Separation and determination of toxic pyrrolizidine alkaloids in traditional Chinese herbal medicines by micellar electrokinetic chromatography with organic modifier

Levels, Toxic Effects, and Risk Assessment of Pyrrolizidine Alkaloids in Foods: A Review

Pyrrolizidine alkaloids (PAs) are naturally occurring secondary metabolites of plants. To date, more than 660 types of PAs have been identified from an estimated 6000 plants, and approximately 120 of these PAs are hepatotoxic. As a result of PAs being found in spices, herbal teas, honey, and milk, PAs are considered contaminants in foods, posing a potential risk to human health. Here, we summarize the chemical structure, toxic effects, levels, and regulation of PAs in different countries to provide a better understanding of their toxicity and risk assessment. With recent research on the risk assessment of PAs, this review also discusses the challenges facing this field, aiming to provide a scientific basis for PA toxicity research and safety assessment.

Doped nanomaterial facilitates 3D printing target plate for rapid detection of alkaloids in laser desorption/ionization mass spectrometry

This work aims to rapidly detect toxic alkaloids in traditional Chinese medicines (TCM) using laser desorption ionization mass spectrometry (LDI-MS). We systematically investigated twelve nanomaterials (NMs) as matrices and found that MoS2 and defect-rich-WO3 (D-WO3) were the best NMs for alkaloid detection. MoS2 and D-WO3 can be used directly as matrices dipped onto conventional ground steel target plates. Additionally, they can be conveniently fabricated as three-dimensional (3D) NM plates, where the MoS2 or D-WO3 NM is doped into resin and formed using a 3D printing process. We obtained good quantification of alkaloids using a chemothermal compound as an internal standard and detected related alkaloids in TCM extracts, Fuzi (Aconiti Lateralis Radix Praeparata), Caowu (Aconiti Kusnezoffii Radix), Chuanwu (Aconiti Radix), and Houpo (Magnoliae Officinalis Cortex). The work enabled the advantageous "dip and measure" method, demonstrating a simple and fast LDI-MS approach that achieves clean backgrounds for alkaloid detection. The 3D NM plates also facilitated mass spectrometry imaging of alkaloids in TCMs. This method has potential practical applications in medicine and food safety. Doped nanomaterial facilitates 3D printing target plate for rapid detection of alkaloids in laser desorption/ionization mass spectrometry.

Multi-template imprinted solid-phase microextraction coupled with UPLC-Q-TOF-MS for simultaneous monitoring of ten hepatotoxic pyrrolizidine alkaloids in scented tea

Pyrrolizidine alkaloids (PAs) are a series of ubiquitous natural toxins in flowering plants, which are associated with serious hepatic disease in humans. However, the simultaneously fast and sensitive monitoring of different PAs are still challenge because of the diversity of PAs and huge amount of interference in complex samples, such as scented tea samples. In this study, molecularly imprinted solid phase microextraction (MIP-SPME) fibers were fabricated by using multi-template imprinting technique for selective recognition and efficient enrichment of different PAs from scented teas. MIP-SPME could be used for selective adsorption of ten types of PAs through specific recognition cavity and strong ionic interaction, including senecionine, lycopsamine, retrorsine, heliotrine, lasiocarpine, monocrotaline, echimidine, erucifoline, europine and seneciphylline. The extraction parameters were also optimized including extraction time, elution solvent and elution time. Then, ultra performance liquid chromatography- quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS) coupled with MIP-SPME method was developed for fast, simple, sensitive and accurate determination of ten PAs in scented teas. The established method was validated and presented satisfactory accuracy and high precision. It was also successfully applied for simultaneous determination of ten PAs in different scented tea samples. PAs were found in most of these scented tea samples, which suggest the cautious use of scented tea for consumers.

Identification and Simultaneous Determination of the Main Toxical Pyrrolizidine Alkaloids in a Compound Prescription of Traditional Chinese Medicine: Qianbai Biyan Tablet

Qianbai biyan tablet (QT) is a compound prescription of traditional Chinese medicine which is used to treat nasal congestion, rhinitis, and nasosinusitis, with Senecio scandens as its main plant material. Several pyrrolizidine alkaloids (PAs) were reported in Senecio scandens and others of Senecio species. Although Senecio scandens is assigned as the legal plant material of QT, whether replaced use of it by other Senecio plants can bring toxicity is unknown because of the lack of quantitative data about toxic PAs between different Senecio species. In the present study, adonifoline, senkirkine, and another PA presumed as emiline have been identified in QT; however, there was no senecionine detected in all tablets. PA contents in QTs varied in different companies and different batches. Adonifoline existed only in Senecio scandens, and senecionine was detected in all eight Senecio plants investigated in the present study. Data showed that replaced use of Senecio scandens with a low level of senecionine by other Senecio plants such as Senecio vulgaris containing a high level of senecionine is advertised to be forbidden. Data of the present study may be used as a reference to make new drug quality regularity and recommendation guideline for the safety of QT.

Farfarae Flos: A review of botany, traditional uses, phytochemistry, pharmacology, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Farfarae Flos (FF; dried flower buds of Tussilago farfara L.), a widely used traditional Chinese medicine (TCM), is also known as "Kuandonghua" (Chinese: ). It has a wide range of pharmacological effects and has long been used to treat various respiratory conditions including cough, asthma, and acute or chronic bronchitis.

AIMS

This study reviews the current advances in the research on the botany, ethnopharmacology, phytochemistry, pharmacology, and toxicology of Farfarae Flos. Prospects for future investigation and application of this herb are also discussed.

MATERIALS AND METHODS

Information on FF was collected from both published materials (such as ancient and modern books, Ph.D. and M. Sc. dissertations, monographs on medicinal plants, and pharmacopoeia) and electronic databases (such as CNKI, SciFinder, WanFang data, PubMed, ScienceDirect, Web of Science, Taylor&Francis, ACS Publications, Wiley, Springer, Europe PMC, EBSCOhost, J-STAGE, and Google Scholar).

RESULTS

Approximately 175 chemical compounds, including terpenoids, organic acids, flavonoids, alkaloids, chromones, volatile oils, and other compounds, have been isolated from FF. This TCM has been reported to produce pharmacological effects on the respiratory, cardiovascular, and digestive systems, and exert antioxidant, anti-inflammatory, and neuroprotective activities. FF is safe in the traditional dose range, but the potential toxicity due to the emergence of pyrrolidine alkaloids needs to be paid more attention.

CONCLUSIONS

FF is a commonly used TCM with pharmacological activities mainly on the respiratory system. This study suggests that the further expansion of the pharmacological effect of FF and in-depth study of its prescription need to be concerned about. The investigations of the role of more active substances and the pharmacokinetics of the hepatotoxic components of FF will help to maximize the therapeutic potential and promote its popularization and application. Meanwhile, it is important to pay attention to pursue research on the similarities and differences between the leaves and the flower buds to find their respective advantages and make rational use of T. farfara L.

Pyrrolizidine Alkaloids: Chemistry, Pharmacology, Toxicology and Food Safety

Pyrrolizidine alkaloids (PA) are widely distributed in plants throughout the world, frequently in species relevant for human consumption. Apart from the toxicity that these molecules can cause in humans and livestock, PA are also known for their wide range of pharmacological properties, which can be exploited in drug discovery programs. In this work we review the current body of knowledge regarding the chemistry, toxicology, pharmacology and food safety of PA.

Safety assessment of food and herbal products containing hepatotoxic pyrrolizidine alkaloids: interlaboratory consistency and the importance of N-oxide determination

INTRODUCTION

Two recent mass spectrometry-based reports concerning Senecio scandens yielded remarkably dissimilar pyrrolizidine alkaloid constituents. In both studies, and in a related analysis of Senecio scandens and Tussilago farfara using micellar electrokinetic chromatography, the presence of hazardous N-oxides of the alkaloids was either not considered or was inadequately considered. This raises concerns about the effectiveness of the methodologies used in these, and similar, studies in assessing the pyrrolizidine alkaloid content and the safety of food, food supplements and medicines for human use.

OBJECTIVE

To highlight essential analytical requirements for confident assessment of pyrrolizidine alkaloid-related safety of food and herbal products for human use.

METHODOLOGY

Direct infusion-ESI MS and HPLC-ESI MS were used to analyse samples derived from liquid-liquid partitioning experiments and from strong cation exchange, solid-phase extraction of pyrrolizidine alkaloids and their N-oxides.

RESULTS

A simple solvent partitioning experiment using pure senecionine and senecionine-N-oxide, two constituents reported in one of the mass spectrometry-based studies of S. scandens, clearly demonstrated the inadequacy of the reported method to detect and quantitate hazardous pyrrolizidine alkaloid N-oxide components. A preliminary LCMS analysis of commercially-prepared extracts of comfrey roots (Symphytum officinale and S. uplandicum s. l.) was used as a model to highlight the analytical importance of N-oxides in the safety assessment of pyrrolizidine alkaloid-containing medicinal herbs.

CONCLUSIONS

This study highlighted significant differences in the reported identification of pyrrolizidine alkaloids from the same plant species, and clearly demonstrated the inadequacy of some procedures to include N-oxides in the assessment of pyrrolizidine alkaloid-related safety of food and herbal products.

Qualitative and quantitative analysis in quality control of traditional Chinese medicines

Separation techniques with high efficiency and sensitive detection have been widely used for quality control of traditional Chinese medicines (TCMs). High-performance liquid chromatography, gas chromatography, and capillary electrophoresis are commonly used to separate various components in TCMs. Ultraviolet detection, fluorescence detection, evaporative light-scattering detection, mass spectrometry and nuclear magnetic resonance can be applied to separation techniques for qualitative and quantitative analysis of TCMs. The development of quality control for TCMs based on quantitative and qualitative analysis from 2000 to 2007 are reviewed; the fingerprint technique is also discussed due to its broad application in the quality control of TCMs. Prospects for further research based on our primary results are also discussed.

Chemical markers for the quality control of herbal medicines: an overview

Selection of chemical markers is crucial for the quality control of herbal medicines, including authentication of genuine species, harvesting the best quality raw materials, evaluation of post-harvesting handling, assessment of intermediates and finished products, and detection of harmful or toxic ingredients. Ideal chemical markers should be the therapeutic components of herbal medicines. However, for most herbal medicines, the therapeutic components have not been fully elucidated or easily monitored. Bioactive, characteristic, main, synergistic, correlative, toxic and general components may be selected. This article reviews the effective use of chemical markers in the quality control of herbal medicines including the selection criteria considering the roles and physicochemical factors which may affect the effective use of chemical markers.

Identification of five hepatotoxic pyrrolizidine alkaloids in a commonly used traditional Chinese medicinal herb, Herba Senecionis scandentis (Qianliguang)

Senecio scandens Buch.-Ham is a plant source for a commonly used traditional Chinese medicinal (TCM) herb Qianliguang. A TCM herbal proprietary product containing Qianliguang as the major herb for the treatment of sinusitis has been used in China for several decades, and has also been exported to other regions and countries worldwide. In the present study, the aqueous extract of S. scandens collected in the Shanxi Province of China was determined, for the first time, to contain hepatotoxic and tumorigenic pyrrolizidine alkaloids (PAs) by using high-performance liquid chromatography/mass spectrometric (HPLC/MS) analysis in various scanning modes. A total of nine toxic and two non-toxic PAs were detected in the aqueous extract of S. scandens, of which six PAs, namely neoplatyphylline, senecionine, senecionine N-oxide, seneciphylline, seneciphylline N-oxide and senkirkine, were unequivocally characterized, while other PAs were tentatively assigned as jacobine, jacozine N-oxide (or erucifoline N-oxide), 7-tigloylplatynecine, usaramine and an isomer of yamataimine. The estimated total content of toxic PAs in S. scandens was 10.82 microg/g herb, which was significantly higher than that (> or =1 microg/g herb) recommended by Belgium and Germany not to be used clinically. Among the PAs definitively identified, senecionine, seneciphylline, and senkirkine are known tumorigens capable of inducing liver tumors in experimental animals, while seneciphylline N-oxide and senecionine N-oxide are probably tumorigenic due to their potential conversion into seneciphylline and senecionine via metabolic reduction in the body. Thus, the current finding of the presence of toxic/tumorigenic PAs in S. scandens challenges the safety of using this TCM herb and its proprietary products.