceae seed PHI
Vitex negundo Five-leafed chaste tree Verbenaceae leaf PHI, VIE
Xanthium strumarium Cocklebur Compositae fruit LAO, VIE
Table 2. List of medicinal plants which are cultivated on commercial scale in Asia.
Species Common name Family Part used Country of collection
Aconitum napellus Aconitum Ranunculaceae root NEP
Adhatoda vasica "Vasaka" Acanthaceae leaf NEP, VIE
Alisma orientale "Tsettsieh" Alismataceae rhizome CPR
Allium domesticum Garlic Liliaceae bulb THA
Aloe barbadense Aloe Vera Liliaceae flower THA
Ammi majus Umbelliferae fruit NEP, VIE
Andrographis paniculata "Fa Thali Chon" Acanthaeae aerial parts THA, INS, VIE
Angelica gigas Korean angelica Umbelliferae root ROK
Areca catechu Arecanut Palmae fruit THA, VIE
Angelica acutiloba "Duong Qui" Umbelliferae VIE
Artemisia annua Qing Hao Compositae aerial parts CPR, THA, VIE
Astragalus membranaceus "Huang Chi" Leguminosae root CPR, VIE
Atractylodes macrocephala Atractylodes Compositae rhizome CPR, ROK,VIE
Atropa belladonna Belladonna Acanthaceae berry,leaf, root IND, NEP, VIE
Baleriana lupilina "Salet Phangphon" Acanthaceae aerial parts THA, VIE
Cassia angustifolia Senna Leguminosae pd, leaf IND, THA, VIE
Catharanthus roseus Periwinkle Apocynaceae root IND, VIE, PHI
57
Table 2. (Continued).
Species Common name Family Part used Country of collection
Cephaelis ipecacuanha Ipecac Rubiaceae root, rhizome IND
Chrysanthemum cineraria Pyrethum Compositae flower IND, VIE
C. morifolium "Kek Huai" Compositae flower CPR, THA, VIE
Cinchona ledgeriana Cinchona Rubiaceae bark IND, THA, VIE
Cinnamomum camphora Camphor Lauraceae berry CPR, THA, VIE
Claviceps purpurea Rye ergot -- sclerotium IND
Clinacanthus nutans "Phaya Yo" Acanthaceae aerial parts THA, VIE
Coptis chinensis "Huang Lien" Ranunculaceae rhizome CPR, VIE
Cornus officinalis "Shan Chu Yu" Cornaceae fruit CPR
Corydalis yanhusua "Yen Hu Suo" Papaveraceae rhizome CPR
Costus speciosus Crape ginger Zingiberaceae rhizome NEP
Croton sublyratus Plan Noi Euphorbiaceae -- THA
Curcuma domestica Turmeric Zingiberaceae rhizome IND, INS, PAK, SRL, THA, VIE
Cymbopogon winteriamus Citronella Gramineae aerial parts IND, INS, NEP, SRL, THA
Dendranthema morifolium "Chu Hua" Asteraceae flower CPR
Dioscorea deltoidea Medicinal yam Dioscoreaceae fruiting body IND
Dioscorea opposita Medicinal yam Dioscoreaceae fruiting body CPR
Dioscorea vomitoria Medicinal yam Dioscorea fruiting body IND
Geranium nepalense fruiting body VIE
Ganoderma luidum "Lingzhi" -- fruiting body CPR, THA
Hibiscus sabdariffa Roselle Malvaceae aerial parts THA, VIE
isatis indigotica "Ta ching Yeh" Cruciferaceae leaf, root CPR
Kaempferia galanga "Kencur" Zingiberaceae rhizome INS, VIE
Ligusticum wallichii CPR
Lonicera japonica Honeysuckle Caprifoliaceae flower CPR
Lycium barbarum "Kou Chi Tzu" Solanaceae fruit CPR
Magnolia officinalis "Hon Po" Magnoliaceae bark CPR
Matricaria chamomile Chamomile Compositae -- NEP
Mentha arvensis var. piperascens Japanese mint Labiatae aerial parts CPR, IND, NEP, PAK, THA, VIE
Morinda officinalis "Pa Chi Tien" Rubiaceae root CPR, VIE
Ophiopogon japonicum Mai Tung Liliaceae root CPR, VIE
Paeonia lactiflora Chinese peony Ranunculaceae root ROK, VIE
Panax ginseng Ginseng Araliaceae root CPR, ROK
Panax notoginseng Ginseng Araliaceae root CPR
Panax pseudoginseng Ginseng Araliaceae root CPR, VIE
Panax quinquefolia American ginseng Araliaceae root CPR
Panax vietnamensis Vietnamese ginseng Araliaceae root VIE
Papaver somniferum Opium poppy Paperveraceae latex IND
Philodendron chinense "Huang Pai" Rutaceae bark CPR, VIE
Piper betel Betel pepper Piperaceae leaf SRL, THA, VIE
Piper nigrum Black pepper Piperaceae bark IND, INS, MAL,SRL,THA,VIE
Piper retrofractum Java long pepper Peperaceae fruit IND, INS, SRL,THA
Plantago ovata Isaphgol Plantaginaceae seed IND
Platycodon grandiflorum Balloon flower Campanulaceae root ROK
Rauvolfia serpentina Rauwolfia Apocynaceae root IND, NEP, VIE
Solanum khasianum -- Solanaceae fruit NEP
Solanum laciniatum -- Solanaceae fruit NEP
Solanum trilobatum "Mawaeng" Solanaceae fruit THA
Solanum viarum Steroid solanum Solanaceae fruit IND
Sophora japonica VIE
Swertia chirata Chirat, Chiretta Gentianaceae aerial parts NEP, PAK
Syzygium aromaticum Clove Myrtaceae flower, bud IND, INS, MAL, SRL
Tinospora crispa Menispermaceae stem IND, PHI
Trichosanthas bracteata "Indreni" Cucurbitacea fruit, root NEP
Valeriana jatamansi Indian valerian Valerianaceae rhizome, root IND, NEP
Valeriana officinalis Valerian Valerianaceae rhizome, root NEP, PAK
Vitex negundo Five-leafed chaste tree Verbenaceae PHI
Withania somnifera Asgand Solanaceae root, leaf IND
Zingiber purpureum "Phlai" Zingiberaceae rhizome THA
Zingiber officinalis Ginger Zingiberaceae rhizome CPR, IND, INS, ROK, SRL, THA
58
Table 3. Countries of production of major medicinal plants in Asia.
Species CPR IND INS NEP PAK PHI SRL THA VIE Others
Aconitum carmichaeli •
Aloe barbadensis ο ο ο
Alisma orientale •
Allium sativum • • ο ο • ROK
Amomum villosum ο
Andrographis paniculata ο ο
Angelica sinensis • ο
Areca catechu •
Artemisia annua • ο ο
Astragalus membranaceus •
Aulandia lappa •
Atractylodes macrocephala •
Atropa belladonna ο ο ο
Cassia angustifolia • ο
Catharanthus roseus •
Chrysanthemum cinerariefolium • ο ο
Chrysanthemum morifolium • ο
Cinchona ledgeriana ο ο
Clinanthus nutans ο
Codonopsis pilosula •
Coptis chinensis •
Cornus officinalis ο
Corydalis yanhusuo ο
Croton sublyrata ο
Curcuma domestica • • ο ο •
Dendranthema morifolium •
Dioscorea deltoidea ο
Dioscorea floribunda •
Dioscorea opposita •
Dioscorea vomitoria ο
Ecommia ulmoides
Ganoderma lucidum • ο
Glycyrrhiza glabra •
Isatis indigotica •
Lycium barbarum •
Magnolia officinalis •
Morinda officinalis ο
Ophiopogon japonicus •
Panax ginseng • ROK•
Panax notoginseng •
Panax quinquefolia • ROKο
Panax vietnamensis ο
Papaver somniferum •
Peonia suffruticosa
Piper betel ο •
Piper nigrum • • ο ο MAL•
Plantago ovata • •
Pogostemon cablin ο • MALο
Rauvolfia serpentina • • ο
Solanum viarum •
Swetia chirata • •
Syzygium aromaticum • • • MALο
Tinospora crispa • ο
Trichosanthes palmatum •
Valeriana wallichii ο ο
Vitex negundo ο MALο, PHIο
Zingiber officinalis • • ο ο • • MALο, ROK
• = major producer, ο = minor producer
59
Table 4. New varieties of medicinal plants developed in India*.
Species Name of Cultivar
Cassia angustifolia AlFT-2
Dioscorea floribunda FB(C)-1, Arka-Upkar
Hyocyamus muticus Autotetraploid
Hyocyamus niger IC-66, Aela
Mentha arvensis var. piperascens MAS-1, MAS-2, Hyb.-77, Siwalik, EC-41911
Ocimum gratissimum Clo-ocimum
Ocimum sanctum EC-1828893
Ocimum viride Thymol type
Papaver somniferum Jawahar Aphim-16 (JA-16)
Plantago ovata Gujarat Isabgol-1, Gujarat Isabgol-2
Rauvolfia serpentina RS-1
Solanum laciatum EC-113465
Solanum viarum Glaxo, IIHR 2n-11, Arka Sanjeevini, Arka Mahima
*(adapted from Gupta, 1993)