Comparison of electrospray ionization and atmospheric pressure photoionization liquid chromatography mass spectrometry methods for analysis of ergot alkaloids from endophyte-infected sleepygrass (Achnatherum robustum)

A critical review of analytical methods for ergot alkaloids in cereals and feed and in particular suitability of method performance for regulatory monitoring and epimer-specific quantification

Cereals and feed contaminated with ergot alkaloids (EAs) have been of concern for several decades. Nowadays, analysis of EAs is focused on ergometrine, ergotamine, ergosine, ergocristine, ergocryptine (a mixture of α- and β-isomers) and ergocornine and their related -inine epimers as listed in the European Commission Recommendation 2012/154/EU. Liquid chromatography with fluorescence detection has been used for quantification of EAs for decades whilst LC-MS has become the work-horse for quantification of EAs in the last decade. However, in LC-MS analysis matrix effects of different magnitudes exist for each EA epimer, especially ergometrine/ergometrinine, even after different clean-up procedures. This leads to an underestimation or overestimation of EAs levels. Moreover, isotopic labelled standards for EAs are still not available in the market. This review aims to provide background information on different analytical methods, discuss their advantages and disadvantages and possible advancement. Moreover, the method performance requirements to support forthcoming regulations are also discussed.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

UPLC-ESI-Q-TOF-MS/MS analysis of anticancer fractions from Ophiocordyceps xuefengensis and Ophiocordyceps sinensis

Ophiocordyceps xuefengensis (O. xuefengensis), a new species of caterpillar fungus, has been identified as the sister taxon of Ophiocordyceps sinensis (O. sinensis). The aims of the present study are to evaluate the anticancer activity and to qualitatively analyze the potential bioactive chemical constituents of O. xuefengensis and O. sinensis, comparatively. An MTT assay was used to evaluate the in vitro anticancer activities of different fractions from O. xuefengensis and O. sinensis. The results show that ethyl acetate fractions of O. xuefengensis and O. sinensis have significant in vitro anticancer activity. These two bioactive fractions were analyzed by ultra-performance liquid chromatography-electrospray ionization with quadrupole-time of flight tandem mass spectrometry technology. A total of 82 compounds and 101 compounds were identified or tentatively characterized in the bioactive fractions of O. xuefengensis and O. sinensis, respectively. Among these compounds, 68 existed in both O. xuefengensis and O. sinensis. A total of 67 compounds were reported in O. xuefengensis and 8 compounds were reported in caterpillar fungus for the first time. This is the first detailed comparative analysis of the in vitro anticancer activity and chemical ingredients between O. xuefengensis and O. sinensis. The application of this work will provide reliable fundamental pharmacological substances for the use of O. xuefengensis by Yao people.

Do Epichloë Endophytes and Their Grass Symbiosis Only Produce Toxic Alkaloids to Insects and Livestock?

Epichloë endophytes in forage grasses have attracted widespread attention and interest of chemistry researchers as a result of the various unique chemical structures and interesting biological activities of their secondary metabolites. This review describes the diversity of unique chemical structures of taxa from Epichloë endophytes and grass infected with Epichloë endophytes and demonstrates their reported biological activities. Until now, nearly 160 secondary metabolites (alkaloids, peptides, indole derivatives, pyrimidines, sesquiterpenoids, flavonoids, phenol and phenolic acid derivatives, aliphatic metabolites, sterols, amines and amides, and others) have been reported from Epichloë endophytes and grass infected with Epichloë endophytes. Among these, non-alkaloids account for half of the population of total metabolites, indicating that they also play an important role in Epichloë endophytes and grass infected with Epichloë endophytes. Also, a diverse array of secondary metabolites isolated from Epichloë endophytes and symbionts is a rich source for developing new pesticides and drugs. Bioassays disclose that, in addition to toxic alkaloids, the other metabolites isolated from Epichloë endophytes and symbionts have notable biological activities, such as antifungal, anti-insect, and phytotoxic activities. Accordingly, the biological functions of non-alkaloids should not be neglected in the future investigation of Epichloë endophytes and symbionts.

Selection and characterization of botanical natural products for research studies: a NaPDI center recommended approach

Covering: up to the end of 2018 Dietary supplements, which include botanical (plant-based) natural products, constitute a multi-billion-dollar industry in the US. Regulation and quality control for this industry is an ongoing challenge. While there is general agreement that rigorous scientific studies are needed to evaluate the safety and efficacy of botanical natural products used by consumers, researchers conducting such studies face a unique set of challenges. Botanical natural products are inherently complex mixtures, with composition that differs depending on myriad factors including variability in genetics, cultivation conditions, and processing methods. Unfortunately, many studies of botanical natural products are carried out with poorly characterized study material, such that the results are irreproducible and difficult to interpret. This review provides recommended approaches for addressing the critical questions that researchers must address prior to in vitro or in vivo (including clinical) evaluation of botanical natural products. We describe selection and authentication of botanical material and identification of key biologically active compounds, and compare state-of-the-art methodologies such as untargeted metabolomics with more traditional targeted methods of characterization. The topics are chosen to be of maximal relevance to researchers, and are reviewed critically with commentary as to which approaches are most practical and useful and what common pitfalls should be avoided.

ESI outcompetes other ion sources in LC/MS trace analysis

Choosing an appropriate ion source is a crucial step in liquid chromatography mass spectrometry (LC/MS) method development. In this paper, we compare four ion sources for LC/MS analysis of 40 pesticides in tomato and garlic matrices. We compare electrospray ionisation (ESI) source, thermally focused/heated electrospray (HESI), atmospheric pressure photoionisation (APPI) source with and without dopant, and multimode source in ESI mode, atmospheric pressure chemical ionisation (APCI) mode, and combined mode using both ESI and APCI, i.e. altogether seven different ionisation modes. The lowest limits of detection (LoDs) were obtained by ESI and HESI. Widest linear ranges were observed with the conventional ESI source without heated nebuliser gas. In comparison to HESI, ESI source was significantly less affected by matrix effect. APPI ranked second (after ESI) by not being influenced by matrix effect; therefore, it would be a good alternative to ESI if low LoDs are not required. Graphical abstract.

Role of Epichloë Endophytes in Defense Responses of Cool-Season Grasses to Pathogens: A Review

Various cool-season grasses are infected by Epichloë endophyte, and this symbiotic relationship is always of benefit to the host grass due to an increased resistance to abiotic and biotic stresses. Fungal diseases adversely affect the yield, quality, and economic benefits of rangelands, which affects the production of animal husbandry. Therefore, it is imperative to breed resistant cultivars and to better understand the role of fungal endophytes in order to protect grasses against pathogens. The present review introduces research regarding how these endophytes affect the growth of pathogens in vitro and how they change the resistance of host plants to plant diseases. From the perspective of physical defense, changes in physiological indexes, and secretion of chemical compounds, we summarize the potential mechanisms by which endophytes are able to enhance the disease resistance of a host grass. Through these, we aim to establish a solid theoretical foundation for plant disease control and disease resistance breeding by application of fungal endophytes. A broader understanding of fungal endophyte effects on hosts could create a new opportunity for managing or introducing fungal symbioses in both agronomic or non-agronomic ecosystems.

Developments in mycotoxin analysis: an update for 2016-2017

This review summarises developments in the determination of mycotoxins over a period between mid-2016 and mid-2017. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of the presented methodologies.

Interspecific and intraspecific hybrid Epichloë species symbiotic with the North American native grass Poa alsodes

The endophyte presence and diversity in natural populations of Poa alsodes were evaluated along a latitudinal transect from the southern distribution range in North Carolina to New York. Two distinct Epichloë hybrid taxa were identified from 23 populations. Each taxon could easily be distinguished by polymerase chain reaction (PCR) genotyping with primers designed to mating type genes and alkaloid biosynthesis genes that encode key pathway steps for ergot alkaloids, indole-diterpenes, lolines, and peramine. The most commonly found Epichloë taxon, Poa alsodes Taxonomic Group-1 (PalTG-1), was detected in 22 populations at high infection frequencies (72-100%), with the exception of one population at high elevation (26% infection). The second taxon, PalTG-2, was observed only in five populations in Pennsylvania constituting 12% of infected samples. Phylogenetic analyses placed PalTG-1 as an interspecific hybrid of E. amarillans and E. typhina subsp. poae ancestors, and it is considered a new hybrid species, which the authors name Epichloë alsodes. PalTG-2 is an intraspecific hybrid of two E. typhina subsp. poae ancestors, similar to E. schardlii from the host Cinna arundinacea, which the authors propose as a new variety, Epichloë schardlii var. pennsylvanica. Epichloë alsodes isolates were all mating type MTA MTB and tested positive for dmaW, easC, perA, and some LOL genes, but only the alkaloid N-acetylnorloline was detected in E. alsodes-infected plant material. Epichloë schardlii var. pennsylvanica isolates were all mating type MTB MTB and tested positive for perA, but peramine was not produced. Both E. alsodes and E. schardlii var. pennsylvanica appeared to have complete perA genes, but point mutations were identified in E. alsodes that would render the encoded perA gene nonfunctional.

Developments in mycotoxin analysis: an update for 2015-2016

This review summarises developments in the determination of mycotoxins over a period between mid-2015 and mid-2016. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed liquid chromatography mass spectrometry based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of presented methodologies.

Simultaneous Determination of 25 Ergot Alkaloids in Cereal Samples by Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry

A liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of 25 ergot alkaloids in cereal samples. The analytes included both -ine and -inine ergot alkaloids and were extracted using an acetonitrile and ammonium carbonate solution, followed by purification with C-18 sorbent. After full separation on a C18 column, the 25 ergot alkaloids were detected by LC-MS/MS using multiple reaction monitoring (MRM) in the positive ion mode. The linear range was 0.05-5.0 μg/kg for the 25 ergot alkaloids. The mean recoveries at three spiked concentrations varied from 76.5 to 120% with RSD < 15%. This method was validated using a FAPAS proficiency test sample of ergot alkaloids in rye flour and was finally applied to analyze real samples, including rye flours, wheat flours, whole wheat flours, bread, and noodles.

Antimicrobial fungal endophytes from the botanical medicine goldenseal (Hydrastis canadensis)

The potential of fungal endophytes to alter or contribute to plant chemistry and biology has been the topic of a great deal of recent interest. For plants that are used medicinally, it has been proposed that endophytes might play an important role in biological activity. With this study, we sought to identify antimicrobial fungal endophytes from the medicinal plant goldenseal (Hydrastis canadensis L., Ranunculaceae), a plant used in traditional medicine to treat infection. A total of 23 fungal cultures were obtained from surface-sterilized samples of H. canadensis roots, leaves and seeds. Eleven secondary metabolites were isolated from these fungal endophytes, five of which had reported antimicrobial activity. Hydrastis canadensis plant material was then analyzed for the presence of fungal metabolites using liquid chromatography coupled to high resolving power mass spectrometry. The antimicrobial compound alternariol monomethyl ether was detected both as a metabolite of the fungal endophyte Alternaria spp. isolated from H. canadensis seeds, and as a component of an extract from the H. canadensis seed material. Notably, fungi of the Alternaria genus were isolated from three separate accessions of H. canadensis plant material collected in a time period spanning 5 years. The concentration of alternariol monomethyl ether (991 mg/kg in dry seed material) was in a similar range to that previously reported for metabolites of ecologically important fungal endophytes. The seed extracts themselves, however, did not possess antimicrobial activity.