Conservation – A Strategy to Overcome Shortages of Ayurveda Herbs
Table of Contents:
Over-exploitation of living resources takes place all over the world in order to meet short-term needs. But very often the process destroys exactly those resources on which the welfare of millions of people depends in the long term. This disregard for sustainable utilization in fact widens the gap between rich and poor countries of the world, as there is an obvious relation between conservation and development. According to the Food and Agriculture Organization of the United Nations (F.A.O.), closed tropical forests or rainforests are disappearing at an alarming rate. Nearly 76,000 km2 of rainforests are being destroyed every year (Hamann 2009).
Destruction of flora has had its effect on the medicinal plant industry. Many years ago, the over- exploitation of wild-growing Rauvolfia serpentina Benth. ex Kurz. in India for export exhausted the supply to such a point that the government of India placed an embargo on the export of this species. This created a major problem in the United States of America, as the United States Pharmacopeia requires that Rauvolfia serpentina be of Indian origin w'hen used in a crude form. Another glaring example of a plant that has been over-exploited in India for export to other Asian countries is Coptis teeta Wall., which has now' attained the status of an endangered plant (Akerele 2009).
On being aw'are of the urgent need for the global conservation of plant wealth, health professionals and plant conservation specialists came together for the first time at the W.H.O./I.U.C.N./W.W.F. International Consultation on Conservation of Medicinal Plants, held in Chiang Mai, Thailand, 21-26 March 1988. They reaffirmed their commitment to the collective goal of “Health for All by the Year 2000” through the primary healthcare approach, and to the principles of conservation and sustainable development outlined in the World Conservation Strategy. The conference adopted the famous Chiang Mai Declaration, which recognized the urgent need for international cooperation and co-ordination to establish programs for the conservation of medicinal plants to ensure that adequate quantities are available for future generations. The members of the Chiang Mai International Consultation called upon all people to commit themselves to Save the Plants that Save Lives (Anonymous 2009a).
Flora of India
India has the distinction of being one of the 17 mega-biodiversity countries of the world, possessing 4 out of 36 of the world’s biodiversity hot spots (Myers et al. 2000; Arisdason and Lakshminarasimhan 2017; Hrdina and Romportl 2017). Among the Himalayan regions, the north-east Indian region harbors several floristically rich forest patches and a high number of endemics. It has been estimated that the north-eastern region comprises approximately 7500 species of flow'ering plants that constitute nearly 40% of the total floristic wealth of the country, w'hich is about 19,400 taxa (Karthikeyan 2000). Pteridophytes are represented by 2479 species follow'ed by 1265 bryophytes and 67 species of gymnosperms (Ravindranath et al. 2006; Chitale et al. 2014; Adhikari et al. 2015; Roy et al. 2015). A total of 4381 species and infra-specific taxa of vascular plants belonging to 1007 genera and 176 families are recorded as strict endemics to the Indian political boundary. Out of that, 4303 species and infra-specific taxa are angiosperms, 12 species are gymnosperms and 66 are pteridophytes (Singh et al. 2015).
Currently, India is experiencing a series of environmental problems like climate change, habitat modification, excessive land-use and land-cover change, environmental pollution, over-exploitation of biological resources and alien species invasion (Barik et al. 2018). Depending on the scale and intensity of these changes, several species are being lost and genetic variability w'ithin the species is being eroded. Anthropogenic factors have also played a pivotal role in controlling species distribution and have led to the extinction of numerous species, w'hile several others have become threatened (Reaka-kudla et al. 1996).
The report of National Medicinal Plants Board (N.M.P.B.) points out that out of 6580 medicinal plant species, 1622 botanicals corresponding to 1178 plant species have been found to be traded in all of India. Only 242 species witness high volume trade (>100 M.T.) annually (Goraya and Ved 2017).
Of the medicinal plants of India, 6580 species have thus far been documented in published literature (IMPLAD 2017). In undocumented form, the knowledge of medicinal plants and their uses may exceed 10,000 species. Their fuller documentation is an important unfinished national ethno- botanical agenda that must engage with the health practices of thousands of ethnic communities that constitute the cultural fabric of India (Mukherjee 2009). As per I.M.P.L.A.D. 2017, the species of medicinal plants recorded in different systems of medicine are presented in Table 8.1.
Botanical Profile of Medicinal Plants
Most of the 6580 medicinal plants are higher flowering plants. One-third are trees, shrubs and climbers, another third are herbs and the rest are lower plants like algae, fungi, lichens, bryo- phytes, pteridophytes, gymnosperms and angiosperms. Medicinal plants of India belong to 2200 genera in 386 families. Most of them belong to the families Asteraceae, Euphorbiaceae, Lamiaceae, Fabaceae, Rubiaceae, Poaceae, Acanthaceae, Rosaceae and Apiacea. Asteraceae has the highest number of medicinal plants, with 419 species belonging to this family alone (IMPLAD 2017).
Distribution of Medicinal Plants in India
With a geographical area of329 million hectares, India is located north of the equator 08°04'-37°06'N and 68°07'-97°25'E. It is bounded by the Indian Ocean in the south, the Arabian Sea in the west, the Bay of Bengal in the east and the Himalayas in the north. India is blessed with a variety of terrain and climate. The majority of India is tropical to subtropical, which means that the environmental temperature is conducive to the growth and development of vegetation. The rainfall also varies greatly from place to place. India receives rain from the monsoons originating in the Arabian Sea and the Bay of Bengal. The range of topography, temperature and rainfall are responsible for the development of a wide variety of macro- and micro-climates, resulting in the rich biological diversity of the Indian subcontinent. The country is divided into ten biogeographic zones based on biota and environmental realms (Singh and Kushwaha 2008).
Medicinal plant species occur naturally across different biogeographic zones of India (Figure 8.1). The biogeographic zones are: (i) Trans Himalaya (5.6%), (ii) Himalaya (6.4%), (iii) Desert (6.4%), (iv) Semi-arid (16.6%), (v) Western Ghats (4.4%), (vi) Deccan Peninsula (42%), (vii) Gangetic plain (10.8%), (viii) Coasts (2.5%), (ix) Northeast (5.2%) and (x) Islands (0.3%).The values in parentheses
Cross-Tabulation Showing Medicinal Plant Species Recorded in Different Indian Medical
Source: I.M.P.L.A.D. (2016). Indian Medicinal Plants Database. TransDisciplinary University, Bangalore India.
represent the percentage of the total geographical area of the country - 32,87,263 km2 (Rodgers and Panwar 1988). India has almost all the representative global ecological zones of south Asia viz., (i) tropical rainforest, (ii) tropical moist deciduous forest, (iii) tropical dry forest, (iv) tropical shrubland, (v) tropical desert, (vi) tropical mountain, (vii) subtropical mountain and (viii) temperate mountain (Chauhan 2007). The largest area of these biogeographic regions is covered by three ecological zones - tropical shrubland, tropical dry forest and tropical moist deciduous forest (Singh and Kushwaha 2008).
The “Trans Himalayan” zone has about 700 known medicinal plant species. The “Himalayan” biogeographic zone consists of North-West Himalaya (2A), West Himalaya (2B), Central Himalaya (2C) and East Himalaya (2D) biotic provinces. The North-West and West Himalaya (2A and 2B) regions are estimated to harbor approximately 1700 medicinal plant species. The Central and Eastern Himalayan (2C and 2D) biotic provinces put together are estimated to harbor around 1200 medicinal plant species. The “Desert” biogeographic zone consisting of Kutch (ЗА) and Thar (3B) harbor around 500 medicinal plant species. The “Semi-Arid” zone consisting of Punjab (4A) and Gujarat Rajware (4B) is estimated to possess around 1000 medicinal plant species. The “Western Ghats” biogeographic zone consisting of Malabar coast (5A) and Western Ghat Mountains (5B) has 2000 medicinal plant species. The “Deccan Peninsula” w'ith Deccan Plateau South (6A), Central Plateau (6B), Eastern Plateau (6C), Chhota Nagpur (6D) and Central Highlands (6E) has the highest proportion of the country’s total medicinal plant diversity, i.e. 3000 medicinal plant species. The “Gangetic Plain” zone covers Upper Gangetic Plain (7A) and Lower Gangetic Plan (7B) with 1000 medicinal plant species. The “North-East India” with two biotic provinces namely Brahmaputra Valley (8A) and Assam Hills (8B) harbor 2000 medicinal plant species. The “Islands” biogeo- graphic zone consists of the Andaman Islands (9A), Nicobar Islands (9B) and Lakshadweep Islands (9C) harboring around 1000 medicinal plant species. Finally, the “Coasts” comprising the West Coast (10A) and the East Coast (10B) are estimated to harbor over 500 medicinal plant species (Ravikumaret al. 2005) (Figure 8.1).
There are 36 terrestrial biodiversity hotspots in the world. Out of these global hotspots, India has four, namely Eastern Himalayas, Western Ghats (and Sri Lanka), North-East India and Andaman Islands (Indo-Burma) and Nicobar Island (Sundaland). The Indo-Burma hotspot is the largest among them with an area of 2.37 million km2. However, Western Ghats-Sri Lanka is the smallest one with an area of 0.19 million km2. These hotspots support a unique biodiversity and are highly species-rich areas with a high rate of endemism. The Himalaya hotspot alone includes all of the world’s mountain peaks higher than 8000 m, and several of the world’s deepest river gorges. The Indo-Burma hotspot is the richest one in biodiversity and includes most of the north-eastern India except Arunachal Pradesh and parts of Assam. The Western Ghats-Sri Lanka hotspot stretches from Gujarat to Kanyakumari and 400 km farther up in Sri Lanka. It has some of the last remaining rainforests and associated high biodiversity. In spite of its higher human population density, the Western Ghats-Sri Lanka hotspot possesses the highest concentration of endemic species. Sundaland lies in South-East Asia and includes Thailand, Singapore, Indonesia, Brunei and Malaysia. The Nicobar Islands represent India (Singh and Kushwaha 2008). The biodiversity hotspots in North-East India and Western Ghats are the repositories of a large number of wild medicinal plant species and even the biogeographic zone “Indian Desert” harbors around 500 medicinal plant species. There is a need for appropriate conservation action and resource augmentation efforts in different parts of the country for specific species which occur in different biogeographical regions (Figure 8.2).
As per the I.M.P.L.A.D. 2017 of the 6580 medicinal plants recorded in different Indian medical systems, the Ayurveda medical system reports 1539 medicinal plant species spread across 190 families. The top ten families are shown in Figure 8.3.