Quality Control is a term that refers to processes
involved in maintaining the quality of validity of a manufactured product. Regardless of the form of herbal
preparation, some degree of quality control should exist.
Currently, there is no organization or government body that
certifies an herb as labeled correctly.
Without proper quality control, there is no assurance that the herb contained in the bottle is the same as what is stated on the outside label. The widespread disregard for quality control in the health food industry has tarnished the reputation of many important medicinal herbs. For example, it has been estimated that because of supplier errors in collection, more than 50% of the Echinacea sold in the United States from 1908 through 1991 was actually Parthenium integrifolium. This highlights the importance of using the Latin name to properly identify herbal source materials, since both of the above-mentioned herbs are often referred to as "Missouri Snakeroot," as well as the need for proper plant identification based upon organoleptic, microscopic, and chemical analyses.
Recent chemical analysis of commercially available Feverfew (Tanacetum parthenium) and Taheebo (Tabebuia avellanedae) for active components, parthenolide and lapachol, respectively, have also shown need for concern. Analysis of over 35 different commercial preparations of Feverfew indicated a wide variation in the amounts of parthenolide in commercial preparations. The majority of product samples contained no parthenolide whatsoever, or only traces. Additionally, analysis of 12 commercial sources of Taheebo could identify lapachol (in trace amounts) in only one product.
The solution to the quality control problem that exists in the United States is for manufacturers and suppliers of herbal products to adhere to quality control standards and good manufacturing practices. With improvements in the identification of plants by laboratory analysis, consumers should at least be guaranteed that the right plant is being used. Consumers, health food stores, pharmacists, and physicians who use or sell herbal products should ask for information from the suppliers of herbal products on their quality control processes. As more consumers, retailers, and professionals begin asking for quality control from the suppliers, it is possible more quality control processes will be utilized by manufacturers.
Currently, only a few manufacturers adhere to complete quality control and good manufacturing procedures including microscopic, physical, chemical/physical, and biological analyses. Companies supplying standardized extracts currently offer the greatest degree of quality control, hence these products typically offer the highest quality.
Most standardized extracts are currently made in Europe under strict guidelines set forth by individual members of the European Economic Council (EEC) as well as those proposed by the EEC. Included are guidelines for acceptable levels of impurities such as parasites (bacterial counts), pesticides, residual solvents, heavy metals, and product stability.
The EEC production of standardized extracts serves as a model for quality control processes for all forms of herbal preparations. In general, it is believed that if the active components of a particular herb are known, whatever form the herb product is, the herb should be analyzed to ensure that it contains these components at an acceptable / standardized level. More accurate dosages can then be given for optimal use of the herb. Products also should be subjected to bacteriological counts.
Currently, in many countries, numerous standardized extracts fulfill requirements for marketing as drugs. These extracts have typically gone through many thorough quality control steps.
Improvements in analytical methods have definitely led to improvements in harvesting schedules, cultivation techniques, storage, activity, stability of active compounds, and product purity. All of these gains have resulted in tremendous improvements in the quality of herbal preparations now available.
For example, optimal activity and quality collection should be done at a time when the active ingredient is present in the greatest amount. Improvements in analysis have led to more precise harvesting of many herbs.
Methods currently utilized in evaluating herbs and their extracts include:
Organoleptic means the "impression of the organs." Organoleptic analysis involves the application of sight, odor, taste, touch, and occasionally even sound, to identify the plant. Obviously, the initial sight of the plant or extract is so specific that it tends to identify itself. If this is not enough, perhaps the plant or extract has a characteristic odor or taste. Organoleptic analysis represents the simplest, yet the most human, form of analysis.
Microscopic evaluation is indispensable in the initial identification of herbs, as well as in identifying small fragments of crude or powdered herbs, and in detection of adulterants (e.g. insects, animal feces, mold, fungi, etc.) as well as identifying the plant by characteristic tissue features. Every plant possesses a characteristic tissue structure, which can be demonstrated through study of tissue arrangement, cell walls, and configuration when properly mounted in stains, reagents, and media.
In crude plant evaluation, physical methods often are used to determine the solubility, specific gravity, melting point, water content, degree of fiber elasticity, and other physical characteristics of the herb material.
Various chemical / physical methods also are used to determine the percentage of active principles, alkaloids, flavonoids, enzymes, vitamins, essential oils, fats, carbohydrates, protein, ash, acid-insoluble ash, or crude fiber present.
The final analytical process requires more precise assays to determine quality. Sophisticated techniques, such as high pressure liquid chromatography (HPLC) and nuclear magnetic resonance (NMR), are often used to separate out molecules. The readings from these machines provide a chemical "fingerprint" as to the nature of chemicals contained in the plant or extract. These techniques are invaluable in the effort to properly and fully identify herbs, as well as standardized extracts.
The plant or extract can then be evaluated by various biological methods to determine pharmacological activity, potency, and toxicity.
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