Quality control of Hypericum perforatum L. analytical challenges and recent progress

Phytochemical Analysis, Antioxidant Potential and Antibacterial Activities of Different Anatomical Parts of Hypericum cordifolium Choisy

The genus Hypericum comprises a large number of species. The flower, leaf, stem, and root of the Hypericum species are widely used in traditional medicine in different cultures. Many Hypericum species have been well investigated phytochemically and pharmacologically. However, only a few reports are available on the H. cordifolium native to Nepal. The present study aims to evaluate the phytochemical composition of different extracts, qualitative analysis of methanol extract of the flower and leaf using thin-layer chromatography (TLC), and the antioxidant properties of components by the TLC-DPPH. assay. The phenolic and flavonoid contents were estimated in different extracts of the leaf and stem, and their antioxidant and antibacterial activities were evaluated. In the phytochemical screening, phenolics and flavonoids were present in ethyl acetate, methanol, and 50% aq methanol extracts of both the leaf and stem. In TLC analysis, the methanol extract of flowers showed the presence of 11 compounds and the leaf extract showed the presence of 8 compounds. Both extracts contained chlorogenic acid and mangiferin. Hyperoside and quercetin were present only in the flower extract. In the TLC-DPPH. assay, almost all of the flower extracts and 5 compounds of the leaf extract showed radical scavenging potential. Estimation of phenolics and flavonoids showed that all the leaf extracts showed higher amounts of phenolics and flavonoids than stem extracts. Among leaf extracts, greater amounts of phenolics were detected in 50% aqueous methanol extract (261.25 ± 1.66 GAE/g extract) and greater amounts of flavonoids were detected in methanol extract (232.60 ± 10.52 CE/g extract). Among stem extracts, greater amounts of flavonoids were detected in the methanol extract (155.12 ± 4.30 CE/g extract). In the DPPH radical scavenging assay, the methanol extract of the leaf showed IC50 60.85 ± 2.67 µg/ml and 50% aq. methanol extract of the leaf showed IC50 63.09 ± 2.98 µg/ml. The methanol extract of the stem showed IC50 89.39 ± 3.23 µg/ml, whereas ethyl acetate and 50% aq. methanol extract showed IC50 > 100 µg/ml. In the antibacterial assay, the methanol extract of the leaf showed the inhibition zone of 12-13 mm and the stem extract showed the inhibition zone of 7-11 mm against S. aureus, E. coli, and S. sonnei, whereas both extracts were inactive against S. typhi. The findings of this study support the traditional use of this plant in Nepal for the treatment of diseases associated with bacterial infections. The present study revealed that the underutilized anatomical parts of H. cordifolium could be the source of various bioactive phytochemicals like other Hypericum species.

Tissue Regeneration and Remodeling in Rat Models after Application of Hypericum perforatum L. Extract-Loaded Bigels

The wound-healing effect of St. John's Wort (SJW) is mainly attributed to hyperforin (HP), but its low stability restricts its topical administration. This study investigates how "free" HP-rich SJW extract (incorporated into a bigel; B/SJW) and extract "protected" by nanostructured lipid carriers (also included in a biphasic semisolid; B/NLC-SJW) affect tissue regeneration in a rat skin excision wound model. Wound diameter, histological changes, and tissue gene expression levels of fibronectin (Fn), matrix metalloproteinase 8 (MMP8), and tumor necrosis factor-alpha (TNF-α) were employed to quantify the healing progress. A significant wound size reduction was achieved after applying both extract-containing semisolids, but after a 21-day application period, the smallest wound size was observed in the B/NLC-SJW-treated animals. However, the inflammatory response was affected more favorably by the bigel containing the "free" SJW extract, as evidenced by histological studies. Moreover, after the application of B/SJW, the expression of Fn, MMP8, and TNF-α was significantly higher than in the positive control. In conclusion, both bigel formulations exhibited beneficial effects on wound healing in rat skin, but B/SJW affected skin restoration processes in a comprehensive and more efficient way.

UPLC-MS-Based Metabolomics Profiling and Chemometric Analysis for Hypericum sinaicum Boiss and the Endophytic Aspergillus foetidus in Comparison to Hypericum perforatum L

One of the endangered plant species in Saint Catherine protectorate is Hypericum sinaicum Boiss which is endemic to Egypt, Jordan, and Saudi Arabia. The fungus-host relationship can assist in the investigation of bioactive compounds produced by H. sinaicum paving the way for economic and medicinal implications. Therefore, a comprehensive metabolic approach via MS and chemical analysis was used to track and compare metabolites from H. sinaicum and Aspergillus foetidus var. pallidus, the endophytic fungus, with Hypericum perforatum. Metabolomics analysis revealed the presence of 25 metabolites distributed among samples and the discovery of new chemotaxonomic compounds, i. e., phloroglucinols and xanthones, allowing the discrimination between species. A. foetidus extract is considered a reliable source of furohyperforin and naphthodianthrone derivatives. In conclusion, using A. foetidus as an in vitro technique for producing potential phytoconstituents was cost effective, having easier optimization conditions and faster growth with fewer contamination rates than other in vitro methods.

Bigel Formulations of Nanoencapsulated St. John's Wort Extract-An Approach for Enhanced Wound Healing

This study aimed to develop a semisolid vehicle for topical delivery of nanoencapsulated St. John's wort (SJW) extract, rich in hyperforin (HP), and explore its wound-healing potential. Four nanostructured lipid carriers (NLCs) were obtained: blank and HP-rich SJW extract-loaded (HP-NLC). They comprised glyceryl behenate (GB) as a solid lipid, almond oil (AO), or borage oil (BO) representing the liquid lipid, along with polyoxyethylene (20) sorbitan monooleate (PSMO) and sorbitan monooleate (SMO) as surfactants. The dispersions demonstrated anisometric nanoscale particles with acceptable size distribution and disrupted crystalline structure, providing entrapment capacity higher than 70%. The carrier exhibiting preferable characteristics (HP-NLC2) was gelled with Poloxamer 407 (PM407) to serve as the hydrophilic phase of a bigel, to which the combination of BO and sorbitan monostearate (SMS) organogel was added. The eight prepared bigels with different proportions (blank and nanodispersion-loaded) were characterized rheologically and texturally to investigate the impact of the hydrogel-to-oleogel ratio. The therapeutic potential of the superior formulation (HP-NLC-BG2) was evaluated in vivo on Wistar male rats through the tensile strength test on a primary-closed incised wound. Compared with a commercial herbal semisolid and a control group, the highest tear resistance (7.764 ± 0.13 N) was achieved by HP-NLC-BG2, proving its outstanding wound-healing effect.

Different Types of Hypericum perforatum cvs. (Elixir, Helos, Topas) In Vitro Cultures: A Rich Source of Bioactive Metabolites and Biological Activities of Biomass Extracts

Microshoot agitated and bioreactor cultures (PlantForm bioreactors) of three Hypericum perforatum cultivars (Elixir, Helos, Topas) were maintained in four variants of Murashige and Skoog medium (MS) supplemented with 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) (in the range of 0.1-3.0 mg/L). In both types of in vitro cultures, the accumulation dynamics of phenolic acids, flavonoids, and catechins were investigated during 5- and 4-week growth cycles, respectively. The contents of metabolites in methanolic extracts from biomasses collected in 1-week intervals were estimated by HPLC. The highest total contents of phenolic acids, flavonoids, and catechins were 505, 2386, and 712 mg/100 g DW, respectively (agitated cultures of cv. Helos). The extracts from biomass grown under the best in vitro culture conditions were examined for antioxidant and antimicrobial activities. The extracts showed high or moderate antioxidant activity (DPPH, reducing power, and chelating activity assays), high activity against Gram-positive bacteria, and strong antifungal activity. Additionally, experiments with phenylalanine feeding (1 g/L) in agitated cultures were performed reaching the highest enhancement of the total contents of flavonoids, phenolic acids, and catechins on day 7 after the addition of the biogenetic precursor (2.33-, 1.73- and 1.33-fold, respectively). After feeding, the highest accumulation of polyphenols was detected in the agitated culture of cv. Elixir (4.48 g/100 g DW). The high contents of metabolites and the promising biological properties of the biomass extracts are interesting from a practical point of view.

Botanical Ingredient Forensics: Detection of Attempts to Deceive Commonly Used Analytical Methods for Authenticating Herbal Dietary and Food Ingredients and Supplements

Botanical ingredients are used widely in phytomedicines, dietary/food supplements, functional foods, and cosmetics. Products containing botanical ingredients are popular among many consumers and, in the case of herbal medicines, health professionals worldwide. Government regulatory agencies have set standards (collectively referred to as current Good Manufacturing Practices, cGMPs) with which suppliers and manufacturers must comply. One of the basic requirements is the need to establish the proper identity of crude botanicals in whole, cut, or powdered form, as well as botanical extracts and essential oils. Despite the legal obligation to ensure their authenticity, published reports show that a portion of these botanical ingredients and products are adulterated. Most often, such adulteration is carried out for financial gain, where ingredients are intentionally substituted, diluted, or "fortified" with undisclosed lower-cost ingredients. While some of the adulteration is easily detected with simple laboratory assays, the adulterators frequently use sophisticated schemes to mimic the visual aspects and chemical composition of the labeled botanical ingredient in order to deceive the analytical methods that are used for authentication. This review surveys the commonly used approaches for botanical ingredient adulteration and discusses appropriate test methods for the detection of fraud based on publications by the ABC-AHP-NCNPR Botanical Adulterants Prevention Program, a large-scale international program to inform various stakeholders about ingredient and product adulteration. Botanical ingredients at risk of adulteration include, but are not limited to, the essential oils of lavender (Lavandula angustifolia, Lamiaceae), rose (Rosa damascena, Rosaceae), sandalwood (Santalum album, Santalaceae), and tea tree (Melaleuca alternifolia, Myrtaceae), plus the extracts of bilberry (Vaccinium myrtillus, Ericaceae) fruit, cranberry (Vaccinium macrocarpon, Ericaceae) fruit, elder (Sambucus nigra, Viburnaceae) berry, eleuthero (Eleutherococcus senticosus, Araliaceae) root, ginkgo (Ginkgo biloba, Ginkgoaceae) leaf, grape (Vitis vinifera, Vitaceae) seed, saw palmetto (Serenoa repens, Arecaceae) fruit, St. John's wort (Hypericum perforatum, Hypericaceae) herb, and turmeric (Curcuma longa, Zingiberaceae) root/rhizome, among numerous others.

Does phenotyping of Hypericum secondary metabolism reveal a tolerance to biotic/abiotic stressors?

In this review we summarize the current knowledge about the changes in Hypericum secondary metabolism induced by biotic/abiotic stressors. It is known that the extreme environmental conditions activate signaling pathways leading to triggering of enzymatic and non-enzymatic defense systems, which stimulate production of secondary metabolites with antioxidant and protective effects. Due to several groups of bioactive compounds including naphthodianthrones, acylphloroglucinols, flavonoids, and phenylpropanes, the world-wide Hypericum perforatum represents a high-value medicinal crop of Hypericum genus, which belongs to the most diverse genera within flowering plants. The summary of the up-to-date knowledge reveals a relationship between the level of defense-related phenolic compounds and interspecific differences in the stress tolerance. The chlorogenic acid, and flavonoids, namely the amentoflavone, quercetin or kaempferol glycosides have been reported as the most defense-related metabolites associated with plant tolerance against stressful environment including temperature, light, and drought, in association with the biotic stimuli resulting from plant-microbe interactions. As an example, the species-specific cold-induced phenolics profiles of 10 Hypericum representatives of different provenances cultured in vitro are illustrated in the case-study. Principal component analysis revealed a relationship between the level of defense-related phenolic compounds and interspecific differences in the stress tolerance indicating a link between the provenance of Hypericum species and inherent mechanisms of cold tolerance. The underlying metabolome alterations along with the changes in the activities of ROS-scavenging enzymes, and non-enzymatic physiological markers are discussed. Given these data it can be anticipated that some Hypericum species native to divergent habitats, with interesting high-value secondary metabolite composition and predicted high tolerance to biotic/abiotic stresses would attract the attention as valuable sources of bioactive compounds for many medicinal purposes.

Identification of Major Constituents of Hypericum perforatum L. Extracts in Syria by Development of a Rapid, Simple, and Reproducible HPLC-ESI-Q-TOF MS Analysis and Their Antioxidant Activities

Hypericum perforatum Linn (St. John's wort) is a popular and widespread medicine in Syria, which is used for a wide range of conditions, including gastrointestinal diseases, heart disease, skin diseases, and psychological disorders. This widespread use prompted us to identify the main compounds of this plant from Syria that are responsible for its medicinal properties, especially since its components differ between countries according to the nature of the soil, climate, and altitude. This is, to the best of our knowledge, the first report in which St. John's wort, a plant native to Syria, is extracted using different solvents and its most important compounds are identified. In this study, the dried above-ground parts, i.e., leaves, stem, petals, and flowers, were extracted using different solvents (water, ethanol, methanol, and acetone) and extraction protocols. By increasing the polarity of the solvent, higher yields were obtained, indicating that mainly hydrophobic compounds were extracted. Therefore, we conclude that extraction using the tea method or using a mixture of water and organic solvents resulted in higher yields compared with pure organic solvents or continuous boiling with water for long periods. The obtained extracts were analyzed using high-performance liquid chromatography equipped with a diode array detector (HPLC-DAD), coupled with UV-visible spectrophotometry at a full spectrum (200-800 nm). The HPLC spectra of the extracts were almost identical at three wavelengths (260 nm for phloroglucinols (hyperforin and derivates), 590 nm for naphthodianthrones (hypericins), and 350 nm for other flavonols, flavones, and caffeoylquinic acids), with differences observed only in the intensity of the peaks. This indicates that the same compounds were obtained using different solvents, but in different amounts. Five standards (chlorogenic acid, quercetin, quercitrin hydrate, hyperoside, and hypericin) were used, and a comparison with retention times and ultraviolet (UV) spectra reported in the literature was performed to identify 10 compounds in these extracts: hyperforin, adhyperforin, hypericin, rutin, quercetin, quercitrin, quercitrin hydrate, hyperoside, biapigenin, and chlorogenic acid. Although the European Pharmacopoeia still describes ultraviolet spectroscopy as a method for determining the quantity of Hyperici herba, interference from other metabolites can occur. Combined HPLC-DAD and electrospray ionization-mass spectrometry (LC-ESI-MS) in the positive mode have therefore also been used to confirm the presence of these compounds in the extracts by correlating known masses with the identified masses or through characteristic fragmentation patterns. Total phenolic contents of the extracts were determined by the Folin-Ciocalteu assay, and antioxidant activity was evaluated as free radical scavenging capacity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The results indicate that the aqueous extracts prepared by the tea method gave the highest total phenols, while the pure organic solvents gave very low phenols. Also, the extracts that contain the largest amount of phenols gave lower IC₅₀ values or higher antioxidant activity than that of others.

Development of new and validated HPTLC methods for the qualitative and quantitative analysis of hyperforin, hypericin and hyperoside contents in Hypericum species

PURPOSE

Hypericum perforatum L. (St. John's wort) is a medicinally important member of Hypericaceae. Many pharmacological activities have been mostly attributed to its hyperforin, hypericin and/or hyperoside contents. Therefore, qualitative and quantitative determinations of these ingredients are essential to justify the beneficial effects of St. John's wort on health. In the European Pharmacopoeia, the TLC and HPLC methods were given for this purpose. High performance thin layer chromatography (HPTLC) has recently become increasingly used as a suitable technique for analysing herbal drugs. This study aims to develop new and validated HPTLC methods to analyse these active components in different Hypericum spp. to find other suitable species to replace the official plant.

METHODS

Three different mobile phases were developed: n-hexane-ethyl acetate (8:2) for hyperforin analysis, toluene-chloroform-ethyl acetate-formic acid (8:5:3.5:0.6) for hypericin analysis and ethyl acetate-formic acid-acetic acid-water (15:2:2:1) for hyperoside analysis. These newly developed and validated HPTLC systems were further applied to determine their concentrations in different Hypericum species.

RESULTS

Hyperforin concentration was found between 6.40 to 26.40 mg/g only in H. triquetrifolium, H. scabrum and two H. perforatum samples; hypericin was detected between 0.81 and 1.41 mg/g only in H. bithynicum, H. perfoliatum, H. triquetrifolium and two H. perforatum samples; and hyperoside was identified in all tested specimens ranging from 1.01 to 9.73 mg/g. The new HPTLC methods developed and validated in the present study may ensure reliable results for the qualification and quantification of hyperforin, hypericin and hyperoside contents in Hypericum species.

Phytochemical profiling of several Hypericum species identified using genetic markers

In the present study, we performed phytochemical profiling of several under-exploited Hypericum representatives taxonomically belonging to the sections Ascyreia, Androsaemum, Inodora, Hypericum, Coridium, Myriandra, and Adenosepalum. The authenticity of the starting plant material was confirmed using the nuclear ribosomal internal transcribed spacer as a molecular marker, DNA content and chromosome number. Phenolic constituents were analyzed using high-performance liquid chromatography to complement species-specific metabolic profiles. In several Hypericum representatives, the pharmacologically important compounds, including naphthodianthrones; phloroglucinol derivatives; chlorogenic acid; and some classes of flavonoids, particularly the flavonols rutin and hyperoside, flavanol catechin, and flavanones naringenin and naringin, were reported for the first time. Comparative multivariate analysis of chemometric data for seedlings cultured in vitro and acclimated to the outdoor conditions revealed a strong genetically predetermined interspecific variability in phenolic compound content. In addition to hypericins, which are the most abundant chemomarkers for the genus Hypericum, rarely employed phenolic metabolites, including phloroglucinol derivatives, chlorogenic acid, catechin, naringenin, naringin, and kaempferol-3-O-glucoside, were shown to be useful for discriminating between closely related species. Given the increasing interest in natural products of the genus Hypericum, knowledge of the spectrum of phenolic compounds in shoot cultures is a prerequisite for future biotechnological applications. In addition, phytochemical profiling should be considered as an additional part of the integrated plant authentication system, which predominantly relies upon genetic markers.

DNA metabarcoding to unravel plant species composition in selected herbal medicines on the National List of Essential Medicines (NLEM) of Thailand

Traditional medicines are widely traded across the globe and have received considerable attention in the recent past, with expectations of heightened demand in the future. However, there are increasing global concerns over admixture, which can affect the quality, safety, and efficacy of herbal medicinal products. In this study, we aimed to use DNA metabarcoding to identify 39 Thai herbal products on the Thai National List of Essential Medicines (NLEM) and assess species composition and admixture. Among the products, 24 samples were in-house-prepared formulations, and 15 samples were registered formulations. In our study, DNA metabarcoding analysis using ITS2 and rbcL barcode regions were employed to identify herbal ingredients mentioned in the products. The nuclear region, ITS2, was able to identify herbal ingredients in the products at the genus- and family-levels in 55% and 63% of cases, respectively. The chloroplast gene, rbcL, enabled genus- and family-level identifications in 58% and 73% of cases, respectively. In addition, plant species were detected in larger numbers (Family identified, absolute %) in registered herbal products than in in-house-prepared formulations. The level of fidelity increases concerns about the reliability of the products. This study highlights that DNA metabarcoding is a useful analytical tool when combined with advanced chemical techniques for the identification of plant species in highly processed, multi-ingredient herbal products.

A Review of Analytical Methods for the Determination of Hypericin in Foods, Herbal, Biological and Pharmaceutical Matrices

Aims:

A review of analytical methods for the determination of hypericin in foods, herbal, biological and pharmaceutical matrices.

Background:

Hypericin (HYP) is a naturally-occurring pigment obtained from some plants of the genus Hypericum. Although HYP has been known for many years, it has recently attracted attention due to its varied biological properties, such as anti-inflammatory and antidepressant activity and it is also an efficient photosensitizer.

Objective:

The objective of this review is to provide insights into the physicochemical properties of HYP, as well as to report the analytical methods existing in the literature and official compendia for different matrices.

Methods:

The survey data were collected by Google Scholar® and Scopus® using keys terms.

Result:

Analytical methods involving HYP are mainly concerned with the quality control of pharmaceutical preparations, foods, beverages, biological samples and drug delivery systems using different types of analysis methods. Some difficulties have also been identified due to the physicochemical properties of HYP. It presents great solubility in alkaline solutions, organic bases and common polar organic solvents.

Conclusion:

It can be analyzed by thin layer chromatography, spectrophotometry in the ultraviolet region, but the most commonly used method is by HPLC. HYP presents monographs in the American, British and European Pharmacopoeias, however, the methods of analysis are not yet harmonized.

Metabolomic fingerprinting and genetic discrimination of four Hypericum taxa from Greece

Hypericum perforatum has plenty of uses in traditional medicine and is the source of top-selling herbal drugs and food supplements. The secondary metabolite chemistry for most of the nearly 500 Hypericum taxa is still unknown, even though they are used interchangeably. In the present study, we characterized four Hypericum populations from Achaia, Greece, belonging to H. perforatum ssp. veronense, H. perfoliatum, H. triquetrifolium, and an uninvestigated taxon, H. empetrifolium ssp. empetrifolium, in terms of their essential oils and polar bioactives in methanolic extracts via GC-MS, LC-HRMS, LC-DAD-MS, and HPLC-DAD. We also performed sequence analysis of nrITS to explore the genetic profile of these taxa and to examine whether their genotype is correlated to the metabolome. Sixty-three non-volatile compounds, phloroglucinols in their majority, and over one hundred (113) volatiles, mostly sesqui- and mono- terpenes, were detected. The concentration of the major polar constituents varied greatly among samples. In particular, phloroglucinols' diversity and abundance in H. empetrifolium ssp. empetrifolium was remarkable. The PCA and Biplot analysis revealed the contribution of each compound to the total chemodiversity and also revealed certain compounds that contribute to the discrimination of the samples. Sequence analysis of nrITS revealed different genetic profiles and markers which can be used for the identification of the four Hypericum taxa. The Mantel test showed a relatively strong correlation between the genetic profile and the volatile compounds and low with the main polar metabolites.

Herbal medicine for psychiatric disorders: Psychopharmacology and neuroscience-based nomenclature

Objectives: Herbs are frequently and concurrently used with prescribed drugs by patients worldwide. While clinical trials have found some herbs to be as useful as standard psychiatric drugs, most clinicians are unaware of their pharmacological mechanisms.Methods: We searched English language and other language literature with English abstracts listed in PubMed website, supplemented by additional through Google Scholar's free academic paper abstract website for publications on herbs, focussing on their clinical use in mental disorders, their neurobiology and their pharmacology.Results: A major reason for herbs remaining outside of mainstream psychiatry is that the terminology and concepts in herbal medicine are not familiar to psychiatrists in general. Many publications regarding the use of herbal medicine for psychiatric disorders are deficient in details regarding diagnosis, criteria for response and the neurobiology details compared with publications on standard psychotropic drugs. Nomenclature for herbal medicine is usually confusing and is not conducive to an easy understanding of their mode of action in psychiatric disorders.Conclusions: The recent neuroscience-based nomenclature (NbN) for psychotropics methodology would be a logical application to herbal medicine in facilitating a better understanding of the use of herbal medicine in psychiatry.

Toward enhanced hyperforin production in St. John's wort root cultures

During the past decades, several trials targeted a stable, sustainable and economic production of St. John's wort (Hypericum perforatum) extract. The value of this extract stems from its use to treat depression and skin irritation due to its hyperforin content. Previously, hyperforin-forming in vitro root cultures were established. Here, detailed growth and production kinetics have been analyzed over 40 days of cultivation. In the first 10 days, sucrose was completely hydrolyzed to glucose and fructose. The ammonium consumption supported the increase in the biomass and hyperforin production. When sucrose was replaced with glucose/fructose, the linear growth phase started 6 days earlier and resulted in a higher space-time-yield. The maximum hyperforin production was 0.82 mg L^-1 day^-1, which was 67 % higher than in the sucrose-supplemented standard cultivation. Buffering the sucrose-supplemented medium with phosphate caused a 2.7-fold increase in the product to biomass yield coefficient. However, the combination of monosaccharides and buffering conditions did not cause an appreciable improvements in the production performance of the shake flask approaches. A potential scalability from flask to lab-scale stirred bioreactors has been demonstrated. The results obtained offer a basis for a scalable production of hyperforin and a sustainable source for a tissue culture-based phytomedicine.

Host metabolite producing endophytic fungi isolated from Hypericum perforatum

In the present study, endophytic fungi have been isolated from various parts of the medicinal herb Hypericum perforatum (St. John’s Wort), which is known as a source of medically important metabolites. The isolated strains were cultured in liquid media and their ability to synthesize hypericin, the secondary metabolite of the host and its suspected precursor, emodin was tested analyzing the extracts of the fermentation broth and the mycelia. The HPLC-UV analysis of the chloroform/methanol extracts of the mycelia revealed that three isolates were able to produce emodin (SZMC 23771, 19.9 ng/mg; SZMC 23772, 20.8 ng/mg; SZMC 23769, 427.9 ng/mg) and one of them also could synthesize hypericin (SZMC 23769, 320.4 ng/mg). These results were also confirmed via UHPLC-HRMS technique both in full scan and MS/MS mode. The strains producing only emodin belong to the section Alternata of the genus Alternaria, while the isolate producing both metabolites was identified as Epicoccum nigrum. The mycelial extracts of E. nigrum and the Alternaria sp. SZMC 23772 showed higher inhibitory activities in the antimicrobial tests against the six selected bacteria compared to the hypericin and emodin standards in the applied concentration (100 μg/mL), while in case of the Alternaria sp. SZMC 23771 lower inhibition activities were observed on Staphylococcus aureus and Streptomyces albus than the pure compounds.

Trace Element Uptake and Accumulation in the Medicinal Herb Hypericum perforatum L. Across Different Geolithological Settings

The worldwide growing interest in traditional medicines, including herbal medicines and herbal dietary supplements, has recently been accompanied by concerns on quality and safety of this type of health care. The content of nutritional and potentially toxic elements in medicinal plants is of paramount interest as it may vary remarkably according to different environmental and ecophysiological factors. In this study, the concentrations of essential and non-essential trace elements-Co, Cr, Cu, Ni, Sr, and Zn-were determined in the roots and aerial parts of the worldwide distributed and economically important medicinal herb Hypericum perforatum L. (St. John's wort) and in its growing substrate. Most of the analyzed trace elements varied considerably in the plant parts according to edaphic conditions and soil geochemistry. However, uptake and retention in H. perforatum compartments of Co, Cr, and Ni, which markedly differentiated the investigated soils, were controlled by excluding mechanisms of the plant. Despite this, the Ni concentrations in the aerial parts, commonly used in herbal preparations, of H. perforatum plants from serpentine soils were not insignificant in relation to eventual human consumption. Good practice to assure the herbal product quality of H. perforatum collected from the wild cannot ignore the thorough understanding of the geolithological and geochemical features of the harvesting areas.

DNA Authentication of St John's Wort (Hypericum perforatum L.) Commercial Products Targeting the ITS Region

There is considerable potential for the use of DNA barcoding methods to authenticate raw medicinal plant materials, but their application to testing commercial products has been controversial. A simple PCR test targeting species-specific sequences within the nuclear ribosomal internal transcribed spacer (ITS) region was adapted to screen commercial products for the presence of Hypericum perforatum L. material. DNA differing widely in amount and extent of fragmentation was detected in a number of product types. Two assays were designed to further analyse this DNA using a curated database of selected Hypericum ITS sequences: A qPCR assay based on a species-specific primer pair spanning the ITS1 and ITS2 regions, using synthetic DNA reference standards for DNA quantitation and a Next Generation Sequencing (NGS) assay separately targeting the ITS1 and ITS2 regions. The ability of the assays to detect H. perforatum DNA sequences in processed medicines was investigated. Out of twenty different matrices tested, both assays detected H. perforatum DNA in five samples with more than 10³ ITS copies µL⁻¹ DNA extract, whilst the qPCR assay was also able to detect lower levels of DNA in two further samples. The NGS assay confirmed that H. perforatum was the major species in all five positive samples, though trace contaminants were also detected.

What's in the box? Authentication of Echinacea herbal products using DNA metabarcoding and HPTLC

BACKGROUND

Differences in regulatory policies between countries as well as a lack of appropriate standardized methods for the authentication and quality control of herbal products directly impact their quality and safety. Echinacea products are among the top-selling herbal products in Europe and the United States with indications for a broad range of ailments. The increased use of Echinacea species has led to concerns about adulterated products resulting from challenges in morphology-based identification, due to overlapping morphological variation, frequent hybridization between species, and deliberate adulteration.

PURPOSE

This study addressed the need for a novel analytical strategy in the authentication of herbal products.

METHODS

A combination of high performance thin layer chromatography (HPTLC) and DNA metabarcoding was employed. Fifty-three Echinacea herbal products marketed across Europe were tested to evaluate the accuracy of these methods in plant identification and their potential for detecting substitutes, adulterants and other unreported plant constituents.

RESULTS

HPTLC provides high resolution in the detection of Echinacea phytochemical target compounds, but does not offer information on the other species within the product. Alternatively, we showed that the limitation of HPTLC in detecting non-targeted species can be overcome by the complementary use of DNA metabarcoding. Using DNA metabarcoding, Echinacea species were detected in 34 out of the 38 retained products (89%), but with a lack of discriminatory resolution at the species level due to the low level of molecular divergence within the Echinacea genus. All of the tested herbal products showed considerable discrepancies between ingredients listed on the label and the ones detected using DNA metabarcoding, registering an overall ingredient fidelity of only 43%.

CONCLUSION

The results confirm that DNA metabarcoding can be used to test for the presence of Echinacea species and simultaneously to detect other species present in even highly processed and multi-ingredient herbal products.

Benefits and Limitations of DNA Barcoding and Metabarcoding in Herbal Product Authentication

INTRODUCTION

Herbal medicines play an important role globally in the health care sector and in industrialised countries they are often considered as an alternative to mono-substance medicines. Current quality and authentication assessment methods rely mainly on morphology and analytical phytochemistry-based methods detailed in pharmacopoeias. Herbal products however are often highly processed with numerous ingredients, and even if these analytical methods are accurate for quality control of specific lead or marker compounds, they are of limited suitability for the authentication of biological ingredients.

OBJECTIVE

To review the benefits and limitations of DNA barcoding and metabarcoding in complementing current herbal product authentication.

METHOD

Recent literature relating to DNA based authentication of medicinal plants, herbal medicines and products are summarised to provide a basic understanding of how DNA barcoding and metabarcoding can be applied to this field.

RESULTS

Different methods of quality control and authentication have varying resolution and usefulness along the value chain of these products. DNA barcoding can be used for authenticating products based on single herbal ingredients and DNA metabarcoding for assessment of species diversity in processed products, and both methods should be used in combination with appropriate hyphenated chemical methods for quality control.

CONCLUSIONS

DNA barcoding and metabarcoding have potential in the context of quality control of both well and poorly regulated supply systems. Standardisation of protocols for DNA barcoding and DNA sequence-based identification are necessary before DNA-based biological methods can be implemented as routine analytical approaches and approved by the competent authorities for use in regulated procedures. © 2017 The Authors. Phytochemical Analysis Published by John Wiley & Sons Ltd.