Views:7 Author:Site Editor Publish Time: 2015-11-10 Origin:Site
As with all crops grown for the marketplace, a variety of considerations bear on commercial value. Market demand in relation to supply is the most obvious factor, but relative stability of demand and supply are also important, since strong fluctuations can be costly to both producers and marketers. Of course, crops differ in their suitability for given regions and climates, and indeed for markets. Ginseng species are especially illustrative of the fact that crops may differ greatly in terms of domestic production, domestic use, exports, and imports.
American ginseng is Canada's most important medicinal crop, but most of it is exported. Very little of the Asian species is grown in Canada, but a substantial amount is imported. American ginseng also provides an example of how crops change, since domestic consumption has been increasing in recent years (although the current market is stagnant).
Another factor is the relationship of the quantity of material that needs to be grown in order to extract commercial amounts. For example, as noted in the chapter on Pacific yew, a huge quantity of material must be harvested in order to extract a very small amount of the medicinal constituent, taxol.
Ginkgo (from Ginkgo biloba), one of the most popular of medicinal plants, is a very large tree, easily and widely grown as an ornamental, and it might seem that adequate material could easily be obtained from a small number of plants. However, large commercial plantations have already been established (for example, 400 ha in South Carolina) and others are being planted in order to obtain the large amount of foliage necessary.
Many medicinal plants have limited crop value specifically for medicinal products, but are nevertheless valuable as crops because of food or industrial value that exceeds their medicinal worth. For example, alfalfa is considered to be one of the most important of medicinal plants, but because huge quantities are produced as forage, and indeed for seeds for production of alfalfa (Medicago sativa L.) sprouts, growing alfalfa solely as a medicinal plant is not practical.
Another example is red clover (Trifolium pratense L.), which like alfalfa is widely grown as forage, but happens to be considered a strongly medicinal plant. Extracted flavourings, oils, dyes, and industrial chemicals are the primary economic reason for growing many herbs which happen to have some or even considerable medicinal value, and so growing the crops strictly as medicinal plants is generally not profitable.
Sometimes, however, different cultivars may be more appropriate for medicinal use than the type of plant that is widely raised as a crop. For example, large quantities of catnip (from Nepeta cataria L.) are grown for cats, but lemon-flavoured catnip is popular in some medicinal teas. The general point to be emphasized is that wide availability of plant species (or at least varieties of those species) strongly tends to lower their profit potential specifically for medicinal purposes, and vice-versa.
The key considerations are price and volume - i.e., whether a good-sized crop can be grown profitably specifically for medicinal purposes. Nutraceuticals that are extracted from crops may have most of their value determined by the process of extraction and market preparation, and those who engage in these aspects of the medicinal industry are not limited by the fact that the source crops may be widely and commonly available at low prices.