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The Use Of Quality Control Parameters In The Evaluation Of Vegetable Crude Drugs
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1.3 STANDARDIZATION OF BOTANICAL HERBS AND QUALITY OF BOTANICAL PREPARATIONS:
Plants
contain several hundred constituents and some of them are present at
very low concentrations. In spite of the modern chemical analytical
procedures available, only rarely do phytochemical investigations
succeed in isolating and characterizing all secondary metabolites
present in the plant extract. Apart from this, plant constituents vary
considerably depending on several factors that impair the quality
control of phytotherapeutic agents. (Jablonski, 2004). Quality control
and standardization of herbal medicines involve several steps. However,
the source and quality of raw materials play a pivotal role in
guaranteeing the quality and stability of herbal preparations. Other
factors such as the use of fresh plants, temperature, light exposure,
water availability, nutrients, period and time of collection, method of
collecting, drying, packing, storage and transportation of raw material,
age and part of the plant collected, etc., can greatly affect the
quality and consequently the therapeutic value of herbal medicines. Some
plant constituents are heat labile and the plants containing them need
to be dried at low temperatures. Also, other active principles are
destroyed by enzymatic processes that continue for long periods of time
after plant collection. This explains why frequently the composition of
herbal based drugs is quite variable. As pointed out before, apart from
these variable factors, others such as the method of extraction and
contamination with microorganisms, heavy metals, pesticides, etc., can
also interfere with the quality, safety and efficacy of herbal drugs.
For these reasons, pharmaceutical companies prefer using cultivated
plants instead of wild-harvested plants because they show smaller
variation in their constituents. Furthermore and certainly more
relevant, when medicinal plants are produced by cultivation, the main
secondary metabolites can be monitored and this permits definition of
the best period for harvesting. (Koo, et al., 2004).
Quality control
of herbal medicines is a critical and essential issue to be considered
in assuring the therapeutic efficacy, safety and to rationalize the use
of herbal medicinal products (HMPs) in healthcare. Definition and
characterization of the material is necessary prior to the assessment of
the relevance of available efficacy and safety data. It is also
important that the material used and available commercially should be
consistent with the evaluated material because any significant change in
quality would trigger the need for re-evaluation of the relevance of
the safety and efficacy data (Mukherjee, 2002). Adulterants, and more
often, the incorrect identification of the herbs, are the causes of low
quality in herbals.
Standardization is a system that ensures a
predefined amount of quantity, quality & therapeutic effect of
ingredients in each dose. Herbal product cannot be considered
scientifically valid if the drug tested has not been authenticated and
characterized in order to ensure reproducibility in the manufacturing of
the product. Moreover, many dangerous and lethal side effects have
recently been reported, including direct toxic effects, allergic
reactions, effects from contaminants, and interactions with herbal
drugs. Therapeutic activity of an herbal formulation depends on its
phytochemical constituents. The development of authentic analytical
methods which can reliably profile the phytochemical composition,
including quantitative analyses of marker/bioactive compounds and other
major constituents, is a major challenge to scientists. Standardization
is an important step for the establishment of a consistent biological
activity, a consistent chemical profile, or simply a quality assurance
program for production and manufacturing of an herbal drug. The
authentication of herbal drugs and identification of adulterants from
genuine medicinal herbs are essential for both pharmaceutical companies
as well as public health and to ensure reproducible quality of herbal
medicine. (Choudhary and Sekhon, 2011).
It is very important that a
system of standardization is established for every plant medicines in
the market because the scope for variation in different batches of
medicine is enormous. Plant materials may vary in its therapeutic effect
according to different places of collection, with different times in a
year for collection, with collection at the same time and place but in
different years, and with different environmental factors surrounding
the cultivation of a particular medicinal plant. Adding to this
variability is the fact that in herbal medicine, several plants may be
used together in the same preparation. These means that there should be a
quality control test for the entire preparation to ensure quality of
the preparation (Prajapati, et al., 2003).
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