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close this bookMedicinal Plants: Rescuing a Global Heritage (WB, 1997, 80 p.)
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View the documentProtecting medicinal-plant biodiversity

Protecting medicinal-plant biodiversity

Due to the destruction of forests, overgrazing of remote and marginal lands, expansion of industry and urbanization, as well as the excessive harvesting of wild rare and endangered plants, biological diversity of medicinal plants is being reduced day by day. The Institute of Medicinal Plant Development (IMPLAD), a WHO Collaborating Centre of Traditional Medicine under the Chinese Academy of Medical Sciences, specializes in research on medicinal plants. A primary function of IMPLAD is to protect and enlarge medicinal-plant resources and improve their quality.

Examples of threatened species include:

· Fritillaria cirrhosa occurring in northwestern Sichuan Province is rarely found today; roots are used for respiratory infections and as a cancer remedy;

· Dioscorea spp. Many species of Chinese yam have been eradicated throughout much of their original range during the past 30 years; roots used as an analgesic, seeds as diuretic, leaf against scorpion stings, and the whole plant as a tea;

· Iphigenia indica populations are under serious threat in northwestern Yunnan as a result of low fecundity and the effects of overharvesting; the bulb (root) has antitumor compounds; and

· licorice (Glycyrrhiza glabra) has also suffered from over-collection and consumption, and exports have been stopped to restore the production base; root extracts used as antidiarrheal, flowers for upper respiratory diseases.

Preserving Wild Genes. It is generally reported that of the 35,000 plant species growing in China, approximately 5136 are used as drugs in Chinese Traditional Medicine (see Table 7).

Table 7: Chinese Medicinal Plants Identified To Date

Origin

Number of Species

Origin

Number of Species

Thallophytes (algae/fungi)

281

Gymnosperms

55

Bryophytes

39

Angiosperms


Pteridophytes

395

Monocotyledons

676



Dicotyledons

3690



Total

5136

Source: Xiao(1991)

Of the 389 rare and endangered plant species listed in the Chinese Red Data Book (1991) 77 are traditional Chinese medicinal plants. Although more than 50 are being grown in botanical gardens, there is still insufficient research on their protection. A number of important medicinal plants have been preserved in genebanks under the auspices of several agricultural institutions and botanical gardens. Every effort is being made to expand research on population genetic variation. One such example is Atractylodes lancea, preparations which inhibit indigestion, edema (fluid build-up), vomiting and chronic gastroenteritis.

In-Situ Conservation. The Biodiversity Conservation Action Plan for China was initiated in 1992 with funding under the Global Environmental Facility (GEF) program. 49 The in-country process is coordinated by the National Environmental Protection Agency (NEPA), which established a Leading Group to provide overall supervision, direction and coordination. It is composed of those agencies with significant biodiversity responsibilities. To date 700 nature reserves, 480 scenic areas and 5 10 forest parks have been established. However, for purposes of coordinating departments and solving management issues there is no single authority, nor any state law or unified set of regulations.

NEPA established a Medical Management Department responsible for the national use and protection of precious medicinal materials (plant, animal and mineral). Some geographical regions have been declared protected areas for the growth of vulnerable species (for example licorice). Authorities believe such action is necessary to restore sustainable production levels.

Ex-Situ Conservation and Cultivation. A number of long-term programs have been established to conserve medicinal plants and enhance their value through cultivation. The agricultural area used for cultivation of medicinal plants increased from 300,000 hectares in 1986 to 440,000 hectares by 1995 and produces about 40 percent of the total output of crude drugs. Each year, approximately 200 medicinal plants species are cultivated. More than 700 farms are engaged in cultivating high-quality medicinal plants. In addition, the Chinese Academy of Sciences, Institute of Botany, Nanjing has a 186 hectare farm that includes a Medicinal Plant Garden and a Rare and Endangered Conservation Garden. The institute has recently established the Jiangsu Plant Ex-Situ Conservation Laboratory that works closely with the Phytochemical Laboratory in research on medicinal plants.

Important measures have been adopted to guarantee the continuous supply of raw materials to industry and the market. Government guidelines have been established regarding the protection, exploitation, and utilization of natural resources. 51 As a result of recent research and development programs, a number of previously wild medicinal plants (for example Glycyrrhiza platycodi, G. gentianae, G. astragali, and G. changii) have been successfully cultivated. 52 Xiao (1991) identified additional wild growing medicinal plants which are needed in large quantities and now being cultivated:

· Chinese licorice (Glycyrrhiza uralensis); roots and lower stem are used as a buffer in herbal prescriptions, act similar to adrenocortical hormones, and are effective against stomach ulcers and Addison's Disease;

· rhubarb (Rheum palmatum); root extracts reduce dyspepsia, fever and diarrhea; Chinese researchers are actively studying anticancer properties;

· broomrape (Cistanche deserticola); a parasitic herb used against impotency;

· China "root" (Poria cocos); a fungus growing on pine tree roots, promotes diuresis; and

· yam (Dioscorea nipponica); root extracts used for rheumatoid arthritis.

In addition, modem biotechnology is used for propagating Lithospermum erythrorhizon, Panax quinquefolium, Corydalis yanhuosu, Scopolia tangutica and others. This has included tissue-culture propagation, for example.

The Beijing Botanical Garden of the Institute of Botany and the Medicinal Botanical Garden of Guangxi Autonomous Region published in 1994 a color atlas of traditional Chinese medicines with text on techniques of their cultivation. The atlas is in two parts and includes: (i) 302 traditional Chinese medicinal plants; plants are listed in eleven categories according to plant parts used; and (ii) cultivation and propagation methods, management, control of pests and diseases, and harvesting and processing of the medicinal products.

Government policy encourages practitioners of traditional medicine to see their work as a long-term business. At the same time, interest-free loans are given to farmers on request as an inducement to grow medicinal plants. Information on demand and supply is widely disseminated. Over-supply of raw materials due to favorable weather conditions is purchased, processed, and held in stock.