Mediciaml Aromatic Plants and Spices - Chapter 1


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Chapter 1


 

                                                                                                                     Chapter 1
                                                                              Medicinal Plants and aromatic plants: An Overview

Medicinal plants are the local heritage with global importance. World is endowed with a rich wealth of medicinal plants. Herbs have always been the principal form of medicine in developing world though of later it is also becoming popular in the developed world as people strive to stay healthy in the face of chronic stress and pollution, and to treat illness with medicines that work in concert with the body’s own defenses. People in Europe, North America and Australia are consulting trained herbal professionals and are using the plant medicines. Medicinal plants also play an important role in the lives of rural people, particularly in remote parts of developing countries with few health facilities. It is also one of the income-generating sources.

It is estimated that around 70,000 plant species from lichens to flowering plants have been used at one time or the other for medicinal purposes. The herbs provide the starting material for the isolation or synthesis of conventional drugs. In Ayurveda about 2,000 plant species are considered to have medicinal value while Chinese Pharmacopoeia lists over 5700 traditional medicines, most of which are of plant origin. About 500 herbs are still employed within conventional medicine, although whole plants are rarely used.

Medicinal plants have curative properties due to the presence of various complex chemical substances of different composition, which are found as secondary plant metabolites in one or more parts of these plants. These plant metabolites according to their composition are grouped as alkaloids, glycosides, corticosteroids, essential oils etc. The alkaloids form the largest groups which includes morphine and codein (poppy), strychnine and brucine (Nux vomica), quinine (cinchona), ergotamine (ergot) etc.

Glycosides form another important group represented by digoxin (foxglove), barbolin (Aloe) etc. Corticosides have come into prominence recently and diosgenin (Dioscorea), solasodin (Solanum sp.) etc now command a large world demand. Some essential oils such as those of valerian kutch and peppermint also possess medicinal properties and are used in the pharmaceutical industry. However it should be stated that in all fairness that tour knowledge of the genetic and physiological make up of most of the medicinal plants is poor and we know still less about the biosynthetic pathways leading to the formation of active constituents for which these crops are valued.

Medicinal and aromatic plants are found in forested areas throughout south Asia, from the plains to high Himalayas, with the greatest concentration in the tropical and subtropical belts and region of Thar Desert. India recognizes more than 2500 plant species having medicinal values, Sri Lanka about 1400, Nepal about 700 and Bhutan about 322. Some of these are found in high altitudes in particularly stressful environments, grow very slowly and cannot survive elsewhere. Others are broadly distributed and adapt more easily to different ecological conditions.

History of medicinal plants
The discovery of curative properties in plants must have sprung from some human instinct. Primitive man used plants for both food and medicine. He would have learnt after perhaps unfortunate experiences that certain plants contained certain properties and was able to identify them by the results they induced. He would also have observed which plants animals utilized when they were sick. After seeing an injured deer rubbing itself against the geum, he might have discovered that this plant heals wounds.

Superstitions/Religious Beliefs
It is likely that religious beliefs also played an early role in the discovery of medicinal plants. Disease was thought to be caused by spirits. Since disease was bad, it followed that you could cure the disease if you eat something that tastes bad (bitter). Using this logic may have sometimes paid off because as it turns out, many bitter-tasting plants contain alkaloids or other biologically active chemicals.

In medieval Europe, the Doctrine of Signatures (Paracelsus; 1493-1524) – stated that God provided clues about the medicinal value of a plant in the plant's general form (God’s signature). Thus, walnuts were thought to be good "brain food" and bloodroot good for circulatory problems. Scientists disregard this idea, though many traditional healers still accept it. The mottled leaves of lungwort (Pulmonaria officinalis) were thought to resemble lung tissue and the plants are still used to treat ailments of respiratory tract.

Medicinal and Aromatic Plants (MAPs): Benefits & Challenges
Traditional, Affordable Health Care

South Asia is home to many rich, traditional systems of medicine. Ayurvedic methods date back to 5000 B.C. Along with the Unani, Siddha and Tibetan systems, they remain an important source of everyday health and livelihood for tens of millions of people. Medicinal and aromatic plants (MAPs), including trees, shrubs, grasses and vines, are a central resource for these traditional health systems, as well as for pharmaceutical (or allopathic) medicines. There are more than 8,000 plant species in South Asia with known medicinal uses.

Medicinal plants are an accessible, affordable and culturally appropriate source of primary health care for more than 80% of Asia's population (WHO). Marginalized people who cannot afford or access formal health care systems are especially dependent on these culturally familiar, technically simple, financially affordable and generally effective traditional medicines. As such, there is widespread interest in promoting traditional health systems to meet primary health care needs. This is especially true in South Asia, as prices of modern medicines spiral and governments find it increasingly difficult to meet the cost of pharmaceutical-based health care. Throughout the region, there is strong and sustained public support for the protection and promotion of the cultural and spiritual values of traditional medicines.

Widespread Demand for MAPs
Conservative estimates put the monetary value of MAP-related global trade at over 60 billion USD (Govt. of India, 2000). With increasing popular demand for medicinal plants, both in South Asia and internationally, this trade is expected to grow to 5 trillion by the year 2050 (FRLHT, 1996). Besides health benefits, MAPs also provide crucial livelihood options for millions of rural people in South Asia, particularly women, tribal peoples, and the very poor. India is the centre of South Asia's export trade in medicinal plants, and in this country alone, it is estimated that the collection and processing of medicinal plants contributes to at least 35 million workdays of employment a year. Unfortunately, while demand rises, inequitable trade practices have meant that only a small margin of the profits from MAPs trickle down to the collectors and harvesters. Highly developed illegal trading networks in Pakistan, Nepal, Bhutan, India and Myanmar control the raw MAPs trade, through lax border controls. Despite this, no regional collaboration in implementing international covenants relating to biodiversity exists to stem this growing illegal market.

Impacts of Commercialization
The expansion of unregulated trade and commercial use of MAPs poses a major threat to biodiversity in the region. Local communities tend to collect the highest value or most popular plant species, leading to over-harvesting or species extinction. Even when MAP species are safely cultivated, if done with mono-cropping systems, local biodiversity can be weakened. Finally, as 95 % of MAPs are harvested and collected in wild, the alarming levels of deforestation and ecosystem degradation in the region are also contributing to a decline in MAPs. Combined, all of these factors have severely reduced the availability of medicinal plant ingredients and the overall environmental sustainability of the region.

Along with the deterioration of resources, the cultural heritage surrounding MAP use is being eroded. Further, the expertise and knowledge of traditional systems of medicine are not being standardized. This coupled with inadequate processing and storage facilities, contribute to ineffective or unsafe treatments. The absence of institutional support, appropriate validation systems, and quality control protocol for indigenous health practices, threatens valuable MAP knowledge and use practices, as well as public health.

Medicinal plants in Bhutan
Introduction

A wide range of plant diversity covers Bhutan's two main mountain ranges, the 'Lho-Menjong' and the Druk-Yul. These rugged mountains are the source of over 300 plant species traditionally used in preparing indigenous (Ayurvedic) medicine.

Medicinal plants collected from Bhutan's temperate and lower zones are known under the traditional broad classification as "THRO-MEN," while plants from the country's alpine zone are known as "NGO-MEN."

In the case of "THRO-MEN" plants, specific parts of the plants (e.g., the roots, bark, wood, leaves, flowers or fruit) are generally collected, while for "NGO-MEN," the whole plant is gathered for its medicinal properties.

Trade in medicinal plants in the past
In the past, medicinal plants, such as manjito (Rubia cordifolia), chereta (Swertia cherita), pipla (Piper nigrum and Piper longum), sarpagandah or nakbhel (Rauvolfia serpentina) and putishing/kutki (Picorrhiza kurroa), among others, were sold to India. The sales method used was the leasing of large tracts of land through tenders or auctions. The highest bidder was given full access to and jurisdiction over seasonal collection in the area allotted. Such produce was classified as minor forest produce (MFP) and could be exported to India upon issuance of a "Certificate of Origin" by the Divisional Forest Officers concerned.

The Royal Government of Bhutan realized that in the long run, however, such nonscientific harvesting of plant species would bring more harm than the revenue generated. Hence the ban on exporting MFP - which included medicinal plants - imposed in the early 1980s, remains valid till date.

Scope for international market
A number of medicinal plant species growing naturally in Bhutan have international market value. Among these are agar wood (Aquilaria agallocha), Rauvolfia serpentina, tshe (Ephedra gerardina), Himalayan yew (Taxus baccata), chutsa (Rheum nobile), chumtsa (Rheum accuminita), kutki/putishing (Picorrhiza kurroa), pangpoi (Nardostachys jatamansi), tsenduk rig (Aconitum spp.), and yartsa-gunbu (Cordyceps sinensis). All are in high demand for pharmaceuticals.

Owing to the great volume of competitive synthetic products currently marketed, the trade in medicinal plants and their derivatives has declined in many industrialized countries (Study on the Market for Selected Medicinal Plants and Their Derivatives, Geneva, 1982.) Trade in botanicals, however, has risen following their relatively recent increased use by the food and cosmetics industries. A renewed interest in traditional medicine in Asia, and the introduction of health foods in Europe and North America, has between them provided new outlets for many botanical products.

Over 400 botanicals are used commercially in Western Europe, with Hamburg as the centre for the trade. Of the Western nations, the United States is the major importer of medicinal plants. Japan is the major importer among Asian countries.
Scope for cultivating medicinal plants

The National Institute of Traditional Medicine (NITM) has a programme for research on, and propagation of, medicinal plants. During the reign of Bhutan's second king, His Majesty Jijme Wangchuck (1926-52), the people of the Bumthang Valley cultivated two medicinal plant species - manu (Innula helenium) and ruta (Saussurea lappa). Both these plants were used for producing "sowa-rigpa" medicine and incense. Unfortunately, the present generation in Bumthang knows little of these two plants.

The manu plant, however, is in demand from NITM in Thimphu. The plant has survived years of neglect and is now cultivated in Ura by one family for supply to the indigenous hospital in Thimphu. The fate of the second plant, ruta, is not known. A survey is needed to determine if it still exists in the valley.

During Bhutan's Fourth Five-Year Plan (1972-77), the planting of agar wood in lower Kheng villages, such as Panbang, Shilingtot, Mamung, and Pantang, was encouraged by the late Dasho Keiji Nishioka on his family's private land. The agar wood plants have now grown to over 10 metres in height and 12 to 15 centimeters in diameter (measured in January, 1993). Some villagers are growing 20 to 30 or more trees, and say the trees are not difficult to propagate. Only those plants infected by a particular fungus, through a yet unknown mechanism, however, produce the highly-valued agar wood. No report has been received so far as to whether some of the planted trees have produced this most valuable type of agar wood.

Ipacac (Cephalus ipacacaunha) and Dioscorea deltoides are cultivated on large plantations in India just across the Bhutanese border. Proceeds from these plantations reportedly amount to over 10 million rupees, or some US$ 319,000, per annum. Similar plantations are quite possible within Bhutan.


Reading 1. Medicinal plants: the Global view
Human beings have been utilizing plants for basic preventive and curative health care since time immemorial. Recent estimates suggest that over 9,000 plants have known medicinal applications in various cultures and countries, and this is without having conducted comprehensive research amongst several indigenous and other communities (Farnsworth and Soejarto 1991).

Medicinal plants are used at the household level by women taking care of their families, at the village level by medicine men or tribal shamans, and by the practitioners of classical traditional systems of medicine such as Ayurveda, Chinese medicine, or the Japanese Kampo system. According to the World Health Organization, over 80% of the world’s population, or 4.3 billion people, rely upon such traditional plant-based systems of medicine to provide them with primary health care (Bannerman et. al. 1983).

Allopathic medicine too owes a tremendous debt to medicinal plants: one in four prescriptions filled in a country like the United States is either a synthesized form of or derived from plant materials (Srivastava, et. al. 1995). Even from the earliest trade data available, it is clear that the global market for medicinal plants has always been very large. According to the International Trade Centre, as far back as 1967, the total value of imports of starting materials of plant origin for the pharmaceutical and cosmetics industry was of the order of USD 52.9 million. From this amount, the total values grew to USD 71.2 million in 1971, and then showed a steady annual growth rate of approximately 5-7% through to the mid-1980s (Atisso, 1983).

To give an example of the extent of trade volumes even at that time, according to one report commissioned by the World Wide Fund for Nature, the total import in 1980 of "vegetable materials used in pharmacy" by the European Economic Community was 80,738 tons (Lewington, 1992). India was the largest supplier by far, with 10,055 tons of plants and 14 tons of vegetable alkaloids and their derivatives.

However, it is only during the last decade that the real significance of the medicinal plants sector has begun to be realized. Interest in natural materials by the dominant economic powers had waned from the late 1960s to the early 1980s as new possibilities in biotechnology and the synthesization of drugs beckoned. However, by the mid-1980s, there was a renewed interest in natural materials and approaches to health care, coupled with a recognition that technology alone could not solve the pressing health care needs of the world’s population (Tempesta and King, 1994).

This new drive for natural and plant-based medicines made it felt in the market from the mid-1980s onwards. As Table 1.1 illustrates, growth in the market in various regions is now on average 3 to 4 times the average growth rates of the national economies in the same regions. Some of these phenomenal rates, in some cases nearly 20%, imply that the market is now doubling in size every 4-5 years.

The participation of various companies in the market also attests to its new strength and importance. By 1990, some 223 major companies worldwide (of which about half were in the United States) were reportedly screening plants for new leads; the figure had been zero in 1980 (Aryal, 1993).

Also in 1990, more than 2000 companies in Europe alone were marketing herbal medicinals, with 30% having a turnover in excess of $20 million- expenditure in the United States on "unconventional, alternative, or unorthodox" therapies reached $13.7 billion dollars during the same year (Tewari, 1996). The so-called "nutraceuticals" sector--consisting of herbal medicines which are dubbed food or dietary supplements in order to pass FDA criteria more easily--is now estimated to be valued at USD 27 billion (Anon 1995).


Table 1.1 Natural Medicines Market: Regional Growth Rates 1991-98 (in %)

Region

1991 - 92

1993 -98

EU

5

8

Rest of Europe

8

12

SE Asia

12

12

Japan

15

15

South Asia

15

15


The use of such alternative medicines has become increasingly popular in the developed world. For example, 1 in 3 Americans have at some time used unconventional medical therapies according to a national telephone survey published in the New England Journal of Medicine in 1993. In another survey conducted in 1994, it was found that 60% of doctors had at some time referred patients to practitioners of alternative medicine. In response to the overwhelming interest in alternative therapies, many of the prestigious allopathic medical institutions have also recognized their importance: an example is the National Institute of Health which created the Office of Alternative Medicine in 1991 to provide the public with information on alternative treatments and to assess those therapies which have proven successful (Kolata, 1996).

According to one account, in 1992 significant amounts of at least 74 species of medicinal plants were being commercially traded in the global market (Handa, 1992). In addition to these major species, hundreds of others are bought and sold in lesser quantities across national boundaries, sometimes illegally.

A comparison of the volumes of traded materials with those of the previous decade also provides dramatic evidence of the market’s growth. During the last 3 years, approximately 40,000 tons of plant drug materials (valued at DM 160 million) were imported into Germany, annually (Lange, 1996), implying that one country’s imports in the mid 1990s equaled half the number of plants imported by the entire continent in the mid 1980s.