Publications by authors named "Yvan Vander Heyden"

206 Publications

Quality Control of Herbal Medicines: From Traditional Techniques to State-of-the-art Approaches.

Planta Med 2021 Aug 19. Epub 2021 Aug 19.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Center for Pharmaceutical Research (CePhaR), Vrije Universiteit Brussel - VUB, Brussels, Belgium.

Herbal medicines are important options for the treatment of several illnesses. Although their therapeutic applicability has been demonstrated throughout history, several concerns about their safety and efficacy are raised regularly. Quality control of articles of botanical origin, including plant materials, plant extracts, and herbal medicines, remains a challenge. Traditionally, qualitative (e.g., identification and chromatographic profile) and quantitative (e.g., content analyses) markers are applied for this purpose. The compound-oriented approach may stand alone in some cases (e.g., atropine in ). However, for most plant materials, plant extracts, and herbal medicines, it is not possible to assure quality based only on the content or presence/absence of one (sometimes randomly selected) compound. In this sense, pattern-oriented approaches have been extensively studied, introducing the use of multivariate data analysis on chromatographic/spectroscopic fingerprints. The use of genetic methods for plant material/plant extract authentication has also been proposed. In this study, traditional approaches are reviewed, although the focus is on the applicability of fingerprints for quality control, highlighting the most used approaches, as well as demonstrating their usefulness. The literature review shows that a pattern-oriented approach may be successfully applied to the quality assessment of articles of botanical origin, while also providing directions for a compound-oriented approach and a rational marker selection. These observations indicate that it may be worth considering to include fingerprints and their data analysis in the regulatory framework for herbal medicines concerning quality control since this is the foundation of the holistic view that these complex products demand.
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http://dx.doi.org/10.1055/a-1529-8339DOI Listing
August 2021

UPLC-PDA-ESI-QTOF-MS/MS and GC-MS analysis of Iranian L.

Food Sci Nutr 2021 Aug 14;9(8):4278-4286. Epub 2021 Jun 14.

Department of Pharmacognosy School of Pharmacy Mashhad University of Medical Sciences Mashhad Iran.

L. is a significant component in the Iranian food basket. This study aimed to investigate the bioactive compounds and biological activities of different extracts obtained from aerial parts. From the aerial parts, a crude methanolic (MeOH) extract and its four sub-fractions, that is, petroleum ether (Pet), ethyl acetate (EtOAc), n-butanol (n-BuOH), and aqueous (water) extracts were obtained. The total phenolic and flavonoid contents as well as the antioxidant and cytotoxic activities of the extracts were determined. Moreover, the phytochemical profiles of the essential oil (EO) and of those extracts with the highest antioxidant activity measured by GC/MS and UPLC-PDA-ESI-QTOF-MS/MS. Results showed that the highest concentrations of phenols and flavonoids as well as the most potent antioxidant potential according to the DPPH method were determined in the EtOAc and MeOH extracts with IC values of 22.0 and 34.4 µg.ml, respectively. Quantitative analysis of these extracts was subsequently performed by UPLC-PDA-ESI-QTOF-MS/MS. Both extracts contained mainly rosmarinic acid, caffeic acid, and 2-hydroxycinnamic acid, which may be responsible for their high antioxidant activity. Moreover, none of the extracts showed cytotoxic effects against MCF7, SW48, and a normal cell line of mouse embryonic fibroblast cells (NIH/3T3) in the tested concentrations (up to 400 μg.ml). Additionally, GC-MS analysis showed that oxygenated monoterpenes (55.4%) were the main constituents of the EO of .
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http://dx.doi.org/10.1002/fsn3.2396DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8358350PMC
August 2021

Improved multi-class discrimination by Common-Subset-of-Independent-Variables Partial-Least-Squares Discriminant Analysis.

Talanta 2021 Nov 15;234:122595. Epub 2021 Jun 15.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel-VUB, Laarbeeklaan 103, B-1090, Brussels, Belgium.

In this study, a new PLS-DA modelling approach for multi-class discriminant analysis, called Common-Subset-of-Independent-Variables Partial-Least-Squares Discriminant Analysis is proposed and evaluated. Because in this method Partial-Least-Squares models for one component are used, it is denoted as CSIV-PLS1-DA. In this method for each class vector, individual PLS1 models with individual model complexities are developed, based on one common set of independent variables, obtained after variable selection by the Final Complexity Adapted Models method, using the absolute values of the PLS regression coefficients, denoted as FCAM-REG. CSIV-PLS1-DA combines a common variable set for all class vectors, which is a characteristic of PLS2-DA, with the individual model complexity for each class vector, which is a characteristic of PLS1-DA. These characteristics make CSIV-PLS1-DA more flexible than PLS2-DA. CSIV-PLS1-DA is found to be an alternative for PLS1-DA or PLS2-DA when the correlations between the responses are low, which is often the case in discriminant analysis. The performance of the CSIV-PLS1-DA method is investigated using one simulated and eight real multi-class data sets from different sources. The classification abilities, measured by the percentage classification accuracy rates (%Acc), resulting from CSIV-PLS1-DA, are statistically compared with those of PLS1-DA and PLS2-DA, using one-tailed paired t-tests at the 95% confidence level. The results show that the %Acc values resulting from the CSIV-PLS1-DA method are significantly higher than those of the corresponding PLS1-DA and PLS2-DA methods, meaning that the classification ability of the CSIV-PLS1-DA method is significantly better.
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http://dx.doi.org/10.1016/j.talanta.2021.122595DOI Listing
November 2021

Cytotoxic, Antioxidant, and Antidiabetic Activities versus UPLC-ESI-QTOF-MS Chemical-Profile Analysis of Ipomoea aquatica Fractions.

Planta Med 2021 Aug 6. Epub 2021 Aug 6.

Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Brussels, Belgium.

is a common green leafy vegetable that has numerous uses in traditional medicine. This study focused on the determination of the cytotoxic, antiradical, and antidiabetic properties of various fractions of the methanolic extract, as well as on the tentative identification of some bioactive compounds in the same fractions. The cytotoxicity was determined by the brine shrimp lethal test. The antioxidant activities of the fractions were investigated through 3 assays. The antidiabetic activity () was measured by -glucosidase and -amylase inhibition assays. Phytochemical qualitative analyses demonstrated the presence of alkaloids, terpenoids, phenols, and flavonoids in the ethyl acetate-methanol and methanol fractions. The total phenolic and total flavonoid contents were found to be highest in the ethyl acetate-MeOH fractions. The evaluation of the cytotoxicity showed that the hexane-dichloromethane fraction is the most toxic, while the others are moderately toxic. The antioxidant activity assays showed that the ethyl acetate-MeOH fractions are the most potent, while the -glucosidase and -amylase assays revealed that the hexane-dichloromethane fraction might contain a potent antidiabetic agent. Some bioactive substances in the MeOH fractions, such as salicylic acid glucoside, 1-O-sinapoyl--D-glucose derivative, and dihydroferulic acid derivative, were tentatively identified. To the best of our knowledge, this is the first report to detect and identify these compounds in this species. Based on the results of this study, it may be concluded that is a potent antioxidant agent and could be a good candidate as a natural antioxidant in food and therapeutics.
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http://dx.doi.org/10.1055/a-1554-2733DOI Listing
August 2021

Cytotoxicity and Antiviral Activities of Haplophyllum tuberculatum Essential Oils, Pure Compounds, and Their Combinations against Coxsackievirus B3 and B4.

Planta Med 2021 Aug 22;87(10-11):827-835. Epub 2021 Jul 22.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Center for Pharmaceutical Research (CePhaR), Vrije Universiteit Brussel (VUB), Belgium.

is a plant commonly used in folk medicine to treat several diseases including vomiting, nausea, infections, rheumatism, and gastric pains. In the current study, essential oils, hydrosols, the pure compounds -(+)-limonene, -(-)-limonene, and 1-octanol, as well as their combinations -(+)-limonene/1-octanol and -(-)-limonene/1-octanol, were screened for their cytotoxicity on HEp-2 cells after 24, 48, and 72 h, and then tested for their activity against Coxsackievirus B3 and B4 (CV-B3 and CV-B4) at 3 different moments: addition of the plant compounds before, after, or together with virus inoculation. Results showed that the samples were more cytotoxic after 72 h than after 24 h or 48 h cell contact. However, the combinations -(+)-limonene/1-octanol and -(-)-limonene/1-octanol showed less effect on HEp-2 cells than pure -(+)-limonene and -(-)-limonene after 24 h, 48 h, and 72 h. 1-octanol exhibited the highest concentration causing 50% cytotoxicity (CC) on HEp-2 cells after 24 h (CC = 93 µg/mL) and 48 h (CC = 83 µg/mL). The antiviral assays showed that the tested samples exhibited potent inhibition of CV-B. IC values ranged from 0.66 µg/mL to 28.4 µg/mL. In addition, CV-B3 was more sensitive than CV-B4. Both CV-B strains are more inhibited when cells were pretreated with the plant compounds. The hydrosols have no effect, neither on HEp-2 cells nor on the virus. 1-octanol, -(-), and -(+)-limonene/1-octanol had important selectivity indexes over time. Although essential oils had potent antiviral activity, they can be considered for application in the pretreatment of cells. However, 1-octanol and the combinations are within the safety limits, and thus, they can be used as an active natural antiviral agent for CV-B3 and CV-B4 inhibition.
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http://dx.doi.org/10.1055/a-1538-5289DOI Listing
August 2021

In Vitro & In Vivo Anti-Hyperglycemic Potential of Saponins Cake and Argan Oil from .

Foods 2021 May 13;10(5). Epub 2021 May 13.

Pharmacodynamic Research Team ERP, Laboratory of Pharmacology and Toxicology, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat BP 6203, Rabat Instituts, Rabat 10100, Morocco.

The Argan tree (. L) is an evergreen tree endemic of southwestern Morocco. For centuries, various formulations have been used to treat several illnesses including diabetes. However, scientific results supporting these actions are needed. Hence, Argan fruit products (i.e., cake byproducts (saponins extract) and hand pressed Argan oil) were tested for their in-vitro anti-hyperglycemic activity, using α-glucosidase and α-amylase assays. The in-vivo anti-hyperglycemic activity was evaluated in a model of alloxan-induced diabetic mice. The diabetic animals were orally administered 100 mg/kg body weight of aqueous saponins cake extract and 3 mL/kg of Argan oil, respectively, to evaluate the anti-hyperglycemic effect. The blood glucose concentration and body weight of the experimental animals were monitored for 30 days. The chemical properties and composition of the Argan oil were assessed including acidity, peroxides, K232, K270, fatty acids, sterols, tocopherols, total polyphenols, and phenolic compounds. The saponins cake extract produced a significant reduction in blood glucose concentration in diabetic mice, which was better than the Argan oil. This decrease was equivalent to that detected in mice treated with metformin after 2-4 weeks. Moreover, the saponins cake extract showed a strong inhibitory action on α-amylase and α-glucosidase, which is also higher than that of Argan oil.
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http://dx.doi.org/10.3390/foods10051078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8152476PMC
May 2021

Comparison of in-silico modelling and reversed-phase liquid chromatographic retention on an octadecyl silica column to predict skin permeability of pharmaceutical and cosmetic compounds.

J Pharm Biomed Anal 2021 Jul 22;201:114095. Epub 2021 Apr 22.

Vrije Universiteit Brussel (VUB), Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Laarbeeklaan 103, B-1090, Brussels, Belgium. Electronic address:

This study focuses on the in-silico modelling of the skin permeability using a test set of pharmaceutical and cosmetic compounds. Two sets of theoretical molecular descriptors, obtained from the E-Dragon and Vega ZZ software programs, were used in the models. Different linear regression methods, i.e. Multiple Linear Regression (MLR) and Partial Least Squares (PLS) regression, were applied for modelling and estimating the skin permeability. The best model was obtained using a stepwise MLR approach on the E-Dragon descriptor set. In a second step, the retention of the test set compounds was measured on a C18 column at two pH levels: pH 5.5 and pH 7. Different organic-modifier fractions were applied in the mobile phase to be able to extrapolate the retention factors to a log k value, with k the estimated retention factor in an aqueous mobile phase without organic modifier. Thereafter it was examined whether combining this chromatographic descriptor with the theoretical descriptors could improve the modelling of the skin permeability. The chromatographic descriptor often did not show an added value compared to the models containing only theoretical descriptors. Therefore, the in-silico models were preferred, and these models could be useful to predict the skin permeability of pharmaceutical and cosmetic compounds.
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http://dx.doi.org/10.1016/j.jpba.2021.114095DOI Listing
July 2021

Feasibility study on exhaled-breath analysis by untargeted Selected-Ion Flow-Tube Mass Spectrometry in children with cystic fibrosis, asthma, and healthy controls: Comparison of data pretreatment and classification techniques.

Talanta 2021 Apr 6;225:122080. Epub 2021 Jan 6.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium. Electronic address:

Selected-Ion Flow-Tube Mass Spectrometry (SIFT-MS) has been applied in a clinical context as diagnostic tool for breath samples using target biomarkers. Exhaled breath sampling is non-invasive and therefore much more patient friendly compared to bronchoscopy, which is the golden standard for evaluating airway inflammation. In the actual pilot study, 55 exhaled breath samples of children with asthma, cystic-fibrosis and healthy individuals were included. Rather than focusing on the analysis of target biomarkers or on the identification of biomarkers, different data analysis strategies, including a variety of pretreatment, classification and discrimination techniques, are evaluated regarding their capacity to distinguish the three classes based on subtle differences in their full scan SIFT-MS spectra. Proper data-analysis strategies are required because these full scan spectra contain much external, i.e. unwanted, variation. Each SIFT-MS analysis generates three spectra resulting from ion-molecule reactions of analyte molecules with HO, NO and O. Models were built with Linear Discriminant Analysis, Quadratic Discriminant Analysis, Soft Independent Modelling by Class Analogy, Partial Least Squares - Discriminant Analysis, K-Nearest Neighbours, and Classification and Regression Trees. Perfect models, concerning overall sensitivity and specificity (100% for both) were found using Direct Orthogonal Signal Correction (DOSC) pretreatment. Given the uncertainty related to the classification models associated with DOSC pretreatments (i.e. good classification found also for random classes), other models are built applying other preprocessing approaches. A Partial Least Squares - Discriminant Analysis model with a combined pre-processing method considering single value imputation results in 100% sensitivity and specificity for calibration, but was less good predictive. Pareto scaling prior to Quadratic Discriminant Analysis resulted in 41/55 correctly classified samples for calibration and 34/55 for cross-validation. In future, the uncertainty with DOSC and the applicability of the promising preprocessing methods and models must be further studied applying a larger representative data set with a more extensive number of samples for each class. Nevertheless, this pilot study showed already some potential for the untargeted SIFT-MS application as a rapid pattern-recognition technique, useful in the diagnosis of clinical breath samples.
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http://dx.doi.org/10.1016/j.talanta.2021.122080DOI Listing
April 2021

New insights into the Argan oil categories characterization: Chemical descriptors, FTIR fingerprints, and chemometric approaches.

Talanta 2021 Apr 6;225:122073. Epub 2021 Jan 6.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, CePhaR, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium. Electronic address:

The characterization of Argan oils to classify them in three categories ('Extra Virgin', 'Virgin' and 'Lower quality') was evaluated. A total of 120 Moroccan Argan oils samples from the Taroudant Argan forest was investigated. The free acidity, peroxide value, spectrophotometric indices (K232 and K270), fatty acids, sterols, and tocopherol contents were assessed. The samples were also scanned by FTIR spectroscopy. The Principal Component Analysis (PCA) and four classification methods, Partial Least Squares Discriminant Analysis (PLS-DA), Soft Independent Modelling of Class Analogy (SIMCA), K-nearest Neighbors (KNN), and Support Vector Machines (SVM), were applied on both the chemical and spectral data. Besides the conventional chemical profiling, FTIR spectra were evaluated for their feasibility as a rapid non-invasive approach for classifying and predicting the oil quality categories. The most important variables for differentiating the oil categories were identified as K, peroxide value, ɣ-tocopherol, δ-tocopherol, acidity, stigma-8-22-dien-3β-ol, stearic acid (C) and linoleic acid (C) and could be used as quality indicators. Eight chemical descriptors or key features from the FTIR spectra (selected by interval-PLS) could also be established as indicators of quality and freshness of Argan oils.
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http://dx.doi.org/10.1016/j.talanta.2020.122073DOI Listing
April 2021

Four Pistacia atlantica subspecies (atlantica, cabulica, kurdica and mutica): A review of their botany, ethnobotany, phytochemistry and pharmacology.

J Ethnopharmacol 2021 Jan 1;265:113329. Epub 2020 Sep 1.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium. Electronic address:

Ethnopharmacological Relevance: Pistacia atlantica (wild pistachio) belongs to the Anacardiaceae family, and growing from the Mediterranean basin to central Asia, especially in Iran, Turkey, Iraq and Saudi Arabia where it is extensively used in traditional medicine for a wide range of ailments related to relieving upper abdominal discomfort and pain, dyspepsia and peptic ulcer.

Objective: Despite the diverse biological activities of P. atlantica, there is no current review summarizing medicinal properties of its subspecies, including cabulica, kurdica and mutica. Thus, this paper aims to explore the current understanding of the chemical, pharmacological, and biochemical properties of the extracts and the main active constituents found in each subspecies of this plant.

Methods: Peer-reviewed articles, using "Pistacia atlantica" as search term (″all fields″), were retrieved from Scifinder, Pubmed, Science direct, Wiley, Springer, ACS, Scielo, Web of Science and other web search instruments (Google Scholar, Yahoo search). Papers published until July 2020 are considered. In addition, various books were consulted that contained botanical and ethnopharmacological information. The information provided in this review is based on peer-reviewed papers in English and French.

Results: Phytochemical studies have shown the presence of numerous valuable compounds, including volatile compounds, flavonoids, phenolic compounds, fatty acids, tocopherols and phytosterols. P. atlantica contains also minerals and trace elements, like iron, lead, copper, potassium, sodium and calcium; fatty acids, like oleic, linoleic, and palmitic acid; fat-soluble vitamins, such as α, β, γ and δ tocopherols; phytosterols, like betasitosterol, stigmasterol, campesterol and Δ-avenasterol. Crude extracts and isolated compounds from P. atlantica show a wide range of pharmacological properties, such as antimicrobial, antifungal, anti-inflammatory, analgesic, antinociceptive, wound healing, anticancer, cytotoxic, anticholinesterase, antidiabetic, hepatoprotective, urease inhibition, antihypertension, nipple fissure healing, antileishmanial and antiplasmodial activities. However, there are no reports summarizing the P. atlantica bioactivity, its therapeutic value, and the roles played by each of the numerous phytoconstituents.

Conclusion: Many traditional uses of P. atlantica and its subspecies have now been confirmed by pharmacologic research. Systematic phytochemical investigation of the P. atlantica subspecies and the pharmacological properties, especially the mechanisms of action and toxicology, to illustrate their ethnomedicinal use, to explore the therapeutic potential and support further health-care product development, will undoubtedly be the focus of further research. Therefore, detailed and extensive studies and clinical evaluation of P. atlantica subspecies should be carried out in future for the safety approval of therapeutic applications.
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http://dx.doi.org/10.1016/j.jep.2020.113329DOI Listing
January 2021

Improvement of quantitative structure-retention relationship models for chromatographic retention prediction of peptides applying individual local partial least squares models.

Talanta 2020 Nov 20;219:121266. Epub 2020 Jun 20.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium.

In Reversed-Phase Liquid Chromatography, Quantitative Structure-Retention Relationship (QSRR) models for retention prediction of peptides can be built, starting from large sets of theoretical molecular descriptors. Good predictive QSRR models can be obtained after selecting the most informative descriptors. Reliable retention prediction may be an aid in the correct identification of proteins/peptides in proteomics and in chromatographic method development. Traditionally, global QSRR models are built, using a calibration set containing a representative range of analytes. In this study, a strategy is presented to build individual local Partial Least Squares (PLS) models for peptides, based on selected local calibration samples, most similar to the specific query peptide to be predicted. Similar local calibration peptides are selected from a possible calibration set. The calibration samples with the lowest Euclidian distances to the query peptide are considered as most similar. Two Euclidian distances are investigated as similarity parameter, (i) in the autoscaled descriptor space and, (ii) in the PLS factor space of the global calibration samples, both after variable selection by the Final Complexity Adapted Models (FCAM) method. The predictive abilities of individual local QSRR PLS models for peptides, developed with both Euclidian distances, are found significantly better than those of two global models, i.e. before and after FCAM variable selection. The predictive abilities of the local models, developed with distances calculated in the PLS factor space, were best.
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http://dx.doi.org/10.1016/j.talanta.2020.121266DOI Listing
November 2020

Three promising antimycobacterial medicinal plants reviewed as potential sources of drug hit candidates against multidrug-resistant tuberculosis.

Tuberculosis (Edinb) 2020 09 16;124:101987. Epub 2020 Aug 16.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103 B-1090, Brussels, Belgium.

Regimens of current drugs for tuberculosis are lengthy and are associated with many adverse effects. Currently, the emergence of different resistant strains has been observed. This urges a need for the discovery and development of novel drugs. The main sources of drug lead candidates are based on natural products. Zanthoxylum leprieurii, Lantana camara, and Cryptolepis Sanguinolenta are among the plants that have antimycobacterial activity. Recent technological methods, such as metabolomics, can rapidly detect and identify active compounds from medicinal plants. In this review, we aim to provide an overview and discussion of the antimycobacterial activity, phytochemical analysis and toxicity profile of these plants and their products as well as the potential of metabolomic fingerprinting of medicinal plants with a given activity on microbes, in the search for the potential drug hit molecules. The information for this review was extracted from databases such as Excerpta Medica Database, Google Scholar, Springer, and PubMed Central. Primary studies, using a combination of the keywords antimycobacterial medicinal plant, multidrug-resistant tuberculosis, phytochemistry, toxicity, Zanthoxylum leprieurii, Lantana camara, Cryptolepis sanguinolenta, and plant metabolomics/metabolic fingerprinting of plant extracts, have been considered. The above-mentioned plant species showed antimycobacterial activity against drug-resistant strains of M. tuberculosis. They may provide potential candidates for novel drugs against multidrug-resistant tuberculosis. However, extensive work is still needed. To our knowledge, there is no or limited literature that reports the metabolic fingerprints of these plants. The analysis of the metabolite fingerprints of medicinal plants with similar antimicrobial activity could be important to determine whether the activity results from common metabolites within different plant species. This review shows that these plants are potential candidates to provide drug hits against multidrug-resistant tuberculosis strains. Future studies of compound optimization, in vivo safety and efficacy, as well as of the specific mechanisms of action are however required.
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http://dx.doi.org/10.1016/j.tube.2020.101987DOI Listing
September 2020

A comparative study of UniSpray and electrospray sources for the ionization of neuropeptides in liquid chromatography tandem mass spectrometry.

J Chromatogr A 2020 Sep 11;1628:461462. Epub 2020 Aug 11.

Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium. Electronic address:

Despite the extensive use of electrospray ionization (ESI) for the quantification of neuropeptides by liquid chromatography-tandem mass spectrometry (LC-MS/MS), poor ionization and transmission efficiency are described for this ionization interface. A new atmospheric pressure ionization source, named UniSpray, was recently developed and commercialized. In this study, the LC-MS performance of this new ionization interface is evaluated and compared with ESI for the quantification of seven neuropeptides. Besides comparison of signal intensities and charge state distributions, also signal-to-noise (S/N) ratios and accuracy and precision were assessed. Additionally, matrix effects of human precipitated plasma and rat microdialysate were evaluated as well as the effect of three supercharging agents on the ionization of the seven neuropeptides. UniSpray ionization resulted in signal intensities four to eight times higher at the optimal capillary/impactor voltage for all seven neuropeptides. S/N values at the other hand only increased by not more than a twofold when the UniSpray source was used. Moreover, UniSpray ionization resulted in a shift towards lower charge states for some neuropeptides. Evaluation of the matrix effects by a post-column infusion set-up resulted in different infusion profiles between ESI and UniSpray. The charge state distributions of the neuropeptides obtained with UniSpray are highly comparable with ESI. Finally, the effect of the supercharging agents on the ionization of the neuropeptides tends to be peptide-dependent with both ionization sources.
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http://dx.doi.org/10.1016/j.chroma.2020.461462DOI Listing
September 2020

Application of Rank Annihilation Factor Analysis for Antibacterial Drugs Determination by Means of pH Gradual Change-UV Spectral Data.

Antibiotics (Basel) 2020 Jul 6;9(7). Epub 2020 Jul 6.

Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Faculty of Food Science and Technology, University of Vigo-Ourense Campus, E-32004 Ourense, Spain.

The main objective of this study was to develop a simple and efficient spectrophotometric technique combined with chemometrics for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in drug formulations. Specifically, we sought: (i) to evaluate the potential use of rank annihilation factor analysis (RAFA) to pH gradual change spectrophotometric data in order to provide sufficient accuracy and model robustness; and (ii) to determine SMX and TMP concentration in drug formulations without tedious pre-treatments such as derivatization or extraction techniques which are time-consuming and require hazardous solvents. In the proposed method, the spectra of the sample solutions at different pH values were recorded and the pH-spectra bilinear data matrix was generated. On these data, RAFA was then applied to estimate the concentrations of SMX and TMP in synthetic and real samples. Applying RAFA showed that the two drugs could be determined simultaneously with concentration ratios of SMX to TMP varying from 1:30 to 30:1 in the mixed samples (concentration range is 1-30 µg mL for both components). The limits of detection were 0.25 and 0.38 µg mL for SMX and TMP, respectively. The proposed method was successfully applied to the simultaneous determination of SMX and TMP in some synthetic, pharmaceutical formulation and biological fluid samples. In addition, the means of the estimated RSD (%) were 1.71 and 2.18 for SMX and TMP, respectively, in synthetic mixtures. The accuracy of the proposed method was confirmed by spiked recovery test on biological samples with satisfactory results (90.50-109.80%).
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http://dx.doi.org/10.3390/antibiotics9070383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7400009PMC
July 2020

Rendering A Chiral Screening Step In Supercritical Fluid Chromatography Mass-Spectrometry Compatible.

J Chromatogr A 2020 Aug 17;1624:461201. Epub 2020 May 17.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium. Electronic address:

Nowadays, sensitive chiral methods are required for the determination of chiral impurities and for assays in biological samples. Supercritical fluid chromatography (SFC), one of the main techniques to separate chiral molecules, can be coupled to MS to provide such sensitive methods. Moreover, chiral separation strategies are very useful to reduce the development time and cost of such methods. This study investigates the transfer of an existing non-MS compatible screening step (as part of a separation strategy) into an MS-compatible one. The initial step had a cumulative success rate of 100 % for 57 tested compounds using methanol or 2-propanol as mobile phase modifier on one of four chiral stationary phases. The additives applied in the original mobile phases, i.e. isopropylamine and trifluoroacetic acid, negatively affect the ionization in SFC-MS and thus need to be replaced. Formic acid, acetic acid, water, ammonia, ammonium acetate and ammonium formate were investigated as MS-compatible additives in different combinations and concentrations. Only methanol-based mobile phases were considered in this study because high system pressures were obtained with isopropanol. The other experimental parameters remained the same as in the initial screening step. The effects of the alternative additives on the obtained resolutions as well as on the global success rate were investigated. The best alternative MS-compatible mobile phase contained 0.5 % CHCOOH and 40 mM NH as additives. This mobile phase provided the highest number of separations and rather high resolutions. An MS-compatible screening step was defined with this alternative mobile phase. Compared to the original additives, a similar success rate was obtained.
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http://dx.doi.org/10.1016/j.chroma.2020.461201DOI Listing
August 2020

Stationary-phase optimized selectivity in supercritical fluid chromatography using a customized Phase OPtimized Liquid Chromatography kit: comparison of different prediction approaches.

Anal Bioanal Chem 2020 Sep 12;412(24):6553-6565. Epub 2020 Jun 12.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium.

The use of stationary-phase optimized selectivity in liquid chromatography (SOS-LC) was shown to be successful for HPLC to analyze complex mixtures using a Phase OPtimized Liquid Chromatography (POPLC) kit. This commercial kit contains five stationary-phase types of varying lengths, which can be coupled to offer an improved separation of compounds. Recently, stationary-phase optimized selectivity supercritical fluid chromatography (SOS-SFC) has been introduced, transferring the methodology to SFC. In this study, the applicability of a customized POPLC expert kit for isocratic SFC runs was explored. Five stationary-phase chemistries were selected as potentially most suitable for achiral separations of polar compounds: aminopropyl (amino), cyanopropyl (CN), diol, ethylpyridine (EP), and silica. The retention factors (k) on the individual stationary phases were used for the prediction of the best stationary-phase combination, based on the POPLC algorithm (via the included software). As an alternative, the best column combination was predicted using multiple linear regression (MLR) models on the results obtained from a simplex centroid mixture design with only three stationary-phase types (amino, silica, and EP). A third approach applied the isocratic POPLC algorithm on the same three stationary-phase data. The proposed combinations were assembled and tested. The predicted and experimental retention factors were compared. The predictions based on the POPLC algorithm provided a stationary phase showing a complete separation of the mixture. The stationary phase suggested by the MLR models, on the other hand, showed co-elution of two compounds, due to an unexpected experimental retention shift. Overall, the customized POPLC kit showed good potential to be applied in SFC. Graphical abstract.
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http://dx.doi.org/10.1007/s00216-020-02739-wDOI Listing
September 2020

CE-MS metabolic profiling of volume-restricted plasma samples from an acute mouse model for epileptic seizures to discover potentially involved metabolomic features.

Talanta 2020 Sep 1;217:121107. Epub 2020 May 1.

Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium. Electronic address:

Currently, a high variety of analytical techniques to perform metabolomics is available. One of these techniques is capillary electrophoresis coupled to mass spectrometry (CE-MS), which has emerged as a rather strong analytical technique for profiling polar and charged compounds. This work aims to discover with CE-MS potential metabolic consequences of evoked seizures in plasma by using a 6Hz acute corneal seizure mouse model. CE-MS is an appealing technique because of its capability to handle very small sample volumes, such as the 10 μL plasma samples obtained using capillary microsampling in this study. After liquid-liquid extraction, the samples were analyzed with CE-MS using low-pH separation conditions, followed by data analysis and biomarker identification. Both electrically induced seizures showed decreased values of methionine, lysine, glycine, phenylalanine, citrulline, 3-methyladenine and histidine in mice plasma. However, a second provoked seizure, 13 days later, showed a less pronounced decrease of the mean concentrations of these plasma metabolites, demonstrated by higher fold change ratios. Other obtained markers that can be related to seizure activities based on literature data, are isoleucine, serine, proline, tryptophan, alanine, arginine, valine and asparagine. Most amino acids showed relatively stable plasma concentrations between the basal levels (Time point 1) and after the 13-day wash-out period (Time point 3), which suggests its effectiveness. Overall, this work clearly demonstrated the possibility of profiling metabolite consequences related to seizure activities of an intrinsically low amount of body fluid using CE-MS. It would be useful to investigate and validate, in the future, the known and unknown metabolites in different animal models as well as in humans.
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http://dx.doi.org/10.1016/j.talanta.2020.121107DOI Listing
September 2020

Bioactive Azepine-Indole Alkaloids from .

J Nat Prod 2020 04 9;83(4):852-863. Epub 2020 Mar 9.

Laboratory of Pharmacognosy and Quality Control of Phytomedicines, Faculty of Pharmacy, Universidade Federal do Rio Grande do Sul-UFRGS, 90610-000 Porto Alegre/RS Brazil.

Phytochemical investigation of the alkaloid extract of the aerial parts of led to the isolation and characterization of 10 azepine-indole alkaloids, i.e., cimitrypazepine (), fargesine (), nemorosines A (), and B (), nemorosinosides A-F (-), as well as two β-carboline derivatives, 10-hydroxyisodolichantoside () and 10-hydroxydolichantoside (), an isoxazole alkaloid, nemorosinoside G (), serotonin (), bufotenine (), and ()-gentianol (). Compounds - have not yet been described. These compounds were isolated by semipreparative HPLC, and their structures were determined by means of HRMS, NMR, and ECD measurements. In addition, the monoamine oxidase-A (MAO-A), MAO-B, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibitory activities were evaluated. Alkaloids - inhibited the MAO-A activity with IC values of 1.4, 1.4, and 0.9 μM, respectively.
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http://dx.doi.org/10.1021/acs.jnatprod.9b00469DOI Listing
April 2020

Analytical techniques for metabolomic studies: a review.

Bioanalysis 2019 Dec;11(24):2297-2318

Department of Pharmaceutical Chemistry, Drug Analysis & Drug Information (FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.

Metabolomics is the comprehensive study of small-molecule metabolites. Obtaining a wide coverage of the metabolome is challenging because of the broad range of physicochemical properties of the small molecules. To study the compounds of interest spectroscopic (NMR), spectrometric (MS) and separation techniques (LC, GC, supercritical fluid chromatography, CE) are used. The choice for a given technique is influenced by the sample matrix, the concentration and properties of the metabolites, and the amount of sample. This review discusses the most commonly used analytical techniques for metabolomic studies, including their advantages, drawbacks and some applications.
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http://dx.doi.org/10.4155/bio-2019-0014DOI Listing
December 2019

Xanthones and Cancer: from Natural Sources to Mechanisms of Action.

Chem Biodivers 2020 Feb 31;17(2):e1900499. Epub 2020 Jan 31.

Núcleo de Investigações Químico-Farmacêuticas (NIQFAR), Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade do Vale do Itajaí - UNIVALI, 88302-901, Itajaí, Brazil.

Xanthones are a class of heterocyclic natural products that have been widely studied for their pharmacological potential. In fact, they have been serving as scaffolds for the design of derivatives focusing on drug development. One of the main study targets of xanthones is their anticancer activity. Several compounds belonging to this class have already demonstrated cytotoxic and antitumor effects, making it a promising group for further exploration. This review therefore focuses on recently published studies, emphasizing their natural and synthetic sources and describing the main mechanisms of action responsible for the anticancer effect of promising xanthones.
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http://dx.doi.org/10.1002/cbdv.201900499DOI Listing
February 2020

Pharmaceutical analysis combined with in-silico therapeutic and toxicological profiling on zileuton and its impurities to assist in modern drug discovery.

J Pharm Biomed Anal 2020 Feb 15;179:112982. Epub 2019 Nov 15.

Department of Quality Assurance, R. C. Patel Institute of Pharmaceutical Education and Research, Karwand Naka, Shirpur. Electronic address:

The obligatory testing of drug molecules and their impurities to protect users against toxic compounds seems to provide interesting opportunities for new drug discovery. Impurities, which proved to be non-toxic, may be explored for their own therapeutic potential and thus be a part of future drug discovery. The essential role of pharmaceutical analysis can thus be extended to achieve this purpose. The present study examined these objectives by characterizing the major degradation products of zileuton (ZLT), a 5-lipoxygenase (5-LOX) inhibitor being prevalently used to treat asthma. The drug sample was exposed to forced degradation and found susceptible to hydrolysis and oxidative stress. The obtained Forced Degradation Products (FDP's) were resolved using an earlier developed and validated Ultra-High-Pressure Liquid Chromatography Photo-Diode-Array (UHPLC-PDA) protocol. ZLT, along with acid-and alkali-stressed samples, were subjected to Liquid-chromatography Mass-spectrometry Quadrupole Time-of-flight (LC/MS-QTOF) studies. Major degradation products were isolated using Preparative TLC and characterized using Q-TOF and/or Proton nuclear magnetic resonance (HNMR) studies. The information obtained was assembled for structural conformation. Toxicity Prediction using Komputer Assisted Technology (TOPKAT) toxicity analyses indicated some FDP's as non-toxic when compared to ZLT. Hence, these non-toxic impurities may have bio-affinity and can be explored to interact with other therapeutic targets, to assist in drug discovery. The drug molecule and the characterized FDP's were subjected to 3-Dimensional Extra Precision (3D-XP)-molecular docking to explore changes in bio-affinity for the 5-LOX enzyme (PDB Id: 3V99). One FDP was found to have a higher binding affinity than the drug itself, indicating it may be a suitable antiasthmatic. The possibility of being active at other sites cannot be neglected and this is evaluated to a reasonable extent by Prediction of Activity Spectra for Substances (PASS). Besides being antiasthmatic, some FDP's were predicted antineoplastic, antiallergic and inhibitors of Complement Factor-D.
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http://dx.doi.org/10.1016/j.jpba.2019.112982DOI Listing
February 2020

Defining a standardized methodology for the determination of the antioxidant capacity: case study of Pistacia atlantica leaves.

Analyst 2020 Jan 26;145(2):557-571. Epub 2019 Nov 26.

Department of Analytical Chemistry, Applied Chemometricsand Molecular Modelling, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090 Brussels, Belgium.

Antioxidant activity can be measured by a variety of methods, that include hydrogen atom transfer (HAT) and single electron transfer (ET) methods. Most of these techniques are spectrophotometric, and thus incapable of quantifying or indicting individual antioxidant compounds. Nowadays, the integration of chromatographic and chemometric approaches allows a high-throughput identification and activity prediction of herbal products. The ethyl acetate fraction from the aqueous-acetone extract of Pistacia atlantica leaves is frequently used for the isolation of antioxidants. In this study it is investigated for its antioxidant properties in order to define a potential methodology for the determination of the antioxidant capacity of herbal extracts (which need to be confirmed by future studies). The seven free radical assays evaluated can be divided into two groups depending on the oxidizing reagent. Three methods use stable, non-biological radicals, i.e. the diphenyl-1-picrylhydrazyl (DPPH) assay, the azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, and the N,N-dimethyl-p-phenylenediamine (DMPD) assay, which have no direct physiological importance. Four methods work with biological radical producers, including superoxide anion (O˙), hydroxyl (˙OH), nitric oxide (NO˙) and peroxyl (ROO˙) are produced metabolically in living organisms, and thus direct information on an extract's protective action is obtained. Furthermore, the reducing power method by potassium ferricyanide (RPC), and the iron (ferrous) ion chelating activity also have been investigated. The antioxidant activities of the samples were measured according to the different methods and modelled as a function of the HPLC fingerprints using the partial least squares (PLS) technique. The regression coefficients of the models were studied to indicate the peaks potentially responsible for the antioxidant activity. From the combined results of the different PLS models, we recommend using the DPPH, RPC and ROO˙ assays, to evaluate the overall antioxidant capacity; in the case study of P. atlantica leaves.
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http://dx.doi.org/10.1039/c9an01643kDOI Listing
January 2020

Defining a system suitability limit to decide on column deterioration and to facilitate column transfers in chiral supercritical fluid chromatography.

Anal Bioanal Chem 2020 Sep 15;412(24):6221-6230. Epub 2019 Nov 15.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling (FABI), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090, Brussels, Belgium.

The separation of enantiomers is an important requirement during the entire drug life cycle in the pharmaceutical industry. High-performance liquid chromatography and supercritical fluid chromatography (SFC) are the main chromatographic techniques used to separate enantiomers. Since chiral stationary phases are often extensively used once a method has been developed, columns will age and must be replaced after a certain period. However, no practical guidelines exist to determine when a column is deteriorated or to decide whether a transfer to another column (with the same chiral selector) is successful. In this study, a system suitability limit for resolution was defined, based on an intermediate (time-different) precision study in SFC on four immobilized polysaccharide-based columns that only differed in manufacturer or particle size. This system suitability limit could be used to decide on column deterioration or as a requirement to evaluate whether a separation transfer was successful. Some method adaptations may be necessary to obtain successful transfers. An approach was proposed, which helped the analyst to make successful transfers. Graphical abstract.
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http://dx.doi.org/10.1007/s00216-019-02173-7DOI Listing
September 2020

In vivo anti-inflammatory response and bioactive compounds' profile of polyphenolic extracts from edible Argan oil (Argania spinosa L.), obtained by two extraction methods.

J Food Biochem 2019 12 1;43(12):e13066. Epub 2019 Oct 1.

Pharmacodynamy Research Team ERP, Laboratory of Pharmacology and Toxicology, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat, Morocco.

The present work examined and assessed the in vivo anti-inflammatory effect of polyphenolic extracts from Moroccan edible Argan oils (Argania spinosa L.), extracted by two extraction processes: Hand pressing and mechanical pressing. Chemical properties, such as acidity, peroxide index, ultraviolet indices, total polyphenols composition, fatty acid composition, tocopherol composition, phenolic profiling, and sterol composition were studied. Then, the anti-inflammatory potential was determined by applying carrageenan, an induced paw edema test in rats. The results revealed an anti-inflammatory effect of edible Argan oil and indicated a higher efficiency of hand-pressed oil compared to mechanical-pressed oil, supporting its traditional use in human health, related to pain and inflammations. The chemical composition of these oils was evaluated, and total polyphenols, tocopherol composition, and some phenolic compounds were found highly concentrated in the hand-pressed oil. PRACTICAL APPLICATIONS: The present study highlights and compares the in vivo anti-inflammatory effect of polyphenolic compounds, extracted from Argan oil by two processes (hand and mechanical extraction). The study demonstrated the better quality of hand-pressed oil over mechanically pressed, supporting the traditional uses of this oil in treating several inflammations and pain-related situations. Moreover, the edible Argan oil may be introduced as a regular diet and food ingredient.
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http://dx.doi.org/10.1111/jfbc.13066DOI Listing
December 2019

Recent advances in untargeted and targeted approaches applied in herbal-extracts and essential-oils fingerprinting - A review.

J Pharm Biomed Anal 2020 Jan 30;177:112849. Epub 2019 Aug 30.

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, CePhaR, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium. Electronic address:

Herbal extracts and essential oils have been used over the centuries for their dietary, cosmetic and therapeutic properties. Quality control is needed to guarantee the safety and quality of these consumables. In this regard, fingerprinting techniques are important for inspection of the authenticity and for quality control. Analytical fingerprinting techniques provide signals related to the composition of a matrix (oil, plant extract, food…). The resulting fingerprint (spectrum or chromatogram) obtained for an untargeted or targeted approach is coupled to chemometric data processing, which may allow, for instance, the desired identification or discrimination of the sample considered. In this context, recent advances in untargeted/targeted fingerprinting approaches (especially chromatographic and spectroscopic) were described and their application in the taxonomic identification, classification and authentication of plants (medicinal) and essential oils discussed. An overview of the applications of untargeted/targeted fingerprinting techniques on herbal-extracts and essential-oils analysis, using different chemometric tools, has been included.
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http://dx.doi.org/10.1016/j.jpba.2019.112849DOI Listing
January 2020

A new potential anti-cancer beta-carboline derivative decreases the expression levels of key proteins involved in glioma aggressiveness: A proteomic investigation.

Drug Dev Res 2020 02 9;81(1):32-42. Epub 2019 Sep 9.

Department of Pharmacotherapy and Pharmaceutics, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium.

Gliomas remain highly fatal due to their high resistance to current therapies. Deregulation of protein synthesis contributes to cancer onset and progression and is a source of rising interest for new drugs. CM16, a harmine derivative with predicted high blood-brain barrier penetration, exerts antiproliferative effects partly through translation inhibition. We evaluated herein how CM16 alters the proteome of glioma cells. The analysis of the gel-free LC/MS and auto-MS/MS data showed that CM16 induces time- and concentration-dependent significant changes in the total ion current chromatograms. In addition, we observed spontaneous clustering of the samples according to their treatment condition and their proper classification by unsupervised and supervised analyses, respectively. A two-dimensional gel-based approach analysis allowed us to identify that treatment with CM16 may downregulate four key proteins involved in glioma aggressiveness and associated with poor patient survival (HspB1, BTF3, PGAM1, and cofilin), while it may upregulate galectin-1 and Ebp1. Consistently with the protein synthesis inhibition properties of CM16, HspB1, Ebp1, and BTF3 exert known roles in protein synthesis. In conclusion, the downregulation of HspB1, BTF3, PGAM1 and cofilin bring new insights in CM16 antiproliferative effects, further supporting CM16 as an interesting protein synthesis inhibitor to combat glioma.
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http://dx.doi.org/10.1002/ddr.21600DOI Listing
February 2020

Antioxidant activity of , , and fruits cultivated in Algeria.

Heliyon 2019 Apr 28;5(4):e01575. Epub 2019 Apr 28.

Department of Toxicology, Dermato-Cosmetology and Pharmacognosy, Vrije Universiteit Brussels, VUB Brussels, Belgium.

Four edible fruits from , , and from Algeria were analyzed in order to determine the total polyphenol, total flavonoid and flavonol contents using classical spectrophotometric methods. The antioxidant activity was established by three different single-electron-transfer-based assays (ABTS radical cation, FRAP, and DPPH assays) and one hydrogen-atom-transfer based assay (ORAC). Among the four fruits tested, the hydroalcoholic extract showed the highest antioxidant capacity with all methods. The results indicated that the antioxidant activity and the total phenolic content of the selected plants are significantly different ().
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http://dx.doi.org/10.1016/j.heliyon.2019.e01575DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6488748PMC
April 2019

Anti-inflammatory and sedative activities of : in vivo studies in mice.

Nat Prod Res 2021 May 29;35(10):1657-1661. Epub 2019 May 29.

Department of Biosciences, Faculty of Chemiscal Sciences, University of Cuenca, Cuenca, Ecuador.

Aerial parts (leaves, flowers, stem) of extract administered to mice, was used to confirm its anti-inflammatory and sedative folk uses. The anti-inflammatory activity was assessed by croton oil-induced ear oedema and myeloperoxidase (acute inflammation); cotton pellet-induced granuloma (sub-acute inflammation) and Lipopolysaccharide (LPS) induced inflammation (cellular mediators). The sedative activity was studied by the pentobarbital-induced sleeping time test. Single doses (300 and 600 mg/kg; i.p.) of the extract reduced croton oil-induced ear oedema and myeloperoxidase activity. Six days administration of the extract (300 mg/kg, i.p.) to mice implanted with cotton pellets diminished granuloma formation. LPS (20 mg/kg, i.p.) enhanced plasma nitrites and TNF-α levels that were inhibited by the extract. The duration but not the onset of sleeping time was enhanced by 300 and 600 mg/kg of the extract. Our results show that has anti-inflammatory and sedative activities in mice, which validates its traditional use.
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http://dx.doi.org/10.1080/14786419.2019.1622104DOI Listing
May 2021

Experimental Design Methodologies for the Optimization of Chiral Separations: An Overview.

Methods Mol Biol 2019 ;1985:453-478

Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, Vrije Universiteit Brussel (VUB), Brussels, Belgium.

In this chapter, the application of design of experiments (DoE) for chiral separation optimization using supercritical fluid chromatography (SFC), liquid chromatography (LC), capillary electrophoresis (CE), and capillary electrochromatography (CEC) methods is reviewed. Both screening and optimization steps are covered, including a discussion of each aspect, such as factor-, level-, and response selection. Different designs are also presented, highlighting their applications.
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http://dx.doi.org/10.1007/978-1-4939-9438-0_27DOI Listing
January 2020

Assessing the suitability of capillary electrophoresis-mass spectrometry for biomarker discovery in plasma-based metabolomics.

Electrophoresis 2019 09 2;40(18-19):2309-2320. Epub 2019 May 2.

Biomedical Microscale Analytics, Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands.

The actual utility of capillary electrophoresis-mass spectrometry (CE-MS) for biomarker discovery using metabolomics still needs to be assessed. Therefore, a simulated comparative metabolic profiling study for biomarker discovery by CE-MS was performed, using pooled human plasma samples with spiked biomarkers. Two studies have been carried out in this work. Focus of study I was on comparing two sets of plasma samples, in which one set (class I) was spiked with five isotope-labeled compounds, whereas another set (class II) was spiked with six different isotope-labeled compounds. In study II, focus was also on comparing two sets of plasma samples, however, the isotope-labeled compounds were spiked to both class I and class II samples but with concentrations which differ by a factor two between both classes (with one compound absent in each class). The aim was to determine whether CEMS-based metabolomics could reveal the spiked biomarkers as the main classifiers, applying two different data analysis software tools (MetaboAnalyst and Matlab). Unsupervised analysis of the recorded metabolic profiles revealed a clear distinction between class I and class II plasma samples in both studies. This classification was mainly attributed to the spiked isotope-labeled compounds, thereby emphasizing the utility of CE-MS for biomarker discovery.
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http://dx.doi.org/10.1002/elps.201900126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6767474PMC
September 2019
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