Botanical supplements come in various forms, including whole or chopped herbs, powders, teas, capsules, tablets, hydroalcoholic tinctures, dry extracts, and syrups. In addition to their use as supplements or medicinal agents, botanicals are also increasingly being added to conventional food products such as cereals, beverage teas, potato chips, soups, and juices, as well as to sundry other products such as toilet paper, shampoos, hair conditioners, and skin care products. The quality assurance and assessment of botanical drugs, traditional or modern, requires that every available tool be accessible and applied as appropriate. Each analytical tool has its purpose and utility, and one is only superior to another in terms of the analytical goal.
It is a legal requirement of nearly all nations to disclose the identity of ingredients in products accurately. For botanical identification purposes, the highest level of confidence in identity that can be achieved is through morphological analysis. However, generally speaking, formal botanical identification is not widely employed in the trade of medicinal plants. Very seldom will manufacturers find ingredient vendors who can provide an affidavit of botanical authenticity, thus raising the question as to the authenticity of plants in trade. However, botanical identification is only specific for identification and is not appropriate for quality assessment or the evaluation of extracts.
The initial set of pharmacognostic tools used for quality assessment of medicinal plant parts is macro- and micro-anatomy and organoleptic analysis (sensory evaluation)— namely, size, shape, color, form, texture, taste, and aroma. Morphological and organoleptic analyses offer a suite of tests that, in trained individuals, can provide an assessment of the most subtle of characteristics that contribute to the identification and true quality of a plant; the microscope allows for the assessment of plant material at a cellular level.
As an analytical tool, botanical microscopy can stand on its own for establishing identity, purity, and, sometimes, the general quality of a medicinal plant; it can help to indicate what the chemist is to look for, and it can assist in supporting the results of chemical assessment. In the absence of an appropriate botanical identification, macroscopic and microscopic features are among the most "stable" of a plant's characteristics when it comes to identification. In many cases, botanical microscopy can succeed in confirming plant identity and detecting adulterants when chemistry alone cannot. Most often, the suite of analytical tools is ultimately best for overall quality assessment of botanical materials (Figure 1.16). Kraemer's previously stated extravagant claims for the broad utility of botanical microscopy were limited by the science of the day. Nevertheless, they showed the practical value placed on microscopy in assessing many different aspects of plant identity, purity, and quality in a single analytical method.
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