گیاهان معطر و دارویی در اگروفاستری (بیشه زراعی) Medicinal and aromatic plants in agroforestry systems

Abstract A large number of people in developing countries have traditionally depended on products derived from plants, especially from forests, for curing human and livestock ailments. Additionally, several aromatic plants are popular for domestic and commercial uses. Collectively they are called medicinal and aromatic plants (MAPs). About 12.5% of the 422 000 plant species documented worldwide are reported to have medicinal values; but only a few hundred are known to be in cultivation. With dwindling supplies from natural sources and increasing global demand, the MAPs will need to be cultivated to ensure their regular supply as well as conservation. Since many of the MAPs are grown under forest cover and are shade tolerant, agroforestry offers a convenient strategy for promoting their cultivation and conservation. Several approaches are feasible: integrating shade tolerant MAPs as lower strata species in multistrata systems; cultivating short cycle MAPs as intercrops in existing stands of plantation tree-crops and new forest plantations; growing medicinal trees as shade providers, boundary markers, and on soil conservation structures; interplanting MAPs with food crops; involving them in social forestry programs; and so on. The growing demand for MAPs makes them remunerative alternative crops to the traditional ones for smallholders in the tropics. Being underexploited species with promising potential, the MAPs require research attention on a wide array of topics ranging from propagation methods to harvesting and processing techniques, and germplasm collection and genetic improvement to quality control and market trends. Joint forest management with farmers and contract farming with drug companies with buyback arrangement will promote cultivation of medicinal plants. Introduction Medicinal and aromatic plants (MAPs) play an important role in the healthcare of people around the world, especially in developing countries. Until the advent of modern medicine, man depended on plants for treating human and livestock diseases. Human societies throughout the world have accumulated a vast body of indigenous knowledge over centuries on medicinal uses of plants, and for related uses including as poison for fish and hunting, purifying water, and for controlling pests and diseases of crops and livestock. About 80% of the population of most developing countries still use traditional medicines derived from plants for treating human diseases (de Silva 1997). China, Cuba, India, Sri Lanka, Thailand, and a few other countries have endorsed the official use of traditional systems of medicine in their healthcare programs. For example, the Indian systems of medicine ‘Ayurveda,’ ‘Sidha’ and ‘Unani’ entirely, and homeopathy to some extent, depend on plant materials or their derivatives for treating human ailments (Prajapati et al. 2003). People in villages and remote areas primarily depend on traditional medicines as the mod ern system is out of reach and expensive. Many among the educated in Asian and African countries use traditional medicines for reasons of firm belief that they are more effective than modern medicines for certain chronic diseases, they do not have side effects of some of the modern medicines, and/or for economic reasons. Thus, in many societies, traditional and modern systems of medicines are used independently. About 12.5% of the 422 000 plant species documented worldwide are reported to have medicinal value; the proportion of medicinal plants to the total documented species in different countries varies from 4.4% to 20% (Schippmann et al. 2002). About 25% of drugs in modern pharmacopoeia are derived from plants (phytomedicines) and many others are synthetic analogues built on prototype compounds isolated from plants. Up to 60% of the drugs prescribed in Eastern Europe consist of unmodified or slightly altered higher plant products (Lancet 1994). These drugs carry important therapeutic properties including contraceptives, steroids and muscle relaxants for anesthesia and abdominal surgery (all made from the wild yam, Dioscorea villosa); quinine and artemisinin against malaria; digitalis derivatives for heart failure; and the anti-cancer drugs vinblastin, etoposide and taxol. These compounds cannot be synthesized costeffectively, which means that their production requires reliable supplies of plant material (van Seters 1997). The global importance of MAP materials is evident from a huge volume of trade at national and international levels. During the 1990s, the reported annual international importation of MAPs for pharmaceutical use amounted on average to 350 000 Mg valued at over USD 1 billion (Table 1). A few countries dominate the international trade with over 80% of the global import and export allotted to 12 countries each. Whereas Japan and Korea are the main consumers of medicinal plants, China and India are the world’s leading producing nations. Hong Kong, United States and Germany stand out as important trade centers. It is estimated that the total number of MAPs in international trade is around 2500 species worldwide (Schippmann et al. 2002).