Anti-diarrheal mechanism of the traditional remedy Uzara via reduction of active chloride secretion

Matrix-free human 2D organoids recapitulate duodenal barrier and transport properties

BACKGROUND

Traditionally, transformed cell line monolayers have been the standard model for studying epithelial barrier and transport function. Recently, intestinal organoids were proposed as superior in recapitulating the intestine. Typically, 3D organoids are digested and seeded as monolayers on gelatinous matrix pre-coated surfaces for anchorage. As this coat could potentially act as a diffusion barrier, we aimed to generate robust human duodenum-derived organoid monolayers that do not need a gelatinous matrix for anchorage to improve upon existing models to study epithelial transport and barrier function.

RESULTS

We characterized these monolayers phenotypically regarding polarization, tight junction formation and cellular composition, and functionally regarding uptake of nutrients, ion transport and cytokine-induced barrier dysfunction. The organoid monolayers recapitulated the duodenum phenotypically as well as functionally regarding glucose and short-chain fatty acid uptake. Tumour necrosis factor-alpha induced paracellular transport of 4-kDa Dextran and transcytosis of 44-kDa horseradish peroxidase. Notably, forskolin-stimulated chloride secretion was consistently lower when organoid monolayers were seeded on a layer of basement membrane extract (BME).

CONCLUSIONS

BME-free organoid monolayers represent an improved model for studying transcytotic, paracellular but especially transcellular transport. As BME is extracted from mice, our model furthers efforts to make organoid culture more animal-free.

Uzara (Xysmalobium undulatum) - An underutilized anti-diarrhoeic and spasmolytic herbal remedy

ETHNOPHARMACOLOGICAL RELEVANCE

Uzara, Xysmalobium undulatum (L.) W.T.Aiton, a herbal medicine for diarrhoea and smooth-muscle cramps is little-known outside Germany, where it has had a market presence for ∼110 years. The early introduction of this Southern African medicinal plant into Europe and the US was entrepreneurially driven, similar to buchu (Agathosma spp.) and Umckaloabo (Pelargonium sidoides DC.). Much of its history of commercialization, from its origin, identity and supply chain to its composition and clinical evidence of efficacy and safety, has been poorly studied and/or scantly published.

AIM OF THE STUDY

The aim of this review is to uncover enough data to create a coherent timeline, many of which are published here for the first time, and to evaluate all published data, mostly historical and/or elusive, to corroborate Uzara's status as a safe and efficacious botanical medicine.

MATERIALS AND METHODS

Multiple searches were conducted in the PubMed, Scopus, Web of Science, Science Direct, and Google Scholar databases with the following keywords: all scientific and common plant names combined with taxonomy, nomenclature, ethnobotany, traditional use, ecology, cultivation, sustainability, economy, trade, CITES, chemistry, biochemistry, compounds, pre-clinical, pharmacology, clinical, RCT, safety, toxicology, veterinary, review for the period of 1600-2022. Reference sections of selected publications were searched manually. Additionally, product registration databases of national competent health authorities in Europe were consulted for products, license holders and formulations.

RESULTS

The authors find an underutilized potential of uzara as anti-diarrhoeic (with or without underlying infection) and spasmolytic remedy. A by-product of this review is a largely inclusive bibliography of publications on uzara.

CONCLUSIONS

Further clinical research supporting antidiarrhoeal and spasmolytic efficacy would be desirable.

E. coli infection disrupts the epithelial barrier and activates intrinsic neurosecretory reflexes in the pig colon

This study aims to assess the barrier integrity and possible activation of enteric neural pathways associated with secretion and motility in the pig colon induced by an enterotoxigenic Escherichia coli (ETEC) challenge. 50 Danbred male piglets were used for this study. 16 were challenged with an oral dose of the ETEC strain F4+ 1.5 × 10⁹ colony-forming unit. Colonic samples were studied 4- and 9-days post-challenge using both a muscle bath and Ussing chamber. Colonic mast cells were stained with methylene blue. In control animals, electrical field stimulation induced neurosecretory responses that were abolished by tetrodotoxin (10^-6M) and reduced by the combination of atropine (10^-4M) and α-chymotrypsin (10U/mL). Exogenous addition of carbachol, vasoactive intestinal peptide, forskolin, 5-HT, nicotine, and histamine produced epithelial Cl^- secretion. At day 4 post-challenge, ETEC increased the colonic permeability. The basal electrogenic ion transport remained increased until day 9 post-challenge and was decreased by tetrodotoxin (10^-6M), atropine (10^-4M), hexamethonium (10^-5M), and ondansetron (10^-5M). In the muscle, electrical field stimulation produced frequency-dependent contractile responses that were abolished with tetrodotoxin (10^-6M) and atropine (10^-6M). Electrical field stimulation and carbachol responses were not altered in ETEC animals in comparison with control animals at day 9 post-challenge. An increase in mast cells, stained with methylene blue, was observed in the mucosa and submucosa but not in the muscle layer of ETEC-infected animals on day 9 post-challenge. ETEC increased the response of intrinsic secretory reflexes and produced an impairment of the colonic barrier that was restored on day 9 post-challenge but did not modify neuromuscular function.

A Review of Preclinical Tools to Validate Anti-Diarrheal Agents

BACKGROUND

Since their inception, preclinical experimental models have played an important role in investigating and characterizing disease pathogenesis. These in vivo, ex vivo, and in vitro preclinical tests also aid in identifying targets, evaluating potential therapeutic drugs, and validating treatment protocols.

INTRODUCTION

Diarrhea is a leading cause of mortality and morbidity, particularly among children in developing countries, and it represents a huge health-care challenge on a global scale. Due to its chronic manifestations, alternative anti-diarrheal medications must be tested and developed because of the undesirable side effects of currently existing anti-diarrheal drugs.

METHODS

Several online databases, including Science Direct, PubMed, Web of Science, Google Scholar and Scopus, were used in the literature search. The datasets were searched for entries of studies up to May, 2022.

RESULTS

The exhaustive literature study provides a large number of in vivo, in vitro and ex vivo models, which have been used for evaluating the mechanism of the anti-diarrheal effect of drugs in chemically-, pathogen-, disease-induced animal models of diarrhea. The advances and challenges of each model were also addressed in this review.

CONCLUSION

This review encompasses diverse strategies for screening drugs with anti-diarrheal effects and covers a wide range of pathophysiological and molecular mechanisms linked to diarrhea, with a particular emphasis on the challenges of evaluating and predictively validating these experimental models in preclinical studies. This could also help researchers find a new medicine to treat diabetes more effectively and with fewer adverse effects.

High affinity interaction of Solanum tuberosum and Brassica juncea residue smoke water compounds with proteins involved in coronavirus infection

The world is in an immediate need of treatment for coronavirus disease (COVID-19). Chronic exposure of hydroxychloroquine in the treatment of COVID-19 may have multiple adverse effects on human physiology, such as cardiac arrhythmias. Natural compounds need to be evaluated as treatment and preventive agents in coronavirus infection. A total of 30 compounds of Solanum tuberosum and Brassica juncea residue smoke water were selected for the virtual screening against SARS-CoV-1, SARS-CoV-2 and cellular proteins involved in the mechanism of infection. Docking analysis identified lead molecules with favorable binding energy, number of poses and hydrogen bond interactions, which indicates the effective modulation of ACE2 and TMPRSS2 receptors. Results indicated (a) curcumenol, (b) N-desmethylselegiline, (c) phentermine and (d) sphingolipid derivatives as a selective and potent candidates in comparison to hydroxychloroquine for COVID-19 treatment. Our in silico findings, therefore, warrant further in vitro validations of the selected compounds for the discovery of novel preventive and therapeutic drug against SARS-CoV-2 infection.

Anti-diarrhoeal activity of a polyherbal formulation in rats and elucidation of its cellular mechanisms

OBJECTIVE

The present study was aimed to study anti-diarrhoeal activity of a polyherbal formulation (PHF) in rats and elucidate its mechanism of action.

MATERIALS AND METHODS

Anti-diarrhoeal activity of PHF was investigated using castor oil-induced diarrhoea, small intestinal transit and enteropooling models in rats. PHF was tested at 75, 150 and 300 mg/kg rat body weight. Loperamide was used as a reference control for in vivo studies. Anti-secretory action was evaluated against heat labile enterotoxin (from Escherichia coli) induced secretion in rat ileal loop model. The effect of PHF (12.5-100 µg/ml) on cAMP-dependent secretory activity was investigated against forskolin-induced cAMP release in HT-29 cells.

RESULTS

PHF demonstrated significant (p≤0.05) anti-diarrhoeal activity by increasing the time for first faecal drop and inhibited diarrhoeal episodes by 43, 58 and 60% at 75, 150 and 300 mg/kg body weight, respectively in a dose-dependent manner. Also, the intestinal transit was inhibited upto 33% and the weight of secretory contents induced by castor oil was significantly reduced by PHF, approximately 29% in enteropooling assay. On the other hand, the intestinal loop instilled with PHF and enterotoxin from E. coli demonstrated 61% inhibition of fluid accumulation as compared to loop instilled with enterotoxin only. In vitro studies indicated that PHF inhibits cAMP release in HT-29 cells corroborating the anti-secretory effects observed in aforesaid studies.

CONCLUSION

The results suggest that the PHF possesses anti-diarrhoeal activity, evident through reduced faecal output, decreased intestinal transit and anti-secretory activities.

A sub-chronic Xysmalobium undulatum hepatotoxicity investigation in HepG2/C3A spheroid cultures compared to an in vivo model

ETHNOPHARMACOLOGY RELEVANCE

Traditional herbal medicines are utilized by 27 million South Africans. Xysmalobium undulatum (Uzara) is one of the most widely used traditional medicinal plants in Southern Africa. A false belief in the safety of herbal medicine may result in liver injury. Herb-induced liver injury (HILI) range from asymptomatic elevation of liver enzymes, to cirrhosis and in certain instances even acute liver failure. Various in vitro and in vivo models are available for the pre-clinical assessment of drug and herbal hepatotoxicity. However, more reliable and readily available in vitro models are needed, which are capable of bridging the gap between existing models and real human exposure. Three-dimensional (3D) spheroid cultures offer higher physiological relevance, overcoming many of the shortcomings of traditional two-dimensional cell cultures.

AIMS OF THIS STUDY

This study investigated the hepatotoxic and anti-prolific effects of the crude X. undulatum aqueous extract during a sub-chronic study (21 days), in both a 3D HepG2/C3A spheroid model and the Sprague Dawley rat model.

METHODS

HepG2/C3A spheroids were treated with a known hepatotoxin, valproic acid, and crude X. undulatum aqueous extract for 21 days with continuous evaluation of cell viability and proliferation. This was done by evaluating cell spheroid growth, intracellular adenosine triphosphate (ATP) levels and extracellular adenylate kinase (AK). Sprague Dawley rats were treated with the same compounds over 21 days, with evaluation of in vivo toxicity effects on serum chemistry.

RESULTS

The results from the in vitro study clearly indicated hepatotoxic effects and possible liver damage following treatment with valproic acid, with associated growth inhibition, loss of cell viability and increased cytotoxicity as indicated by reduced intracellular ATP levels and increased AK levels. These results were supported by the increased in vivo levels of AST, ALT and LDH following treatment of the Sprague Dawley rats with valproic acid, indicative of hepatic cellular damage that may result in hepatotoxicity. The in vitro 3D spheroid model was also able to predict the potential concentration dependant hepatotoxicity of the crude X. undulatum aqueous extract. Similarly, the results obtained from the in vivo Sprague Dawley model indicated moderate hepatotoxic potential.

CONCLUSION

The data from both the 3D spheroid model and the Sprague Dawley model were able to indicate the potential concentration dependant hepatotoxicity of the crude X. undulatum aqueous extract. The results obtained from this study also confirmed the ability of the 3D spheroid model to effectively and reliably predict the long-term outcomes of possible hepatotoxicity.

Uzara - A quality control perspective of Xysmalobium undulatum

CONTEXT

Xysmalobium undulatum (L.) Aiton f var. (Asclepiadaceae), commonly known as uzara, is an ethnomedicinally important plant from southern Africa used to treat a variety of ailments. In addition to local use in African Traditional Medicine (ATM), formulations containing uzara have been successfully marketed by a number of pharmaceutical companies. Despite its commercialization, published adequate quality control (QC) protocols are lacking.

OBJECTIVE

The study was conducted to develop QC protocols for uzara based on chromatographic and spectroscopic techniques.

MATERIALS AND METHODS

High performance thin layer chromatography (HPTLC) and liquid chromatography coupled to mass spectrometry (LC-MS) were used to develop phytochemical fingerprints of ethanolic root extracts of 47 uzara samples collected from eight distinct localities in South Africa. Mid-infrared (MIR) spectroscopy was also explored as a suitable alternative technique for rapid and economic quantification of uzarin.

RESULTS

Adequate chromatographic profiles were obtained using both HPTLC and LC-MS analyses. The chromatographic patterns showed qualitative similarities among plants collected from different locations. The levels of uzarin, the major constituent of uzara, were highly variable between locations, ranging from 17.8 to 139.9 mg/g (dry weight). A good coefficient of determination (R(2 )= 0.939) and low root mean square error of prediction (RMSEP = 7.9 mg/g) confirmed the accuracy of using MIR-PLS calibration models for the quantification of uzarin.

DISCUSSION AND CONCLUSION

Both HPTLC and LC-MS can be used as tools in developing quality control procedures for uzara. MIR in combination with chemometrics provides a fast alternative method for the quantification of uzarin.

Xysmalobium undulatum (Uzara) research- how everything began

ETHNOPHARMACOLOGICAL RELEVANCE

Xysmalobium undulatum (Uzara) is a traditionally used medicinal plant from South Africa. It found its way into European research in the early 20th century and is widely used as a remedy against diarrhoea. The purpose of this study was to explore the circumstances of knowledge transfer and early research into phytochemistry and therapeutic potential of Xysmalobium undulatum.

RESULTS

The drug was brought to Europe through a former soldier, Wilhelm Heinrich Adolph Hopf (1887-1929). Some details about his life are provided here the first time, as well as some aspects of early research on the drug, which has mainly been done at the University of Marburg, Germany.

Xysmalobium undulatum (uzara) - review of an antidiarrhoeal traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Xysmalobium undulatum, commonly known as uzara, is traditionally used as an antidiarrhoeal and to treat stomach cramps, dysmenorrhoea and afterbirth cramps. In addition, it was reportedly used to treat anxiety and other conditions relating to mental health.

AIM OF THE REVIEW

To unite the botanical aspects, ethnopharmacology, phytochemistry, biological activity, pharmacokinetic and pharmacodynamic data, toxicity and commercial aspects of the scientific literature available on uzara.

METHOD

An extensive review of the literature covering 1917-2014 was carried out. Electronic databases including Scopus, Pubmed, Google Scholar and Google were used to assemble the data. All abstracts, full-text articles and books written in English and German were examined and included.

RESULTS

The phytochemistry of uzara has been comprehensively investigated and at least 18 compounds have been isolated and characterised. Uzara contains mainly cardenolide glycosides such as uzarin and xysmalorin and cardenolide aglycones such as uzarigenin and xysmalogenin. Limited scientific studies on the biological activity of uzara have been done. In vitro antisecretory antidiarrhoeal action was confirmed. Central nervous system activity was conflicting, in vitro and in vivo (animals) studies were inconclusive and no clinical studies have been performed. No antimutagenic effects have been reported and no toxicity up to date has been associated with uzara consumption. Significant cross-reactivity of uzara compounds with commercial digoxin and digitoxin assays may interfere with therapeutic drug monitoring.

CONCLUSIONS

The key traditional uses associated with uzara have been investigated in vitro and in vivo (animal), but clinical trial data is lacking.

A preliminary pilot randomized crossover study of uzara (Xysmalobium undulatum) versus ibuprofen in the treatment of primary dysmenorrhea

OBJECTIVE

Preliminary evaluation of efficacy and safety of uzara use in treatment of moderate and severe primary dysmenorrhea in comparison to ibuprofen.

MATERIALS AND METHODS

This randomized, comparative two way cross-over study comprised 60 single female students at Faculty of Medicine, Ain Shams University, Egypt, aged 19-28 years with moderate (n = 46) or severe (n = 14) primary dysmenorrhea. Participants were randomized to take either uzara (80 mg/8 hours for two doses, then 40 mg/8 hours) then ibuprofen (400 mg/6 hours) in two subsequent cycles or vice versa. The pain intensity, using VAS, was recorded immediately before taking the medication (0 hour) and after 4, 12, 24, 48-60, 96-120 hours. Main outcome measures included effectiveness of pain relief defined as drop of VAS to 3 or less, patient's global evaluation of the drug, absence from school, the use of a rescue medication, and, in those who continued the treatment, the pain intensity difference (PID) at different points after start of medication and its sum (SPID).

RESULTS

Uzara was comparably effective to ibuprofen (78.3% vs. 86.7% of cycles; respectively), with comparable rates of effectiveness on global evaluation (being around 50% for either drug), and rates of school absences (11.7% vs. 13.3%; respectively). The need for rescue medication was different (18.3% and 10%; respectively), albeit with no statistical significance. The means of PID at different time points and SPID were comparable, with significantly lower average mean of VAS scores compared to that felt with no medication (1.6 vs. 6.8, p<0.001). Side effects were less with uzara than ibuprofen (0% vs. 8.3%, p<0.05).

CONCLUSIONS

Uzara might be as effective as ibuprofen in management of primary dysmenorrhea but with less side effects. These findings need to be confirmed by a properly designed trial with a larger sample size.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN25618258.

Discerning apical and basolateral properties of HT-29/B6 and IPEC-J2 cell layers by impedance spectroscopy, mathematical modeling and machine learning

Quantifying changes in partial resistances of epithelial barriers in vitro is a challenging and time-consuming task in physiology and pathophysiology. Here, we demonstrate that electrical properties of epithelial barriers can be estimated reliably by combining impedance spectroscopy measurements, mathematical modeling and machine learning algorithms. Conventional impedance spectroscopy is often used to estimate epithelial capacitance as well as epithelial and subepithelial resistance. Based on this, the more refined two-path impedance spectroscopy makes it possible to further distinguish transcellular and paracellular resistances. In a next step, transcellular properties may be further divided into their apical and basolateral components. The accuracy of these derived values, however, strongly depends on the accuracy of the initial estimates. To obtain adequate accuracy in estimating subepithelial and epithelial resistance, artificial neural networks were trained to estimate these parameters from model impedance spectra. Spectra that reflect behavior of either HT-29/B6 or IPEC-J2 cells as well as the data scatter intrinsic to the used experimental setup were created computationally. To prove the proposed approach, reliability of the estimations was assessed with both modeled and measured impedance spectra. Transcellular and paracellular resistances obtained by such neural network-enhanced two-path impedance spectroscopy are shown to be sufficiently reliable to derive the underlying apical and basolateral resistances and capacitances. As an exemplary perturbation of pathophysiological importance, the effect of forskolin on the apical resistance of HT-29/B6 cells was quantified.

CCR7 deficiency causes diarrhea associated with altered ion transport in colonocytes in the absence of overt colitis

The chemokine receptor CCR7 is a central regulator in the maintenance of cellular homeostasis of mucosal tissues. CCR7⁻/⁻ mice develop autoimmune gastritis and exocrinopathy accompanied by the formation of mucosal tertiary lymphoid follicles. Here we found that CCR7-deficient mice frequently suffered from chronic diarrhea linked with increased gastrointestinal motility and the development of severe anorectal prolapse. Enhanced formation of intestinal lymphoid follicles was associated with an elevated proportion of activated colonic T cells and increased production of the cytokine interleukin (IL)-1β. To uncover the pathomechanisms of diarrhea in CCR7⁻/⁻ mice, colonic epithelial barrier and ion channel activities were analyzed in Ussing chambers. Although overt acute colitis was absent, CCR7 deficiency resulted in reduced electrogenic sodium absorption and colonic chloride secretion. As it is known that IL-1β regulates epithelial sodium channel (ENaC) activity, these data imply a causal link between CCR7 expression, IL-1β level, and Na⁺ malabsorption owing to altered ENaC expression and diarrhea.