ABSTRACT
Herbal medicines are the most ancient form of health remedies known to mankind. In spite of the great advances achieved in modern medicine, plants still make an important contribution to health care, and several specic herbal extracts have demonstrated to be efcacious for specic conditions. Moreover, at least 120 distinct chemical substances derived from plants are considered as important drugs currently in use, and several other drugs are simple synthetic modications of natural products (Fabricant and Farnsworth 2001). Plants can be regarded as “living factories” producing a variety of chemical compounds, including primary metabolites important for the growth of the plants (amino acids, proteins, carbohydrates) and secondary metabolites (alkaloids, terpenoids, phenylpropanoids, polyketides, avonoids, saccharides). All these components may work together to deliver a synergistic effect in the nished product. Certain herbal medicines, because of the complexity of their chemical content and the variety of bioactivities, can provide the polypharmacology which orthodox drugs cannot deliver. Natural products are rarely evaluated in the well-controlled clinical trials that are required to receive the approval by regulatory bodies, and therefore tend to have less “scientic” evidence to support their efcacy. However, all medicinal compounds are chemicals, whether synthesized in plants, animals, or manufacturing laboratories; therefore, all medicinal chemical compounds should be held accountable to similar standards of quality (identity, purity, and stability), clinical effectiveness, and safety, irrespective of their source: “If it is found to be reasonably safe and effective, it will be accepted” (Angell and Kassirier 1998). Reliable and consistent quality is the basis of efcacy and safety of herbal medicinal products (HMPs). Given the nature of products of plant origin, which are highly variable and complex products with numerous biologically active components that are rarely completely identi-ed, therapeutic results and safety issues vary greatly from product to product, even within a single class. Therefore, the evidence of both benets and risks is specic to the product tested and cannot
19.1 Introduction ........................................................................................................................ 279 19.2 Herbal Medicinal Products .................................................................................................280 19.3 Phytotherapy ....................................................................................................................... 281 19.4 Quality Control ................................................................................................................... 281 19.5 Variability ........................................................................................................................... 282 19.6 Safety and Efcacy .............................................................................................................284 19.7 Industry Challenges ............................................................................................................284 19.8 Conclusion ..........................................................................................................................285 References ......................................................................................................................................285
