Herbs and herbal products are of paramount importance for human health. To be able to guarantee safety and quality, standards and testing methods are needed. Pharmacopoeias contain quality control protocols setting the standards which are then required by governments. The quality traits are many, including the intrinsic variables of medicinal plant, e.g. the levels of the active compounds, and the absence of possibly natural occurring toxic compounds. On the other hand, many quality traits are related to agricultural conditions and practices, or to the harvesting and post-harvest processing. With so many variables, quality control of the end product becomes extremely complex, time consuming and costly. To ensure the quality of medicinal plants for human consumption quality management -the use of "good practices" at each step, from seed to final product- becomes a crucial aspect.
In general, quality control includes the inspection of the product’s identity, purity, and content, based on its physical, chemical or biological properties. To ensure the quality of herbal medications, criteria such as botanical quality, type of preparation, physical constants, adulteration, contaminants, chemical constituents, pesticides residues et al. should be examined. Meanwhile, authentication of herbs is needed to avoid possible adulteration or contaminating plants, even toxic herbs such as
Aristolochia species. Many of the methods are long standing, such as microscopy in combination with color reactions, but some 50 years ago chromatography developed as a major tool for both qualitative and quantitative analysis of herbal preparations. Nowadays, research is working on the improvement of these methods and on the development of novel tools.
For instance, next generation sequencing and mass spectrometry imaging, are emerging as new technologies for the quality control of herbal medicines. With these technologies, quick testing of herbal products and of mixed herbal powder preparations, including the testing for specific plant parts (botanical drugs), can be achieved. Also, novel chemical tools such as metabolomics and Near Infrared Red (NIR) spectroscopy are being developed as powerful tools to identify and to link these with activity by using chemometric tools such as multivariate analysis. Finally, progress of informatic tools such as machine learning helps to deal with the big data generated by sequencing or mass spectrometry. However, these new technologies, like all other new born technologies, should be tested and perfected for a broader range of products.
This Research Topic will focus on the advanced technologies for herbal medicine quality control and standardization, including the aspects of botanical identification and chemical analysis. We encourage studies focusing on the validation of such methods with the ultimate aim of including these in legally binding quality control protocols. Advantages as well as limitations will be dealt with the aim to show what tools could be implemented for setting the standards of herbal preparations. Contributions on new technologies and their applications are welcome in this Research Topic. These include, but are not limited to:
• New chemical methods for herbal identification and analysis like metabolomics NMR, GC, LC, MS, HPTLC, NIR.
• Nucleic-acid based identification, e.g. DNA barcodes; NGS sequencing; transcriptomes.
• New imaging methods.
We hope this Research Topic will help to set the standards for the quality control and management of herbal medicines.
Important Note: Studies with the specific aim to either improve local healthcare by developing products based on such knowledge or studies in the context of drug discovery/development from natural sources will be considered if they are based on biological resources with a clear and well-defined local or traditional use. Purely biodiversity-based screening studies and studies of established natural products and their mechanism of action are outside the scope of this section. Studies reporting such local and traditional uses will only be accepted if the comply with the ConSEFS standards (
Heinrich et al. 2017). Toxicological research and clinical studies on medicinal plants are welcome.
The following basic guidelines, focused on best practice in ethnopharmacology, should be followed by all submissions:
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Botanical - The
Etnopharmachology Specialty Section of
Frontiers in Pharmacology subscribes to the taxonomic standards laid down most importantly at the
Kew MPNS portal and also the Royal Botanic Gardens/Kew/Missouri Botanical Garden
"The Plant List" initiative. Of course, full botanical documentation is essential (i.e. a voucher specimen deposited in a recognized herbarium).
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Pharmacological - Antioxidant activity: here in vivo or in vitro studies using generally acceptable pharmaceutical models are essential. Simple in silico and pharmacologically irrelevant assays for antioxidant activity (e.g. the DPPH assay, FRAP (Ferric Reducing Ability of Plasma), ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) are not acceptable as a main tool for assessing an extract or a compound for activity. Such assays are commonly used in food chemistry and other fields, but are not of pharmacological relevance.
- Dose ranges must be pharmacologically relevant. While impossible to define an exact cut-off, studies testing extracts at implausibly high doses are increasingly common in the literature.
- Positive and negative controls must be included.
- Models must be pharmacologically relevant and plausible - a complex issue depending on the specific goals of the study. Authors must consider the ethical acceptability of further
in vivo studies on an already well-studied species, demonstrating some common activity (e.g. an anti-inflammatory effect studied in the rat-paw oedema).
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Chemical - The composition of the study material must be described in sufficient detail.
- If 'pure' compounds are used information on the level of purity must be included.
In case of ethnopharmacological field studies you must follow the
ConSEFS standards.