27 results on '"Hermans, N."'
Search Results
2. Quest for New Lead Compounds Against Malaria Based on Natural Prodrugs Present in Nauclea pobeguinii and Their Metabolites
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Peeters, L, primary, Hermans, N, additional, Foubert, K, additional, and Pieters, L, additional
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- 2022
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3. Comparison of In Vitro Biotransformation of Olive Polyphenols Between Healthy Young and Elderly.
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Lauwers S, Weyns AS, Breynaert A, Van Rillaer T, Van Huynegem V, Fransen E, Bittremieux W, Lebeer S, Tuenter E, and Hermans N
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Background: Olive leaves are a rich source of polyphenols, predominantly secoiridoids, flavonoids, and simple phenols, which exhibit various biological properties. Extracts prepared from olive leaves are associated with hypoglycemic, hypotensive, diuretic, and antiseptic properties. Upon ingestion, a substantial fraction of these polyphenols reaches the colon where they undergo extensive metabolism by the gut microbiota. Host characteristics, like age, can influence the composition of the gut microbiome, potentially affecting the biotransformation of these compounds. Therefore, it can be hypothesised that differences in the gut microbiome between young and elderly individuals may impact the biotransformation rate and the type and amount of metabolites formed., Methods: An in vitro biotransformation model was used to mimic the conditions in the stomach, small intestine and colon of two age groups of healthy participants (20-30 years old, ≥65 years old), using oleuropein as a single compound and an olive leaf extract as test compounds. The bacterial composition and metabolite content were investigated., Results: The study revealed that, while the same metabolites were formed in both age groups, in the young age group, less metabolite formation was observed, likely due to a reduced viable cell count. Most biotransformation reactions took place within the first 24 h of colon incubation, and mainly, deglycosylation, hydrolysis, flavonoid ring cleavage, and demethylation reactions were observed. A bacterial composition analysis showed a steep drop in α-diversity after 24 h of colon incubation, likely due to favourable experimental conditions for certain bacterial species., Conclusions: Both age groups produced the same metabolites, suggesting that the potential for polyphenols to exert their health-promoting benefits persists in healthy older individuals.
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- 2025
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4. Towards standardization of person-reported outcomes (PROs) in pediatric diabetes research: A consensus report.
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Barnard-Kelly K, Marrero D, de Wit M, Pouwer F, Khunti K, Hermans N, Pierce JS, Laffel L, Holt RIG, Battelino T, Naranjo D, Fosbury J, Fisher L, Polonsky W, Weissberg-Benchell J, Hood KK, Schnell O, Messer LH, Danne T, Nimri R, Skovlund S, Mader JK, Sherr JL, Schatz D, O'Neill S, Doble E, Town M, Lange K, de Beaufort C, Gonder-Frederick L, Jaser SS, Liberman A, Klonoff D, Elsayed NA, Bannuru RR, Ajjan R, Parkin C, and Snoek FJ
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Background: Diabetes ranks among the most common chronic conditions in childhood and adolescence. It is unique among chronic conditions, in that clinical outcomes are intimately tied to how the child or adolescent living with diabetes and their parents or carers react to and implement good clinical practice guidance. It is widely recognized that the individual's perspective about the impact of trying to manage the disease together with the burden of self-management should be addressed to achieve optimal health outcomes. Standardized, rigorous assessment of behavioural and mental health outcomes is crucial to aid understanding of person-reported outcomes alongside, and in interaction with, physical health outcomes. Whilst tempting to conceptualize person-reported outcomes as a focus on perceived quality of life, the reality is that health-related quality of life is multi-dimensional and covers indicators of physical or functional health status, psychological well-being and social well- being., Methods: In this context, this Consensus Statement has been developed by a collection of experts in diabetes to summarize the central themes and lessons derived in the assessment and use of person-reported outcome measures in relation to children and adolescents and their parents/carers, helping to provide a platform for future standardization of these measures for research studies and routine clinical use., Results: This consensus statement provides an exploration of person-reported outcomes and how to routinely assess and incorporate into clincial research., (© 2024 Diabetes UK.)
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- 2024
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5. Validation and optimisation of reduced glutathione quantification in erythrocytes by means of a coulometric high-performance liquid chromatography analytical method.
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Lauwers S, Van Herreweghe M, Foubert K, Theunis M, Breynaert A, Tuenter E, and Hermans N
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- Chromatography, High Pressure Liquid methods, Reproducibility of Results, Humans, Linear Models, Oxidative Stress, Erythrocytes chemistry, Erythrocytes metabolism, Glutathione analysis, Glutathione blood, Limit of Detection
- Abstract
Glutathione (GSH), a tripeptide that consists of cysteine, glutamate and glycine, is present in all mammalian tissues in the millimolar range. Besides having numerous cellular functions, GSH is an important antioxidant and is considered a valuable biomarker in evaluating oxidative stress. This paper provides a sensitive analytical method using HPLC-ECD to quantify GSH in erythrocytes, validated using the ICH guidelines for Bioanalytical Method Validation. The sample preparation was optimised using centrifugal filtration and a hypotonic phosphate buffer for extracting GSH from erythrocytes. HPLC-ECD parameters were adjusted to allow a fast, reversed phase, isocratic separation in 10 min. The detector response was linear between 0.3 and 9.5 μg/mL with a satisfactory regression coefficient and a LOQ of 0.11 μg/mL. Intra- and inter-day repeatability ranged between 1.10% and 8.57% with recoveries ranging from 94.3% to 106.0%. Dilution integrity, benchtop, freeze-thaw and long-term stability were investigated. Samples were stable for up to 6 months at -80°C. This method has a good linear response and is repeatable, precise and accurate. It minimises GSH auto-oxidation using a centrifugal filter during sample preparation, instead of acidification. Therefore, this analytical method is suitable for quantifying GSH in erythrocytes as a marker of oxidative stress., (© 2024 The Author(s). Biomedical Chromatography published by John Wiley & Sons Ltd.)
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- 2024
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6. Mycobacterium tuberculosis complex sample processing by mechanical lysis, an essential step for reliable whole genome sequencing.
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Hermans N, de Zwaan R, Mulder A, van den Dool J, van Soolingen D, Kremer K, and Anthony R
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- Humans, Specimen Handling methods, Tuberculosis microbiology, Mycobacterium tuberculosis genetics, Mycobacterium tuberculosis isolation & purification, Whole Genome Sequencing methods, DNA, Bacterial genetics, DNA, Bacterial isolation & purification, Genome, Bacterial
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Mycobacterium tuberculosis complex (MTBC) whole genome sequencing (WGS) turnaround time and WGS success rates are highly influenced by DNA extraction protocols even from cultures. Efficient mycobacterial lysis is crucial for obtaining sufficient DNA from cultures to facilitate reliable genomic drug susceptibility prediction and accurate genotyping with WGS. We compared four DNA extraction protocols from BD BACTEC™ Mycobacterial Growth Indicator Tubes (MGIT) for WGS with a focus on the lysis step: protocol A) column-based protocol without mechanical lysis; protocol B) an adapted protocol including a bead beating step; protocol C) DNA extraction from primary received cultures using bead beating: and protocol D) DNA extraction from pre MGIT-positive (enriched) cultures. Protocol B increased DNA yield approximately 60-fold, and significantly improved the sequencing success rate. The increased yield also allowed DNA extraction from primary cultures with high success rates (protocol C). Additionally, by using pre-positive enriched MGIT cultures, we demonstrated that bead beating opens the possibility of reliable WGS up to five days before a MGIT tube would be flagged positive (protocol D). The most optimal bead beating-based DNA extraction was also evaluated for Nanopore sequencing. Shortening bead beating duration to 15 s resulted in longer read lengths (N50 from 1.4 kb to 2.6 kb) while still providing efficient lysis. Furthermore, AmpureXP bead beating-based DNA capture / purification proved to be as efficient as Qiagen column-based DNA extraction, further simplifying and shortening the DNA extraction protocol. Adding a mechanical lysis step to our routine MTBC DNA extraction protocol has allowed us to reduce the turnaround time while maintaining DNA quality sequencing success rates., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kristin Kremer, Noud Hermans, Richard Anthony reports financial support was provided by Netherlands National Postcode Lottery. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2024
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7. Tert-butylhydroquinone and tert-butylcatechol positivity as warning lights of skin sensitization to tert-butylphenol derivatives in adhesives and diabetes devices.
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Dendooven E, Naessens T, Foubert K, Hermans N, and Aerts O
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- Humans, Female, Male, Middle Aged, Adult, Aged, Antioxidants adverse effects, Phenols adverse effects, Gas Chromatography-Mass Spectrometry, Dermatitis, Allergic Contact etiology, Dermatitis, Allergic Contact diagnosis, Hydroquinones adverse effects, Catechols adverse effects, Adhesives adverse effects, Patch Tests
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Introduction: Tert-butylphenol (TBP) derivatives, antioxidants in adhesives and diabetes devices, may provoke allergic contact dermatitis (ACD)., Objectives: The objective of this study is to report sensitization to TBP derivatives in medical devices and to highlight that tert-butylhydroquinone (BHQ) and tert-butylcatechol (TBC) are potential screeners in this regard., Methods: Fifteen patients with ACD from adhesives and diabetes devices were patch tested to different TBPs: BHQ 1% pet., TBC 0.25% pet., BHA 2% pet., BHT 2% pet., 4-tert-butylphenol (TBP) 1% pet. and 2,4-di-tert-butylphenol (di TBP) 1% pet. The culprit devices (medical adhesives, sanitary pads, diabetes devices) and TBP patch preparations were analysed using gas chromatography-mass spectrometry (GC-MS)., Results: BHQ (9/13), TBC (7/13), and to a lesser extent BHT (3/15), BHA (2/15) and TBP (2/13) gave positive reactions. Seven patients had developed ACD from adhesives and diabetes devices, respectively, and one patient from sanitary pads. GC-MS analyses of the medical devices and patch test materials confirmed the presence of the patch-test positive TBPs, or chemically related derivatives, or, interestingly, tert-butylbenzoquinones (BBQ) were found, that is, spontaneously formed, highly reactive TBP metabolites, likely (pseudo-) cross reacting with the patch tested TBPs., Conclusion: TBPs might be overlooked sensitizers in medical devices, and BHQ and TBC are potential screeners in this regard., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
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- 2024
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8. Clinical Relevance of Oxidative Stress Biomarkers in Human Flavivirus Infections as Predictors of Disease Progression and Severity.
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Van Herreweghe M, De Bruyne T, Hermans N, and Huits R
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- Humans, Severity of Illness Index, Flavivirus physiology, Animals, Prognosis, Clinical Relevance, Biomarkers, Oxidative Stress, Disease Progression, Flavivirus Infections diagnosis, Flavivirus Infections virology
- Abstract
Several Flaviviridae constitute an emerging threat to global health because of their continuing spread and the expansion of vector habitats, largely driven by climate change and intensified global travel. Infections can result in severe neurological or visceral pathologies. The relationship between oxidative stress (OS), an imbalance between generated reactive oxygen species and the antioxidant defences of the host, and flavivirus infection has been repeatedly demonstrated in in vitro and animal studies, but measuring biomarkers of oxidative stress in vivo could prove useful in clinical patient management. We summarise the knowledge and prospects of measuring peripheral OS biomarker levels for clinical case management and correlation with disease severity in six important human flavivirus infections (dengue virus (DENV), Japanese encephalitis virus, West Nile virus (WNV), tick-borne encephalitis virus (TBEV), yellow fever virus and zika virus). We searched the Medline and Web of Science databases for 'Oxidative Stress' AND 'Biomarkers' AND 'Flavivirus', combined with 'clinical', 'in vivo/in vivo', 'patient' and/or 'disease' and included 43 peer-reviewed publications. Correlation between OS and infection has been studied in all six Flaviviridae, but most clinically relevant data are available for DENV, TBEV and WNV. Plasma protein carbonyls, glutathione peroxidase activity and nitrogen monoxide are promising prognostic markers, but their measurement would benefit from methodological harmonisation. Future studies should investigate a broad range of OS biomarkers as predictors of clinically relevant outcomes. We advocate the validation and use of universal or disease-specific oxidative stress indexes that incorporate the most significant outcomes into one, easy-to-use clinical determinant., (© 2024 The Author(s). Reviews in Medical Virology published by John Wiley & Sons Ltd.)
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- 2024
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9. Enhancing pediatric attention-deficit hyperactivity disorder treatment: exploring the gut microbiota effects of French maritime pine bark extract and methylphenidate intervention.
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Weyns AS, Ahannach S, Van Rillaer T, De Bruyne T, Lebeer S, and Hermans N
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Introduction: The pathogenesis of Attention-Deficit Hyperactivity Disorder (ADHD) is thought to be multifactorial, with a potential role for the bidirectional communication between the gut microbiome and brain development and function. Since the "golden-standard" medication therapy with methylphenidate (MPH) is linked to multiple adverse effects, there is a need for alternative treatment options such as dietary polyphenols. These secondary plant metabolites exert antioxidant and anti-inflammatory effects, but much less is known about their impact on the gut microbiota. Since polyphenols are believed to modulate gut microbial composition, interventions might be advantageous in ADHD therapy. Therefore, intervention studies with polyphenols in ADHD therapy investigating the gut microbial composition are highly relevant., Methods: Besides the primary research questions addressed previously, this study explored a potential prebiotic effect of the polyphenol-rich French Maritime Pine Bark Extract (PBE) compared to MPH and a placebo in pediatric ADHD patients by studying their impact on the gut microbiota via amplicon sequencing of the full length 16S rRNA gene ribosomal subunit (V1-V9)., Results: One interesting finding was the high relative abundance of Bifidobacteria among all patients in our study cohort. Moreover, our study has identified that treatment (placebo, MPH and PBE) explains 3.94% of the variation in distribution of microbial taxa (adjusted p -value of 0.011)., Discussion: Our small sample size (placebo: n = 10; PBE: n = 13 and MPH: n = 14) did not allow to observe clear prebiotic effects in the patients treated with PBE. Notwithstanding this limitation, subtle changes were noticeable and some limited compositional changes could be observed., Clinical Trial Registration: doi: 10.1186/S13063-017-1879-6., Competing Interests: SL is an academic board member of the International Scientific Association on Probiotics and Prebiotics ISAPP (www.isappscience.org) she is a co-founder of YUN and has received industrial research funding from DSM, Lesaffre, YUN, Puratos, Pathosense and BioOrg/Metatecta. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Weyns, Ahannach, Van Rillaer, De Bruyne, Lebeer and Hermans.)
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- 2024
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10. Towards the standardisation of adult person-reported outcome domains in diabetes research: A Consensus Statement development panel.
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Barnard-Kelly K, Marrero D, de Wit M, Pouwer F, Khunti K, Hermans N, Pierce JS, Laffel L, Holt RIG, Battelino T, Naranjo D, Fosbury J, Fisher L, Polonsky W, Weissberg-Benchell J, Hood KK, Schnell O, Messer LH, Danne T, Nimri R, Skovlund SE, Mader JK, Sherr JL, Schatz D, O'Neill S, Doble E, Town M, Lange K, de Beaufort C, Gonder-Frederick L, Jaser SS, Liberman A, Klonoff D, ElSayed NA, Bannuru RR, Parkin CG, and Snoek F
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- Humans, Adult, Consensus, Health Status, Patient Reported Outcome Measures, Quality of Life, Diabetes Mellitus therapy, Diabetes Mellitus psychology
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Diabetes is unique among chronic diseases because clinical outcomes are intimately tied to how the person living with diabetes reacts to and implements treatment recommendations. It is further characterised by widespread social stigma, judgement and paternalism. This physical, social and psychological burden collectively influences self-management behaviours. It is widely recognised that the individual's perspective about the impact of trying to manage the disease and the burden that self-management confers must be addressed to achieve optimal health outcomes. Standardised, rigorous assessment of mental and behavioural health status, in interaction with physical health outcomes is crucial to aid understanding of person-reported outcomes (PROs). Whilst tempting to conceptualise PROs as an issue of perceived quality of life (QoL), in fact health-related QoL is multi-dimensional and covers indicators of physical or functional health status, psychological and social well-being. This complexity is illuminated by the large number of person reported outcome measures (PROMs) that have been developed across multiple psychosocial domains. Often measures are used inappropriately or because they have been used in the scientific literature rather than based on methodological or outcome assessment rigour. Given the broad nature of psychosocial functioning/mental health, it is important to broadly define PROs that are evaluated in the context of therapeutic interventions, real-life and observational studies. This report summarises the central themes and lessons derived in the assessment and use of PROMs amongst adults with diabetes. Effective assessment of PROMs routinely in clinical research is crucial to understanding the true impact of any intervention. Selecting appropriate measures, relevant to the specific factors of PROs important in the research study will provide valuable data alongside physical health data., (© 2024 Diabetes UK.)
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- 2024
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11. GPX4 overexpression does not alter atherosclerotic plaque development in ApoE knock-out mice.
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Coornaert I, Breynaert A, Hermans N, De Meyer GRY, and Martinet W
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Ferroptosis is a type of regulated necrosis that is associated with iron-dependent accumulation of lipid hydroperoxides. Given that iron deposition and lipid peroxidation initiate ferroptosis in atherosclerosis and contribute to further plaque development, we hypothesized that inhibition of ferroptosis could be of value in the treatment of atherosclerosis. Glutathione peroxidase 4 (GPX4) is the only enzyme known capable of reducing lipid hydroperoxides. Previous studies have demonstrated that inactivation of GPX4 results in ferroptosis, while overexpression of GPX4 confers resistance to ferroptosis. In the present study, we examined the impact of GPX4 overexpression on the development of atherosclerotic plaques. GPX4-overexpressing mice (GPX4Tg/+) were crossbred with ApoE-/- mice and fed a western-type diet for 16 weeks. Atherosclerotic plaques of GPX4Tg/+ ApoE-/- mice showed increased GPX4 expression and a reduced amount of lipid hydroperoxides. However, plaque size and composition were not different as compared to control animals. Similarly, GPX4-overexpressing vascular smooth muscle cells and bone marrow-derived macrophages were not protected against lipid peroxidation and cell death triggered by the ferroptosis inducers erastin and 1S,3R-RSL3. We concluded that GPX4 overexpression reduces lipid peroxidation in plaques of ApoE-/- mice, yet GPX4 overexpression is not sufficiently powerful to change plaque size or composition.
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- 2024
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12. α-Tocopherol inhibits atherogenesis and improves cardiac function in mice independently of its antioxidant properties.
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Coornaert I, Breynaert A, Hermans N, De Meyer GRY, and Martinet W
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The impact of α-tocopherol on atherosclerosis is unclear and controversial. While some studies suggest potential benefits, such as antioxidant properties that may reduce oxidative stress, other studies indicate no significant preventive effects. The intricate interplay of various factors, including dosage, individual differences, and study methodologies, contributes to the ongoing uncertainty surrounding α-tocopherol's role in atherosclerosis. Further research is needed to clarify its impact and establish clearer guidelines. Therefore, we aimed to evaluate the impact of α-tocopherol on atherogenesis in ApoE-/- fibrillin (Fbn)1C1039G/+ mice, which is a unique mouse model of advanced atherosclerosis with typical features, such as large necrotic cores, high levels of inflammation, and intraplaque neovascularization, that resemble the unstable phenotype of human plaques. ApoE-/- Fbn1C1039G+/- mice were fed a western-type diet (WD) supplemented with a high dose of α-tocopherol (500 mg/kg diet), while control mice were fed a WD containing a low dose of α-tocopherol (50 mg/kg diet). The high dose of α-tocopherol reduced plaque thickness and necrotic core area in the right common carotid artery (RCCA) after 24 weeks WD. Moreover, α-tocopherol decreased plaque formation and intraplaque neovascularization in the RCCA. In addition to its antiatherogenic effect, chronic supplementation of α-tocopherol improved cardiac function in ApoE-/- Fbn1C1039G/+ mice. However, chronic supplementation of α-tocopherol did not decrease lipid peroxidation. On the contrary, α-tocopherol acted as a prooxidant by increasing plasma levels of oxidized LDL and plaque malondialdehyde, an end product of lipid peroxidation. Our data indicate that α-tocopherol inhibits atherogenesis and improves cardiac function independent of its antioxidant properties.
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- 2024
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13. Design and Synthesis of 1,3-Diarylpyrazoles and Investigation of Their Cytotoxicity and Antiparasitic Profile.
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Bozdag M, Mertens F, Matheeussen A, Van Pelt N, Foubert K, Hermans N, De Meyer GRY, Augustyns K, Martinet W, Caljon G, and Van der Veken P
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- Humans, Antiparasitic Agents pharmacology, Antiparasitic Agents chemical synthesis, Antiparasitic Agents chemistry, Drug Design, Leishmania infantum drug effects, Structure-Activity Relationship, Trypanosoma brucei rhodesiense drug effects, Antiprotozoal Agents pharmacology, Antiprotozoal Agents chemical synthesis, Antiprotozoal Agents chemistry, Pyrazoles pharmacology, Pyrazoles chemistry, Pyrazoles chemical synthesis, Trypanosoma cruzi drug effects
- Abstract
Herein, we report a series of 1,3-diarylpyrazoles that are analogues of compound 26 /HIT 8. We previously identified this molecule as a 'hit' during a high-throughput screening campaign for autophagy inducers. A variety of synthetic strategies were utilized to modify the 1,3-diarylpyrazole core at its 1-, 3-, and 4-position. Compounds were assessed in vitro to identify their cytotoxicity properties. Of note, several compounds in the series displayed relevant cytotoxicity, which warrants scrutiny while interpreting biological activities that have been reported for structurally related molecules. In addition, antiparasitic activities were recorded against a range of human-infective protozoa, including Trypanosoma cruzi , T. brucei rhodesiense , and Leishmania infantum . The most interesting compounds displayed low micromolar whole-cell potencies against individual or several parasitic species, while lacking cytotoxicity against human cells.
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- 2024
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14. Hepatoprotective effects of leaf extract of Annona senegalensis against aflatoxin B1 toxicity in rats.
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Makhuvele R, Foubert K, Hermans N, Pieters L, Verschaeve L, and Elgorashi E
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- Rats, Animals, Aflatoxin B1 toxicity, Alanine Transaminase pharmacology, Alkaline Phosphatase pharmacology, Creatinine pharmacology, Liver, Plant Extracts pharmacology, Plant Extracts therapeutic use, Aspartate Aminotransferases pharmacology, Lactate Dehydrogenases, Annona, Curcumin pharmacology
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Global aflatoxin contamination of agricultural commodities is of the most concern in food safety and quality. This study investigated the hepatoprotective effect of 80% methanolic leaf extract of Annona senegalensis against aflatoxin B1 (AFB1)-induced toxicity in rats. A. senegalensis has shown to inhibit genotoxicity of aflatoxin B1 in vitro. The rats were divided into six groups including untreated control, aflatoxin B1 only (negative control); curcumin (positive control; 10 mg/kg); and three groups receiving different doses (100 mg/kg, 200 mg/kg, and 300 mg/kg) of A. senegalensis extract. The rats received treatment (with the exception of untreated group) for 7 days prior to intoxication with aflatoxin B1. Serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, and creatinine were measured. Hepatic tissues were analysed for histological alterations. Administration of A. senegalensis extract demonstrated hepatoprotective effects against aflatoxin B1-induced toxicity in vivo by significantly reducing the level of serum aspartate aminotransferase and alanine aminotransferase and regenerating the hepatocytes. No significant changes were observed in the levels of alkaline phosphatase, lactate dehydrogenase, and creatinine for the AFB1 intoxicated group, curcumin+AFB1 and Annona senegalensis leaf extract (ASLE)+AFB1 (100 mg/kg, 200 mg/kg, and 300 mg/kg body weight [b.w.]) treated groups. Annona senegalensis is a good candidate for hepatoprotective agents and thus its use in traditional medicine may at least in part be justified.Contribution: The plant extract investigated in this study can be used in animal health to protect the organism from toxicity caused by mycotoxins.
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- 2024
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15. Human gut microbiota stratified by (+)-catechin metabolism dynamics reveals colon region-dependent metabolic profile.
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Li Q, Stautemas J, Omondi Onyango S, De Mey M, Duchi D, Tuenter E, Hermans N, Calders P, and Van de Wiele T
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- Humans, Colon microbiology, Bacteria genetics, Bacteria metabolism, Metabolome, Gastrointestinal Microbiome, Catechin metabolism, Microbiota
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Catechins have proven to have several health benefits, yet a huge interindividual variability occurs. The metabolic potency of the colonic microbiota towards catechin is a key determinant of this variability. Microbiota from two donors - previously characterized as a fast and a slow converter- were incubated with (+)-catechin in vitro. The robustness of in vitro metabolic profiles was verified by well-fitted human trials. The colon region-dependent and donor-dependent patterns were reflected in both metabolic features and colonic microbiota composition. Upstream and downstream metabolites were mainly detected in the proximal and distal colons, respectively, and were considered important explanatory variables for microbiota clustering in the corresponding colon regions. Higher abundances of two catechin-metabolizing bacteria, Eggerthella and Flavonifractor were found in the distal colon compared to the proximal colon and in slow converter than fast converter. Additionally, these two bacteria were enriched in treatment samples compared to sham treatment samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2023
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16. In Vitro Biotransformation and Anti-Inflammatory Activity of Constituents and Metabolites of Filipendula ulmaria .
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Van der Auwera A, Peeters L, Foubert K, Piazza S, Vanden Berghe W, Hermans N, and Pieters L
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(1) Background: Filipendula ulmaria (L.) Maxim. (Rosaceae) (meadowsweet) is widely used in phytotherapy against inflammatory diseases. However, its active constituents are not exactly known. Moreover, it contains many constituents, such as flavonoid glycosides, which are not absorbed, but metabolized in the colon by gut microbiota, producing potentially active metabolites that can be absorbed. The aim of this study was to characterize the active constituents or metabolites. (2) Methods: A F. ulmaria extract was processed in an in vitro gastrointestinal biotransformation model, and the metabolites were characterized using UHPLC-ESI-QTOF-MS analysis. In vitro anti-inflammatory activity was evaluated by testing the inhibition of NF-κB activation, COX-1 and COX-2 enzyme inhibition. (3) Results: The simulation of gastrointestinal biotransformation showed a decrease in the relative abundance of glycosylated flavonoids such as rutin, spiraeoside and isoquercitrin in the colon compartment, and an increase in aglycons such as quercetin, apigenin, naringenin and kaempferol. The genuine as well as the metabolized extract showed a better inhibition of the COX-1 enzyme as compared to COX-2. A mix of aglycons present after biotransformation showed a significant inhibition of COX-1. (4) Conclusions: The anti-inflammatory activity of F. ulmaria may be explained by an additive or synergistic effect of genuine constituents and metabolites.
- Published
- 2023
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17. Saponin and Fatty Acid Profiling of the Sea Cucumber Holothuria atra , α-Glucosidase Inhibitory Activity and the Identification of a Novel Triterpene Glycoside.
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Puspitasari YE, Tuenter E, Foubert K, Herawati H, Hariati AM, Aulanni'am A, Pieters L, De Bruyne T, and Hermans N
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- Animals, Glycosides pharmacology, alpha-Glucosidases, Sea Cucumbers chemistry, Holothuria chemistry, Saponins, Triterpenes pharmacology, Cardiac Glycosides
- Abstract
Saponin-rich sea cucumber extracts have shown antidiabetic effects in a few reports. Although the triterpene glycosides of sea cucumbers are commonly isolated from their Cuvierian tubules, these are absent in Holothuria atra Jaeger. Therefore, this study intended to investigate the saponin profile in the body wall of H. atra , as well as to assess the α-glucosidase inhibitory activity of the H. atra extracts. The chemical profiling of sea cucumber extracts was conducted by UPLC-HRMS analysis. This resulted in the tentative identification of 11 compounds, 7 of which have not been reported in the H. Atra body wall before. Additionally, two triterpene glycosides were purified and their structures were elucidated based on HRMS and NMR data: desholothurin B (1), and a novel epimer, 12-epi-desholothurin B (2). Moreover, the fatty acid profile of the H. atra body wall was investigated by GC-MS. It was found that the Me90 fraction of the H. atra body wall showed the strongest α-glucosidase inhibitory activity (IC
50 value 0.158 ± 0.002 mg/mL), thus making it more potent than acarbose (IC50 value 2.340 ± 0.044 mg/mL).- Published
- 2023
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18. Can Biomarkers of Oxidative Stress in Serum Predict Disease Severity in West Nile Virus Infection? A Pilot Study.
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Van Herreweghe M, Breynaert A, De Bruyne T, Popescu CP, Florescu SA, Lustig Y, Schwartz E, Gobbi FG, Hermans N, and Huits R
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West Nile virus (WNV) can cause asymptomatic infection in humans, result in self-limiting febrile illness, or lead to severe West Nile Neuroinvasive disease (WNND). We conducted a pilot study to compare selected biomarkers of oxidative stress in sera of viremic West Nile virus patients and asymptomatic infected blood donors to investigate their potential as predictors of disease severity. We found that total oxidant status was elevated in WNND and in uncomplicated WNV infections (median 9.05 (IQR 8.37 to 9.74) and 7.14 (7.03 to 7.25) µmol H
2 O2 equiv./L, respectively) compared to asymptomatic infections (0.11 (0.07 to 0.19) µmol H2 O2 equiv./L) ( p = 0.048). MDA levels showed a similar trend to TOS, but differences were not significant at α = 0.05. Total antioxidant status did not differ significantly between different disease severity groups. Oxidative stress appears to be associated with more severe disease in WNV-infected patients. Our preliminary findings warrant prospective studies to investigate the correlation of oxidative stress with clinical outcomes and severity of WNV infection.- Published
- 2022
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19. The "Dutch Reading Test for Adults" has Been Used for 29 Years to Estimate the Premorbid Performance Level, does it Still Meet the Expectations?
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Hermans N and van Dijck JP
- Abstract
To detect cognitive change after brain damage, it is important to know the level of premorbid intellectual functioning. A popular instrument in this context is the "Nederlandse Leestest voor Volwassenen" (NLV; Schmand et al., 1992). In this test, 50 words with irregular pronunciation must be read out loud. The score on this test used to be considered as a good estimate of someone's premorbid IQ, due to high correlations with the Verbal and Full-Scale IQ estimates of the WAIS (Verbal IQ: r = .85, Full Scale IQ: r = .74; Schmand et al., 1992). Despite some updates of the normative data (e.g., Bouma et al., 2012), the validity of the test has not been re-evaluated since. The aim of the current study was to evaluate whether the NLV still correlates sufficiently with the WAIS-IV to warrant its proper use as a psychodiagnostic tool. In Study 1, 30 participants (age range: 20-29 year) were tested, and in Study 2, 51 participants (age range: 45-65 year). We checked whether the NLV-generated IQ-score estimates correlated with the different IQ indices of the WAIS-IV. In the younger group, no correlations were found between the NLV-generated IQ-score estimate and any of the WAIS-IV indices nor the Full-Scale IQ. In the older group, the NLV-generated IQ-score estimate correlated with Full scale IQ and the indices of Verbal Comprehension, Working Memory and Processing Speed. These correlations were all <.46 which is far below the typically hold standard in test development of >.70. Based on these findings we conclude the NLV in its current form is not appropriate anymore to estimate premorbid IQ in both young and older adults., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2022 The Author(s).)
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- 2022
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20. Acute Effects of Cocoa Flavanols on Blood Pressure and Peripheral Vascular Reactivity in Type 2 Diabetes Mellitus and Essential Hypertension.
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Tanghe A, Heyman E, Lespagnol E, Stautemas J, Celie B, Op 't Roodt J, Rietzschel E, Dias Soares D, Hermans N, Tuenter E, Shadid S, and Calders P
- Subjects
- Antihypertensive Agents pharmacology, Antihypertensive Agents therapeutic use, Blood Pressure, Cross-Over Studies, Double-Blind Method, Essential Hypertension, Humans, Polyphenols pharmacology, Cacao, Diabetes Mellitus, Type 2, Hypertension
- Abstract
Background: Type 2 diabetes mellitus (T2DM) is associated with a high risk of vascular complications. Interestingly, cocoa flavanols (CF) can exert beneficial vascular effects in non-diabetic subjects. However, these effects have only been scarcely studied in T2DM. Therefore, we performed a study to assess the effects on vascular reactivity of a single dose of CF (790 mg) in T2DM and whether certain antihypertensive drugs may modulate these effects., Methods: 24 non-diabetic and 11 T2DM subjects were studied in a cross-over design. Fasting blood samples, blood pressure (BP), and arterial vasoreactivity (flow-mediated dilation) were assessed before and 70 min after capsule ingestion. Muscle microvascular reactivity was only assessed after capsule ingestion. Age, waist-to-hip ratio, BP at baseline, and the use of antihypertensive drugs were regarded as covariates in a mixed models analysis., Results: CF ingestion did not affect any parameter. However, independent of the type of capsules ingested, a decrease in diastolic BP by 3 mmHg (95% CI: -4.0; -2.0) and an increase in the change in brachial artery diameter (pre vs. post occlusion) by 0.06 mm (95% CI: 0.01; 0.12) were detected in the non-diabetic group, while they remained unchanged in the T2DM group., Conclusion: No beneficial effects of CF were detected on vascular reactivity parameters in T2DM and non-diabetic participants.
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- 2022
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21. Spontaneous Riboflavin-Overproducing Limosilactobacillus reuteri for Biofortification of Fermented Foods.
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Spacova I, Ahannach S, Breynaert A, Erreygers I, Wittouck S, Bron PA, Van Beeck W, Eilers T, Alloul A, Blansaer N, Vlaeminck SE, Hermans N, and Lebeer S
- Abstract
Riboflavin-producing lactic acid bacteria represent a promising and cost-effective strategy for food biofortification, but production levels are typically insufficient to support daily human requirements. In this study, we describe the novel human isolate Limosilactobacillus reuteri AMBV339 as a strong food biofortification candidate. This strain shows a high natural riboflavin (vitamin B2) overproduction of 18.36 μg/ml, biomass production up to 6 × 10
10 colony-forming units/ml (in the typical range of model lactobacilli), and pH-lowering capacities to a pH as low as 4.03 in common plant-based (coconut, soy, and oat) and cow milk beverages when cultured up to 72 h at 37°C. These properties were especially pronounced in coconut beverage and butter milk fermentations, and were sustained in co-culture with the model starter Streptococcus thermophilus . Furthermore, L. reuteri AMBV339 grown in laboratory media or in a coconut beverage survived in gastric juice and in a simulated gastrointestinal dialysis model with colon phase (GIDM-colon system) inoculated with fecal material from a healthy volunteer. Passive transport of L. reuteri AMBV339-produced riboflavin occurred in the small intestinal and colon stage of the GIDM system, and active transport via intestinal epithelial Caco-2 monolayers was also demonstrated. L. reuteri AMBV339 did not cause fecal microbiome perturbations in the GIDM-colon system and inhibited enteric bacterial pathogens in vitro . Taken together, our data suggests that L. reuteri AMBV339 represents a promising candidate to provide riboflavin fortification of plant-based and dairy foods, and has a high application potential in the human gastrointestinal tract., Competing Interests: A patent application EP20210606.8 (owned by the University of Antwerp and with SA, IS, SW, and SL as inventors) has been submitted based on the results described in this manuscript. SL has received (research) funding from several companies, but they were not involved in this study. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Spacova, Ahannach, Breynaert, Erreygers, Wittouck, Bron, Van Beeck, Eilers, Alloul, Blansaer, Vlaeminck, Hermans and Lebeer.)- Published
- 2022
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22. Mitigation of benznidazole toxicity and oxidative stress following ascorbic acid supplementation in an adult traveller with chronic indeterminate Chagas' disease.
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Van Den Broucke S, Van Herreweghe M, Breynaert A, Van Esbroeck M, Truyens C, De Bruyne T, Hermans N, and Huits R
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- Adult, Antioxidants therapeutic use, Ascorbic Acid pharmacology, Ascorbic Acid therapeutic use, Biomarkers, Dietary Supplements, Humans, Oxidative Stress, Chagas Disease drug therapy, Drug-Related Side Effects and Adverse Reactions, Nitroimidazoles adverse effects
- Abstract
Background: Benznidazole is an effective drug in the trypanocidal treatment of acute and chronic indeterminate Chagas' disease (CD). However, adverse drug reactions (ADR) are common and frequently cause patients to discontinue treatment., Objectives: We hypothesized that antioxidant supplementation could mitigate benznidazole-induced toxicity., Methods: We co-supplemented an adult traveller with chronic indeterminate CD who experienced benznidazole ADR with ascorbic acid (AA), 1000 mg/day. We measured selected serum biomarkers of oxidative stress [total antioxidant status (TAS), total oxidative status (TOS), nuclear factor erythroid 2-related factor 2 (Nrf2), malondialdehyde (MDA), extracellular glutathione peroxidase (GPX3), catalase (CAT) and total superoxide dismutase (T-SOD)] at timepoints before and throughout benznidazole treatment and after AA co-supplementation., Results: AA co-supplementation effectively mitigated benznidazole-induced ADR during the aetiological treatment of chronic indeterminate CD. The kinetics of serum biomarkers of oxidative stress suggested significantly decreased oxidative insult in our patient., Conclusions: We hypothesize that the key pathophysiological mechanism of benznidazole-associated toxicity is oxidative stress, rather than hypersensitivity. AA co-supplementation may improve adherence to benznidazole treatment of chronic indeterminate (or acute) CD. Oxidative stress biomarkers have the potential to guide the clinical management of CD. Prospective studies are needed to establish the benefit of antioxidant co-supplementation to benznidazole treatment of CD in reducing benznidazole toxicity, parasite clearance and the prevention of end-organ damage., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2022
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23. Availability and Metabolic Fate of Olive Phenolic Alcohols Hydroxytyrosol and Tyrosol in the Human GI Tract Simulated by the In Vitro GIDM-Colon Model.
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Sakavitsi ME, Breynaert A, Nikou T, Lauwers S, Pieters L, Hermans N, and Halabalaki M
- Abstract
Hydroxytyrosol (HTyr) and tyrosol (Tyr) are the most well studied phenolic alcohols of olive oil and olive products demonstrating numerous and significant beneficial health effects. However, their activity in the human organism as food bioactives is strongly associated with their bioavailability and metabolism, while manifested through their metabolites. Nevertheless, there are limited studies investigating their biotransformation and mainly catabolism by gut microflora under a holistic interpretation close to the human organism. Thus, in the present study, the GastroIntestinal Dialysis (GIDM)-colon model, a continuous flow in vitro dialysis system mimicking physiological conditions during human gastrointestinal digestion, was used to explore the metabolism of HTyr and Tyr as pure compounds. The GIDM-colon model simulates absorption from the lumen to the mucosa, followed by the colon phase using pooled human fecal suspensions. Samples were collected at different time points and analyzed via LC-Orbitrap MS. An integrated approach combining Multivariate Data Analysis (MVA) and thorough dereplication procedures led to the identification of HTyr and Tyr metabolites in different phases (gastric, small intestine, and colon), yielding also valuable information about metabolites kinetics. To our knowledge, this is the first study reporting full spectrometric data of HTyr and Tyr metabolites along with possible transformation mechanisms in the GI tract.
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- 2022
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24. Protective effects of methanolic leaf extracts of Monanthotaxis caffra against aflatoxin B1-induced hepatotoxicity in rats.
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Makhuvele R, Foubert K, Hermans N, Pieters L, Verschaeve L, and Elgorashi E
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- Aflatoxin B1 metabolism, Aflatoxin B1 toxicity, Alanine Transaminase metabolism, Alanine Transaminase pharmacology, Animals, Aspartate Aminotransferases metabolism, Aspartate Aminotransferases pharmacology, Creatinine metabolism, Creatinine pharmacology, Lactate Dehydrogenases metabolism, Liver, Male, Methanol metabolism, Methanol pharmacology, Plant Extracts pharmacology, Rats, Rats, Sprague-Dawley, Chemical and Drug Induced Liver Injury metabolism, Chemical and Drug Induced Liver Injury pathology, Chemical and Drug Induced Liver Injury prevention & control, Chemical and Drug Induced Liver Injury veterinary
- Abstract
Aflatoxins are potent hepatotoxic and carcinogenic secondary metabolites produced by toxigenic fungi. The present study investigated the protective effect of methanolic leaf extracts of Monanthotaxis caffra (MLEMC) against aflatoxin B1-induced toxicity in male Sprague-Dawley rats. The rats were randomly divided into 6 groups of 8 animals each. Five groups were administered orally for seven days with three different concentrations of MLEMC (100 mg/kg, 200 mg/kg and 300 mg/kg), curcumin (10 mg/kg) or vehicle (25% propylene glycol). The following day, these groups were administered 1 mg/kg b.w. of aflatoxin B1 (AFB1). The experiment was terminated three days after administration of AFB1. Group 6 represented untreated healthy control. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatinine and liver histopathology were evaluated. Methanolic leaf extracts of M. caffra decreased the levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and creatinine in the sera of rats as compared with the AFB1 intoxicated group. Co-administration of MLEMC improved the histological characteristics of the hepatocytes in contrast to the AFB1 treated group, which had mild to severe hepatocellular injuries including bile duct proliferation, bile duct hyperplasia, lymphoplasmacytic infiltrate and fibrosis. Extracts of M. caffra were beneficial in mitigating the hepatotoxic effects of AFB1 in rats by reducing the levels of liver enzymes and preventing hepatic injury.
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- 2022
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25. Obesity influences the microbiotic biotransformation of chlorogenic acid.
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Mortelé O, Xavier BB, Lammens C, Malhotra-Kumar S, Jorens PG, Dirinck E, van Nuijs ALN, and Hermans N
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- Biotransformation, Dysbiosis, Feces microbiology, Female, Humans, Obesity, Chlorogenic Acid metabolism, Renal Dialysis
- Abstract
Obesity is a major public health problem. Gut microbiome dysbiosis has been associated with obesity, however, little is known on the effect of the dysbiosis on the microbiotic bio-transformation of xenobiotics. Fecal samples of lean (n = 9) and obese (n = 4) female volunteers were collected and characterized by 16 S rDNA gene sequencing. The microbiotic biotransformation of chlorogenic acid was studied using the collected fecal samples of lean and obese subjects in the colon stage of the gastro-intestinal dialysis model with colon stage (GIDM-Colon). The concentration of anaerobic bacteria was lower for all obese samples in comparison to the samples of the lean volunteers. Differences in gut microbiome composition and bacterial concentration were observed between the two populations. The obese gut microbiome presented a lower metabolic activity in comparison to the lean population. Chlorogenic acid was completely biotransformed after 24 h colonic dialysis in the lean population while it was still present in the obese population. Furthermore, 23 and 13 biotransformation products were identified in the lean and obese population, respectively; 11 unique biotransformation products from the caffeic, feruoylquinic and quinic acid pathways were identified in the lean population. The results confirm that changes in gut microbiota related to obesity are associated with differences in microbiotic biotransformation of xenobiotics and thus possibly influencing the activity, bioavailability and toxicity of orally administered xenobiotics and drugs., (Copyright © 2022. Published by Elsevier B.V.)
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- 2022
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26. Effects of medicagenic acid metabolites, originating from biotransformation of an Herniaria hirsuta extract, on calcium oxalate crystallization in vitro.
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Peeters L, Foubert K, Breynaert A, Schreurs G, Verhulst A, Pieters L, and Hermans N
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- Animals, Cell Survival drug effects, Crystallization, Dogs, Madin Darby Canine Kidney Cells, Medicine, Traditional, Plant Extracts chemistry, Triterpenes metabolism, Calcium Oxalate chemistry, Caryophyllaceae chemistry, Phytotherapy, Plant Extracts pharmacology, Triterpenes chemistry, Triterpenes pharmacology
- Abstract
Ethnopharmacological Relevance: Herniaria hirsuta is traditionally used in Moroccan folk medicine for treatment of urinary stones and as a diuretic. It is rich in saponins, which are known to be deglycosylated in the colon, whereafter aglycones such as medicagenic acid are absorbed and further metabolized in the liver., Aim of the Study: A sample of hepatic metabolites of medicagenic acid, with medicagenic acid glucuronide as the most abundant one, was evaluated for in vitro activity against urinary stones. A crystallization assay and a crystal-cell interaction assay were used to evaluate in vitro activity of hepatic metabolites of medicagenic acid on CaC
2 O4 (calciumoxalate) crystals, present in the majority of urinary stones., Materials and Methods: In the crystallization assay the effects on nucleation of Ca2+ and C2 O4 2- and aggregation of the CaC2 O4 crystals are studied. In the crystal-cell interaction assay crystal retention is investigated by determining the amount of Ca2+ bound to injured monolayers of MDCK I cells., Results: Results of the crystallization assay showed a tentative effect on crystal aggregation. The crystal-cell interaction assay showed a significant inhibition of crystal binding, which may reduce crystal retention in the urinary tract., Conclusions: As both formation of crystals by inhibiting aggregation and retention of crystals is affected, the beneficial effect of H. hirsuta against urinary stones may at least in part be attributed to medicagenic acid metabolites, indicating that saponins containing medicagenic acid may act as prodrugs., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2022
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27. Antiplasmodial activity of constituents and their metabolites after in vitro gastrointestinal biotransformation of a Nauclea pobeguinii extract.
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Peeters L, Foubert K, Baldé MA, Tuenter E, Matheeussen A, Van Pelt N, Caljon G, Hermans N, and Pieters L
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- Biotransformation, Plant Extracts, Alkaloids pharmacology, Antimalarials pharmacology, Rubiaceae
- Abstract
Nauclea pobeguinii is traditionally used for treatment of malaria. Previous studies on the plant extract and strictosamide, the putative active constituent, showed a profound in vivo activity of the extract but no in vitro activity of strictosamide. This might indicate that one or more compounds present in the extract, most likely alkaloids, act as prodrugs undergoing biotransformation after oral administration resulting in the active compounds. The phytochemical composition of a N. pobeguinii extract was characterized using UHPLC-UV-HRMS (Ultrahigh-Performance Liquid Chromatography-Ultraviolet-High Resolution Mass Spectrometry) data. An in vitro gastrointestinal model was used to simulate biotransformation of the extract allowing monitoring of the relative abundances of individual constituents over time on one hand, while antiplasmodial activity and cytotoxicity of the biotransformed extract could be evaluated on the other hand. A diversity of compounds was (tentatively) identified in the extract, mainly saponins and alkaloids, including 32 compounds that have not been reported before in N. pobeguinii. The automated data analysis workflow used for unbiased screening for metabolites showed that glycosylated compounds decreased in intensity over time. Alkaloids containing no sugar moieties, including angustine-type alkaloids, showed no gastrointestinal biotransformation. In vitro gastrointestinal biotransformation of strictosamide did not result in a major metabolite. Moreover, multivariate data analysis using Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA) showed no in vitro activity of strictosamide or its metabolites suggesting that other compounds or metabolites present in the extract are responsible for the antiplasmodial effect of the N. pobeguinii extract. The OPLS-DA proposes alkaloids with a β-carboline moiety as active principles, suggesting that antiplasmodial activity of N. pobeguinii derives from an additive or synergistic effect of multiple minor alkaloids and their metabolites present in the bark extract of N. pobeguinii., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
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- 2022
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