DNA barcode ITS effectively distinguishes the medicinal plant Boerhavia diffusa from its adulterants

Current Trends in Toxicity Assessment of Herbal Medicines: A Narrative Review

Even in modern times, the popularity level of medicinal plants and herbal medicines in therapy is still high. The World Health Organization estimates that 80% of the population in developing countries uses these types of remedies. Even though herbal medicine products are usually perceived as low risk, their potential health risks should be carefully assessed. Several factors can cause the toxicity of herbal medicine products: plant components or metabolites with a toxic potential, adulteration, environmental pollutants (heavy metals, pesticides), or contamination of microorganisms (toxigenic fungi). Their correct evaluation is essential for the patient’s safety. The toxicity assessment of herbal medicine combines in vitro and in vivo methods, but in the past decades, several new techniques emerged besides conventional methods. The use of omics has become a valuable research tool for prediction and toxicity evaluation, while DNA sequencing can be used successfully to detect contaminants and adulteration. The use of invertebrate models (Danio renio or Galleria mellonella) became popular due to the ethical issues associated with vertebrate models. The aim of the present article is to provide an overview of the current trends and methods used to investigate the toxic potential of herbal medicinal products and the challenges in this research field.

Advancements and future prospective of DNA barcodes in the herbal drug industry

Ethnopharmacological relevance: The past couple of decades have witnessed the global resurgence of medicinal plants in the field of herbal-based health care. Increased consumption of medicinal plants and their derivative products is the major cause of the adulteration issues in herbal industries. As a result, the quality of herbal products is affected by spurious and unauthorized raw materials. Recent development in molecular plant identification using DNA barcodes has become a robust methodology to identify and authenticate the adulterants in herbal samples. Hence, rapid and accurate identification of medicinal plants is the key to success for the herbal industry. Aim of the study: This paper provides a comprehensive review of the application of DNA barcoding and advanced technologies that have emerged over the past 10 years related to medicinal plant identification and authentication and the future prospects of this technology. Materials and methods: Information on DNA barcodes was compiled from scientific databases (Google Scholar, Web of Science, SciFinder and PubMed). Additional information was obtained from books, Ph.D. thesis and MSc. Dissertations. Results: Working out an appropriate DNA barcode for plants is challenging; the single locus-based DNA barcodes (rbcL, ITS, ITS2, matK, rpoB, rpoC, trnH-psbA) to multi-locus DNA barcodes have become the successful species-level identification among herbal plants. Additionally, multi-loci have become efficient in the authentication of herbal products. Emerging advances in DNA barcoding and related technologies such as next-generation sequencing, high-resolution melting curve analysis, meta barcodes and mini barcodes have paved the way for successful herbal plant/samples identification. Conclusion: DNA barcoding needs to be employed together with other techniques to check and rationally and effectively quality control the herbal drugs. It is suggested that DNA barcoding techniques combined with metabolomics, transcriptomics, and proteomics could authenticate the herbal products. The invention of simple, cost-effective and improved DNA barcoding techniques to identify herbal drugs and their associated products of medicinal value in a fool-proof manner will be the future thrust of Pharmacopoeial monograph development for herbal drugs.

DNA barcoding: an efficient technology to authenticate plant species of traditional Chinese medicine and recent advances

Traditional Chinese medicine (TCM) plays an important role in the global traditional health systems. However, adulterated and counterfeit TCM is on the rise. DNA barcoding is an effective, rapid, and accurate technique for identifying plant species. In this study, we collected manuscripts on DNA barcoding published in the last decade and summarized the use of this technique in identifying 50 common Chinese herbs listed in the Chinese pharmacopoeia. Based on the dataset of the major seven DNA barcodes of plants in the NCBI database, the strengths and limitations of the barcodes and their derivative barcoding technology, including single-locus barcode, multi-locus barcoding, super-barcoding, meta-barcoding, and mini-barcoding, were illustrated. In addition, the advances in DNA barcoding, particularly identifying plant species for TCM using machine learning technology, are also reviewed. Finally, the selection process of an ideal DNA barcoding technique for accurate identification of a given TCM plant species was also outlined.

Evaluation of Nutritional Substances and Investigation of Antioxidant and Antimicrobial Potentials of Boerhavia diffusa with in Silico Molecular Docking

Boerhavia diffusa L. Nyctanginaceae (B. diffusa) is a medicinal herb commonly considered as a weed. The exploration of phytochemicals in different parts of B. diffusa with different solvents will create awareness, along with the suitable solvent and method for extraction of pharmaceutical compounds. Hence, the present study focuses on phytochemical analysis of B. diffusa leaves, stems, and roots in various solvents with hot and cold extraction. The decoctions performed well in most of the qualitative and quantitative tests, along with the DPPH assay. The aqueous extract showed a good result in the FRAP assay and ABTS assay. In the antimicrobial test, the B. diffusa root ethanol extract inhibited the growth of Pseudomonas aeruginosa and Staphylococcus aureus with zones of inhibition of about 8 mm and 20 mm at 200 µg concentration, respectively. Using a molecular docking approach, the top four ranked molecules from the crude extract of B. diffusa profiled from GC–MS spectroscopy in terms of growth inhibition of the pathogenic bacterium P. aeruginosa were selected; among them, 2-(1,2 dihydroxyethyl)-5-[[2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-3,4-dihydrochromen-6-yl]oxy]oxolane-3,4-diol exhibited the minimum binding score, revealing high affinity in complex. B. diffusa is highly nutritious, and the maceration and decoction extracts were similar except for the chloroform extract that was found to be weak.

A Review on Application of DNA Barcoding Technology for Rapid Molecular Diagnostics of Adulterants in Herbal Medicine

The rapid molecular diagnostics of adulterants in herbal medicine using DNA barcoding forms the core of this meticulously detailed review, based on two decades of data. With 80% of the world's population using some form of herbal medicine, authentication, quality control, and detection of adulterants warrant DNA barcoding. A combined group of keywords were used for literature review using the PubMed, the ISI Web of Knowledge, Web of Science (WoS), and Google Scholar databases. All the papers (N = 210) returned by the search engines were downloaded and systematically analyzed. Detailed analysis of conventional DNA barcodes were based on retrieved sequences for internal transcribed spacer (ITS) (412,189), rbcL (251,598), matK (210,835), and trnH-psbA (141,846). The utility of databases such as The Barcode of Life Data System (BOLD), NCBI, GenBank, and Medicinal Materials DNA Barcode Database (MMDBD) has been critically examined for the identification of unknown species from known databases. The current review gives an overview of the ratio of adulterated to authentic drugs for some countries along with the state of the art technology currently being used in the identification of adulterated medicines. In this review, efforts were made to systematically analyze and arrange the research and reviews on the basis of technical progress. The review concludes with the future of DNA-based herbal medicine adulteration detection, forecasting the reliance on the metabarcoding technology. DNA barcoding technology for differentiating adulterated herbal medicine.

A Comprehensive Study of the Genus Sanguisorba (Rosaceae) Based on the Floral Micromorphology, Palynology, and Plastome Analysis

Sanguisorba, commonly known as burnet, is a genus in the family Rosaceae native to the temperate regions of the Northern hemisphere. Five of its thirty species are distributed in Korea: Sanguisorba officinalis, S. stipulata, S. hakusanensis, S. longifolia, and S. tenuifolia. S. officinalis has been designated as a medicinal remedy in the Chinese and Korean Herbal Pharmacopeias. Despite being a valuable medicinal resource, the morphological and genomic information, as well as the genetic characteristics of Sanguisorba, are still elusive. Therefore, we carried out the first comprehensive study on the floral micromorphology, palynology, and complete chloroplast (cp) genome of the Sanguisorba species. The outer sepal waxes and hypanthium characters showed diagnostic value, despite a similar floral micromorphology across different species. All the studied Sanguisorba pollen were small to medium, oblate to prolate-spheroidal, and their exine ornamentation was microechinate. The orbicules, which are possibly synapomorphic, were consistently absent in this genus. Additionally, the cp genomes of S. officinalis, S. stipulata, and S. hakusanensis have been completely sequenced. The comparative analysis of the reported Sanguisorba cp genomes revealed local divergence regions. The nucleotide diversity of trnH-psbA and rps2-rpoC2, referred to as hotspot regions, revealed the highest pi values in six Sanguisorba. The ndhG indicated positive selection pressures as a species-specific variation in S. filiformis. The S. stipulata and S. tenuifolia species had psbK genes at the selected pressures. We developed new DNA barcodes that distinguish the typical S. officinalis and S. officinalis var. longifolia, important herbal medicinal plants, from other similar Sanguisorba species with species-specific distinctive markers. The phylogenetic trees showed the positions of the reported Sanguisorba species; S. officinalis, S. tenuifolia, and S. stipulata showed the nearest genetic distance. The results of our comprehensive study on micromorphology, pollen chemistry, cp genome analysis, and the development of species identification markers can provide valuable information for future studies on S. officinalis, including those highlighting it as an important medicinal resource.

DNA barcoding and TLC as tools to properly identify natural populations of the Mexican medicinal species Galphimia glauca Cav

Galphimia glauca is a plant that is endemic to Mexico and has been commonly used since pre-Hispanic times to treat various illnesses, including central nervous system disorders and inflammation. The first studies investigating a natural population of G. glauca in Mexico showed that the plant has anxiolytic and sedative activities in mice and humans. The plant's bioactive compounds were isolated and identified, and they belong to a family of nor-secofriedelanes called galphimines. The integration of DNA barcoding and thin-layer chromatography analysis was performed to clarify whether the botanical classification of the populations in the study, which were collected in different regions of Mexico, as G. glauca was correct or if the populations consist of more than one species of the genus Galphimia. We employed six DNA barcodes (matK, rbcL, rpoC1, psbA-trnH, ITS1 and ITS2) that were analyzed individually and in combination and then compared each other, to indicate differences among the studied populations. In the phylogenetic analysis, ITS1 and ITS2 markers as well as the combination of all DNA regions were the most efficient for discriminating the population studied. The thin-layer chromatography analysis exhibited four principal chemical profiles, one of which corresponded to the populations that produced galphimines. DNA barcoding was consistent and enabled us to differentiate the populations that produce galphimines from those that do not. The results of this investigation suggest that the studied populations belong to at least four different species of the genus Galphimia. The phylogenetic analysis and the thin-layer chromatography chemical profiles were convenient tools for establishing a strong relationship between the genotype and phenotype of the studied populations and could be used for quality control purposes to prepare herbal medicines from plants of the genus Galphimia.

DNA barcoding detects floral origin of Indian honey samples

The unique medicinal and nutritional properties of honey are determined by its chemical composition. To evaluate the quality of honey, it is essential to study the surrounding vegetation where honeybees forage. In this study we used conventional melissopalynological and DNA barcoding techniques to determine the floral source of honey samples collected from different districts of the state of Mizoram, India. Pollen grains were isolated and genomic DNA was extracted from the honey samples. PCR amplification was carried out using universal barcode candidates ITS2 and rbcL to identify the plant species. Furthermore, TA cloning was carried out to screen the PCR amplicon libraries to identify the presence of multiple plant species. Results from both the melissopalynological and DNA barcoding analyses identified almost exactly the same 22 species, suggesting that both methods are suitable for analysis. However, DNA barcoding is easier and widely practiced. Hence, it can be concluded that DNA barcoding is a useful tool in determining the medicinal and commercial value of honey.

Employing barcoding markers to authenticate selected endangered medicinal plants traded in Indian markets

The high demand of medicinal plants and their unrestricted collection have rendered many of these as rare or endangered. The restrictions imposed on their collection and trade are difficult to implement because of the inability to identify them in fragmented form. The rarity of these plants in nature and lack of their cultivation raise doubt about the authenticity of the herbals sold in markets. Therefore, in the present investigation, ITS/ITS2, matK, rbcL and rpoC1 sequences of fourteen species of important medicinal plants, some of which are endangered, were generated and checked for their species-specificity (sequences having maximum similarity only with their own) by BLAST1 and/or BOLD identifications. ITS sequences of 12 species were species-specific. However, ITS2 of only 10 of these 12 species were species-specific. As for the chloroplast loci, rbcL and rpoC1 sequences of all 14 species could be obtained, while matK sequences of only 10 of these could be generated. Of the retrieved sequences, rbcL, rpoC1 and matK sequences of 7, 11 and 7 species, respectively, were species-specific. The sequences of the targeted loci from the herbal samples of these species were difficult to retrieve because of failure in the amplification or sequencing. Nevertheless, based on ITS2 and/or one or more of the chloroplast loci targeted, the botanical identities of 22 herbal market samples were checked by phylogenetic tree, BLAST1 and BOLD identification methods. Of these 22 samples, only one of each of Rauvolfia serpentina and Picrorhiza kurroa were found to be authentic.

Nuclear ribosomal DNA – ITS region based molecular marker to distinguish Gmelina arborea Roxb. Ex Sm. from its substitutes and adulterants

Roots of Gmelina arborea (Gambhari) is a medicinally important raw drug traded in India. However, Gmelinaasiatica and Mallotus nudiflorus are also found in the raw drug markets as Gambhari. The current study aims to identify molecular markers based on the nuclear ribosomal DNA – ITS1 region to distinguish the authentic species from substitute/adulterants. The nuclear ribosomal internal transcribed spacer 1 (ITS1) was amplified to identify species-specific markers using universal primers. Based on the sequence of the ITS region, specific primers were designed for G. arborea, G. asiatica and M. nudiflorus which efficiently amplified 142 bp, 93 bp and 150 bp of the ITS1 region of the respective species. The notable feature of this molecular method is that it is technically accurate, practically convenient and suitable for analyzing large numbers of samples. This study demonstrates that the ITS1 region can be used for reliable authentication of medicinal plants and detection of adulterants and substitutes of Gambhari.

Review: DNA Barcoding and Chromatography Fingerprints for the Authentication of Botanicals in Herbal Medicinal Products

In the last two decades, there has been a tremendous increase in the global use of herbal medicinal products (HMPs) due to their claimed health benefits. This has led to increase in their demand and consequently, also, resulted in massive adulteration. This is due to the fact that most of the traditional methods cannot identify closely related species in a process product form. Therefore the urgent need for simple and rapid identification methods resulted in the discovery of a novel technique. DNA barcoding is a process that uses short DNA sequence from the standard genome for species identification. This technique is reliable and is not affected by external factors such as climates, age, or plant part. The difficulties in isolation of DNA of high quality in addition to other factors are among the challenges encountered using the DNA barcoding in the authentication of HMP. These limitations indicated that using DNA barcoding alone may ineffectively authenticate the HMP. Therefore, the combination of DNA barcoding with chromatographic fingerprint, a popular and generally accepted technique for the assessment and quality control of HMP, will offer an efficient solution to effectively evaluate the authenticity and quality consistency of HMP. Detailed and quality information about the main composition of the HMPs will help to ascertain their efficacy and safety as these are very important for quality control.

DNA barcode and identification of the varieties and provenances of Taiwan's domestic and imported made teas using ribosomal internal transcribed spacer 2 sequences

The major aim of made tea identification is to identify the variety and provenance of the tea plant. The present experiment used 113 tea plants [Camellia sinensis (L.) O. Kuntze] housed at the Tea Research and Extension Substation, from which 113 internal transcribed spacer 2 (ITS2) fragments, 104 trnL intron, and 98 trnL-trnF intergenic sequence region DNA sequences were successfully sequenced. The similarity of the ITS2 nucleotide sequences between tea plants housed at the Tea Research and Extension Substation was 0.379–0.994. In this polymerase chain reaction-amplified noncoding region, no varieties possessed identical sequences. Compared with the trnL intron and trnL-trnF intergenic sequence fragments of chloroplast cpDNA, the proportion of ITS2 nucleotide sequence variation was large and is more suitable for establishing a DNA barcode database to identify tea plant varieties. After establishing the database, 30 imported teas and 35 domestic made teas were used in this model system to explore the feasibility of using ITS2 sequences to identify the varieties and provenances of made teas. A phylogenetic tree was constructed using ITS2 sequences with the unweighted pair group method with arithmetic mean, which indicated that the same variety of tea plant is likely to be successfully categorized into one cluster, but contamination from other tea plants was also detected. This result provides molecular evidence that the similarity between important tea varieties in Taiwan remains high. We suggest a direct, wide collection of made tea and original samples of tea plants to establish an ITS2 sequence molecular barcode identification database to identify the varieties and provenances of tea plants. The DNA barcode comparison method can satisfy the need for a rapid, low-cost, frontline differentiation of the large amount of made teas from Taiwan and abroad, and can provide molecular evidence of their varieties and provenances.

Ethnomedicinal uses, phytochemistry and pharmacological properties of the genus Boerhavia

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Boerhavia is widely distributed in tropical, subtropical and temperate regions of the world including Mexico, America, Africa, Asia, Indian Ocean Islands, Pacific Islands and Australia. The genus Boerhavia is extensively used by local peoples and medicinal practitioners for treatments of hepatitis, urinary disorders, gastro intestinal diseases, inflammations, skin problems, infectious diseases and asthma. Present review focused on traditional uses, phytochemistry, pharmacology and toxicology of Boerhavia genus to support potential scope for advance ethnopharmacological study.

MATERIALS AND METHODS

Information on the Boerhavia species was collected from classical books on medicinal plants, pharmacopoeias and scientific databases like PubMed, Scopus, GoogleScholar, Web of Science and others. Also scientific literatures based on ethnomedicinal surveys, Ph.D. and M.Sc. dissertations, published papers from Elsevier, Taylor and Francis, Springer, ACS as well as Wiley publishers and reports by government bodies and documentations were assessed.

RESULTS

A total of 180 compounds from Boerhavia genus were isolated of which B. diffusa alone shared around 131 compounds and for most of which it is currently an exclusive source. In the genus, phenolic glycosides and flavonoids contribute approximately 97 compounds. These includes eupalitin, rotenoids like boeravinones, coccineons, alkaloid i.e. betanin and punarnavine etc., showing vital pharmaceutical activities such as anticancer, anti-inflammatory, antioxidant and immunomodulatory.

CONCLUSION

Boerhavia is an important genus with wide range of medicinal uses. However, most of the available scientific literatures have lacked relevant doses, duration and positive controls for examining bioefficacy of extracts and its active compounds. In some studies, taxonomic errors were encountered. Moreover, there is need for accurate methods in testing the safety and ethnomedicinal validity of Boerhavia species.

Authentication of Cordyceps sinensis by DNA Analyses: Comparison of ITS Sequence Analysis and RAPD-Derived Molecular Markers

Cordyceps sinensis is an endoparasitic fungus widely used as a tonic and medicinal food in the practice of traditional Chinese medicine (TCM). In historical usage, Cordyceps specifically is referring to the species of C. sinensis. However, a number of closely related species are named themselves as Cordyceps, and they are sold commonly as C. sinensis. The substitutes and adulterants of C. sinensis are often introduced either intentionally or accidentally in the herbal market, which seriously affects the therapeutic effects or even leads to life-threatening poisoning. Here, we aim to identify Cordyceps by DNA sequencing technology. Two different DNA-based approaches were compared. The internal transcribed spacer (ITS) sequences and the random amplified polymorphic DNA (RAPD)-sequence characterized amplified region (SCAR) were developed here to authenticate different species of Cordyceps. Both approaches generally enabled discrimination of C. sinensis from others. The application of the two methods, supporting each other, increases the security of identification. For better reproducibility and faster analysis, the SCAR markers derived from the RAPD results provide a new method for quick authentication of Cordyceps.

DNA barcoding, microarrays and next generation sequencing: recent tools for genetic diversity estimation and authentication of medicinal plants

DNA barcoding, microarray technology and next generation sequencing have emerged as promising tools for the elucidation of plant genetic diversity and its conservation. They are proving to be immensely helpful in authenticating the useful medicinal plants for herbal drug preparations. These newer versions of molecular markers utilize short genetic markers in the genome to characterize the organism to a particular species. This has the potential not only to classify the known and yet unknown species but also has a promising future to link the medicinally important plants according to their properties. The newer trends being followed in DNA chips and barcoding pave the way for a future with many different possibilities. Several of these possibilities might be: characterization of unknown species in a considerably less time than usual, identification of newer medicinal properties possessed by the species and also updating the data of the already existing but unnoticed properties. This can assist us to cure many different diseases and will also generate novel opportunities in medicinal drug delivery and targeting.

DNA barcoding of medicinal plant material for identification

Because of the increasing demand for herbal remedies and for authentication of the source material, it is vital to provide a single database containing information about authentic plant materials and their potential adulterants. The database should provide DNA barcodes for data retrieval and similarity search. In order to obtain such barcodes, several molecular methods have been applied to develop markers that aid with the authentication and identification of medicinal plant materials. In this review, we discuss the genomic regions and molecular methods selected to provide barcodes, available databases and the potential future of barcoding using next generation sequencing.