Medicinal plants are used as a popular alternative to synthetic drugs, both in developed and developing countries. The economic importance of the herbal and natural supplement industry is increasing every year. As the herbal industry grows, consumer safety is one issue that cannot be overlooked. Herbal products in Thai local markets are commonly sold without packaging or labels. Plant powders are stored in large bags or boxes, and therefore buying local herbal products poses a high risk of acquiring counterfeited, substituted and/or adulterated products. Due to these issues, a reliable method to authenticate products is needed. Here DNA barcoding was used in combination with High Resolution Melting analysis (Bar-HRM) to authenticate three medicinal Acanthaceae species (Acanthus ebracteatus, Andrographis paniculata and Rhinacanthus nasutus) commonly used in Thailand. The rbcL barcode was selected for use in primers design for HRM analysis to produce standard melting profiles of the selected species. Melting data from the HRM assay using the designed rbcL primers showed that the three chosen species could be distinguished from each other. HRM curves of all fifteen test samples indicated that three of tested products did not contain the indicated species. Two closely related species (A. paniculata and R. nasutus), which have a high level of morphological similarity, were interchanged with one another in three tested products. Incorrect information on packaging and labels of the tested herbal products was the cause of the results shown here. Morphological similarity among the species of interest also hindered the collection process. The Bar-HRM method developed here proved useful in aiding in the identification and authentication of herbal species in processed samples. In the future, species authentication through Bar-HRM could be used to promote consumer trust, as well as raising the quality of herbal products.

Large tropical and subtropical rivers are among the most biodiverse ecosystems worldwide, but also suffer from high anthropogenic pressures. These rivers are hitherto subject to little or no routine biomonitoring, which would be essential for identification of conservation areas of high importance. Here, we use a single environmental DNA multi-site sampling campaign across the 200,000 km² Chao Phraya river basin, Thailand, to provide key information on fish diversity. We found a total of 108 fish taxa and identified key biodiversity patterns within the river network. By using hierarchical clustering, we grouped the fish communities of all sites across the catchment into distinct clusters. The clusters not only accurately matched the topology of the river network, but also revealed distinct groups of sites enabling informed conservation measures. Our study reveals novel opportunities of large-scale monitoring via eDNA to identify relevant areas within whole river catchments for conservation and habitat protection.

Uvaria longipes (Craib) L.L.Zhou, Y.C.F.Su & R.M.K.Saunders, Artabotrys burmanicus A.DC, Marsypopetalum modestum (Pierre) B.Xue & R.M.K.Saunders and Dasymaschalon sp. have been used for traditional medicine to treat cancer-like symptoms in some ethnic groups of Thailand and Laos. We evaluated the anti-cancer activity of these Annonaceae plants against several human cancer cell lines. The apoptosis induction was detected by Annexin/propidium iodide (PI) staining. Phytochemical screening was tested by standard protocols and bioactive compounds were determined by HPLC. The crude extracts from leaves of U. longipes, Dasymaschalon sp., A. burmanicus, and M. modestum showed particular effects that were found to vary depending on the cancer cell line, suggesting that the effect was in a cell-type specific manner. Interestingly, the induction of apoptotic cell death was prominent by the leaves-derived crude extract of M. modestum. This crude was, therefore, subjected to cell cycle analysis by PI staining. Results showed that this crude extract arrested cell cycle and increased the percentage of cells in the SubG1 phase in some cancer cell lines. The phytochemical screening tests indicated that all crude extracts contained tannins and flavonoids. HPLC of flavonoids using standards identified rutin as an active compound in U. longipes and Dasymaschalon sp., whereas quercetin was found in U. longipes and M. modestum. These crude extracts provide a new source for rutin and quercetin, which might be capable of inducing cancer cell apoptotic death in a cell-type specific manner. This suggests, by analyzing the major bioactive compounds, the potential use of these crudes for chemotherapy in the future.

Nowadays, medicinal plants are used as a popular alternative to synthetic drugs. Many medicinal plant products have now been commercialized throughout various markets. These products are commonly sold in processed or modified forms such as powders, dried material and capsules, making it almost impossible to accurately identify the constituent species. The herbal plant known as ‘Rang Chuet’ in Thai has been widely used as remedies for various ailments. However, two medicinal plants species, Thunbergia laurifolia and Crotalaria spectabilis share this name. Duo to the similarity in nomenclature, the commercial products labeled as ‘Rang Chuet’ could be any of them. Recently, the evidence of hepatotoxic effects linked to use of C. spectabilis were reported and is now seriously concern. There is a need to find an approach that could help with species identification of these herbal products to ensure the safety and efficacy of the herbal drug. Here DNA barcoding was used in combination with High Resolution Melting analysis (Bar-HRM) to authenticate T. laurifolia species. Four DNA barcodes including matK, rbcL, rpoC and trnL were selected for use in primers design for HRM analysis to produce standard melting profiles of the selected species. Commercial products labeled as ‘Rang Chuet’ were purchased from Thai markets and authentication by HRM analyses. Melting data from the HRM assay using the designed primers showed that the two ‘Rang Chuet’ species could easily be distinguished from each other. The melting profiles of the all four region amplicons of each species are clearly separated in all three replicates. The method was then applied to authenticate products in powdered form. HRM curves of all ten test samples indicated that three of the tested products did not only contain the T. laurifolia species. The herbal drugs derived from different plants must be distinguished from each other even they share the same vernacular name. The Bar-HRM method developed here proved useful in the identification and authentication of herbal species in processed samples. In the future, species authentication through Bar-HRM could be used to promote consumer trust, as well as raising the quality of herbal products.

DNA barcoding coupled high resolution melting (Bar-HRM) is an emerging method for species discrimination based on DNA dissociation kinetics. The aim of this work was to evaluate the suitability of different primer sets, derived from selected DNA regions, for Bar-HRM analysis of species in Croton (Euphorbiaceae), one of the largest genera of plants with over 1,200 species. Seven primer pairs were evaluated (matK, rbcL1, rbcL2, rbcL3, rpoC, trnL and ITS1) from four plastid regions, matK, rbcL, rpoC, and trnL, and the nuclear ribosomal marker ITS1. The primer pair derived from the ITS1 region was the single most effective region for the identification of the tested species, whereas the rbcL1 primer pair gave the lowest resolution. It was observed that the ITS1 barcode was the most useful DNA barcoding region overall for species discrimination out of all of the regions and primers assessed. Our Bar-HRM results here also provide further support for the hypothesis that both sequence and base composition affect DNA duplex stability.