Volume 52, Part B, November 2015, Pages 344–362
Highlights
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- Plants are complex multicomponent mixtures and their composition depends on many external factors.
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- Starting materials need to be correctly authenticated and must be free of adulterants and contaminants.
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- The production process of herbal medicinal products needs to be strictly monitored and standarized.
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- For valid and reproducible pharmacological and toxicological studies, products must be characterized.
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- Knowledge on ADME characteristics of the bioactive constituents is essential.
Abstract
As
all medicines, herbal medicinal products are expected to be safe,
effective, and of appropriate quality. However, regulations on herbal
medicinal products vary from country to country, and herbal preparations
do occur not only in the form of medicinal products but also as less
strictly regulated product groups like dietary supplements. Therefore,
it is not always easy for the consumers to discriminate high-quality
products from low-quality products. On the other hand, herbal medicines
have many special features that distinguish them from conventional
medicinal products. Plants are complex multicomponent mixtures; in
addition, their phytochemical composition is not constant because of
inherent variability and a plethora of external influences.
Therefore,
the production process of an herbal medicinal product needs to be
strictly monitored. First of all, the starting materials need to be
correctly authenticated and free of adulterants and contaminants. During
plant growth, many factors like harvest season and time, developmental
stage, temperature, and humidity have a strong impact on plant
metabolite production. Also, postharvest processing steps like drying
and storage can significantly alter the phytochemical composition of
herbal material. As the production of many phytopharmaceuticals includes
an extraction step, the extraction solvent and conditions need to be
optimized in order to enrich the bioactive constituents in the extract.
The quality of finished preparations needs to be determined either on
the basis of marker constituents or on the basis of analytical
fingerprints. Thus, all production stages should be accompanied by
appropriate quality assessment measures. Depending on the particular
task, different methods need to be applied, ranging from macroscopic,
microscopic, and DNA-based authentication methods to spectroscopic
methods like vibrational spectroscopy and chromatographic and hyphenated
methods like HPLC, GC–MS and LC–MS.
Also, when
performing pharmacological and toxicological studies, many features
inherent in herbal medicinal products need to be considered in order to
guarantee valid results: concerning in vitro studies, difficulties are
often related to lacking knowledge of ADME characteristics of the
bioactive constituents, nuisance compounds producing false positive and
false negative results, and solubility problems. In in vivo animal
studies, the route of administration is a very important issue. Clinical
trials on herbal medicinal products in humans very often suffer from a
poor reporting quality. This often hampers or precludes the pooling of
clinical data for systematic reviews. In order to overcome this problem,
appropriate documentation standards for clinical trials on herbal
medicinal products have been defined in an extension of the CONSORT
checklist.
This article is part of a Special Issue entitled “Botanicals for Epilepsy”.
Abbreviations
- AAS, atomic absorption spectrometry;
- CAD, charged aerosol detector;
- CE, capillary electrophoresis;
- CZE, capillary zone electrophoresis;
- DAD, diode array detector;
- DSHEA, Dietary Supplement Health and Education Act;
- ELSD, electric light scattering detector;
- EMA, European Medicines Agency;
- FID, flame ionization detector;
- GACP, good agricultural and collection practice;
- GC, gas chromatography;
- GMP, good manufacturing practice;
- HILIC, hydrophilic interaction chromatography;
- HPLC, high-performance liquid chromatography;
- HR-MS, high-resolution mass spectrometry;
- ICP-OES, inductively coupled plasma-optical emission spectrometry;
- IR, infrared;
- MEKC, micellar electrokinetic chromatography;
- MIR, mid-infrared;
- MS, mass spectrometry;
- NIR, near-infrared;
- NMR, nuclear magnetic resonance;
- TCM, traditional Chinese medicine;
- TLC, thin layer chromatography;
- UHPLC, ultrahigh-pressure liquid chromatography;
- WHO, World Health Organization;
- XRFS, X-ray fluorescence spectroscopy
Keywords
- Pharmacognosy;
- Herbal medicinal products;
- Quality control
- Corresponding author. Tel.:
+ 43 316 380 8700; fax: + 43 316 380 9860.
Copyright © 2015 Elsevier Inc. All rights reserved.
