Molecular identification of commercialized medicinal plants in southern Morocco.

Robert Desalle,Anneleen Kool,Anders Rydberg,Abdelaziz Abbad,Åsa Krüger,Gary Martin,Hugo J De Boer,Lars Björk

doi:10.1371/journal.pone.0039459

Robert Desalle, Anneleen Kool + Show 6 more

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https://doi.org/10.1371/journal.pone.0039459

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Abstract

BackgroundMedicinal plant trade is important for local livelihoods. However, many medicinal plants are difficult to identify when they are sold as roots, powders or bark. DNA barcoding involves using a short, agreed-upon region of a genome as a unique identifier for species– ideally, as a global standard.Research QuestionWhat is the functionality, efficacy and accuracy of the use of barcoding for identifying root material, using medicinal plant roots sold by herbalists in Marrakech, Morocco, as a test dataset.MethodologyIn total, 111 root samples were sequenced for four proposed barcode regions rpoC1, psbA-trnH, matK and ITS. Sequences were searched against a tailored reference database of Moroccan medicinal plants and their closest relatives using BLAST and Blastclust, and through inference of RAxML phylograms of the aligned market and reference samples.Principal FindingsSequencing success was high for rpoC1, psbA-trnH, and ITS, but low for matK. Searches using rpoC1 alone resulted in a number of ambiguous identifications, indicating insufficient DNA variation for accurate species-level identification. Combining rpoC1, psbA-trnH and ITS allowed the majority of the market samples to be identified to genus level. For a minority of the market samples, the barcoding identification differed significantly from previous hypotheses based on the vernacular names.Conclusions/SignificanceEndemic plant species are commercialized in Marrakech. Adulteration is common and this may indicate that the products are becoming locally endangered. Nevertheless the majority of the traded roots belong to species that are common and not known to be endangered. A significant conclusion from our results is that unknown samples are more difficult to identify than earlier suggested, especially if the reference sequences were obtained from different populations. A global barcoding database should therefore contain sequences from different populations of the same species to assure the reference sequences characterize the species throughout its distributional range.

Highlights

1.1 Marrakech Medicinal Plant Trade and the Moroccan Herbal PharmacopoeiaTraditional medicine has played an important role in many North African societies, and continues to do so today [1]
Chinese Medicine as opposed to the processed medicinal products themselves. Their arguments to include a marker from the nuclear genome are legitimate, but we find that polymorphism and fungal contamination do cause problems in using ITS as a marker for DNA barcoding
3.7 Conclusions Roughly one fifth of the market samples that were analyzed proved to be something other than what was hypothesized on the basis of the Moroccan pharmacopoeia

Summary

Introduction

Traditional medicine has played an important role in many North African societies, and continues to do so today [1] This is evident not least in the Moroccan city of Marrakech, situated at a crossroads of trade routes between the High Atlas Mountains and surrounding coastal plains. The traditional equivalent of the doctor in Moroccan medicine is the herbalist – a profession that continues to be practiced in Marrakech, manifested by the herbalist-owned drug stores that line the market districts of the medina, or old town (Fig. 1). In these shops, Marrakech herbalists stock a variety of plant parts and plant-derived products, sold either separately or in mixtures. Research Question: What is the functionality, efficacy and accuracy of the use of barcoding for identifying root material, using medicinal plant roots sold by herbalists in Marrakech, Morocco, as a test dataset

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