Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev
Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev
14 QUALITY CONTROL OF MEDICINAL AND AROMATIC PLANTS AND THEIR EXTRACTED PRODUCTS BY HPLC AND HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY nutraceuticals. South America, which has given the world some of the all-time great plant medicines like quinine and pilocarpine, follows the medical system of North America. Australia has a strong impact from Chinese medicines on the continent which is otherwise dominated by the modern system of medicine. 14.2 Quality Control of Medicinal Plants and their Products The quality control of consumer products has become more challenging and demanding. The quality considerations of drugs are the most stringent among all consumer products. The purity of active pharmaceutical ingredients has been stretched to an all-time high with more and more restrictions on the level of the impurities. The situation is opposingly different in the case of plant-derived medicine, where we are still striving to define specifications to ensure consistency and safety. Therefore, the standards of plant drugs are more relaxed and are in the process of development. The inherent problems of plant drugs are obvious; unlike single chemical entities of modern drugs, they are combinations of infinite chemical molecules, known and unknown; the knowledge of the active components is incomplete; the natural variations in content and quantity of the chemical constituents are large and exercising a precise control is impractical; and the complete chemical profiling of plant drugs is beyond scope. Therefore, laying standards for such drugs is not an easy task and a comprehensive system of standards cannot be laid down for such drugs. As our knowledge of plant drugs will advance, the standards for them will become more meaningful and complete. The quality issue of plant drugs was irrelevant in ancient times when these medicines were dispensed by the medical men for their patients. However, the issue has taken front seat with the commercialization of plant drugs. The matter has been further complicated by the vested interest of manufacturers who are out to exploit the loopholes in the standards and laws governing the production and distribution of plant drugs. Several national and international agencies have prioritized the issue of assuring the quality of plant drugs. The effort of the World Health Organization is outstanding: over 20 years ago it fi rst published Quality control methods for medicinal plant materials, which has been regularly updated and followed by a series of monographs on globally important medicinal plants. The quality of a plant product cannot be assured without assuring the quality of the raw material. Also required to ensure quality products are in-process control, quality control of the fi nished product, good manufacturing practice (GMP) controls and process validation. In this regard, it is imperative to defi ne specifi cations of raw materials to minimize variations in the quality of fi nished products and to achieve consistency. The specifi ca- 240
EXTRACTION TECHNOLOGIES FOR MEDICINAL AND AROMATIC PLANTS tions of plant materials include macro- and microscopic descriptions, tests of identity, and analytical and physicochemical determinations. The expected results of these tests and measurements are presented as numerical limits or as a range or discretely observable result. While fixing the limits of specifications, naturally met variations in plant drugs need to be accommodated. A plant material conforming to the prescribed specifications should be considered acceptable for intended use. Several factors contribute to variation in the content and composition of raw materials. These factors can broadly be grouped in four categories of climatic, nutritional, collection and post-harvest factors. Climatic factors include prevailing temperature, rainfall, humidity, daylight and altitude of the growing region. The nutritional factors are those which affect the health of a growing plant and are reflected in the production of biomass and its composition; several soil factors such as availability of micro- and macronutrients, pH and cation exchange capacity are important for optimal growth of plants. Collection factors control the content of active components by giving due attention to the age, season, collection time and part of the plant collected. Post-harvest factors are important as the collected material is still live and carries out metabolic processes and respires; the enzymatic processes continue after collection until they are deactivated by drying or other suitable treatment; the crushing and cutting of material leads to de-compartmentalization of reactive chemical constituents of plants which were naturally located in intact cells; and the collected material faces direct impact of oxidation by air and light besides physical loss of some components. The World Health Organization, in its volume Quality control methods for medicinal plant materials, has listed several parameters which are valuable in assuring quality of plant drugs. These include identification, visual inspection, sensory characters, macro- and microscopic characteristics, moisture content, foreign matter, fingerprint by thin layer chromatography (TLC), ash values, extractive values, volatile matter, microbial load, heavy metals and pesticide residues, radioactive contaminants and, according to the nature of the drug, one or more determinations for bitter value, tanning test, foaming, hemolytic and swelling indices. The European Medicines Agency’s “Guideline on quality of herbal medicinal products” and “Guideline on specifications” more precisely describe the quality-related issues of medicinal plants. These documents define and differentiate herbal substances (equivalent to herbal drugs), herbal preparations (equivalent to herbal drug preparations) and herbal medicinal products (equivalent to traditional herbal medicinal products). The guidelines emphasize the quantification of active or analytical markers and describe procedures to ensure quality of raw material, semifinished and finished products. 241
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14 QUALITY CONTROL OF MEDICINAL AND AROMATIC PLANTS AND THEIR EXTRACTED PRODUCTS<br />
BY HPLC AND HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY<br />
nutraceuticals. South America, which has given the world some of the all-time<br />
great plant medicines like quinine <strong>and</strong> pilocarpine, follows the medical system<br />
of North America. Australia has a strong impact from Chinese medicines on the<br />
continent which is otherwise dominated by the modern system of medicine.<br />
14.2 Quality Control of <strong>Medicinal</strong> Plants <strong>and</strong> their<br />
Products<br />
The quality control of consumer products has become more challenging<br />
<strong>and</strong> dem<strong>and</strong>ing. The quality considerations of drugs are the most<br />
stringent among all consumer products. The purity of active pharmaceutical<br />
ingredients has been stretched to an all-time high with more <strong>and</strong> more restrictions<br />
on the level of the impurities. The situation is opposingly different in<br />
the case of plant-derived medicine, where we are still striving to define specifications<br />
to ensure consistency <strong>and</strong> safety. There<strong>for</strong>e, the st<strong>and</strong>ards of plant<br />
drugs are more relaxed <strong>and</strong> are in the process of development. The inherent<br />
problems of plant drugs are obvious; unlike single chemical entities of modern<br />
drugs, they are combinations of infinite chemical molecules, known <strong>and</strong><br />
unknown; the knowledge of the active components is incomplete; the natural<br />
variations in content <strong>and</strong> quantity of the chemical constituents are large <strong>and</strong><br />
exercising a precise control is impractical; <strong>and</strong> the complete chemical profiling<br />
of plant drugs is beyond scope. There<strong>for</strong>e, laying st<strong>and</strong>ards <strong>for</strong> such drugs is<br />
not an easy task <strong>and</strong> a comprehensive system of st<strong>and</strong>ards cannot be laid<br />
down <strong>for</strong> such drugs. As our knowledge of plant drugs will advance, the st<strong>and</strong>ards<br />
<strong>for</strong> them will become more meaningful <strong>and</strong> complete.<br />
The quality issue of plant drugs was irrelevant in ancient times<br />
when these medicines were dispensed by the medical men <strong>for</strong> their patients.<br />
However, the issue has taken front seat with the commercialization of<br />
plant drugs. The matter has been further complicated by the vested interest<br />
of manufacturers who are out to exploit the loopholes in the st<strong>and</strong>ards <strong>and</strong><br />
laws governing the production <strong>and</strong> distribution of plant drugs.<br />
Several national <strong>and</strong> international agencies have prioritized the<br />
issue of assuring the quality of plant drugs. The ef<strong>for</strong>t of the World Health<br />
Organization is outst<strong>and</strong>ing: over 20 years ago it fi rst published Quality control<br />
methods <strong>for</strong> medicinal plant materials, which has been regularly updated<br />
<strong>and</strong> followed by a series of monographs on globally important medicinal<br />
plants.<br />
The quality of a plant product cannot be assured without assuring<br />
the quality of the raw material. Also required to ensure quality products<br />
are in-process control, quality control of the fi nished product, good manufacturing<br />
practice (GMP) controls <strong>and</strong> process validation. In this regard, it is<br />
imperative to defi ne specifi cations of raw materials to minimize variations<br />
in the quality of fi nished products <strong>and</strong> to achieve consistency. The specifi ca-<br />
240