1. Product description
2. Trade
3. Prices
4. Cultivated vs. wild medicinal plants
5. Individual plants' profiles
6. Future trends
A large number of higher plants have been used as a source of drugs by mankind for several thousand years. It is estimated that 35,000 to 70,000 plant species have at one time or another been used in some culture for medicinal purposes. In China alone 5,000 of 35,000 species growing over there are used as drugs in Chinese traditional medicine. The Chinese system of medicine which derives 80 per cent of its medicaments from higher plants, is also popular in Asian countries such as Hong Kong, Korea, Indonesia and Malaysia. A similar situation exists in India, Pakistan, Bangladesh, Sri Lanka and Nepal (Husain, 1991).
It has been estimated that 1/4th of all prescriptions dispensed in the USA are likely to contain one or more constituents derived from higher plants (Fransworth and Soejarto, 1985). Some 95 plant species have been listed as sources of 121 clinically useful prescription drugs derived from higher plants (Fransworth et al, 1985), but a far higher figure is associated to great variety of medicines bought over-the-counter. There is a very large trade in plants used for the preparation of 'phytomedicines' or 'herbal medicines', as used by homeopaths and herbalists, and which can be purchased in health food shops, super markets and pharmacies (Lewington, 1993).
With regard to the final use of
medical plants traded, ITC (1982) found that a large quantity was used in herbal and
medicinal teas. It was also noted that botanical suppliers and traders have extended their
potential markets by supplying plant extracts and medicinal herbs and spices to the food,
flavour, fragrance and cosmetic industries. At the time of ITC study, pharmaceutical
applications represented less than 20 per cent of the total market for botanical products.
World trade in medicinal plants is of the magnitude of US$ 853,000, on an average, based on import statistics for the period 1987-1991 (Table 9). The trade generally showed an upward trend, except for 1990, when it dipped slightly, probably due to Gulf War. Total value of world trade in medicinal plants during 1991 was of the order of US$ 1.08 million. Export statistics for the corresponding period has also been shown in the table to illustrate the magnitude of persistent under reporting.
Table 9. Value of world trade in medicinal plants from 1987 to 1991.
Year
|
Trade value (1000 US$) |
|
Imports |
Exports |
|
1987 |
960.39 |
733.38 |
1988 |
1,046.61 |
829.64 |
1989 |
1,059.38 |
795.79 |
1990 |
1,122.87 |
901.87 |
1991 |
1,080.12 |
694.25 |
Average |
853.87 |
590.99 |
Source: COMTRADE data base
China is the biggest producer as well as exporter of medicinal plants, accounting for 30% of total world trade (by value) in 1991, followed by Korea, USA, India and Chile. Singapore and Hong Kong are the main re-exporters of medicinal plants in Asia. Japan, USA, Germany, France, Italy, Malaysia, Spain and US are the major markets. Hamburg is the world trading centre in medicinal plants. About 53 countries supply medicinal plants to Germany, of which important ones are India, Argentina, former Yugoslavia, Greece, China, Poland, Egypt, Hungary, Czechoslovakia, Zaire, Albania, the Netherlands and France.
About 4,000 to 6,000 botanicals are of commercial importance. Lewington (1993) reports that between 500 to 600 medicinal plants are traded via Hamburg. Trade statistics for individual medicinal plants cannot be estimated as these are not itemised in national trade data. Only those plants entering a country in very large quantities are listed individually, but the situation is further complicated by the multiple use of such plants. For example, liquorice (Glycorrhiza spp.) in addition to being used as an expectorant and anti-inflammatory, has a multitude of other uses ranging from flavouring for chocolate, beer, tobacco and toothpaste to stabilising the foam in fire extinguishers (Lewington, 1993).
At the same time, some of the essential oils such as mint oil, eucalyptus oil, cinnamon leaf oil and oil of Cinnamomum camphora as a source of natural camphor are also used in medicine.
This complexity is illustrated in the 1982 ITC report on Medicinal Plants and their Derivatives in the following words:
"It is not possible to assess the volume or value of the trade in all botanicals that are used medicinally because trade statistics do not identify all the plants individually and of those listed, the statistics do not identify medicinal and other uses separately. Products reported as medicinal plants often include gums, spices and plants used in food industry; certain plant products include those used for teas and infusions; large volume of plants such as pyrethrum are used in manufacture of insecticides; plants used by cosmetic industry are also included. While hundreds of medicinal plants are items of commerce, details of the volume traded in most of these will only be obtained from individual traders and users".
Lewington (1993) reports that the
situation in medicinal plants' trade is rather more complicated because of various levels
of secrecy maintained by the traders and the complexity of the trade structure itself.
Prices of many medicinal plants,
particularly those collected from wild sources, tend to vary in a cyclic manner. Price
cycles of 6-7 years are common as the availability of many plants goes from over supply to
scarcity very quickly and then takes several years to return to normal. The prices of
plants traded directly by the user companies are never published (Lewington, 1993). Prices
for some of the medicinal plants are indicated under individual products' profiles.
Lewington (1993) reports that the precise origin of medicinal plants entering in world trade is difficult to ascertain, because traders are reluctant to reveal their sources. It is, however, certain that the vast majority of the medicinal plants come from wild sources. The plants which are only cultivated are very few. Example of such plants are:
Catharanthus roseus
Examples of the medicinal plants obtained from both the wild and cultivated sources include:
and A. acuminataAtropa belldonna
5.1. Cinchona bark
5.2. Psyllium seed and husk
5.3. Belladonna
5.4. Hyoscyamus spp.
5.5. Duboisia spp.
5.6. Digitalis spp.
5.7. Licorice
5.8. Serpent wood
5.9. Ipecac
5.10. Senna
5.11. Periwinkle
5.12. Berberis spp.
5.13. Ginseng
Available information on some of the
important medicinal plant; is summarised in the following sections.
Cinchona is one of widely produced and traded medicinal plant product. Various species of Cinchona exploited commercially are C. officinalis, C. ledgeriana and C. succirubra and C. calisaya. The bark of the tree contains 6-7% total alkaloids. Although it contains a number of alkaloids, the most important ones are quinine and quinidine. Demand for cinchona bark had gone down, but with the increase in resistance of the malarial parasite to synthetic medicines, the use of quinine has increased recently. This coupled with the increasing use of quinidine as an antiarrhythmic compound has increased the demand for cinchona bark.
The main producing countries are
Indonesia, Zaire, Tanzania, Kenya, Rwanda, Sri Lanka, Bolivia, Colombia, Costa Rica and
India. These countries produce approximately 400-500 tonne; of alkaloids obtained from
8,000-10,000 tonnes of bark produced annually (Husain, 1991). In 1991, its wholesale price
at Hamburg was DM 2.25/kg (ITC, 1992a).
Psyllium husk is obtained from the
ripe seeds of Plantago ovate and P. psyllium. India is one of the main
producers, where the drug is cultivated over an area of 22,500 ha, producing around 20,000
tonnes of psyllium seed and husk. It is used as the safest bulk laxative. During 1991-92,
India exported 14,393 tonnes of psyllium husk and 3,151 tonnes of seed, valued at Indian
Rs. 620.28 million and 65.20 million, respectively. The average price (fob) works out to
be Rs. 43,100/tonne for husk and Rs. 20,690/tonne for seed. Average import price of
psyllium husk and seed at North European ports was US$ 1,800 to 2,000 per tonne and US$
600 per tonne, respectively, during 1992 (ITC, 1993c).
The drug is obtained from flowering
tops and roots of Atropa belladonna. The plant is indigenous to Western
Europe and temperate forests of India and Pakistan. It as also cultivated in England,
Germany, former USSR, USA and India. During 1992, the average wholesale price of
belladonna in German markets was DM 1.50 (ITC, 1992a).
There are two species of Hyoscyamus
containing alkaloids which are used in medicine in different parts of the world. These are
black henbane (Hyoscyamus niger) and Egyptian herbane (Hyoscyamus muticus).
Black herbane is cultivated to a limited extent in USA, UK and India. About 500-600 tonnes
of Egyptian herbane are collected from wild sources annually in Egypt and are exported to
Germany (Husain, 1991).
Species of Duboisia are
indigenous to Australia and are major sources of tropane alkaloids today in the world.
Present production in Australia is around 700-800 tonnes of dry leaves (Husain, 1991). The
plant has been introduced to India, where it is cultivated to a limited extent.
Digitalis purpurea and D.
lanata are commonly used as a source of cardiac glycosides. The major Digitalis
producing countries are USA, UK, the Netherlands, Switzerland, Germany and the former
USSR. In most of the developed countries the glycosides are obtained from D. lantana.
Licorice (or liquorice) is obtained
from dried leaves and rhizomes of Glycorrhiza glabra, indigenous to Southern
Europe and Asia Minor. Most of the supply comes from former USSR, Spain, Turkey, Syria,
Iraq and Afghanistan. A major portion of the commercial supply comes from wild sources and
there is only limited area under cultivation. Total production is between 40,000 and
50,000 tonnes per annum (Husain, 1991). In addition to medicinal uses, licorice has a
number of industrial uses as a flavouring agent in chocolates, beverages and tobacco.
During 1992, the average import price at North European ports was US$ 500 per tonne (ITC,
1992a).
The drug is obtained from the roots
and rhizomes of Rauwolfia serpentine. Three alkaloids are obtained from it;
used as hypotensive and tranquillizer. Approximately 400 to 500 tonnes of the roots are
exploited annually, mainly in India, Thailand, Bangladesh and Sri Lanka. Another 800
tonnes are collected from wild sources in the western coast of Africa, mainly in Zaire,
Mozambique and Rwanda, from where it is exported to Italy and West Germany (Husain, 1991).
Ipecac consists of dried roots and rhizomes of Cephaelis ipecacuanha or Brazilian ipecac and is indigenous to Brazil, from where most of the present supplies originate. It is also cultivated to a limited extent in India and Malaysia. C. acuminata referred to as Cartagena or Nicaragua or Panama Ipecac is indigenous to Colombia, Panama and Nicaragua. The drug is used in the form of crude extract as emetic and expectorant. It is also used as a source of emetine, which is used to treat amoebic dysentery.
The demand for ipecac had
considerably gone down because of a highly effective synthetic antiamoebic drug.
Continuous use of this drug, however, caused resistant strains of the protozoan, resulting
in revival of the demand for ipecac. At present there is worldwide shortage of the drug.
Total production of ipecac in the world is approximately 100 tonnes per year, most of
which comes from Nicaragua, Brazil and India. Indian production is confined to 7-10
tonnes, coming exclusively from cultivation in West Bengal (Husain, 1991).
Senna comprises of dried leaves and pods of Cassia angustifolia, called Indian senna, and C. acutifolia, referred to as Alexandrian senna. Indian senna is cultivated in the state of Tamil Nadu. Alexandrian senna grows wild in Sudan, Egypt and in other parts of Africa. Originally, Alexandrian senna was obtained principally from Sudan, but it is now cultivated in both Egypt and Sudan.
India is the world's largest producer and exporter of senna leaves and pods, exporting about 5,000 to 7,000 tonnes of leaves and pods annually, mainly to Germany, US, Japan, the Netherlands, France, Switzerland and the UK. About 700 to 800 tonnes of senna leaves and pods of Alexandrian senna are exploited annually in Sudan (Husain, 1991). The leaves and pods contain a glycoside, used mostly as laxatives all over the world.
Based on 1992 import statistics, the average prices of senna leaves and pods at North European ports were as follows (ITC, 1993c):
Origin |
Price (US$/tonne) |
|
Pods |
Leaves |
|
India |
1,600 |
800-1,000 |
Sudan |
1,200 |
600-800 |
The drug is obtained from leaves and
roots of Catharanthus roseus. The plant is indigenous to Madagascar and is
being cultivated in India, Madagascar, Israel and the United States. Roots and leaves of
the plant contain more than 100 alkaloids, which are used in treatment of a number of
ailments, including cancer (Husain, 1991).
The drug berberine is obtained from
the roots and rhizomes of various species of Berberis and Mahonia. About
600700 tonnes of roots of the plant are exploited annually in India (Husain, 1991).
Roots of Ginseng (Panax spp.) are extensively used as a general well being drug to improve resistance and to treat various kinds of weaknesses (adaptogenic drug). Panax ginseng is indigenous to northern China and Korea and is cultivated in China, Japan, the Republic of Korea and the former USSR. American ginseng (P. quinquefolium) is indigenous to Canada and the USA and is cultivated in the USA.
The Republic of Korea, China and the USA are the main producers of ginseng. Korea produces approximately 900-1000 tonnes of ginseng roots from an area of 1600 ha. Korean exports of ginseng and ginseng products are worth approximately 300 million dollars. The USA produces about 200 tonnes annually (Husain, 1991).
Ginseng is key forest plant in north China. China produces about 40% of the world total. American ginseng was introduced in China in 1975 and is planted in 10 provinces. Current production of American ginseng alone has reached 50 tonnes per annum (Kunshan, 1991).
Based on 1992 UK import statistics,
the average prices of whole and powdered ginseng roots was £ 15.53 per kg and £ 2050 per
kg, respectively (ITC, 1993c).
Use of medicinal plants is expected to rise globally, both in allopathic and herbal or traditional medicine. This upward trend is predicted not only because of population explosion, but also due to increasing popularity for 'natural-based, environmentally friendly products'. Increasing trend towards self-medication, reduction in costs of subsidized health care, EEC legislation improving the status of herbal medicine industry, renewed interest of companies in isolating useful compounds from plants, and marketing strategies by the companies dealing in herbal medicine are some of the other contributory factors enlisted by Lewington (1993). Thus, trade in medicinal plants is likely to expand.
It implies increasing pressure on wild plant resources and therefore, the need for serious conservation efforts including development of cultivation techniques has never been greater. Serious over-exploitation of many medicinal plants such as Rauwolfia, Discorea, Swertia chirata, Valeriana, Orchis and Harpagophytum procumbens has already occurred (Lewington, 1993).