Plant Analysis – State of the Art and Future Developments

Medicinal plants and products thereof are undoubtedly of great medicinal and economic importance; however, compared with conventional pharmaceutical preparations they also present a number of unique features and challenges. First, they are usually comprised of a complex mixture of compounds that can vary considerably even within the same species, depending on environmental (e.g., climate, altitude) and genetic factors. Second, sometimes different herbs are used as a mixture, which further complicates the composition of a sample. And finally, the compounds responsible for therapeutic effects are frequently unknown or can only partially explain a plant's usage. Quality control is therefore of utmost importance in any herbal product, from using authenticated plant material to the development of suitable analytical techniques for ensuring a finished product's consistency and efficacy.

This special issue of Planta Medica is devoted to plant analysis, a field nearly as manifold and diverse as the array of compounds produced in (medicinal) plants themselves. The analyst not only has to allow for the particular chemical and physical properties of the compounds of interest but also needs to select the most promising analytical approach. Therefore any publication dealing with plant analysis should not be limited to the description of currently employed analytical techniques but also address the specific problems and challenges associated with the matrices investigated as well as indicate future trends and perspectives.

The first manuscripts in this special issue aim to familiarize the reader with historical aspects of plant analysis and pinpoint several general aspects, such as the importance of reference compounds, the impact of sample preparations and the legal status of commercial products. Comparing the most important markets for herbal medications, which are Europe (and here especially Germany and France) and the United States, reveals significant differences in the legal understanding of these products. This explains the fact why they may be classified either as dietary supplements or as herbal medicinal products. Even though there may not be much difference for the consumer at first glance, these terms refer to two completely different product categories with different rules and regulations regarding quality control and efficacy claims.

In the second and major part of this volume technical aspects and applications are described and discussed. This includes not only currently employed analytical techniques like thin-layer chromatography, high-performance liquid chromatography and capillary electrophoresis, but also innovative developments. The latter include, for example, the use of near infrared spectroscopy, metabolic fingerprinting and quantitative determinations based on nuclear magnetic resonance spectra. Last but not least recent analytical applications on Traditional Chinese Medicines, a currently booming product segment, are presented.

By choosing such a broad approach to plant analysis we aim to provide a comprehensive summary of the current status quo and point to possible future trends and developments. Therefore this special issue of Planta Medica should not only be of interest to scientists already working in this field but also to others from related areas.

The editors are grateful to the authors for their interesting contributions and to the reviewers for their valuable comments. We also would like to thank Prof. Matthias Hamburger and Prof. Luc Pieters for giving us the opportunity to serve as guest editors for this special issue of Planta Medica.