Medicinal plants such as Cassia, Senna, and Chamaecrista (belonging to the family Fabaceae) are well known for their laxative properties. They are extensively used within indigenous health care systems in India and several other countries. India exports over 5000 metric tonnes per year of these specific herbal products, and the demand for natural health product market is growing at approximately 10-15% annually. The raw plant material used as active ingredients is almost exclusively sourced from wild populations. Consequently, it is widely suspected that the commercial herbal products claiming to contain these species may be adulterated or contaminated. In this study, we have attempted to assess product authentication and the extent of adulteration in the herbal trade of these species using DNA barcoding. Our method includes four common DNA barcode regions: ITS, matK, rbcL, and psbA-trnH. Analysis of market samples revealed considerable adulteration of herbal products: 50% in the case of Senna auriculata, 37% in Senna tora, and 8% in Senna alexandrina. All herbal products containing Cassia fistula were authentic, while the species under the genus Chamaecrista were not in trade. Our results confirm the suspicion that there is rampant herbal product adulteration in Indian markets. DNA barcodes such as that demonstrated in this study could be effectively used as a regulatory tool to control the adulteration of herbal products and contribute to restoring quality assurance and consumer confidence in natural health products.

The global economy of the international trade of herbal products has been increasing by 15% annually, with the raw material for most herbal products being sourced from South and Southeast Asian countries. In India, of the 8000 species of medicinal plants harvested from the wild, approximately 960 are in the active trade. With increasing international trade in herbal medicinal products, there is also increasing concern about the widespread adulteration and species admixtures in the raw herbal trade. The adverse consequences of such species adulteration on the health and safety of consumers have only recently begun to be recognised and documented. We provide a comprehensive review of the nature and magnitude of species adulteration in the raw herbal trade, and identify the underlying drivers that might lead to such adulteration. We also discuss the possible biological and chemical equivalence of species that are used as adulterants and substitutes, and the consequences thereof to consumer health and safety, and propose a framework for the development of a herbal trade authentication service that can help regulate the herbal trade market.

No abstract

Ayurveda is one of the oldest systems of medicine in the world, but the growing commercial interest in Ayurveda based products has increased the incentive for adulteration and substitution within this herbal market. Fraudulent practices such as the use of undeclared fillers and use of other species of inferior quality is driven both by the increased as well as insufficient supply capacity of especially wild plant species. Developing novel strategies to exhaustively assess and monitor both the quality of raw materials and final marketed herbal products is a challenge in herbal pharmacovigilance. Seventy-nine Ayurvedic herbal products sold as tablets, capsules, powders, and extracts were randomly purchased via e-commerce and pharmacies across Europe, and DNA metabarcoding was used to assess the ability of this method to authenticate these products. Our analysis reveals that only two out of 12 single ingredient products contained only one species as labeled, eight out of 27 multiple ingredient products contained none of the species listed on the label, and the remaining 19 products contained 1 to 5 of the species listed on the label along with many other species not specified on the label. The fidelity for single ingredient products was 67%, the overall ingredient fidelity for multi ingredient products was 21%, and for all products 24%. The low level of fidelity raises concerns about the reliability of the products, and detection of threatened species raises further concerns about illegal plant trade. The study highlights the necessity for quality control of the marketed herbal products and shows that DNA metabarcoding is an effective analytical approach to authenticate complex multi ingredient herbal products. However, effort needs to be done to standardize the protocols for DNA metabarcoding before this approach can be implemented as routine analytical approaches for plant identification, and approved for use in regulated procedures.