25-06-2012, 12:16 PM
MEDICINAL PLANTS
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IMPORTANCE AND SCOPE
Herbs are staging a comeback and herbal ‘renaissance’ is happening all over the
globe. The herbal products today symbolise safety in contrast to the synthetics that are
regarded as unsafe to human and environment. Although herbs had been priced for their
medicinal, flavouring and aromatic qualities for centuries, the synthetic products of the
modern age surpassed their importance, for a while. However, the blind dependence on
synthetics is over and people are returning to the naturals with hope of safety and security.
Over three-quarters of the world population relies mainly on plants and plant extracts
for health care. More than 30% of the entire plant species, at one time or other, were used for
medicinal purposes. It is estimated that world market for plant derived drugs may account for
about Rs.2,00,000 crores. Presently, Indian contribution is less than Rs.2000 crores. Indian
export of raw drugs has steadily grown at 26% to Rs.165 crores in 1994-’95 from Rs.130
crores in 1991-’92. The annual production of medicinal and aromatic plant’s raw material is
worth about Rs.200 crores. This is likely to touch US $1150 by the year 2000 and US $5
trillion by 2050.
CLASSIFICATION OF MEDICINAL PLANTS
Of the 2,50,000 higher plant species on earth, more than 80,000 species are reported
to have at least some medicinal value and around 5000 species have specific therapeutic
value. They are classified according to the part used, habit, habitat, therapeutic value etc,
besides the usual botanical classification.
CULTIVATION OF MEDICINAL PLANTS
Most of medicinal plants, even today, are collected from wild. The continued
commercial exploitation of these plants has resulted in receding the population of many
species in their natural habitat. Vacuum is likely to occur in the supply of raw plant materials
that are used extensively by the pharmaceutical industry as well as the traditional
practitioners. Consequently, cultivation of these plants is urgently needed to ensure their
availability to the industry as well as to people associated with traditional system of
medicine. If timely steps are not taken for their conservation, cultivation and mass
propagation, they may be lost from the natural vegetation for ever. In situ conservation of
these resources alone cannot meet the ever increasing demand of pharmaceutical industry. It
is, therefore, inevitable to develop cultural practices and propagate these plants in suitable
agroclimatic regions. Commercial cultivation will put a check on the continued exploitation
from wild sources and serve as an effective means to conserve the rare floristic wealth and
genetic diversity.
PROCESSING AND UTILIZATION
Medicinal principles are present in different parts of the plant like root, stem, bark,
heartwood, leaf, flower, fruit or plant exudates. These medicinal principles are separated by
different processes; the most common being extraction. Extraction is the separation of the
required constituents from plant materials using a solvent. In the case of medicinal plants, the
extraction procedure falls into two categories (Paroda, 1993).
a) Where it is sufficient to achieve within set limits equilibrium of concentration between
drug components and the solution. Eg. Tinctures, decoction, teas, etc.
b) Where it is necessary to extract the drug to exhaustion, ie., until all solvent extractables
are removed by the solvent.