The analysis of medicinal plants has had a long history, and especially with regard to assessing a plant’s quality. The first techniques were organoleptic using the physical senses of taste, smell, and appearance. Then gradually these led on to more advanced instrumental techniques. Though different countries have their own traditional medicines China currently leads the way in terms of the number of publications focused on medicinal plant analysis and number of inclusions in their Pharmacopoeia. The monographs contained within these publications give directions on the type of analysis that should be performed, and for manufacturers, this typically means that they need access to more and more advanced instrumentation. We have seen developments in many areas of analytical analysis and particularly the development of chromatographic and spectroscopic methods and the hyphenation of these techniques. The ability to process data using multivariate analysis software has opened the door to metabolomics giving us greater capacity to understand the many variations of chemical compounds occurring within medicinal plants, allowing us to have greater certainty of not only the quality of the plants and medicines but also of their suitability for clinical research. Refinements in technology have resulted in the ability to analyze and categorize plants effectively and be able to detect contaminants and adulterants occurring at very low levels. However, advances in technology cannot provide us with all the answers we need in order to deliver high-quality herbal medicines and the more traditional techniques of assessing quality remain as important today.

Value chain analyses are commonly used to understand socioeconomic and power relationships in the production chain from the initial starting material to a final (generally high value) product. These analyses help in terms of understanding economic processes but also have been used in the context of socioeconomic and socioecological research. However, there is a gap in the ethnopharmacological literature in terms of understanding what relevance a critical analysis of value chains of herbal medicines could have. Here we provide a research framework for achieving such an analysis. An extensive review of the literature available on value chains and their analysis was conducted, based both on a systematic online search of the relevant literature and a hand search of bibliographies and discussions with experts in value chain analysis While the concept of value chains is commonly used in the relevant industries, very few studies investigate the value chains of herbal medicines and products derived from them. The studies identified mostly look at socio-ecological aspects, especially in the context of sustainable resource use. We suggest an analytical framework which can help in understanding value chains in the context of ethnopharmacology and can serve as a basis for addressing questions related to value chains and their relevance in ethnopharmacology. We identified a crucial gap in current ethnopharmacological and medicinal plant research which impacts on a wide-range of factors relevant for a sustainable, socio-culturally equitable and safe supply of herbal medicines.

Rhodiola rosea L. Crassulaceae, root (Golden Root, Arctic Root) is a high-value herbal medicinal product, registered in the UK for the treatment of stress-induced fatigue, exhaustion and anxiety based on traditional use and used throughout Europe as a herbal medicinal product for similar indications. Numerous unregistered supplements are also available. There are several Chinese species used in traditional Chinese medicine (TCM), including Rhodiola crenulata (Hook.f. & Thomoson) that is believed to be a common adulterant in the R. rosea value chain. The project is embedded in a larger study aiming to investigate the diverse value chains that lead to the production of R. rosea as an herbal medicinal product or supplement. Here we focus on a comparison of the quality of the finished products and assess any phytochemical variation between products registered under the Traditional Herbal Medicine Products Directive (THMPD) and products obtained from the market without any registration (i.e. generally unlicensed supplements). Our key aim is to establish the extent of the problem in terms of adulteration of consumer products claiming to contain R. rosea (or R. crenulata). Approximately 40 commercial products (granulated powders and extracts) were sourced from different suppliers. We analysed these samples using high performance thin layer chromatography (HPTLC), mass spectrometry (MS) and (1)H NMR spectroscopy coupled with multi-variate analysis software following a method previously developed by our group for the analysis of turmeric products. We investigate the phytochemistry of the different species and assess the potential of R. crenulata as an adulterant at the end of the R. rosea value chains. The consistency of the products varies significantly. Approximately one fifth of commercial products that claimed to be R. rosea did not contain rosavin (the key reference markers used to distinguish R. rosea from related species). Moreover some products appeared not to contain salidroside, another marker compound found in other Rhodiola species. Approximately 80% of the remaining commercial products were lower in rosavin content than the registered products and appeared to be adulterated with other Rhodiola species. The variation in phytochemical constituents present in Rhodiola products available to European buyers via the internet and other sources is a major cause for concern. Adulteration with different species, and other sometimes unknown adulterants, appears to be commonplace. Good quality systems and manufacturing practices, including those required under the THMPD, enable consumers to have confidence that products are authentic and meet a high specification for quality and safety.

Chemical methods are the most important and widely used traditional plant identification techniques recommended by national and international pharmacopoeias. We have reviewed the successful use of different chemical methods for the botanical authentication of 2,386 commercial herbal products, sold in 37 countries spread over six continents. The majority of the analyzed products were reported to be authentic (73%) but more than a quarter proved to be adulterated (27%). At a national level, the number of products and the adulteration proportions varied very widely. Yet, the adulteration reported for the four countries, from which more than 100 commercial products were purchased and their botanical ingredients chemically authenticated, was 37% (United Kingdom), 31% (Italy), 27% (United States), and 21% (China). Simple or hyphenated chemical analytical techniques have identified the total absence of labeled botanical ingredients, substitution with closely related or unrelated species, the use of biological filler material, and the hidden presence of regulated, forbidden or allergenic species. Additionally, affecting the safety and efficacy of the commercial herbal products, other low quality aspects were reported: considerable variability of the labeled metabolic profile and/or phytochemical content, significant product-to-product variation of botanical ingredients or even between batches by the same manufacturer, and misleading quality and quantity label claims. Choosing an appropriate chemical technique can be the only possibility for assessing the botanical authenticity of samples which have lost their diagnostic microscopic characteristics or were processed so that DNA cannot be adequately recovered.

The fast developing international trade of products based on traditional knowledge and their value chains has become an important aspect of the ethnopharmacological debate. The structure and diversity of value chains and their impact on the phytochemical composition of herbal medicinal products has been overlooked in the debate about quality problems in transnational trade. Different government policies and regulations governing trade in herbal medicinal products impact on such value chains. Medicinal Rhodiola species, including Rhodiola rosea L. and Rhodiola crenulata (Hook.f. & Thomson) H.Ohba, have been used widely in Europe and Asia as traditional herbal medicines with numerous claims for their therapeutic effects. Faced with resource depletion and environment destruction, R. rosea and R. crenulata are becoming endangered, making them more economically valuable to collectors and middlemen, and also increasing the risk of adulteration and low quality. We compare the phytochemical differences among Rhodiola raw materials available on the market to provide a practical method for Rhodiola authentication and the detection of potential adulterant compounds. Samples were collected from Europe and Asia and nuclear magnetic resonance spectroscopy coupled with multivariate analysis software and high performance thin layer chromatography techniques were used to analyse the samples. A method was developed to quantify the amount of adulterant species contained within mixtures. We compared the phytochemical composition of collected Rhodiola samples to authenticated samples. Rosavin and rosarin were mainly present in R. rosea whereas crenulatin was only present in R. crenulata. 30% of the Rhodiola samples purchased from the Chinese market were adulterated by other Rhodiola spp. Moreover, 7 % of the raw-material samples were not labelled satifactorily. The utilisation of both 1H-NMR and HPTLC methods provided an integrated analysis of the phytochemical differences and novel identification method for R. rosea and R. crenulata. Using 1H-NMR spectroscopy it was possible to quantify the presence of R. crenulata in admixtures with R. rosea. This quantitative technique could be used in the future to assess a variety of herbal drugs and products. This project also highlights the need to further study the links between producers and consumers in national and trans-national trade.