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70 result(s) for "Duez, Pierre"
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Biological activity and toxicity of the Chinese herb Magnolia officinalis Rehder & E. Wilson (Houpo) and its constituents
Traditional Chinese herbal drugs have been used for thousands of years in Chinese pharmacopoeia. The bark of Magnolia officinalis Rehder & E. Wilson, known under the pinyin name “Houpo”, has been traditionally used in Chinese and Japanese medicines for the treatment of anxiety, asthma, depression, gastrointestinal disorders, headache, and more. Moreover, Magnolia bark extract is a major constituent of currently marketed dietary supplements and cosmetic products. Much pharmacological activity has been reported for this herb and its major compounds, notably antioxidant, anti-inflammatory, antibiotic and antispasmodic effects. However, the mechanisms underlying this have not been elucidated and only a very few clinical trials have been published. In vitro and in vivo toxicity studies have also been published and indicate some intriguing features. The present review aims to summarize the literature on M. officinalis bark composition, utilisation, pharmacology, and safety.
Microfluidic Diffusion Sizing Applied to the Study of Natural Products and Extracts That Modulate the SARS-CoV-2 Spike RBD/ACE2 Interaction
The interaction between SARS-CoV-2 spike RBD and ACE2 proteins is a crucial step for host cell infection by the virus. Without it, the entire virion entrance mechanism is compromised. The aim of this study was to evaluate the capacity of various natural product classes, including flavonoids, anthraquinones, saponins, ivermectin, chloroquine, and erythromycin, to modulate this interaction. To accomplish this, we applied a recently developed a microfluidic diffusional sizing (MDS) technique that allows us to probe protein-protein interactions via measurements of the hydrodynamic radius (Rh) and dissociation constant (KD); the evolution of Rh is monitored in the presence of increasing concentrations of the partner protein (ACE2); and the KD is determined through a binding curve experimental design. In a second time, with the protein partners present in equimolar amounts, the Rh of the protein complex was measured in the presence of different natural products. Five of the nine natural products/extracts tested were found to modulate the formation of the protein complex. A methanol extract of Chenopodium quinoa Willd bitter seed husks (50 µg/mL; bisdesmoside saponins) and the flavonoid naringenin (1 µM) were particularly effective. This rapid selection of effective modulators will allow us to better understand agents that may prevent SARS-CoV-2 infection.
Examining overlap and homogeneity in ASD, ADHD, and OCD: a data-driven, diagnosis-agnostic approach
The validity of diagnostic labels of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and obsessive compulsive disorder (OCD) is an open question given the mounting evidence that these categories may not correspond to conditions with distinct etiologies, biologies, or phenotypes. The objective of this study was to determine the agreement between existing diagnostic labels and groups discovered based on a data-driven, diagnosis-agnostic approach integrating cortical neuroanatomy and core-domain phenotype features. A machine learning pipeline, called bagged-multiview clustering, was designed to discover homogeneous subgroups by integrating cortical thickness data and measures of core-domain phenotypic features of ASD, ADHD, and OCD. This study was conducted using data from the Province of Ontario Neurodevelopmental Disorders (POND) Network, a multi-center study in Ontario, Canada. Participants (n = 226) included children between the ages of 6 and 18 with a diagnosis of ASD (n = 112, median [IQR] age = 11.7[4.8], 21% female), ADHD (n = 58, median [IQR] age = 10.2[3.3], 14% female), or OCD (n = 34, median [IQR] age = 12.1[4.2], 38% female), as well as typically developing controls (n = 22, median [IQR] age = 11.0[3.8], 55% female). The diagnosis-agnostic groups were significantly different than each other in phenotypic characteristics (SCQ: χ2(9) = 111.21, p < 0.0001; SWAN: χ2(9) = 142.44, p < 0.0001) as well as cortical thickness in 75 regions of the brain. The analyses revealed disagreement between existing diagnostic labels and the diagnosis-agnostic homogeneous groups (normalized mutual information < 0.20). Our results did not support the validity of existing diagnostic labels of ASD, ADHD, and OCD as distinct entities with respect to phenotype and cortical morphology.
Perceptions and use of traditional African medicine in Lubumbashi, Haut-Katanga province (DR Congo): A cross-sectional study
In the Democratic Republic of Congo, the desire of the Ministry of Health to integrate Traditional African Medicine into the Official Health System remains limited by the lack of reliable data on several aspects of this medicine. This study aims to determine the perceptions of the Lubumbashi population towards Traditional African Medicine and the contexts of recourse to these therapeutic modalities. We conducted semi-structured interviews of population samples in each of the 7 Lubumbashi municipalities, which were semi-randomly selected in proportions to each population size, from January to June 2017 and from February to July 2018. A total of 4278 people (average age, 32.1 ± 10.4 years; 36.5% of women) have been surveyed. Among them, 75.8% define \"Traditional African Medicine\" as \"herbal-based treatments\"; 79.4% have resorted to traditional medicine, for several pathologies and social problems. This medicine was preferred for efficiency, speed of healing and low cost, as well as the presence of the diseases against which it would be the only one used. Most, (52.1%) have started with Conventional Medicine, then resorted to Traditional African Medicine, 34.7% started directly with Traditional African Medicine, while 13.2% combined these two medicines. From those who have resorted to Traditional African Medicine (n = 3396), 55% declare no concern towards traditional medicine, while 42.5% fear looseness, overdose, intoxication, and lack of hygiene; from those who have not resorted to Traditional African Medicine (n = 882), 78% are fearful of fear looseness, witchcraft, and fetishism. Traditional African Medicine remains an important health care resource for the Lubumbashi people. It is essential that decision-makers consider the importance of this health sector for the population, but also the reported fears and hindrances, and work towards the regulation, sanitization, and control of this medicine to ensure its safe use.
Impact of Growth Sites on the Phenolic Contents and Antioxidant Activities of Three Algerian Mentha Species (M. pulegium L., M. rotundifolia (L.) Huds., and M. spicata L.)
Research studies about the effect of environmental agents on the accumulation of phenolic compounds in medicinal plants are required to establish a set of optimal growth conditions. Hence, in this work, we considered the impact of habitat types, soil composition, climatic factors, and altitude on the content of phenolics in Mentha species [ M. pulegium L. (MP), M. rotundifolia (L.) Huds. (MR), and M. spicata L. (MS)] grown in different regions of Algeria. The phenolic contents and antioxidant activities were analyzed using spectrophotometric and HPTLC methods. The harvesting localities differ by their altitudes and climates, but their soils are quite similar, characterized by slight alkalinity, moderate humidity, no-salinity, and high levels in organic matter. Both the contents in total phenolics (TPC), total flavonoids (TFC), and rosmarinic acid (RAC), and the antioxidant activities of Mentha samples collected from these Algerian localities are affected by the geographical regions of origin. The samples of MS and MP from the Khemis–Miliana region showed the highest concentration in TPC (MS, 7853 ± 265 mg GAE/100 g DW; MP, 5250 ± 191 mg GAE/100 g DW), while in Chemini, the MR samples were the richest in these compounds (MR, 3568 ± 195 mg GAE/100 g DW). Otherwise, the MP (from Tichy), MR (from Tajboudjth), and MS (from Khemis–Miliana) specimens exhibited the highest levels of TFC and RAC. The antioxidant levels in a total activity test (reduction of phosphomolybdate) appear correlated with the total phenolic contents, but this was not the case for most of the important ROS-scavenging and iron-chelating capacities for which the quality of polyphenols is probably more important than their amounts. A principal component analysis (PCA) score plot indicates that all of the Mentha samples can be divided into four groups. These discriminated groups appear comparatively similar in phenolic contents and antioxidant activities. As for the harvest localities, the Mentha samples were divided into four groups in which the phenolic contents and antioxidant activities were comparatively equivalent.
Endogenous Synthesis of Tetrahydroisoquinoline Derivatives from Dietary Factors: Neurotoxicity Assessment on a 3D Neurosphere Culture
Tetrahydroisoquinoline (THIQ) alkaloids and their derivatives have a structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a well-known neurotoxin. THIQs seem to present a broad range of actions in the brain, critically dependent on their catechol moieties and metabolism. These properties make it reasonable to assume that an acute or chronic exposure to some THIQs might lead to neurodegenerative diseases including essential tremor (ET). We developed a method to search for precursor carbonyl compounds produced during the Maillard reaction in overcooked meats to study their reactivity with endogenous amines and identify the reaction products. Then, we predicted in silico their pharmacokinetic and toxicological properties toward the central nervous system. Finally, their possible neurological effects on a novel in vitro 3D neurosphere model were assessed. The obtained data indicate that meat is an alkaloid precursor, and we identified the alkaloid 1-benzyl-1,2,3,4-tetrahydroisoquinoline-6,7-diol (1-benz-6,7-diol THIQ) as the condensation product of phenylacetaldehyde with dopamine; in silico study of 1-benz-6,7-diol-THIQ reveals modulation of dopamine receptor D1 and D2; and in vitro study of 1-benz-6,7-diol-THIQ for cytotoxicity and oxidative stress induction does not show any difference after 24 h contact for all tested concentrations. To conclude, our in vitro data do not support an eventual neurotoxic effect for 1-benz-6,7-diol-THIQ.
Natural Deep Eutectic Solvents (NADESs) for the Extraction of Bioactive Compounds from Quinoa (Chenopodium quinoa Willd.) Leaves: A Semi-Quantitative Analysis Using High Performance Thin-Layer Chromatography
Natural deep eutectic solvents (NADESs) have emerged as a promising eco-friendly alternative to petrochemicals for extracting plant metabolites. Considering that the demand for sustainable “green” ingredients for industrial applications is growing, those solvents are purported to develop extracts with interesting phytochemical fingerprints and biological activities. Given the interest in flavonoids from Chenopodium quinoa Willd. leaves, an efficient “green” extraction method was developed by investigating eight NADESs with defined molar ratios, i.e., malic acid-choline chloride (chcl)-water (w) (1:1:2, N1), chcl-glucose-w (5:2:5, N2), proline-malic acid-w (1:1:3, N3), glucose-fructose-sucrose-w (1:1:1:11, N4), 1,2-propanediol-chcl-w (1:1:1, N5), lactic acid-glucose-w (5:1:3, N6), glycerol-chcl-w (2:1:1, N7), and xylitol-chcl-w (1:2:3, N8). Rheological measurements of all NADESs confirmed their pseudoplastic behaviors. To improve the extraction processes, differential scanning calorimetry (DSC) allowed us to determine the maximum amount of water that could be added to the most stable NADES (N1, N2, N3, and N4; 17.5%, 20%, 10%, and 10% w/w, respectively) to lower their viscosities without disturbing their eutectic environments. The phytochemical compositions of NADES extracts were analyzed using high-performance thin-layer chromatography (HPTLC), and their free radical scavenging and α-amylase inhibitory properties were assessed using HPTLC-bioautography. N2, diluted with 20% of water, and N7 presented the best potential for replacing methanol for an eco-friendly extraction of flavonoids, radical scavengers, and α-amylase inhibitors from quinoa leaves. Their biological properties, combined with a good understanding of both thermal behavior and viscosity, make the obtained quinoa leaf NADES extracts good candidates for direct incorporation in nutraceutical formulations.
Asteraceae Paradox: Chemical and Mechanical Protection of Taraxacum Pollen
Excessive pollen harvesting by bees can compromise the reproductive success of plants. Plants have therefore evolved different morphological structures and floral cues to narrow the spectrum of pollen feeding visitors. Among “filtering” mechanisms, the chemical and mechanical protection of pollen might shape bee-flower interactions and restrict pollen exploitation to a specific suite of visitors such as observed in Asteraceae. Asteraceae pollen is indeed only occasionally exploited by generalist bee species but plentifully foraged by specialist ones (i.e., Asteraceae paradox). During our bioassays, we observed that micro-colonies of generalist bumblebee (Bombus terrestris L.) feeding on Taraxacum pollen (Asteraceae) reduced their pollen collection and offspring production. Bees also experienced physiological effects of possible defenses in the form of digestive damage. Overall, our results suggest the existence of an effective chemical defense in Asteraceae pollen, while the hypothesis of a mechanical defense appeared more unlikely. Pre- and post-ingestive effects of such chemical defenses (i.e., nutrient deficit or presence of toxic compounds), as well as their role in the shaping of bee-flower interactions, are discussed. Our results strongly suggest that pollen chemical traits may act as drivers of plant selection by bees and partly explain why Asteraceae pollen is rare in generalist bee diets.
Pseudomonas aeruginosa Biofilm Formation and Persistence, along with the Production of Quorum Sensing-Dependent Virulence Factors, Are Disrupted by a Triterpenoid Coumarate Ester Isolated from Dalbergia trichocarpa, a Tropical Legume
Recently, extracts of Dalbergia trichocarpa bark have been shown to disrupt P. aeruginosa PAO1 quorum sensing (QS) mechanisms, which are key regulators of virulence factor expression and implicated in biofilm formation. One of the active compounds has been isolated and identified as oleanolic aldehyde coumarate (OALC), a novel bioactive compound that inhibits the formation of P. aeruginosa PAO1 biofilm and its maintenance as well as the expression of the las and rhl QS systems. Consequently, the production of QS-controlled virulence factors including, rhamnolipids, pyocyanin, elastase and extracellular polysaccharides as well as twitching and swarming motilities is reduced. Native acylhomoserine lactones (AHLs) production is inhibited by OALC but exogenous supply of AHLs does not restore the production of virulence factors by OALC-treated cultures, indicating that OALC exerts its effect beyond AHLs synthesis in the QS pathways. Further experiments provided a significant inhibition of the global virulence factor activator gacA by OALC. OALC disorganizes established biofilm structure and improves the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Finally, a significant reduction of Caenorhabditis elegans paralysis was recorded when the worms were infected with OALC-pre-treated P. aeruginosa. Taken together, these results show that triterpenoid coumarate esters are suitable chemical backbones to target P. aeruginosa virulence mechanisms.
Perceptions and use of traditional African medicine in Lubumbashi, Haut-Katanga province (DR Congo): A cross-sectional study
In the Democratic Republic of Congo, the desire of the Ministry of Health to integrate Traditional African Medicine into the Official Health System remains limited by the lack of reliable data on several aspects of this medicine. This study aims to determine the perceptions of the Lubumbashi population towards Traditional African Medicine and the contexts of recourse to these therapeutic modalities. We conducted semi-structured interviews of population samples in each of the 7 Lubumbashi municipalities, which were semi-randomly selected in proportions to each population size, from January to June 2017 and from February to July 2018. A total of 4278 people (average age, 32.1 ± 10.4 years; 36.5% of women) have been surveyed. Among them, 75.8% define \"Traditional African Medicine\" as \"herbal-based treatments\"; 79.4% have resorted to traditional medicine, for several pathologies and social problems. This medicine was preferred for efficiency, speed of healing and low cost, as well as the presence of the diseases against which it would be the only one used. Most, (52.1%) have started with Conventional Medicine, then resorted to Traditional African Medicine, 34.7% started directly with Traditional African Medicine, while 13.2% combined these two medicines. From those who have resorted to Traditional African Medicine (n = 3396), 55% declare no concern towards traditional medicine, while 42.5% fear looseness, overdose, intoxication, and lack of hygiene; from those who have not resorted to Traditional African Medicine (n = 882), 78% are fearful of fear looseness, witchcraft, and fetishism. Traditional African Medicine remains an important health care resource for the Lubumbashi people. It is essential that decision-makers consider the importance of this health sector for the population, but also the reported fears and hindrances, and work towards the regulation, sanitization, and control of this medicine to ensure its safe use.