Medicinal Plants: Treasure Trove for Future

Asia has abundant species of medicinal and aromatic plants (MAPs) and traditional medicine has been practiced in Asia since ancient times. The Chinese and the Indians have made use of medicinal plants to cure ailments for thousands of years. Medicinal plants also play an important role in the lives of rural people in India with few health facilities. The plants that possess therapeutic properties or exert beneficial pharmacological effects on the animal body are generally designated as “Medicinal Plants”. They play a significant role in providing primary health care services to rural India. They serve as therapeutic agents as well as important raw materials for the manufacture of traditional and modern medicine. Substantial amount of foreign exchange can be earned by exporting medicinal plants to other countries. In India there are 880 medicinal plants species involved in all India trade. Of this, 48 species are exported and about 42 spices are imported. The Ministry of Environment and Forests, Government of India, reveals that there are over 8000 species of medicinal plants grown in the country. About 70 percent of these plants are found in the tropical forest; spread across the Western and Eastern Ghats. The Export-Import Bank of India, in its report for the year 1997, puts medicinal plants related trade in India at $.5.5 billion and the same is growing rapidly. According to World Health Organization (WHO) the international market of herbal products is around $6.2 billion, which is poised to grow to $5 trillion by the year 2050. Unfortunately, India’s share in the global medicinal plants related export trade is just 0.5 percent. The export of Medicinal plants is Rs.33453.23 lakhs during 1991-92 to 2002-2003. Its overall trend has been increased in 0.21 percent. And the average Import of Rs.2827.01 lakhs. Also its trend has been increased in 0.39 percent.


Introduction
A medicinal plant is any plant which, in one or more of its organ, contains substance that can be used for therapeutic purpose or which is a precursor for synthesis of useful drugs. This definition of Medicinal Plant has been formulated by WHO [1,2].
WHO suggest that increase in many Medicinal plants industries although old and vast are still being managed on traditional ethos and practices and lack a proactive and socially responsible image. Many studies have confirmed that traders and pharmaceutical companies are responsible for inefficient, imperfect, informal and opportunistic marketing of medicinal plants. As a result, the raw material supply situation is shaky, unsustainable and exploitative. It is in the best interest of the industry to develop a long term "social contract" with the collectors or growers.
The medicinal plant sector has traditionally occupied an important position in socio-cultural, spiritual and medical area of rural and tribal lives of India. In recent years, due to growing recognition of natural products and process in sustaining human as well as environmental, importance of medicinal plant resources have increased tremendously. Cultivation of medicinal plants in wasteland can improve the ecology and economy of the area.
WHO has issued several guidelines pertaining to quality control, assessment of herbal medicines, programme on traditional medicine, and for evaluating the safety and efficacy of herbal medicines. In view of the present trends of commercialization in the preparation and marketing of Aryurvedic, Siddha, Unani and Homoeopathic medicines, the existing Drug & Cosmetic Act needs revision and further amendment. Furthermore, patenting of plant product should be handled with great care.
The quality of' medicinal plant material is usually high when derived from the cultivated plants of standard varieties. Concerted efforts are necessary in the area of biotechnology and agro-technology for encouraging cultivation. Marketing which is one of the most important item in the development of any product should get a major attention in formalizing and organizing the markets. Quality control and standardization have to be organized to boost the export. Confusion exists in the identification of plant materials where the orgin of a particular drug is assigned to more than one plant, sometimes having vastly different morphological and taxonomical characters. There are few others, where the identity of plant sources is doubtful or still unknown; therefore, adulteration is common in such cases. The quality of medicinal plants depends on the geographical origin, time and stage of growth when collection has been done and post harvest handling completed.
The true source of the crude drug in such cases can be located only after detailed chemical and pharmacological studies. Detailed chemical investigation on Bacopamonnieri and Centetllaasiatica, the two plants variously-' described by the name Brahmi has revealed entirely different phytochemical compositiop. The former contains alakaloids brahmine, herpestine, gama amino butyric acid and bacoside A&B which have been found to have important action on brain function, while Centellaasiatica contains asiaticosidc. brahmoside. hydrocotyline. etc. which have hardly any relationship with the properties ascribed to the drug Brahmi in the text.
The quality of medicinal plants depends on the geographical origin, time and stage of growth when collection has been done and post harvest handling completed [4]. The collections in most cases are done by villagers/tribals residing in the vicinity of forests in their spare time. The plant part is collected without paying attention to the stage of maturity, dried haphazardly and stored for long periods under unsuitable conditions.The quality of collected material as such is often degraded.
There is a vast, secretive and largely unregulated trade in medicinal plants mainly due to involvement of petty traders .As the prices paid to the gatherers tend to be very, low, they often "mine" the natural resources than manage them, as their main objective is to generate an income. A critical factor in the wild harvesting is the availability of cheap labor to undertake the very labor intensive work of gathering. Such harvesting is bound to erode biological diversity of the country. Cultivation is difficult to establish when prices for wild source material are so low that there is little incentive for investment in cultivation of many species [5].
Threat assessment exercise as per latest IUCN guidelines has listed around 200 species of medicinal plants under various degrees of threat CITES has notified 11 Indian medicinal plants species in its schedule and in 1998, the Government of India restricted export of 19 species which are believed to be threatened in the wild.

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There are usually the dried parts of medicinal plants (roots, stem wood, bark, leaves, flowers, fruits that form the essential raw materials for the production of traditional remedies of Ayurveda and Siddha, Unani, Homoeopathy, Amachi, Tibbetan and other systems of medicine including the folklore ethno or tribal medicines. The crude drugs are also used to obtain therapeutically active chemical constituents by specialized methods of extraction, isolation, fractionation and purification and are used as phycochemicals for-the production of modern allopathic medicines or herbal/ phytomedicines [6]. Some of the important plants with major chemical constituents are as per Table 1. The crude drug is either used singly or in combination with other materials of plant, animal or mineral origin. Such medicines are prepared under special methods of heating and roasting, extraction with water, oil, milk, fat or even animal urine; fermentation under specifically controlled conditioning or regulated grinding [7]. The final products used in traditional systems of medicine are powders (Chumams). Concentrated extracts (Avalehas), fermented liquors (Asavas and Aristhas) and medicated oils and fats (Tail and Ghrita). The modern system of medicine use extracts, spirits and therapeutically active compounds isolated from crude drugs. The main chemical compounds so isolated include alkalyoids, glycosides, steroids and carbohydrates. Some of the major chemical compounds isolated from crude plant materials are as per Table 2.

Exports
Herbs are traded internationally in the dried form. The main product groups of the herb markets are: Natural products ingredients/ extractives which include herbal teas, dietry supplements, hydroalcoholic extract etc.
II. Speciality extract-food ingredients, photochemical and their salts and derivatives with health benefits; III. Medicinal plants-International conventional medicines, phytomedicines and pesticides.

V.
Preventive medicines-cosmetic ingredients etc.
For continuous and uniform supply of crude drugs cultivation of medicinal plants has to be given priority. However, research support is needed in providing superior genotype, agronomical practices and linking of production with industries to ensure buy back guarantee to the farmers. Important species to be cultivate are as per Table 3.

Conclusion
According to the World Health Organisation (WHO), the goal of 'Health for All' cannot be achieved without herbal medicines. While the demand for herbal medicines is growing in developing countries, there are indications that consumers in developed countries are becoming disillusioned with modern healthcare and are seeking alternatives. This has renewed interest by the multinational pharmaceutical industry in bioprospecting. But the lack of national legislation or effective international agreements on conservation of biodiversity has resulted in 'slaughter harvesting' of medicinal plants and massive depletion of biodiversity. This trend does not augur well for sustainable use of medicinal plants resources but there are mainly the, following constraints in developing the medicinal plants sector in the country: a.
Depletion of the resource base, which is the foundation of entire sector; b.
Decline of folk traditional medicine, a source of primary health care for the majority of the people; c.
Impoverishment of rural and tribal people, who are the stewards of the resources and the holders of the ecological and medical knowledge, through inequitable marketing channels. d.
The major opportunities in this sector are: e. The country is rich in biological diversity, human and medico culture and associated traditional and contemporary knowledge systems; f.
The medicinal plants and their uses in indigenous medicine is well known to the people; g.
Strong classical traditional medicine sector with developed industries and user base, exist in the country; h.
Good work has been carried out in the field of cultivation and chemical processing of medicinal plants; and i.
As a policy the country is prepared to afforest wastelands with the involvement of people giving preference to growing of medicinal plants; and attempts have been made for conservation, sustainable use, marketing and trade of medicinal plants in national and global markets.
Therefore, the use of medicinal plants for treating common ailments has assumed great contemporary release because of side effects of the chemical drugs the failure of primary health care services to course a significant.