Chapter 6 - Quality control, extraction methods, and standardization: Interface between traditional use and scientific investigation

Abstract

Herbal medicines and remedies are included in the general therapy discipline known as complementary and alternative medicines (CAMs). While global use of these medicines is escalating exponentially, their quality, safety, and efficacy are major concerns due to lack of appropriate regulatory control. Herbal medicines mainly contain plant material consisting of complex constituents where many, if not all, of the active principles are often unknown. The amount of incorporated ingredients can vary greatly due to numerous factors that can result in variation in the quality of raw materials. Quality is highly dependent on the source of plants and related materials, which in turn are dependent on numerous intrinsic (genotype) and extrinsic factors such as taxonomy, selection, and cultivation including environmental conditions and geography. Although, traditional methods do provide anecdotal evidence of preparation of herbal medicines, these methods may not provide details of actual active ingredient(s). Hence, correct identification of species, careful collection, and appropriate storage are essential requirements for the quality control of raw materials to ensure that products containing plant material or extracts are of the requisite quality. Extraction of plant material, isolation, and identification of active ingredients using appropriate validated analytical methods and procedures for QC of products for two specific plants, as examples, are described in this chapter. Unlike allopathic medicines, QC of herbal medicines remains largely unregulated resulting in high variability in specific content and potency between batches and questionable control of impurities and presence of possible toxic contaminants. The application of appropriate extraction procedures and the use of qualified reference standards in conjunction with good manufacturing practice (GMP) to produce high-quality products remains an important objective to ensure appropriate clinical performance of such products.