Intestinal permeability and gut microbiota interactions of phytochemicals from herbal drugs used in the treatment of depressive, anxiety and sleeping disorders

The use of herbal medicines to treat depression, anxiety and sleeping disorders is a tendency that has increased over the past decades. Valerian (Valeriana officinalis L., Caprifoliaceae), St. John’s wort (Hypericum perforatum L., Hypericaceae) and California poppy (Eschscholzia californica, Cham., Papaveraceae) are herbal medicines that are commonly used for the management of these disorders. They contain pharmacologically relevant compounds such as valerenic acid (valerian), hyperforin and hypericin (St. John’s wort), and californidine, escholtzine and protopine (California poppy). To date, the intestinal permeability of these herbal compounds has been poorly investigated. In addition, the reciprocal interactions between these compounds and the human gut microbiota have not been explored; in particular, their possible biotransformation by the gut microbiome, or a possible impact of the exposure of these herbal compounds or extracts on the microbial metabolism of short-chain fatty acids (SCFAs) and on the bacterial viability. In light of the growing number of studies describing the biotransformation of oral compounds (drugs, dietary compounds, or phytochemicals) by the gut microbiome, or the emerging evidence that gut microbial metabolites such as SCFAs play a significant role in the modulation of the central nervous system (CNS) via the microbiota-gut-brain axis, an assessment of these gut microbiota interactions is necessary. Finally, considering herbal medicines, unlike for valerian and St. John’s wort, only very few studies have determined the contents of pharmacologically active constituents in commercial preparations of California poppy (californidine, escholtzine and protopine), making it challenging to estimate the levels that can be anticipated in patients. Firstly, the intestinal permeability of herbal compounds valerenic acid, hyperforin, hypericin, californidine, escholtzine and protopine was studied, with filter-grown Caco-2 cell monolayers as a model of the human small intestinal epithelium. The model was validated with markers of low-to-moderately and highly permeable compounds, atenolol and propranolol, respectively. The transport of all compounds was assessed in both directions, from apical to basolateral and vice versa. Thereafter, the gut microbiota interactions between herbal extracts and compounds were evaluated with short-term batch fermentation experiments (24 h) using an in vitro gut microbiota, the Polyfermentor Intestinal Model (PolyFermS). Experiments were conducted with effluents from two PolyFermS, each one generated from a different healthy fecal donor. The validity of both PolyFermS was confirmed by stable gut microbiota composition and steady metabolic activity (production of SCFAs), hallmarks of a healthy gut microbiome. Batch fermentation experiments allowed, on the one hand, the assessment of a microbiota-mediated biotransformation of herbal compounds, and on the other hand, the measurement of microbial metabolic activity (SCFAs production) and bacterial viability in the presence of herbal compounds and extracts. SCFAs were quantified by HPLC coupled with a refractive index detector and total viable and dead bacterial cells were determined by flow cytometry. Furthermore, the contents of californidine, escholtzine and protopine were determined in eight commercial preparations of California poppy, sold as phytomedicines or food supplements. The preparations consisted of dry herbal powders, dry extracts or fluid extracts of flowering aerial parts of California poppy. For each herbal compound, a sensitive and selective UHPLC-MS/MS method was developed and validated for the analysis of Caco-2 cells, gut microbiota and California poppy samples. Valerenic acid, hyperforin, escholtzine and protopine were highly absorbed in the Caco-2 cell model. A carrier-mediated process was possibly involved in the transport of valerenic acid (uptake), escholtzine (efflux) and protopine (efflux), whereas hyperforin was likely transported by passive diffusion. In addition, the low recovery values (13 – 69%) obtained for valerenic acid, escholtzine and protopine suggest that the compounds might be metabolized in the Caco-2 cells. In turn, hypericin and californidine showed a low-to-moderate absorption, possibly with passive diffusion as transport process for hypericin and active transport for californidine (efflux). These data indicate that hypericin and californidine have the potential to be found at relevant concentrations in the colon segment, where the gut microbiome is the densest. All the herbal compounds showed a high stability in the batch fermentation experiments, suggesting that they are not biotransformed by the human gut microbiome. These results support that the disposition of these herbal compounds is not influenced by the gut microbiome. Furthermore, the exposure of herbal extracts and compounds did not markedly impact the bacterial metabolism of SCFAs or the bacterial viability. This suggests that valerian, St. John’s wort or California poppy, at the tested concentrations, may not exert an indirect effect on the CNS via modulation of bacterial SCFAs implicated in microbiota-gut-brain axis signaling, at least not after a short-term exposure (24 h). Given the high inter-individual variabilities between human gut microbiota and short-term experiments setup, these findings need to be confirmed with a larger number of microbiota and with continuous fermentation models to further evaluate the possible impact on microbiota metabolic activity and bacterial viability, over a prolonged exposure. Alkaloid contents differed strongly between the commercial products of California poppy, ranging from 0.13 – 2.55 mg/g for californidine, 0.05 – 0.63 mg/g for escholtzine and 0.008 – 0.200 mg/g for protopine. These marked variations are likely due, at least in part, to differing extraction procedures. Based on these data and the dosage recommended by manufacturers, maximum daily doses for the three alkaloids were calculated to range from 0.16 to 2.97, 0.10 to 1.11, and 0.02 to 0.31 mg/day, respectively. Thus, for patients using different California poppy preparations, significant variations in the daily intake of californidine, escholtzine and protopine, have to be expected

Immunological evaluation of herbal extracts commonly used for treatment of mental diseases during pregnancy

Nonpsychotic mental diseases (NMDs) affect approximately 15% of pregnant women in the US. Herbal preparations are perceived a safe alternative to placenta-crossing antidepressants or benzodiazepines in the treatment of nonpsychotic mental diseases. But are these drugs really safe for mother and foetus? This question is of great relevance to physicians and patients. Therefore, this study investigates the influence of St. John's wort, valerian, hops, lavender, and California poppy and their compounds hyperforin and hypericin, protopine, valerenic acid, and valtrate, as well as linalool, on immune modulating effects in vitro. For this purpose a variety of methods was applied to assess the effects on viability and function of human primary lymphocytes. Viability was assessed via spectrometric assessment, flow cytometric detection of cell death markers and comet assay for possible genotoxicity. Functional assessment was conducted via flow cytometric assessment of proliferation, cell cycle and immunophenotyping. For California poppy, lavender, hops, and the compounds protopine and linalool, and valerenic acid, no effect was found on the viability, proliferation, and function of primary human lymphocytes. However, St. John's wort and valerian inhibited the proliferation of primary human lymphocytes. Hyperforin, hypericin, and valtrate inhibited viability, induced apoptosis, and inhibited cell division. Calculated maximum concentration of compounds in the body fluid, as well as calculated concentrations based on pharmacokinetic data from the literature, were low and supported that the observed effects in vitro would probably have no relevance on patients. In-silico analyses comparing the structure of studied substances with the structure of relevant control substances and known immunosuppressants revealed structural similarities of hyperforin and valerenic acid to the glucocorticoids. Valtrate showed structural similarities to the T cells signaling modulating drugs

Medicinal Plants for the Treatment of Mental Diseases in Pregnancy: An In Vitro Safety Assessment

Pregnancy is a critical period for medical care, during which the well-being of woman and fetus must be considered. This is particularly relevant in managing non-psychotic mental disorders since treatment with central nervous system-active drugs and untreated NMDs may have negative effects. Some well-known herbal preparations (phytopharmaceuticals), including St. Johnʼs wort, California poppy, valerian, lavender, and hops, possess antidepressant, sedative, anxiolytic, or antidepressant properties and could be used to treat mental diseases such as depression, restlessness, and anxiety in pregnancy. Our goal was to assess their safety in vitro, focusing on cytotoxicity, induction of apoptosis, genotoxicity, and effects on metabolic properties and differentiation in cells widely used as a placental cell model (BeWo b30 placenta choriocarcinoma cells). The lavender essential oil was inconspicuous in all experiments and showed no detrimental effects. At low-to-high concentrations, no extract markedly affected the chosen safety parameters. At an artificially high concentration of 100 µg/mL, extracts from St. Johnʼs wort, California poppy, valerian, and hops had minimal cytotoxic effects. None of the extracts resulted in genotoxic effects or altered glucose consumption or lactate production, nor did they induce or inhibit BeWo b30 cell differentiation. This study suggests that all tested preparations from St. Johnʼs wort, California poppy, valerian, lavender, and hops, in concentrations up to 30 µg/mL, do not possess any cytotoxic or genotoxic potential and do not compromise placental cell viability, metabolic activity, and differentiation. Empirical and clinical studies during pregnancy are needed to support these in vitro data

Role of SiC substrate surface on local tarnishing of deposited silver mirror stacks

International audienceThe role of the SiC substrate surface on the resistance to the local initiation of tarnishing of thin-layered silver stacks for demanding space mirror applications was studied by combined surface and interface analysis on model stack samples deposited by cathodic magnetron sputtering and submitted to accelerated aging in gaseous H2S. It is shown that suppressing the surface pores resulting from the bulk SiC material production process by surface pretreatment eliminates the high aspect ratio surface sites that are imperfectly protected by the SiO2 overcoat after the deposition of silver. The formation of channels connecting the silver layer to its environment through the failing protection layer at the surface pores and locally enabling H2S entry and Ag2S growth as columns until emergence at the stack surface is suppressed, which markedly delays tarnishing initiation and thereby preserves the optical performance. The results revealed that residual tarnishing initiation proceeds by a mechanism essentially identical in nature but involving different pathways short circuiting the protection layer and enabling H2S ingress until the silver layer. These permeation pathways are suggested to be of microstructural origin and could correspond to the incompletely coalesced intergranular boundaries of the SiO2 layer

Local Degradation Mechanisms by Tarnishing of Protected Silver Mirror Layers Studied by Combined Surface Analysis

International audienceIn this work, we addressed the local degradation mechanisms limiting the pre-launch environmental durability of thin-layered silver stacks for demanding space mirror applications. Local initiation and propagation of tarnishing were studied by combined surface and interface analysis on model stack samples consisting of thin silver layers supported on light-weight SiC substrates and protected by thin SiO2 overcoats, deposited by cathodic magnetron sputtering and submitted to accelerated aging in gaseous H2S. The results show that tarnishing is locally initiated by the formation of Ag2S columns erupting above the stack surface. Ag2S growth is promoted at high aspect ratio defects (surface pores) of the SiC substrate as a result of an imperfect protection by the SiO2 overcoat. Channels most likely connect the silver layer to its environment through the protection layer, which enables local H2S entry and Ag2S growth. The silver sulfide columns grow in number and size eventually leading to coalescence with increasing H2S exposure. In more advanced stages, tarnishing slows down owing to saturation of all pre-existing imperfectly protected sites of preferential sulfidation. However, it progresses radially at the basis of the Ag2S columns underneath the protection layer, consuming the metallic silver layer and deteriorating the protecting overcoat

Intestinal permeability and gut microbiota interactions of pharmacologically active compounds in valerian and St. John’s wort

Phytomedicines such as valerian and St. John's wort are widely used for the treatment of sleeping disorders, anxiety and mild depression. They are perceived as safe alternatives to synthetic drugs, but limited information is available on the intestinal absorption and interaction with human intestinal microbiota of pharmacologically relevant constituents valerenic acid in valerian, and hyperforin and hypericin in St. John's wort. The intestinal permeability of these compounds and the antidepressant and anxiolytic drugs citalopram and diazepam was investigated in the Caco-2 cell model with bidirectional transport experiments. In addition, interaction of compounds and herbal extracts with intestinal microbiota was evaluated in artificial human gut microbiota. Microbiota-mediated metabolisation of compounds was assessed, and bacterial viability and short-chain fatty acids (SCFA) production were measured in the presence of compounds or herbal extracts. Valerenic acid and hyperforin were highly permeable in Caco-2 cell monolayers. Hypericin showed low-to-moderate permeability. An active transport process was potentially involved in the transfer of valerenic acid. Hyperforin and hypericin were mainly transported through passive transcellular diffusion. All compounds were not metabolized over 24 h in the artificial gut microbiota. Microbial SCFA production and bacterial viability was not substantially impaired nor promoted by exposure to the compounds or herbal extracts

Placental Passage of Protopine in an Ex Vivo Human Perfusion System

The placental passage of protopine was investigated with a human ex vivo placental perfusion model. The model was first validated with diazepam and citalopram, 2 compounds known to cross the placental barrier, and antipyrine as a positive control. All compounds were quantified by partially validated U(H)PLC-MS/MS bioanalytical methods. Protopine was transferred from the maternal to the fetal circuit, with a steady-state reached after 90 min. The study compound did not affect placental viability or functionality, as glucose consumption, lactate production, and beta-human chorionic gonadotropin, and leptin release remained constant. Histopathological evaluation of all placental specimens showed unremarkable, age-appropriate parenchymal maturation with no pathologic findings

Transplacental passage of hyperforin, hypericin, and valerenic acid

Safe medications for mild mental diseases in pregnancy are needed. Phytomedicines from St. John’s wort and valerian are valid candidates, but safety data in pregnancy are lacking. The transplacental transport of hyperforin and hypericin (from St. John’s wort), and valerenic acid (from valerian) was evaluated using the ex vivo cotyledon perfusion model (4 h perfusions, term placentae) and, in part, the in vitro Transwell assay with BeWo b30 cells. Antipyrine was used for comparison in both models. U(H)PLC-MS/MS bioanalytical methods were developed to quantify the compounds. Perfusion data obtained with term placentae showed that only minor amounts of hyperforin passed into the fetal circuit, while hypericin did not cross the placental barrier and valerenic acid equilibrated between the maternal and fetal compartments. None of the investigated compounds affected metabolic, functional, and histopathological parameters of the placenta during the perfusion experiments. Data from the Transwell model suggested that valerenic acid does not cross the placental cell layer. Taken together, our data suggest that throughout the pregnancy the potential fetal exposure to hypericin and hyperforin – but not to valerenic acid – is likely to be minimal

Redocumentariser la Tapisserie de Bayeux : base de données documentaire et système d’informations spatialisées

Dans le cadre du projet de refonte du Musée de la Tapisserie de Bayeux à l’horizon 2024, mené par la Ville de Bayeux et la DRAC Normandie, en collaboration avec la région Normandie et le département Calvados, des outils numériques permettant de découvrir et d’étudier la Tapisserie sous un angle nouveau ont été élaborés.Ces outils consistent en un « Système d’information documentaire spatialisée » (SIDS), combinaison d’un système documentaire et d’un système d’information spatialisé. Ils offrent des solutions de gestion et de valorisation des ressources documentaires relatives à la Tapisserie de Bayeux, et doivent à terme accompagner l’ensemble des publics qui s’intéressent à l’œuvre, notamment les chercheurs en sciences humaines, les conservateurs-restaurateurs, les spécialistes du textile, le grand public. Ce projet est le fruit d’un étroit partenariat entre l’État, la Ville de Bayeux, l’université de Caen Normandie, le CNRS et l’Ensicaen.Alongside the renewal of the Bayeux Tapestry Museum planned for 2024, led by the city of Bayeux, the DRAC Normandy, the Normandy region and the Calvados department, several numeric tools have been created to discover and examine the Tapestry in new ways.Those tools consist in a Spatialised Document Information System (SDIS), combining a Document database and a Spatialised information system. They offer solutions to manage and to enhance documentary resources related to the Bayeux Tapestry and should, at the end, accompany all the persons interested in the Tapestry, particularly scholars in Humanities, curators-restorers, specialists in textile and the public. This project is the result of a close collaboration between the State, the city of Bayeux, the University of Caen Normandy, the CNRS and the Ensicaen.Nell’ambito del progetto di ristrutturazione del Museo dell’Arazzo di Bayeux che dovrebbe concludersi nel 2024, portato avanti dalla Città di Bayeux e dalla DRAC Normandie, in collaborazione con la regione Normandia e il dipartimento del Calvados, sono stati elaborati nuovi strumenti informatici che permettono di scoprire e studiare l’Arazzo da un nuovo punto di vista.Questi strumenti consistono in un « Sistema d’informazione documentaria spazializzata » (SIDS), combinazione di un sistema documentario e di un sistema d’informazione spazializzato. Essi offrono delle soluzioni di gestione e di valorizzazione delle fonti documentarie relative all’Arazzo di Bayeux, e devono accompagnare i vari fruitori dell’opera, soprattutto i ricercatori in scienze umane, i conservatori-restauratori, gli specialisti del tessile, il grande pubblico. Questo progetto è il frutto di uno stretto partenariato tra lo Stato, la Città di Bayeux, l’Università di Caen Normandie, il CNRS e l’ENSICAEN