Herbal products: The need of quality assurance and recent advances in quality control

The use of medicinal plants for healing purposes has a long tradition in Europe. Nowadays, two categories of herbal products have to be differentiated, i.e. (traditional) herbal medicinal products ((T)HMP) and herbal food supplements (so-called botanicals). (T)HMP are subject to the common regulations for medicinal products in Europe, whereas botanicals are regulated by the food legislation. Both product categories have to be safe by law, but only for (T)HMP the safety as well as the quality and efficacy (the latter at least by traditional use) have to be officially approved for marketing authorisation or registration, respectively. Prerequisite for both safety and efficacy of any medicinal product is its high and reproducible quality. Therefore, also (T)HMP have to meet high quality requirements. Since the active pharmaceutical ingredients of (T)HMP (i.e. mostly herbal extracts) are complex multicomponent mixtures, the quality control and assurance are however challenging and elaborate. The composition of a (T)HMP is dependent on the used herbal drug and its quality as well as on the mode of its preparation, which is influenced by many parameters. Besides the adaption of both GACP and GMP guidelines, the individual specification is therefore an essential element of quality assurance. For this, the methods and quality criteria of the European Pharmacopoeia (EP), although permanently advanced, are helpful, but not sufficient. For example, neither combination (T)HMP nor stability testing are considered in the EP. To meet the regulatory requirements, high-sophisticated methods are necessary and meanwhile applied in the industrial quality assurance (e.g. varios LC-MS techniques, NMR-, NIR-spectroscopy, DNA-, PSE analyses). It is comprehensible that the quality requests on (T)HMP are often questioned in view of the fact that there are no corresponding quality regulations for botanicals. Moreover, the consumers are usually not aware of this discrepancy and the consequence that there may actually be large quality differences between (T)HMP and botanicals as well as between various botanicals. That quality is however a relevant factor is demonstrated by numerous publications and reports on severe side effects by non-medicinal herbal products due to quality failures.