Interactions between Plant Metabolites Affect Herbivores: A Study with Pyrrolizidine Alkaloids and Chlorogenic Acid

The herbal preparation coffee charcoal is produced by over-roasting and milling green dried Coffea arabica L. seeds, and has a long-standing tradition in the treatment of inflammatory and gastrointestinal disorders. Its therapeutic properties are commonly attributed to adsorptive and astringent effects. This insufficiently explains its mode of action, especially when used in the treatment of inflammatory diseases in lower dosages. Our investigations aimed to identify bioactive secondary plant metabolites affecting cytokine-signaling. Thus, a phytochemical analysis of coffee charcoal extract was conducted using HPLC and LC/MS. Trigonelline, neochlorogenic acid, chlorogenic acid, caffeine, cryptochlorogenic acid, feruloylquinic acid isomers, and a caffeoylquinolacton were identified in the extract. Subsequently, the effects of coffee charcoal extract, chlorogenic acid isomers, their metabolite caffeic acid, caffeine, and trigonelline on cytokine (TNF, IL-6, MCP-1) release from LPS-challenged human THP-1 macrophages were examined to evaluate anti-inflammatory activity. Coffee charcoal showed concentration-dependent mild-to-medium inhibitory effects. The chlorogenic acid isomers and caffeic acid inhibited the TNF release, with cryptochlorogenic acid exerting the most distinct effects, as well as decreasing the release of IL-6 and MCP-1. In addition, scanning electron microscopic images provided an impression of the particle constitution, indicating a larger particle size and less structured surface of coffee charcoal in comparison to activated charcoal. In conclusion, our findings underline that beyond adsorptive effects, coffee charcoal exhibits pharmacological properties, which derive from a spectrum of secondary plant metabolites and support the therapeutic use in inflammatory diseases. Chlorogenic acids, particularly cryptochlorogenic acid, appear as pivotal bioactive compounds.

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Identification of Polyphenols from Coniferous Shoots as Natural Antioxidants and Antimicrobial Compounds

Molecules ◽

10.3390/molecules25153527 ◽

2020 ◽

Vol 25 (15) ◽

pp. 3527 ◽

Cited By ~ 3

Author(s):

Marcin Dziedzinski ◽

Joanna Kobus-Cisowska ◽

Daria Szymanowska ◽

Kinga Stuper-Szablewska ◽

Marlena Baranowska

Keyword(s):

Ferulic Acid ◽

Chlorogenic Acid ◽

Antimicrobial Properties ◽

Natural Antioxidants ◽

Hydroxybenzoic Acid ◽

Plant Metabolites ◽

Food Ingredient ◽

Reducing Ability ◽

Bacteria And Fungi

Currently, coniferous shoots are almost absent as a food ingredient despite their wide availability in many parts of the world. The aim of the study was to assess and compare the composition of selected plant metabolites, evaluate the antioxidant and antimicrobial properties of selected shoots collected in 2019 from the arboretum in Zielonka (Poland), including individual samples from Picea abies L. (PA), Larix decidua Mill (LD), Pinus sylvestris L. (PS), Pseudotsuga menziesii (PM) and Juniperus communis L. (JC). The present work has shown that aqueous extracts obtained from tested shoots are a rich source of phenols such as caffeic acid, ferulic acid, chlorogenic acid, 4-hydroxybenzoic acid and many others. Obtained extracts exhibit antioxidant and antimicrobial properties in vitro. The highest sum of the studied phenolic compounds was found in the PA sample (13,947.80 µg/g dw), while the lowest in PS (6123.57 µg/g dw). The samples were particularly rich in ferulic acid, chlorogenic acid and 4-hydroxybenzoic acid. The highest values regarding the Folin-Ciocâlteu reagent (FCR) and ferric reducing ability of plasma (FRAP) reducing ability tests, as well as the total flavonoid content assay, were obtained for the LD sample, although the LD (14.83 mg GAE/g dw) and PM (14.53 mg GAE/g dw) samples did not differ statistically in the FCR assay. With respect to free radical quenching measurements (DPPH), the PA (404.18-μM Trolox/g dw) and JC (384.30-μM Trolox/g dw) samples had the highest radical quenching ability and did not differ statistically. Generally, extracts obtained from PA and PS showed the highest antimicrobial activity against tested Gram-negative bacteria, Gram-positive bacteria and fungi.

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Plants producing pyrrolizidine alkaloids: sustainable tools for nematode management?

Nematology ◽

10.1163/138855409x12549869072248 ◽

2010 ◽

Vol 12 (1) ◽

pp. 1-24 ◽

Cited By ~ 18

Author(s):

Michael Boppré ◽

Tim Thoden

Keyword(s):

Plant Species ◽

Plant Extracts ◽

Pyrrolizidine Alkaloids ◽

Nematode Species ◽

Parasitic Nematodes ◽

Plant Metabolites ◽

Secondary Plant Metabolites ◽

Nematode Management

Abstract1,2-dehydropyrrolizidine ester alkaloids (pyrrolizidine alkaloids; PAs) are a class of secondary plant metabolites found in hundreds of plant species. In vitro, PAs are known to affect plant-parasitic nematodes. Thus, PA-producing plants might be used in nematode management. So far, however, Crotalaria is the only PA-producing plant that has been used for nematode control. Consequently, we reviewed the literature on other PA plants and their effects on nematodes. This included the analysis of in vitro experiments with PA plant extracts, host tests with PA plants, as well as experiments in which PA-producing plants were used as different types of soil amendments (mulch, in situ mulching, extracts). Our results clearly show that, in addition to Crotalaria, certain other PA-producing plant species have the potential to be used in sustainable nematode management. This is especially true for management of sedentary endoparasitic nematode species. Promising applications include the use of PA plant extracts and mulches, as well as the use of PA plants for in situ mulching.

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The Food Contaminants Pyrrolizidine Alkaloids Disturb Bile Acid Homeostasis Structure-Dependently in the Human Hepatoma Cell Line HepaRG

Foods ◽

10.3390/foods10051114 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1114

Author(s):

Josephin Glück ◽

Marcus Henricsson ◽

Albert Braeuning ◽

Stefanie Hessel-Pras

Keyword(s):

Bile Acid ◽

Cell Line ◽

Pyrrolizidine Alkaloids ◽

Hepatoma Cell ◽

Hepatoma Cell Line ◽

Human Hepatoma ◽

Plant Metabolites ◽

Human Hepatoma Cell ◽

Human Hepatoma Cell Line ◽

Expression Of Genes

Pyrrolizidine alkaloids (PAs) are a group of secondary plant metabolites being contained in various plant species. The consumption of contaminated food can lead to acute intoxications in humans and exert severe hepatotoxicity. The development of jaundice and elevated bile acid concentrations in blood have been reported in acute human PA intoxication, indicating a connection between PA exposure and the induction of cholestasis. Additionally, it is considered that differences in toxicity of individual PAs is based on their individual chemical structures. Therefore, we aimed to elucidate the structure-dependent disturbance of bile acid homeostasis by PAs in the human hepatoma cell line HepaRG. A set of 14 different PAs, including representatives of all major structural characteristics, namely, the four different necine bases retronecine, heliotridine, otonecine and platynecine and different grades of esterification, was analyzed in regard to the expression of genes involved in bile acid synthesis, metabolism and transport. Additionally, intra- and extracellular bile acid levels were analyzed after PA treatment. In summary, our data show significant structure-dependent effects of PAs on bile acid homeostasis. Especially PAs of diester type caused the strongest dysregulation of expression of genes associated with cholestasis and led to a strong decrease of intra- and extracellular bile acid concentrations.

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Spread of Jacobaea vulgaris and Occurrence of Pyrrolizidine Alkaloids in Regionally Produced Honeys from Northern Germany: Inter- and Intra-Site Variations and Risk Assessment for Special Consumer Groups

Toxins ◽

10.3390/toxins12070441 ◽

2020 ◽

Vol 12 (7) ◽

pp. 441 ◽

Cited By ~ 2

Author(s):

Christoph Gottschalk ◽

Florian Kaltner ◽

Matthias Zimmermann ◽

Rainer Korten ◽

Oliver Morris ◽

...

Keyword(s):

Risk Assessment ◽

Pyrrolizidine Alkaloids ◽

Individual Data ◽

Plant Metabolites ◽

Northern Germany ◽

Secondary Plant Metabolites ◽

Jacobaea Vulgaris ◽

Site Investigations ◽

Raw Honey ◽

Bee Colonies

Pyrrolizidine alkaloids (PA) and PA N-oxides (PANO) are secondary plant metabolites exhibiting genotoxic and carcinogenic properties. Apart from the roots and leaves, PA/PANO are particularly present in pollen and nectar. Therefore, the spread of Jacobaea vulgaris in certain regions of northern Germany has an impact on the safety of honey produced in that region. In this study, raw honey samples (n = 437) were collected from usually three individual beehives per site (n = 73) in the district of Ostholstein and analyzed for 25 PA/PANO. The results reveal mean levels of 8.4, 1.5, and 72.6 µg/kg and maximum levels of 111, 59.4, and 3313 µg/kg, depending on the season (summer 2015 and spring/summer 2016, respectively). As far as individual data are concerned, sites near areas with J. vulgaris growth did not necessarily result in high PA/PANO values. Furthermore, intra-site investigations revealed remarkable differences in PA/PANO levels of raw honey collected by different bee colonies at the same site. Consumption of these regionally produced honeys entails an increased exposure to PA/PANO, especially in children and high consumers. Margin of exposure values of <10,000 and an exceedance of the health-based guidance value highlight that regionally produced and marketed honey must be considered with care for a proper risk assessment and risk management.

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Active Transport of Hepatotoxic Pyrrolizidine Alkaloids in HepaRG Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22083821 ◽

2021 ◽

Vol 22 (8) ◽

pp. 3821

Author(s):

Anne-Margarethe Enge ◽

Florian Kaltner ◽

Christoph Gottschalk ◽

Albert Braeuning ◽

Stefanie Hessel-Pras

Keyword(s):

Pyrrolizidine Alkaloids ◽

Hepatoma Cell ◽

Metabolic Activation ◽

Hepatoma Cell Line ◽

Dependent Manner ◽

Food Contaminants ◽

Plant Metabolites ◽

Human Hepatoma Cell ◽

Secondary Plant Metabolites ◽

Heparg Cells

1,2-unsaturated pyrrolizidine alkaloids (PAs) are secondary plant metabolites occurring as food contaminants that can cause severe liver damage upon metabolic activation in hepatocytes. However, it is yet unknown how these contaminants enter the cells. The role of hepatic transporters is only at the beginning of being recognized as a key determinant of PA toxicity. Therefore, this study concentrated on assessing the general mode of action of PA transport in the human hepatoma cell line HepaRG using seven structurally different PAs. Furthermore, several hepatic uptake and efflux transporters were targeted with pharmacological inhibitors to identify their role in the uptake of the PAs retrorsine and senecionine and in the disposition of their N-oxides (PANO). For this purpose, PA and PANO content was measured in the supernatant using LC-MS/MS. Also, PA-mediated cytotoxicity was analyzed after transport inhibition. It was found that PAs are taken up into HepaRG cells in a predominantly active and structure-dependent manner. This pattern correlates with other experimental endpoints such as cytotoxicity. Pharmacological inhibition of the influx transporters Na+/taurocholate co-transporting polypeptide (SLC10A1) and organic cation transporter 1 (SLC22A1) led to a reduced uptake of retrorsine and senecionine into HepaRG cells, emphasizing the relevance of these transporters for PA toxicokinetics.

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Occurrence and Risk Assessment of Pyrrolizidine Alkaloids in Spices and Culinary Herbs from Various Geographical Origins

Toxins ◽

10.3390/toxins12030155 ◽

2020 ◽

Vol 12 (3) ◽

pp. 155 ◽

Cited By ~ 4

Author(s):

Florian Kaltner ◽

Michael Rychlik ◽

Manfred Gareis ◽

Christoph Gottschalk

Keyword(s):

Pyrrolizidine Alkaloids ◽

Botanical Origin ◽

Plant Metabolites ◽

Worst Case ◽

Potential Health ◽

Secondary Plant Metabolites ◽

High Consumption ◽

Adults And Children ◽

Culinary Herbs ◽

Existing Data

Pyrrolizidine alkaloids (PA) and their N-oxides (PANO) are a group of toxic secondary plant metabolites occurring predominantly as contaminants in (herbal) teas, honeys and food supplements, as well as in spices and culinary herbs. Depending on the botanical origin of the contaminating plant, the pattern of PA/PANO can strongly vary within a sample. The current study aimed to broaden the existing data on the occurrence of PA/PANO in spices and culinary herbs. For this, 305 authentic samples covering 15 different matrices mainly harvested in 2016 or 2017 and originating from 36 countries were investigated for the presence of 44 PA/PANO. Fifty-eight percent of the samples contained at least one PA/PANO. The average sum content over all samples was 323 µg/kg (median of 0.9 µg/kg, 95% percentile of 665 µg/kg). The highest amount of 24.6 mg/kg was detected in an oregano sample. Additionally, conspicuous analyte patterns were discovered in samples from similar cultivation regions, indicating related botanical sources of PA/PANO contaminations. Particularly, oregano and cumin from Turkey often contained high amounts of PA/PANO. The results were used to assess the acute and chronic health risks related to PA/PANO intake via spices and culinary herbs, indicating a potential health risk in particular for adults and children with high consumption or when considering worst-case contamination scenarios of a sum content of 5500 µg/kg.

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Tobacco Mosaic Virus-Infected Tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119375 ◽

1985 ◽

Vol 43 ◽

pp. 510-511

Author(s):

Egbert W. Henry

Keyword(s):

Nicotiana Tabacum ◽

Tobacco Mosaic Virus ◽

Chlorogenic Acid ◽

Mosaic Virus ◽

Host Resistance ◽

Oxidative Metabolism ◽

Leaf Tissue ◽

Vein Clearing ◽

Basal Septum ◽

Concentration Levels

Tobacco mosaic virus (TMV) infection has been studied in several investigations of Nicotiana tabacum leaf tissue. Earlier studies have suggested that TMV infection does not have precise infective selectivity vs. specific types of tissues. Also, such tissue conditions as vein banding, vein clearing, liquification and suberization may result from causes other than direct TMV infection. At the present time, it is thought that the plasmodesmata, ectodesmata and perhaps the plasmodesmata of the basal septum may represent the actual or more precise sites of TMV infection.TMV infection has been implicated in elevated levels of oxidative metabolism; also, TMV infection may have a major role in host resistance vs. concentration levels of phenolic-type enzymes. Therefore, enzymes such as polyphenol oxidase, peroxidase and phenylalamine ammonia-lyase may show an increase in activity in response to TMV infection. It has been reported that TMV infection may cause a decrease in o-dihydric phenols (chlorogenic acid) in some tissues.

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