Medicinal Plants in Trade
Table of Contents:
In order to have a sharper focus on conservation of plant species which are under sizable commercial exploitation, there is a need to analyze the pattern and quantum of consumption of medicinal plant materials by the herbal sector. According to a published report of the N.M.RB. (Goraya and Ved 2017), out of 6580 medicinal plant species traditionally used by Indian communities, only 1622 botanicals corresponding to 1178 plant species are found to be traded in all of India. Of these 42% are herbs, 27% trees and 31% are shrubs and climbers. Only 242 species witness high volume trade (>100 M.T.) annually. Diverse parts of plants (leaf, flowers, fruit, seed, bark, root, resin, gum) serve as medicinal raw drugs. Nearly 53% of the medicinal plant species are subject to destructive methods of harvest, as the medicinal parts harvested include underground parts, wood, bark and the whole plant. It is observed that 85% of the traded species and 70% of the demand are even today met from wild sources.
Substitutes and Adulterants
Adulteration and substitution of herbal drugs is a burning problem in the herbal industry, and it has evolved to be a major threat to research on commercial natural products. The deforestation and
FIGURE 8.3 Top ten botanical families.
Important Medicinal Plants with Their Substitutes and Known Adulterants
Source: Ved and Goraya 2008
extinction of many species and incorrect identification of many plants have resulted in adulteration and substitution of raw drugs. Table 8.2 lists selected medicinal plants with their possible adulterants and substitutes.
Species Traded in High Volume
Of the total 242 top traded medicinal plants, 225 are included in the list of ayurvedic medicinal plants. These species are sourced from the wild, cultivated or imported, primarily for use as herbal raw drugs. For example, makoi (Solatium nigrum Linn.) is found naturally growing in habitats outside forests and as agriculture weeds, and it is this wild-grown population that forms the major source of its supply to the end-users. This species has, however, been recently brought under cultivation also primarily to meet the part supply of its fruits. Cultivation of Atees (Aconitum hetero- phyllum Wall, ex Royle.), a red-listed Himalayan species, has been recently initiated, even as major supplies of this herb continue to be met from wild collections (Goraya and Ved 2017).
Major Supply Sources
Analysis of the top traded species in the Ayurveda medical system reveals that the major supply source of 11 of these species is imports and that 49 are largely sourced from cultivation. The major source of supply of the remaining species is wild collections from forests (108 species). Further analysis of the 108 species reveals that 33 species are obtained from Himalayan forests and the remaining 75 species are from tropical forests.
Local health traditions (L.H.T.s) cannot be revitalized without ensuring the health of the medicinal plant resource base. Given that the funds, human resources and efforts available are limited, it is very much needed to prioritize and assess the threat status of medicinal plants, in order to focus the conservation action. To accomplish the prioritization of medicinal plants within a reasonable time and cost, the Conservation Breeding Specialist Group (C.B.S.G.) of the Species Survival Commission has developed a rapid assessment methodology called C.A.M.P. (Conservation Assessment and Management Plan) (Anonymous 2020a). C.A.M.P. workshops provide strategic guidance for the application of intensive management and information collection techniques to the threatened plants. They also provide a comprehensive means of testing the applicability of the I.U.C.N. criteria to the threatened taxa. The Foundation for Revitalization of Local Health Traditions (F.R.L.H.T.) and the University of Trans-disciplinary Health Sciences and Technology (T.D.U.) anchored C.A.M.P. workshops in 19 states across the country and assessed 354 medicinal plants with I.U.C.N. threat status. Of these 47 species of endemic medicinal plants were appended into the I.U.C.N. Database (Anonymous 2020b). The details of the C.A.M.P. workshops are provided in Table 8.3.
To illustrate species above near-threatened status, analysis of 1539 medicinal plant species showed 24 medicinal plant species to be critically endangered, 26 species endangered and
Summary of the C.A.M.P.s Held in 19 States of the Country by F.R.L.H.T.
FIGURE 8.4 Threatened medicinal plant species.
42 species as vulnerable (see Figure 8.4). Selected traded medicinal plants of conservation concern are: Aconitum heterophyllum, Boswellia serrata Roxb., Chlorophytum borivilianum Linn., Cochlospermum religiosum (Linn.) Alston., Gymnema sylvestre R. Br., Oroxylum indicum Vent., Pterocarpus marsupium Roxb., Rauvolfia serpentina, Taxus wallichiana Zucc., Sterculia urens Roxb. and Stereospermum. chelonoides (Linn, f.) DC.
In Situ Conservation
Most medicinal plants are endemic species, and their medicinal properties are mainly because of the presence of secondary metabolites that respond to stimuli in natural environments, and may not be expressed under culture conditions (Figueiredo et al. 2009; Coley et al. 2003). In situ conservation is the process of conserving the living species, especially the wild and endangered species in their natural habitats and environment. In situ conservation of biodiversity includes biosphere reserves and national parks (Hamilton and Hamilton 2006). In situ conservation of whole communities allows us to protect indigenous plants and maintain natural communities, along with their intricate network of relationships (Gepts 2006).
Ex Situ Conservation
Ex situ conservation is the conservation of biological diversity outside their natural habitats in locations that imitate their natural habitats. This involves the conservation of genetic resources, as well as wild and cultivated species. The approach draws on a diverse array of techniques and facilities, including seed banks in vitro plant tissue and microbial culture collections, artificial propagation of plants, with possible reintroduction into the wild and botanic gardens (Maunder et al. 2004).
Conservation of plant genetic resources can be achieved in situ as well as ex situ. Both cultivated and domesticated plant species are also maintained in their natural habitats as well as in field conditions (Cruz-Cruz 2013; Langhu and Deb 2014). Due to habitat destruction and transformation of the natural environment, several species have been lost from the ecosystems. Therefore, in situ methods alone are insufficient for conserving the threatened species. Under these circumstances, ex situ conservation is a viable alternative for preventing the extinction of threatened species. In some cases, it is the only viable strategy to conserve certain species. In situ and ex situ methods are complementary and not mutually exclusive. The selection of appropriate strategy should be based on a number of criteria including the status of the species and feasibility of applying the chosen methods (Engelmann 2012).
Ex situ conservation is not always sharply separated from in situ conservation, but it is an effective complement to it, especially for those over-exploited and endangered medicinal plants with slow growth, low abundance and high susceptibility to replanting diseases (Hamilton 2004; Havens et al. 2006; Yu et al. 2010). Ex situ conservation aims to cultivate and naturalize threatened species to ensure their continued survival and sometimes to produce large quantities of planting material used in the creation of drugs, and it is often an immediate action taken to sustain medicinal plant resources (Swarts and Dixon 2009; Pulliam 2000).
Many species of previously wild medicinal plants can not only retain high potency when grown in gardens far away from the habitats where they naturally occur but can have their reproductive materials selected and stored in seed banks for future replanting (Hamilton 2004). For example, F.R.L.H.T. established several ex situ conservation sites to complement in situ conservation. Ex situ conservation was undertaken to improve the livelihood of indigenous people and enhance the use of plants through the establishment of Medicinal Plants Conservation Parks (M.P.C.P.s). It comprises nurseries, the establishment of living collections of a limited number of specimens of the medicinal plants and promotion of kitchen herbal gardens and home herbal gardens (Singh et. al. 2008).