Cellular mechanisms underlying the laxative effect of flavonol naringenin on rat constipation model

Overweight/bowel dysmotility crosslinking and analogous laxative actions of two edible wild fruits in obese/constipated rats

BACKGROUND

The prompt development of obesity/constipation is the most serious problem for both children and adults. Limited studies suggested an association between them but lacked preclinical studies. This study allows to evaluate their crosslink and to compare the aqueous extracts laxative actions of two edible wild fruits of Arbutus unedo (AUAE) and Crataegus monogyna (CMAE) in constipated high-fat diet (HFD) rats.

METHODS

Wistar rats were divided into experimental groups for 13 weeks: standard (SD) and HFD groups. SD-rats were randomly redivided into 2 groups: SD and SD + Loperamide (LOP, 3 mg/kg, b.w.). HFD-rats were randomly reseparated into HFD-group, (HFD + LOP)-group, [HFD + Yohimbine (YOH, 2 mg/kg, b.w.)]-group, [HFD+ LOP]-groups+ various doses of AUAE or CMAE (75, 150, and 300 mg/kg, b.w.). Diversified indicators were investigated to achieve the expected objectives, including; fecal parameters, gastrointestinal transit (GIT), gastric emptying (GE), oxidative stress-(OxS), blood biochemical analysis, and accompanied small/large bowel histological modification.

KEY RESULTS

The liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS) analysis of AUAE and CMAE allowed the identification of 11 and 6 phenolic compounds, respectively. In HFD-rats, the subsequent dysregulation of GI motility was markedly aggravated. More importantly, with the same way (CMAE and AUAE)-treated groups showed alleviated outcomes for the following: most stool parameters, GIT, and GE were remarkably recovered; a similar recovery pattern was observed in the histopathological structure, OxS, and blood biochemical indicators.

CONCLUSIONS & INFERENCES

Our results experimentally confirmed the crosslink between overweight and constipation and both fruits have potential as functional foods to reduce metabolic risk of the obesity associated with bowel dysmotility.

Yiqi Kaimi prescription regulates protein phosphorylation to promote intestinal motility in slow transit constipation

ETHNOPHARMACOLOGICAL RELEVANCE

The clinical efficacy of the Yiqi Kaimi prescription has been confirmed in slow transit constipation. However, the effects and biological mechanism of Yiqi Kaimi prescription are still unclear.

AIMS OF THE STUDY

To identify the effects of Yiqi Kaimi prescription on intestinal motility; To reveal the potential key targets and pathways of Yiqi Kaimi prescription for the treatment of slow transit constipation.

MATERIALS AND METHODS

The effects of Yiqi Kaimi prescription on slow transit constipation were investigated in a mouse model. The terminal ink propulsion experiment and fecal indocyanine green imaging was used to measure the intestinal transit time. Protein phosphorylation changes in colon tissues treated with Yiqi Kaimi prescription were detected using a Phospho Explorer antibody microarray. Bioinformatic analyses were performed using the Database for Annotation Visualization and Integrated Discovery (DAVID) and the Search Tool for the Retrieval of Interacting Genes (STRING). Western blot analysis and immunohistochemistry confirmed the observed changes in phosphorylation.

RESULT

s: Yiqi Kaimi prescription significantly increased the intestinal transit rate (P < 0.05 vs. model) and reduced the time to first discharge of feces containing fecal indocyanine green imaging in mice (P < 0.05 vs. model). The administration of Yiqi Kaimi prescription induced phosphorylation changes in 41 proteins, with 9 upregulated proteins and 32 downregulated proteins. Functional classification of the phosphorylated proteins with DAVID revealed that the critical biological processes included tyrosine protein kinases, positive regulation of calcium-mediated signaling and response to muscle stretch. The phosphorylation of the spleen tyrosine kinase (SYK) at Tyr348 increased 2.19-fold, which was the most significant change. The phosphorylation level of the transcription factor p65 (RELA) at Thr505 was decreased 0.57-fold. SYK was a hub protein in the protein-protein interaction network and SYK and RELA formed the core of the secondary subnetwork. The key protein phosphorylation after treatment with Yiqi Kaimi prescription were verified by Western blot analysis and immunohistochemistry.

CONCLUSION

Yiqi Kaimi prescription significantly enhanced intestinal motility. This effect was attributed to alterations in the phosphorylation levels of various target proteins. The observed changes in protein phosphorylation, including SYK and RELA, may serve as crucial factors in the treatment of slow transit constipation.

Naringenin attenuated airway cilia structural and functional injury induced by cigarette smoke extract via IL-17 and cAMP pathways

BACKGROUND

Cigarette smoke impairs mucociliary clearance via mechanisms such as inflammatory response and oxidative injury, which in turn induces various respiratory diseases. Naringenin, a naturally occurring flavonoid in grapes and grapefruit, has exhibited pharmacological properties such as anti-inflammatory, expectorant, and antioxidant properties. However, it is still unclear whether naringenin protects airway cilia from injury caused by cigarette smoke.

PURPOSE

This study aimed to investigate the effect of naringenin on cigarette smoke extract (CSE)-induced structural and functional abnormalities in airway cilia and highlight the potential regulatory mechanism.

METHODS

Initially, network pharmacology was used to predict the mechanism of action of naringenin in ciliary disease. Next, HE staining, immunofluorescence, TEM, qRT-PCR, western blot, and ELISA were performed to assess the effects of naringenin on airway cilia in tracheal rings and air-liquid interface (ALI) cultures of Sprague Dawley rats after co-exposure to CSE (10% or 20%) and naringenin (0, 25, 50, 100 μM) for 24 h. Finally, transcriptomics and molecular biotechnology methods were conducted to elucidate the mechanism by which naringenin protected cilia from CSE-induced damage in ALI cultures.

RESULTS

The targets of ciliary diseases regulated by naringenin were significantly enriched in inflammation and oxidative stress pathways. Also, the CSE decreased the number of cilia in the tracheal rings and ALI cultures and reduced the ciliary beat frequency (CBF). However, naringenin prevented CSE-induced cilia damage via mechanisms such as the downregulation of cilia-related genes (e.g., RFX3, DNAI1, DNAH5, IFT88) and ciliary marker proteins such as DNAI2, FOXJ1, and β-tubulin IV, the upregulation of inflammatory factors (e.g., IL-6, IL-8, IL-13), ROS and MDA. IL-17 signaling pathway might be involved in the protective effect of naringenin on airway cilia. Additionally, the cAMP signaling pathway might also be related to the enhancement of CBF by naringenin.

CONCLUSION

In this study, we first found that naringenin reduces CSE-induced structural disruption of airway cilia in part via modulation of the IL-17 signaling pathway. Furthermore, we also found that naringenin enhances CBF by activating the cAMP signaling pathway. This is the first report to reveal the beneficial effects of naringenin on airway cilia and the potential underlying mechanisms.

Flavonoids in Amomum tsaoko Crevost et Lemarie Ameliorate Loperamide-Induced Constipation in Mice by Regulating Gut Microbiota and Related Metabolites

Amomum tsaoko (AT) is a dietary botanical with laxative properties; however, the active ingredients and mechanisms are still unclear. The active fraction of AT aqueous extract (ATAE) for promoting defecation in slow transit constipation mice is the ethanol-soluble part (ATES). The total flavonoids of ATES (ATTF) were the main active component. ATTF significantly increased the abundance of Lactobacillus and Bacillus and reduced the dominant commensals, such as Lachnospiraceae, thereby changing the gut microbiota structure and composition. Meanwhile, ATTF changed the gut metabolites mainly enriched in pathways such as the serotonergic synapse. In addition, ATTF increased the serum serotonin (5-HT) content and mRNA expression of 5-hydroxytryptamine receptor 2A (5-HT_2A), Phospholipase A2 (PLA2), and Cyclooxygenase-2 (COX2), which are involved in the serotonergic synaptic pathway. ATTF increased Transient receptor potential A1 (TRPA1), which promotes the release of 5-HT, and Myosin light chain 3(MLC3), which promotes smooth muscle motility. Notably, we established a network between gut microbiota, gut metabolites, and host parameters. The dominant gut microbiota Lactobacillus and Bacillus, prostaglandin J2 (PGJ2) and laxative phenotypes showed the most significant associations. The above results suggest that ATTF may relieve constipation by regulating the gut microbiota and serotonergic synaptic pathway and has great potential for laxative drug development in the future.

Naringenin modulates Cobalt activities on gut motility through mechanosensors and serotonin signalling

IntroductionCobalt chloride-(CoCl₂) exerts beneficial and toxic activities depending on dose however Naringenin-(Nar) a flavonoid, chelates heavy metals. Absorption of ingested heavy metals, or chelates are dependent on gut motility (gastric emptying and intestinal transit time) and mechanosensor regulation. Literature is vague on CoCl₂ activities on gut motility and mechanosensor nor probable chelating actions with naringenin which was investigated in this study.MethodOne hundred male Wistar rats were grouped viz; A to D (25, 62, 150 and 300 mg/kg CoCl₂), E to H doses of CoCl₂+Nar (50 mg/kg), I-Narigenin and J-Control. Gastric emptying and intestinal transit time were evaluated by day eight, intestinal tissue assayed for biochemical, histological and immunohistochemistry reactivity.ResultCoCl₂ significantly increased Gastric emptying (150 and 300 mg/kg) and Intestinal transit time unlike Naringenin. CoCl₂ (150 mg/kg) significantly increased Catalase and Nitric oxide but ameliorated by Naringenin. ATPase activities significantly increased in 150 mg/kg-CoCl₂ but ameliorated by Naringenin. Carbonyl levels increased in all CoCl₂+Nar groups. High Enterochromaffin-cell count in 25 and 62 mg/kg-CoCl₂ were ameliorated by Naringenin. Serotonin immunoreactivity increased in CoCl₂ (25, 62, 300 mg/kg) but reduced in CoCl₂+Nar groups.ConclusionCobalt chloride enhanced gastric motility via increased mechanosensor activities and serotonin expression at low doses. Naringenin ameliorated toxicity of high cobalt chloride via metal-flavonoid chelates.

Mechanistic Prediction of Chinese Herb Compound (Zhi Zhu Ma Ren Pill) in the Treatment of Constipation Using Network Pharmacology and Molecular Docking

Background: Constipation is one of the most prevalent chronic gastrointestinal diseases. Notably, previous studies have demonstrated that Chinese herbal compounds may exert effects on constipation. The present study aimed to predict the mechanisms underlying the effects of Zhi Zhu Ma Ren Pill (ZZMRP), which includes Aurantii Fructus Immaturus, Atractylodis Macrocephalae Rhizoma, Fructus Cannabis, Paeonia lactiflora and Radix Asteris in the treatment of constipation, using network pharmacology and molecular docking. Methods: The components and target information of ZZMRP were accessed using the Traditional Chinese Medicine Systems Pharmacology database and analysis platform, and the associated targets of constipation were obtained from the GeneCards, Disgenet, Online Mendelian Inheritance in Man, DrugBANK and Therapeutic Target Database databases. The major targets were subsequently selected using a Venn diagram and network topology analysis, which was followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was performed to authenticate the binding activity between active components and core targets. Results: A total of 44 active components, 249 targets of ZZMRP and 1501 targets associated with constipation were acquired. A total of 122 intersection targets were discovered between ZZMRP and constipation. Subsequently, 18 key targets were authenticated, including tumor protein 53, RAC-alpha serine/threonine-protein kinase, JUN and caspase-3. GO and KEGG pathway enrichment analysis indicated that mitogen-activated protein kinase, tumor necrosis factor, and phosphoinositide 3-kinase/protein kinase B signaling pathways may be involved in the treatment of constipation using ZZMRP. Molecular docking suggested that quercetin, kaempferol, and luteolin exhibited high binding affinities with several of the primary targets. Conclusions: The active components, core targets, and signaling pathways of ZZMRP in the treatment of constipation were predicted, which may be applicable to the development of treatments for constipation and application of ZZMRP.

Research progress in the treatment of slow transit constipation by traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Slow transit constipation (STC) is a common gastrointestinal disorder seriously impacting patients' quality of life. At present, although conventional chemical drugs effectively control STC symptoms in the short term, the long-term effects are poor, and the side effects are significant. In this regard, traditional Chinese medicine (TCM) offers an opportunity for STC treatment. Many pharmacological and clinical studies have confirmed this efficacy of TCM with multiple targets and mechanisms.

AIM OF THE STUDY

This review attempted to summarize the characteristics of TCM (compound prescriptions, single Chinese herbs, and active ingredients) for STC treatment and discussed their efficacy based on analyzing the pathogenesis of STC.

MATERIALS AND METHODS

The information was acquired from different databases, including PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang databases. We then focused on the recent research progress in STC treatment by TCM. Finally, the future challenges and trends are proposed.

RESULTS

TCM has good clinical efficacy in the treatment of STC with multi-mechanisms. Based on the theory of syndrome differentiation, five kinds of dialectical treatment for STC by compound TCM prescriptions were introduced, namely: Nourishing Yin and moistening the intestines; Promoting blood circulation and removing blood stasis; Warming Yang and benefiting Qi; Soothing the liver and regulating Qi; and Benefiting Qi and strengthening the spleen. In addition, six single Chinese herbs and eight active ingredients also show good efficacy in STC treatment.

CONCLUSIONS

TCM, especially compound prescriptions, has bright prospects in treating STC attributed to its various holistic effects.

Citric Acid-Enriched Extract of Ripe Prunus mume (Siebold) Siebold & Zucc. Induces Laxative Effects by Regulating the Expression of Aquaporin 3 and Prostaglandin E2 in Rats with Loperamide-Induced Constipation

Previously, we demonstrated that extracts of the ripe fruit (rPM) and unripe fruit (uPM) of Prunus mume (Siebold) Siebold & Zucc. and citric acid have a laxative effect, which is at least partially mediated by the increase in fecal parameters as seen in the low-fiber diet-induced constipation model rats. This study aims at investigating the laxative effects of citric acid-enriched aqueous extracts of rPM, uPM, and its active compounds, such as citric acid and malic acid, on loperamide-induced constipation rat models. Animal studies were conducted with loperamide-induced constipation animal models. The results showed that rPM and citric acid, the major organic acid compounds, significantly improved stool parameters (number, weight, and water content of the stools) generated in loperamide-induced constipation rats, without adverse effects of diarrhea. The gastrointestinal (GI) motility was activated fully in the rPM- and citric acid-treated rats than in rats treaded with loperamide alone. In addition, when rPM and citric acid were added to RAW264.7 cells and used to treat loperamide-induced constipation model rats, the secretion of prostaglandin E2 (PGE2) increased significantly in cells and tissue. Furthermore, rPM and citric acid decreased the expression of the aquaporin 3 (AQP3) in the rat colons. Our results demonstrated that rPM and citric acid, the major organic acid compound in rPM, can effectively promote defecation frequency and regulate PGE2 secretion and AQP3 expression in the colon, providing scientific evidence to support the use of rPM as a therapeutic application.

Heat Shock Protein 70 Mediates the Protective Effect of Naringenin on High-Glucose-Induced Alterations of Endothelial Function

Endothelial dysfunction plays a pivotal role in the development and progression of diabetic vascular complications. Naringenin (Nar) is a flavanone bioactive isolated from citrus fruits known to have in vitro and in vivo antidiabetic properties. However, whether Nar affects endothelial function remains unclear in diabetes or under high-glucose (HG) condition. Using an in vitro model of hyperglycemia in human umbilical vein endothelial cells (HUVECs), we found that Nar administration markedly attenuated HG-induced alterations of endothelial function, evidenced by the mitigation of oxidative stress and inflammation, the reduction of cell adhesion molecular expressions, and the improvement of insulin resistance. We also found that HG exposure significantly reduced the levels of intracellular heat shock protein 70 (iHSP70 or iHSPA1A) and the release of HSP70 from HUVECs. HSP70 depletion mimicked and clearly diminished the protective effects of Nar on HG-induced alterations of endothelial function. In addition, Nar treatment significantly enhanced iHSP70 protein levels through a transcription-dependent manner. These results demonstrated that Nar could protect HUVECs against HG-induced alterations of endothelial function through upregulating iHSP70 protein levels. These findings are also helpful in providing new therapeutic strategies that are promising in the clinical use of Nar for the treatment of diabetes and diabetic complications.

Targeting the T-type calcium channel Cav3.2 in GABAergic arcuate nucleus neurons to treat obesity

OBJECTIVE

Cav3.2, a T-type low voltage-activated calcium channel widely expressed throughout the central nervous system, plays a vital role in neuronal excitability and various physiological functions. However, the effects of Cav3.2 on energy homeostasis remain unclear. Here, we examined the role of Cav3.2 expressed by hypothalamic GABAergic neurons in the regulation of food intake and body weight in mice and explored the underlying mechanisms.

METHODS

Male congenital Cana1h (the gene coding for Cav3.2) global knockout (Cav3.2KO) mice and their wild type (WT) littermates were first used for metabolic phenotyping studies. By using the CRISPR-Cas9 technique, Cav3.2 was selectively deleted from GABAergic neurons in the arcuate nucleus of the hypothalamus (ARH) by specifically overexpressing Cas9 protein and Cav3.2-targeting sgRNAs in ARH Vgat (VgatARH) neurons. These male mutants (Cav3.2KO-VgatARH) were used to determine whether Cav3.2 expressed by VgatARH neurons is required for the proper regulation of energy balance. Subsequently, we used an electrophysiological patch-clamp recording in ex vivo brain slices to explore the impact of Cav3.2KO on the cellular excitability of VgatARH neurons.

RESULTS

Male Cav3.2KO mice had significantly lower food intake than their WT littermate controls when fed with either a normal chow diet (NCD) or a high-fat diet (HFD). This hypophagia phenotype was associated with increased energy expenditure and decreased fat mass, lean mass, and total body weight. Selective deletion of Cav3.2 in VgatARH neurons resulted in similar feeding inhibition and lean phenotype without changing energy expenditure. These data provides an intrinsic mechanism to support the previous finding on ARH non-AgRP GABA neurons in regulating diet-induced obesity. Lastly, we found that naringenin extract, a predominant flavanone found in various fruits and herbs and known to act on Cav3.2, decreased the firing activity of VgatARH neurons and reduced food intake and body weight. These naringenin-induced inhibitions were fully blocked in Cav3.2KO-VgatARH mice.

CONCLUSION

Our results identified Cav3.2 expressed by VgatARH neurons as an essential intrinsic modulator for food intake and energy homeostasis, which is a potential therapeutic target in the treatment of obesity.

Laxative Effects of a Standardized Extract of Dendropanax morbiferus H. Léveille Leaves on Experimental Constipation in Rats

Background and Objectives: This study aimed at investigating the laxative effects of a standardized aqueous extract of Dendropanax morbiferus H. Lév. on two different constipation rat models. Materials and Methods: Animal studies were conducted with low-fiber diet-induced and loperamide-induced constipation animal models, and isolated colons were used in ex vivo analysis to determine the changes in colonic motility caused by D. morbiferus H. Lév. leaf extract (DPL). Results: The results showed that DPL administration significantly improved certain reduced fecal parameters (number, weight, and water content of the stools) in a both low-fiber diet and loperamide-induced constipation models without adverse effects of diarrhea. The laxative effect of DPL was confirmed to improve the charcoal excretion time upon DPL treatment in a low-fiber diet or loperamide-induced constipation model through gastrointestinal (GI) motility evaluation using the charcoal meal test. In addition, when DPL was administered to RAW264.7 cells and loperamide-induced constipation model rats, the production of prostaglandin E₂ (PGE₂) increased significantly in cells and tissue. Furthermore, DPL dose-dependently stimulated the spontaneous contractile amplitude and frequency of the isolated rat colon. Conclusion: Although our study did not provide information on the acute or chronic toxicity of DPL, our results demonstrated that DPL can effectively promote defecation frequency and rat colon contraction, providing scientific evidence to support the use of DPL as a therapeutic application. However, further toxicity studies of DPL are needed prior to the initiation of clinical trials and clinical applications.

Naringenin Regulates Lipopolysaccharide-Induced Abnormal Airway Surface Liquid Secretion

Airway surface liquid (ASL) is one of the key factors affecting the respiratory system's physiological function. Abnormal ASL secretion can increase the incidence of various respiratory diseases. Lipopolysaccharide (LPS) stimulation can damage the airway epithelial barrier, affect the concentration of ASL contents, and down-regulate ion channel expression, which in turn causes abnormal ASL secretion. Naringenin, which exists in many Citrus foods, has the ability to promote airway surface liquid secretion. This work is designed to investigate the regulatory mechanism of naringenin on LPS-induced abnormal ASL secretion. The effects of naringenin and LPS on the viability of Calu-3 cells were measured by CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS). ASL secretion volume was measured by a micropipette on air–liquid interface cultured cells. The concentration of Cl−, Na+, lysozyme, and total protein in ASL were respectively measured by assay kits. The mRNA expressions were determined by quantitative real-time polymerase chain reaction, and proteins were measured by enzyme-linked immunosorbent assay. The results indicated that LPS could affect ASL secretion and regulate cystic fibrosis transmembrane conductance regulator (CFTR), aquaporin 1 (AQP1) and aquaporin 5 (AQP5) expression. Naringenin had the ability to regulate the ASL secretion by increasing secretion volume, and Cl− and Na+ concentrations, reducing lysozyme and total protein content, and regulating CFTR, AQP1, and AQP5 expression. This study indicated that naringenin had regulating effects to attenuate LPS-induced abnormal ASL secretion.

Prebiotics/Probiotics Mixture Induced Changes in Cecal Microbiome and Intestinal Morphology Alleviated the Loperamide-Induced Constipation in Rat

The aim of this study was to investigate the effect of a mixture of multi-strain probiotics and prebiotics on loperamide-induced constipation in Sprague-Dawley rats. A multi-strain probiotics alone (loperamide-induced group with multi-strain probiotics mixture group; Lop-Pro) and a mixture of multi-strain probiotics and prebiotics (loperamide-induced group with multi-strain probiotics and prebiotics mixture group; Lop-Pro/Pre) were administered orally after inducing constipation. The fecal water content was significantly higher (by 42%) in the Lop-Pro/Pre group (33.5%) than in the loperamide-induced group (Lop) (23.7%) (p<0.05). The intestinal mucosal thickness, crypt cell area, and interstitial cells of Cajal area were significantly higher in the Lop-Pro/Pre group compared to the Lop group by 16.4%, 20.6%, and 42.3%, respectively. Additionally, the total short-chain fatty acid content was significantly increased in the Lop-Pro and Lop-Pro/Pre groups by 56.4% and 54.2%, respectively, compared with the Lop group. The Lop-Pro and Lop-Pro/Pre groups recovered loperamide-induced alteration in Bacteroidetes and Verrucomicrobia abundance among intestinal microbiota, whereas the Lop-Pro/Pre group recovered Akkermansia, Lactobacillus, Clostridium, Bacteroides, and Oscillibacter abundance. Moreover, the relative abundance of Oscillibacter and Clostridium was significantly different in the Lop-Pro/Pre group compared to the Lop group. Collectively, administration of synbiotics rather than multi-strain probiotics alone is effective in alleviating constipation.

Pediococcus pentosaceus B49 from human colostrum ameliorates constipation in mice

Constipation is a prevalent and burdensome gastrointestinal (GI) disorder that seriously affects the quality of human life. This study evaluated the effects of the P. pentosaceus B49 (from human colostrum) on loperamide (Lop)-induced constipation in mice. Mice were given P. pentosaceus B49 (5 × 109 CFU or 5 × 1010 CFU) by gavage daily for 14 days. The result shows that P. pentosaceus B49 treatment relieved constipation in mice by shortening the defecation time, increasing the GI transit rate and stool production. Compared with the constipation control group, the P. pentosaceus B49-treated groups showed decreased serum levels of inhibitory neurotransmitters (vasoactive intestinal peptide and nitric oxide), increased serum levels of excitatory neurotransmitters (acetylcholinesterase, motilin, and gastrin), and elevated cecal concentration of short chain fatty acids (SCFAs). Analysis of cecal microbiota reveals that P. pentosaceus B49 was colonized in the intestine of constipated mice, and altered the cecal microbiota by increasing beneficial SCFAs-producing bacteria (i.e., Lactobacillus, Ruminococcaceae_UCG-014, and Bacteroidales_S24-7) and decreasing potential pathogenic bacteria (i.e., Staphylococcus and Helicobacter). Moreover, transcriptome analysis of the colon tissue shows that P. pentosaceus B49 partly normalized the expression of genes related to GI peristalsis (i.e., Ache, Chrm2, Slc18a3, Grp, and Vip), water and electrolyte absorption and transport (i.e., Aqp4, Aqp8, and Atp12a), while down-regulating the expression of pro-inflammatory and pro-oncogenic genes (i.e., Lbp, Lgals2, Bcl2, Bcl2l15, Gsdmc2, and Olfm4) in constipated mice. Our findings indicate that P. pentosaceus B49 effectively relieves constipation in mice and is a promising candidate for treating constipation.

Research progress regarding potential effects of traditional Chinese medicine on postoperative intestinal obstruction

OBJECTIVES

Postoperative intestinal obstruction is a common postoperative complication with typical symptoms of abdominal pain, vomiting, abdominal distension and constipation. The principal aim of this paper is to provide a full-scale review on the categories and characteristics of postoperative intestinal obstruction, pathophysiology, effects and detailed mechanisms of compounds and monomers from traditional Chinese medicine for treating postoperative intestinal obstruction. Moreover, the possible development and perspectives for future research are also analyzed.

METHODS

Literature regarding postoperative intestinal obstruction as well as the anti-pio effect of aqueous extracts and monomers from traditional Chinese medicine in the last 20 years was summarized.

KEY FINDINGS

To date, approximately 30 compounds and 25 monomers isolated from traditional Chinese medicine including terpenes, alkaloids, polysaccharides, flavonoids, phenylpropanoids and quinones, have exerted significant antipio effect. This paper reviews the effective doses, models, detailed mechanisms, and composition of these traditional Chinese medicine compounds, as well as the structure of these monomers. Moreover, challenges existed in the current investigation and further perspectives were discussed as well, hoping to provide a reference for future clinical treatment of postoperative intestinal obstruction and the development of new drugs.

CONCLUSIONS

Above all, the convincing evidence from modern pharmacology studies powerfully supported the great potential of traditional Chinese medicine in the management of postoperative intestinal obstruction. Regrettably, less attention was currently paid on the mechanisms of traditional Chinese medicine compounds and monomers with antipio effect. Consequently, future study should focus on monomer-mechanism and structure-function relationship.

Exploring the Active Components of Simotang Oral Liquid and Their Potential Mechanism of Action on Gastrointestinal Disorders by Integrating Ultrahigh-Pressure Liquid Chromatography Coupled with Linear Ion Trap-Orbitrap Analysis and Network Pharmacology

Simotang oral liquid (SMT), a well-known traditional Chinese medicine formula composed of four medicinal and edible plants, has been extensively used for treating gastrointestinal disorders (GIDs) since ancient times. However, the major active constituents and the underlying molecular mechanism of SMT on GIDs are still partially understood. Herein, the preliminary chemical profile of SMT was first identified by ultrahigh-pressure liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap). In total, 70 components were identified. Then, a network pharmacology approach integrating target prediction, pathway enrichment analysis, and network construction was adopted to explore the therapeutic mechanism of SMT. As a result, 170 main targets were screened out and considered as effective players in ameliorating GIDs. More importantly, the major hubs were found to be highly enriched in a calcium signaling pathway. Furthermore, 26 core SMT-related genes were identified, which may play key roles in ameliorating gastrointestinal motility. In conclusion, this work would provide valuable information for further development and clinical application of SMT.

Purgative/laxative actions of Globularia alypum aqueous extract on gastrointestinal-physiological function and against loperamide-induced constipation coupled to oxidative stress and inflammation in rats

BACKGROUND

Chronic constipation is a gastrointestinal functional disorder which affects patient quality of life. Therefore, many studies were oriented to search herbal laxative agents. In this study, we investigated the effect of Globularia alypum L. leaves aqueous extract (GAAE) against loperamide (LOP)-produced constipation.

METHODS

Animals were given LOP (3 mg/kg, b.w., i.p.) and GAAE (100, 200, and 400 mg/kg, b.w., p.o.) or yohimbine (2 mg/kg, b.w., i.p.), simultaneously, for 1 week. Gastric-emptying test and intestinal transit were determined. Colon histology was examined, and oxidative status was evaluated using biochemical-colorimetric methods.

KEY RESULTS

GAAE ameliorates significantly gastric emptying (64% to 76.5%) and intestinal transit (66.65% to 84.73%). LOP negatively influenced defecation parameters and generated a stress situation. GAAE administration in contrast ameliorated those parameters and re-established oxidative balance.

CONCLUSION

GAAE showed a modest action against oxidative stress and decreased LOP effect and thereby can be considered a pharmacological agent in constipation.

Laxative and antioxidant effects of ramie (Boehmeria nivea L.) leaf extract in experimental constipated rats

Ramie leaf (Boehmeria nivea L.) is rich in cellulose, polyphenol compounds, vitamin C, and minerals. The leaves of this plant, which are used for medicinal purposes, have long been reported to have anti-inflammatory, antioxidant, anticolitis, and antidiabetic effects. We investigated the protective effects of ramie leaf ethanol extract (RLE) against loperamide-induced constipation and oxidative stress in rats. Male Sprague-Dawley rats were administered 200 or 400 mg/kg body weight of RLE (RLEL and RLEH groups) by gavage, while normal (NOR) and control (CON) rats received saline. Loperamide (4.0 mg/kg, twice per day) was injected subcutaneously to induce constipation in RLEL, RLEH, and CON groups. Total fecal number, wet weight, and water content decreased, while the total number of loperamide-induced fecal pellets in the distal colon increased with administration of RLE in a dose-dependent manner. Gastrointestinal transit time was more greatly reduced in RLE-treated groups than in the CON group. Serum total cholesterol (TC) level, as well as alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activity, was significantly lower in both RLEL and RLEH groups compared with the CON group. Intestinal mucosa malondialdehyde (MDA) and hydrogen peroxide (H2O2) production decreased significantly in a dose-dependent manner in the RLE-treated groups. Loperamide decreased the antioxidant enzyme activity, including that of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), while RLE administration increased the antioxidant activity. These results suggest that RLE exerts potent laxative and antioxidant effects in model rats with loperamide-induced constipation.

Laxative Activities of 80% Methanolic Extract of the Leaves of Grewia ferruginea Hochst Ex A Rich in Mice

BACKGROUND

There are numerous medicinal plants including the leaves of Grewia ferruginea used as traditional medicine for the treatment of constipation. This study was conducted to evaluate the laxative activity of the leaves of G ferruginea.

METHODS

The laxative activity of the leaves of G ferruginea was tested using 3 models: laxative activity, gastrointestinal motility, and gastrointestinal secretion tests. The effect of the plant extract on mean number of feces, fecal water content, ratio of intestinal distance traveled by the charcoal meal and intestinal fluid accumulation were evaluated and analyzed.

RESULTS

Significant increase was observed in the mean weight of wet fecal matter at 200 (1.00 ± 0.03 g, P < .05) and 400 mg/kg (1.01 ± 0.02 g, P < .01), relative to loperamide constipated negative control group. Similarly, percent fecal water content was significantly improved in extract treated groups at 100 mg/kg (52.10% ± 2.04%, P < .05), 200 mg/kg (54.02% ± 2.15%, P < .01), and 400 mg/kg (54.25% ± 2.50%, P < .01) compared with the negative control group. The gastroinestinal transit ratio was also significantly increased with 200 mg/kg (P < .01) and 400 mg/kg (P < .001) of the extract relative to the constipated negative control. The crude extract showed significant increase in intestinal fluid accumulation at 200 mg/kg (0.48 ± 0.07 g, P < .05) and 400 mg/kg (0.51 ± 0.08 g, P < .01) compared with the negative control.

CONCLUSION

The results of the present study indicated that 80% methanol extract of the leaves of G ferruginea possessed significant laxative activity. As such, this study corroborates the traditional claim of using G ferruginea in the treatment of constipation.

Antioxidant and laxative effects of taurine-xylose, a synthetic taurine-carbohydrate derivative, in loperamide-induced constipation in Sprague-Dawley rats

PURPOSE

In this study, we examined the in vitro antioxidant activities and laxative effects of taurine-xylose (T-X), a synthetic taurine-carbohydrate derivative, in a rat model of constipation induced by loperamide.

METHODS

The animals were divided into four treatment groups: normal untreated rats (NOR group), loperamide-treated control rats (CON group), loperamide and taurine-xylose (15 mg/kg)-treated rats (T-X group), and loperamide and commercial Dulcolax S (5.5 mg/kg)-treated rats (DS group).

RESULTS

In the present study, T-X exhibited potent reducing power and free radical scavenging activities for DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS+ (2,2'-azino-bis (3-ethylbenzothiazoline 6-sulfonic acid ammonium salt) radicals. The laxative effects of T-X were dependent on food, body weight, fecal properties, gastrointestinal transit (GIT) ratio, and serum metabolic parameters. In the T-X group, the number, wet weight, and water content of fecal pellets were noticeably increased compared to those in the loperamide-induced group. T-X treatment significantly increased the activities of hepatic antioxidant enzymes, including those of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT), relative to those in loperamide-induced constipated rats. Furthermore, the GIT ratio and loperamide-induced metabolic parameters in serum, including gastrin (GAS), motilin (MTL), and somatostatin (SS) levels, were significantly improved by T-X treatment.

CONCLUSION

These results suggest that taurine-xylose exerts antioxidant activities and laxative effects on loperamide-induced constipation by promoting gastrointestinal motility.

The Natural Flavonoid Naringenin Elicits Analgesia through Inhibition of NaV1.8 Voltage-Gated Sodium Channels

Naringenin (2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-4-one is a natural flavonoid found in fruits from the citrus family. Because (2S)-naringenin is known to racemize, its bioactivity might be related to one or both enantiomers. Computational studies predicted that (2R)-naringenin may act on voltage-gated ion channels, particularly the N-type calcium channel (CaV2.2) and the NaV1.7 sodium channel-both of which are key for pain signaling. Here we set out to identify the possible mechanism of action of naringenin. Naringenin inhibited depolarization-evoked Ca²⁺ influx in acetylcholine-, ATP-, and capsaicin-responding rat dorsal root ganglion (DRG) neurons. This was corroborated in electrophysiological recordings from DRG neurons. Pharmacological dissection of each of the voltage-gated Ca²⁺ channels subtypes could not pinpoint any selectivity of naringenin. Instead, naringenin inhibited NaV1.8-dependent and tetrodotoxin (TTX)-resistant while sparing tetrodotoxin sensitive (TTX-S) voltage-gated Na⁺ channels as evidenced by the lack of further inhibition by the NaV1.8 blocker A-803467. The effects of the natural flavonoid were validated ex vivo in spinal cord slices where naringenin decreased both the frequency and amplitude of sEPSC recorded in neurons within the substantia gelatinosa. The antinociceptive potential of naringenin was evaluated in male and female mice. Naringenin had no effect on the nociceptive thresholds evoked by heat. Naringenin's reversed allodynia was in mouse models of postsurgical and neuropathic pain. Here, driven by a call by the National Center for Complementary and Integrative Health's strategic plan to advance fundamental research into basic biological mechanisms of the action of natural products, we advance the antinociceptive potential of the flavonoid naringenin.

Laxative effects of triple fermented barley extracts (FBe) on loperamide (LP)-induced constipation in rats

BACKGROUND

Constipation, a common health problem, causes discomfort and affects the quality of life. This study intended to evaluate the potential laxative effect of triple fermented barley (Hordeum vulgare L.) extract (FBe), produced by saccharification, Saccharomyces cerevisiae, and Weissella cibaria, on loperamide (LP)-induced constipation in Sprague-Dawley (SD) rats, a well-established animal model of spastic constipation.

METHODS

Spastic constipation was induced via oral treatment with LP (3 mg/kg) for 6 days 1 h before the administration of each test compound. Similarly, FBe (100, 200 and 300 mg/kg) was orally administered to rats once a day for 6 days. The changes in number, weight, and water content of fecal, motility ratio, colonic mucosa histology, and fecal mucous contents were recorded. The laxative properties of FBe were compared with those of a cathartic stimulant, sodium picosulfate. A total of 48 (8 rats in 6 groups) healthy male rats were selected and following 10 days of acclimatization. Fecal pellets were collected one day before administration of the first dose and starting from immediately after the fourth administration for a duration of 24 h. Charcoal transfer was conducted after the sixth and final administration of the test compounds.

RESULTS

In the present study, oral administration of 100-300 mg/kg of FBe exhibited promising laxative properties including intestinal charcoal transit ratio, thicknesses and mucous producing goblet cells of colonic mucosa with decreases of fecal pellet numbers and mean diameters remained in the lumen of colon, mediated by increases in gastrointestinal motility.

CONCLUSION

Therefore, FBe might act as a promising laxative agent and functional food ingredient to cure spastic constipation, with less toxicity observed at a dose of 100 mg/kg.

Laxative Effect of Spicatoside A by Cholinergic Regulation of Enteric Nerve in Loperamide-Induced Constipation: ICR Mice Model

Researches on spicatoside A (SpiA)-containing natural products suggest the possibility of SpiA as a potential laxative to alleviate chronic constipation. However, no studies have been conducted with single compound administration of SpiA. To verify the laxative effects and mechanism of action of SpiA on chronic constipation, we investigated alterations in the excretion parameters, histological structure, and cholinergic regulation of the enteric nerve in the colons of Institute of Cancer Research (ICR) mice with loperamide (Lop)-induced constipation after exposure to 20 mg/kg of SpiA. Decrease in the number, weight and water contents of stools in the Lop+Vehicle treated group significantly recovered after SpiA treatment, and alterations in the histological structure and transmission electron microscopy (TEM) images were improved in the Lop+SpiA treated group. Similar recovery effects were observed in the ability for mucin secretion and expression of the membrane water channel gene (aquaporin 8, AQP8). Furthermore, significant improvements were observed in the acetylcholinesterase (AChE) activity and acetylcholine receptors' (AChRs) downstream signaling pathway after treatment of SpiA. The levels of gastrointestinal (GI) hormones including cholecystokinin (CCK) and gastrin were also remarkably enhanced in the Lop+SpiA treated group as compared to the Lop+Vehicle treated group. The expression of receptor tyrosine kinase (C-kit) and protein gene product 9.5 (PGP9.5) in Cajal and neural cells, as well as the phosphorylation of myosin light chain (MLC) in smooth muscle cells, were recovered after SpiA exposure. Taken together, the results of the present study provide the first strong evidence that SpiA improves chronic constipation through muscarinic cholinergic regulation of the enteric nerve in a Lop-induced constipation ICR mice model.

Anti-Inflammatory Response and Muscarinic Cholinergic Regulation during the Laxative Effect of Asparagus cochinchinensis in Loperamide-Induced Constipation of SD Rats

Several types of saponins and herbal plants containing saponins have been reported to have anti-inflammatory or laxative activities. To verify the therapeutic effects of saponin-enriched extracts of Asparagus cochinchinensis (SPA) on the anti-inflammatory response and on the cholinergic regulation in the gastrointestinal system, an alteration on the constipation phenotypes, on the inflammatory responses, and on the muscarinic cholinergic regulation were investigated in the transverse colons of Sprague Dawley (SD) rats with loperamide (Lop)-induced constipation after the treatment of SPA. Significant increases were observed on the total number of stools, the gastrointestinal transit, the thickness of the mucosal layer, the flat luminal surface, the number of paneth cells, and the lipid droplets in the Lop + SPA-treated group as compared to the Lop + Vehicle-treated group. SPA treatment induced the recovery of inflammatory cytokines (TNF-α, IL-1β) and IL-6), inflammatory mediators (NF-κB and iNOS), the total number of infiltered mast cells, and mucin secretion. Also, some similar improvements were observed on the levels of acetylcholine esterase (AChE) activity and on the phosphorylation of myosin light chains (MLC) as well as the expression of muscarinic acetylcholine receptors M2/M3 (mAChR M2/M3) and their mediators. The results presented herein provide the first strong evidence that SPA stimulates anti-inflammatory responses and the muscarinic cholinergic regulation when exerting its laxative effects in the chronic constipation of Lop-induced models.

Laxative Effects of Taurine on Loperamide-Induced Constipation in Rats

In the present study, we investigated the laxative effects of taurine in a rat model of loperamide-induced constipation. Rats were divided into six groups of six animals each: normal (NOR), control (CON), loperamide + Dulcolax (5.5 mg/kg, p.o.), and loperamide + various doses of taurine (7.5, 15, and 30 mg/kg, p.o.). Laxative activity was determined based on body weight, feeding characteristics, fecal properties, gastrointestinal transit (GIT) ratio, and the levels of serum gastrointestinal hormones. Taurine supplementation significantly increased the number, wet weight, and water content of fecal pellets in rats with loperamide-induced constipation. GIT ratio and loperamide-induced serum metabolic parameters, such as gastrin (GAS), motilin (MTL), and somatostatin (SS) significantly changed after supplementation with taurine in loperamide-induced constipated rats. We suggest that taurine had a potent effect against loperamide-induced constipation in part by increasing gastrointestinal motility.

The combination of Cassia obtusifolia L. and Foeniculum vulgare M. exhibits a laxative effect on loperamide-induced constipation of rats

Chronic constipation is a functional gastrointestinal disease that is detrimental to the quality of patient life. Cassia obtusifolia L. (CO) and Foeniculum vulgare M. (FV) are commonly used as medicinal foods in many countries. We aimed to examine the laxative effect and their underlying mechanism of CO and FV mixture on loperamide (lop)-induced constipated rats. To determine the laxative effects of these compounds, Sprague-Dawley rats were divided into six groups: the control, lop-induced constipated (2mg/kg), and three doses (100, 300, and 500mg/kg) of CO and FV mixture-, and Bisacodyl (bis, 3.3mg/kg)-treated groups. The mixture of CO and FV and bis were orally administered once a day for 4 weeks. For induction of constipation, the lop were treated with a dose of 2 mg/kg twice a day on the 3^rd week after treatments of CO and FV extracts and bis. The results were revealed that the CO and FV mixture has the laxative effects more than those in CO and FV-alone treatments on constipated rats by determining the stool parameters, including stool number and weight. Indeed, stool parameters, such as, stool number, weight, and water contents and colonic peristalsis from the intestinal transit length and ratio were dramatically improved by CO and FV mixture treatment. Histological study also revealed that CO and FV mixture enhanced the thicknesses of mucosa and muscular layers of the colon in constipated rats. For their underlying mechanism, the mRNAs and proteins expression of muscarinic acetylcholine receptors (mAchR) M2 and M3 and their downstream signaling were preserved by CO and FV mixture treatment in constipated rats. Therefore, this study suggests that treatment with CO and FV mixture has beneficial effects against constipation. We further suggest that CO and FV mixture may be utilized as an alternative therapeutic strategy for constipation.

Assessment of the laxative activity of an ethanolic extract of Bambusa arundinacea (Retz.) Willd. shoot

ETHNOBOTANICAL RELEVANCE

Bambusa arundinacea (Retz.) Willd., commonly known as Kanta Bans, plays an important ethnobotanical role, especially in Asia. In traditional medicine it has reportedly been used for the treatment of constipation, blood-diseases, leucodema, inflammation and urinary discharges. A number of ethnomedicinal records exist regarding the use of B. arundinaceae shoots as a laxative, however, there are no scientific studies reported on its laxative activity. Therefore, the aim of this present study was to evaluate the laxative activity of an ethanolic B. arundinaceae shoot extract in mice.

MATERIALS AND METHODS

B. arundinacea shoots were collected from Dhaka, Bangladesh in July 2015. An ethanolic shoot extract was obtained and its laxative activity was evaluated by faecal consistency, gastrointestinal transit and entero-pooling assays in a mouse model. Furthermore, a phytochemical investigation of the extract was conducted by UHPLC-ESI-QqQ MS and UHPLC-ESI-Orbitrap MS analysis.

RESULTS

The ethanolic shoot extract of B. arundinacea showed significant laxative activity in our mouse model, with significant increases in (i) the amount of wet faeces, with the maximum effect at 2h for 500mg/kg (47.92%), (ii) gastrointestinal transit (67.18% and 60.03% for doses of 250 and 500mg/kg, respectively), and (iii) small intestine content at the test doses of 250 and 500mg/kg p.o. Phytochemical investigation identified a total of thirty compounds in the ethanolic shoot extract of B. arundinacea using UHPLC-ESI-QqQ MS and UHPLC-ESI-Orbitrap MS analysis.

CONCLUSIONS

The results of this study provide support for the traditional use of B. arundinacea shoot as a laxative.

Effects of rhein on intestinal transmission, colonic electromyography and expression of aquaporin-3 by colonic epithelium cells in constipated mice

Constipation is one of the most common gastrointestinal diseases in the world. This study was to investigate the effects of rhein on intestinal transmission and colonic electromyography and expression of aquaporin-3 (AQP3) in the colonic mucosa of mice with constipation. The mouse model of constipation was established using the compound diphenoxylate. The first defecation time, the number of stools in the initial 6 hours and the promoting rate of eosin were measured as the bowel transit function. The BL-420F system was used to compare changes in the myoelectrical signals in the colons of the mice. Immunohistochemical analysis was used to detect the expression of AQP3 in the colonic mucosa of mice. Rhein had an obvious effect on the first defecation time and the number of red stool in the initial 6 hours. The first defecation time is reduced, and the number of red stools in 6 hours and the promoting rate of the small intestine were significantly increased after the treatment of rhein. In the rhein group, the slow-wave frequency and slow-wave amplitude of colonic myoelectrical activity were increased, and the mean optical density of AQP3 in the colonic mucosa and the area of positive expression were decreased. In conclusion, rhein can improve motor function and colonic electromyography of constipation mice, and reduce expression of AQP3 in the colonic mucosa, thereby relieving the symptoms of constipation effectively.

Naringenin induces laxative effects by upregulating the expression levels of c-Kit and SCF, as well as those of aquaporin 3 in mice with loperamide-induced constipation

Constipation is a common affliction which causes discomfort and affects the quality of life of affected individuals. Naringenin (NAR), a natural flavonoid widely found in citrus fruits and tomatoes, has been reported to exhibit various pharmacological effects, such as anti-inflammatory, anti-atherogenic, anti-mutagenic, hepatoprotective and anticancer effects. Increasing evidence has indicated that NAR has potential for use in the treatment of constipation. Thus, the aim of this study was to evaluate the laxative effects of NAR in mice with loperamide-induced (Lop-induced) constipation. The data indicated that NAR relieved Lop-induced constipation in mice based on the changes of fecal parameters (numbers, weight and water content), the intestinal charcoal transit ratio and the histological alteration. ELISA revealed that NAR regulated the production levels of gastrointestinal metabolic components, such as motilin (MTL), gastrin (Gas), endothelin (ET), substance P (SP), acetylcholinesterase (AChE) and vasoactive intestinal peptide (VIP) in serum. The expression levels of enteric nerve-related factors, glial cell line-derived neurotrophic factor (GDNF), transient receptor potential vanilloid 1 (TRPV1), nitric oxide synthase (NOS), c-Kit, stem cell factor (SCF) and aquaporin 3 (AQP3) were examined by western blot analysis and RT-PCR analysis. The results of this study suggest that NAR relieves Lop-induced constipation by increasing the levels of interstitial cells of Cajal markers (c-Kit and SCF), as well as AQP3. Thus, NAR may be effective as a candidate in patients suffering from lifestyle-induced constipation.

Effect of Lactic Acid Bacteria-Fermented Mulberry Leaf Extract on the Improvement of Intestinal Function in Rats

This study examined the laxative effects of mulberry leaf extract (MLE) fermented by lactic acid bacteria (LAB), which contains high levels of polyphenolic and flavonoid compounds, against loperamide-induced constipation in rats. Sprague-Dawley rats were divided into a normal group (N) and three experimental groups; loperamide treated group (C), loperamide and LAB-fermented MLE 300 mg/kg treated group (MLEL), and loperamide and LAB-fermented MLE 600 mg/kg treated group (MLEH). After 33 d, fecal pellet amount, fecal weight, water content of fecal, gastrointestinal transit time and length, and serum lipid profiles were measured. Constipation was induced via subcutaneous injection of loperamide (2.0 mg/kg b.w., twice a day) for the final 5 d of the experiment. After loperamide administration, the LAB-fermented MLE groups showed a significantly increase in the fecal pellets number, wet weight, and water content in rats compared with the C group. Moreover, increases in the intestinal length and viable Lactobacillus numbers in the feces were observed in the LAB-fermented MLE groups. The intestinal transit time was shorter in the LAB-fermented MLE groups than in the C group. In addition, the LAB-fermented MLE groups showed a significant decrease in triglyceride and total cholesterol levels and an increase in HDL-cholesterol level. These results indicated that oral administration of LAB-fermented MLE shows laxative effect in loperamide-induced constipated rats.

Uridine stimulate laxative effect in the loperamide-induced constipation of SD rats through regulation of the mAChRs signaling pathway and mucin secretion

Background

Uridine (Urd), which has been reported as a major component of RNA, plays an important role in various biological process including neuroprotection, biochemical modulation and glycolysis, although its role in constipation has yet to be established. Therefore, in this study, we investigated the laxative effects of Urd on chronic constipation.

Methods

The constipation phenotypes and their related mechanisms were investigated in the transverse colons of SD rats with loperamide (Lop)-induced constipation after treatment with 100 mg/kg of Urd.

Results

The number, weight and water contents of stools were significantly higher in the Lop + Urd treated group than the Lop + Vehicle treated group, while food intake and water consumption of the same group were maintained at a constant level. The thickness of the mucosa layer, muscle and flat luminal surface, as well as the number of goblet cells, paneth cells and lipid droplets were enhanced in the Lop + Urd treated group. Furthermore, the expression of the muscarinic acetylcholine receptors M2 and M3 (mAChR M2 and M3) at the transcriptional and translational level was recovered in the Lop + Urd treated group, while some markers such as Gα and inositol triphosphate (IP3) in their downstream signaling pathway were completely recovered by Urd treatment. Moreover, the ability for mucin secretion and the expression of membrane water channel (aquaporine 8, AQP8) were increased significantly in the Lop + Urd treated group compared with Lop + Vehicle treated group. Finally, the activity of Urd was confirmed in primary smooth muscle of rat intestine cells (pRISMC) based on Gα expression and IP3 concentration.

Conclusions

The results of the present study provide the first strong evidence that Urd can be considered an important candidate for improving chronic constipation induced by Lop treatment in animal models.

Characterization of Changes in Global Genes Expression in the Distal Colon of Loperamide-Induced Constipation SD Rats in Response to the Laxative Effects of Liriope platyphylla

To characterize the changes in global gene expression in the distal colon of constipated SD rats in response to the laxative effects of aqueous extracts of Liriope platyphylla (AEtLP), including isoflavone, saponin, oligosaccharide, succinic acid and hydroxyproline, the total RNA extracted from the distal colon of AEtLP-treated constipation rats was hybridized to oligonucleotide microarrays. The AEtLP treated rats showed an increase in the number of stools, mucosa thickness, flat luminal surface thickness, mucin secretion, and crypt number. Overall, compared to the controls, 581 genes were up-regulated and 216 genes were down-regulated by the constipation induced by loperamide in the constipated rats. After the AEtLP treatment, 67 genes were up-regulated and 421 genes were down-regulated. Among the transcripts up-regulated by constipation, 89 were significantly down-regulated and 22 were recovered to the normal levels by the AEtLP treatment. The major genes in the down-regulated categories included Slc9a5, klk10, Fgf15, and Alpi, whereas the major genes in the recovered categories were Cyp2b2, Ace, G6pc, and Setbp1. On the other hand, after the AEtLP treatment, ten of these genes down-regulated by constipation were up-regulated significantly and five were recovered to the normal levels. The major genes in the up-regulated categories included Serpina3n, Lcn2 and Slc5a8, whereas the major genes in the recovered categories were Tmem45a, Rerg and Rgc32. These results indicate that several gene functional groups and individual genes as constipation biomarkers respond to an AEtLP treatment in constipated model rats.

A ghrelin receptor agonist is an effective colokinetic in rats with diet-induced constipation

BACKGROUND

Despite constipation being a common problem, the treatments that are available have side effects and are only partly effective. Recent studies show that centrally penetrant ghrelin receptor agonists cause defecation in humans and other species. Here, we describe some features of a rat model of low fiber-induced constipation, and investigate the effectiveness of the ghrelin agonist, capromorelin.

METHODS

Rats were given low-fiber diets for 5 weeks. Their colorectal responsiveness to distension and to a behavioral test, water avoidance and colon histology were compared to those of rats on a standard diet.

KEY RESULTS

After the low-fiber diet, distension of the colon produced fewer propulsive contractions, behaviorally induced defecation was reduced, and the lining of the colorectum was inflamed. However, capromorelin was similarly effective in causing defecation in constipated and non-constipated rats.

CONCLUSIONS & INFERENCES

Low-fiber diet in rats produces a constipation phenotype, characterized by reduced responsiveness of the colorectum to distension and to a behavioral stimulus of defecation, water avoidance. The effectiveness of capromorelin suggests that centrally penetrant ghrelin receptor stimulants may be effective in treating constipation.

Constipation enhances the propensity to seizure in pentylenetetrazole-induced seizure models of mice

Epilepsy is characterized by spontaneous recurrent seizures and represents one of the most frequent neurological diseases, affecting about 60 million people worldwide. The cellular and neurocircuit bases of epilepsy are poorly understood. Constipation is a common gastrointestinal disorder characterized by symptoms such as straining, hard stool, and infrequent defecation. Population-based studies have shown that the prevalence of constipation is up to 30% of the population in developed countries. The causal link between seizure and constipation is a common belief among patients and physicians, but there are no scientific data to support this association. The current investigation evaluated the effects of constipation induced by loperamide (a peripheral μ-opioid receptor agonist without effect on central nervous system receptors) and clidinium (a quaternary amine antimuscarinic agent with reduced central nervous system effects) on two different seizure models of mice: (1) myoclonic, clonic, and generalized tonic seizures and death induced by intraperitoneal administration of pentylenetetrazole and (2) clonic seizure threshold induced by intravenous infusion of pentylenetetrazole. We demonstrated that the measured intestinal transit (%intestinal transit) decreased after loperamide or clidinium treatment for 3days. Constipation in mice which was induced by loperamide or clonidine caused a decrease in threshold to clonic seizure in the intravenous pentylenetetrazole seizure model. Moreover loperamide- or clidinium-induced constipation decreased latencies to, clonic, and tonic seizures and death in the intraperitoneal pentylenetetrazole model of mice. Serum ammonia levels were slightly elevated in both loperamide- and clidinium-treated mice. In conclusion, loperamide- or clidinium-induced constipated mice are more prone to seizure which might confirm the belief of patients and physicians about constipation as a trigger of seizure.

External application of the volatile oil from Blumea balsamifera may be safe for liver--a study on its chemical composition and hepatotoxicity

Ainaxiang (Blumea balsamifera), also known as Sambong, is an important ancient medicinal herb in Southeast Asia. It is rich in volatile oil, and still widely used nowadays for skin wound healing and treatment of sore throats. We analyzed the volatile oil from Blumea balsamifera (BB oil) by gas chromatography-mass spectrometry (GC-MS). Forty one components, including l-borneol, were identified. Next, the damaging effects of BB oil diluted with olive oil on liver at different concentrations (100%, 50%, 20%), were evaluated, using both normal and wounded skin. Plasma ALT, AST, ALP and TBili were assessed, along with liver histopathology. The results showed that serum levels of liver toxicity markers in the high concentration groups (100% w/v) increased compared with control groups, whereas no significant changes was observed in histopathology of liver samples. In the wound groups, treatment with BB oil resulted in a decrease in serum toxicity index, compared with normal animal groups. This study confirms the safety of short term BB oil consumption, though high BB oil doses may lead to mild liver injury and this response might be weakened in the case of cutaneous wounds. These results are expected to be helpful for guiding appropriate therapeutic use of BB oil.

Laxative effects of fermented rice extract in rats with loperamide-induced constipation

Constipation is a common problem in males and females. The aim of the present study was to evaluate the laxative effects of fermented rice extract (FRe) on rats with loperamide-induced constipation. FRe (100, 200 and 300 mg/kg) was administered orally once per day for six days following 1 h loperamide treatment. The laxative effects of FRe were compared with those of sodium picosulfate (S. picosulfate). Following the induction of constipation in the rats, a marked decrease was observed in the fecal pellet number and water content discharged over 24 h, the surface mucus thickness in the colonic lumen, intestinal charcoal transit ratio, thickness of the colonic mucosa and the number of mucus-producing cells, while an increase was observed in the number of fecal pellets remaining in the colonic lumen and their mean diameter, as compared with the normal vehicle control rats. These conditions were significantly alleviated following the administration of the three doses of FRe when compared with the loperamide control group. However, the alleviating effects were lower than those of S. picosulfate, with the exception of the intestinal charcoal transit ratio. Similar effects on the intestinal charcoal transit ratio were detected for the three doses of FRe when compared with the S. picosulfate-treated rats. In conclusion, the results indicated that FRe exhibits a laxative effect without causing diarrhea, as compared with sodium picosulfate; thus, FRe may be effective as a complementary medicine in patients suffering from lifestyle-induced constipation.

Synergistic effect of fermented rice extracts on the probiotic and laxative properties of yoghurt in rats with loperamide-induced constipation

Aim. The objective was to evaluate the synergistic effects of fermented rice extracts (FRe) on the laxative and probiotic properties of yoghurt in rats with loperamide-induced constipation. Methods. After constipation induction, yoghurt containing FRe (BFRe; 0.05%, 0.1%, or 1%) was administered orally once per day for 6 days. Results. Loperamide treatment caused marked decreases in fecal pellet numbers and water content discharged, as well as in the surface mucosal thickness of the colonic lumen, intestinal charcoal transit ratio, thickness, and number of mucous-producing goblet cells in the colonic mucosa, whereas it increased the remnant fecal pellet number and the mean diameter of the colonic lumen. However, this loperamide-induced constipation was ameliorated by treatment with FRe, yoghurt single formula, or 0.05%, 0.1%, or 1% BFRe (10 mL/kg). Additionally, the viable numbers of Lactobacillus in the cecal contents and feces were markedly higher than those in constipated rats. Moreover, greater probiotic and laxative effects were detected in BFRe-treated rats than in rats treated with equivalent doses of yoghurt or FRe single formula. Conclusion. The results suggest that addition of FRe to liquid yoghurt will enhance the probiotic and beneficial laxative effects of yoghurt in the digestive tract, without causing side effects.

The synergism mechanism of Rhubarb Anthraquinones on constipation elucidated by comparative pharmacokinetics of Rhubarb extract between normal and diseased rats

In the study, it was hypothesized that Rhubarb Anthraquinones synergistically enhanced the purgative effect on constipation rat from the direct and indirect pathway at the same time. A validated HPLC method was successfully applied to elucidate the synergism mechanism from pharmacokinetics aspect after oral administration of Rhubarb extract with a dose of 0.25 g to normal and constipation rats. Comparison of the pharmacokinetic data of normal and constipation rats showed that there were significant differences (p < 0.05) in the main pharmacokinetic parameters. The C max and AUC of emodin in constipation rats were about ten times that of normal rats, while the t 1/2 was remarkably decreased (p < 0.05). However, a significant decrease (p < 0.05) in AUC value for aloe-emodin and rhein was observed in model group compared with normal group. The results may be attributed to the direct action of aloe-emodin and rhein on intestinal cell membranes and the indirect action of emodin on bowel movement through the adjustment by nervous system.

Naringenin inhibits the growth of Dictyostelium and MDCK-derived cysts in a TRPP2 (polycystin-2)-dependent manner

BACKGROUND AND PURPOSE

Identifying and characterizing potential new therapeutic agents to target cell proliferation may provide improved treatments for neoplastic disorders such as cancer and polycystic diseases.

EXPERIMENTAL APPROACH

We used the simple, tractable biomedical model Dictyostelium to investigate the molecular mechanism of naringenin, a dietary flavonoid with antiproliferative and chemopreventive actions in vitro and in animal models of carcinogenesis. We then translated these results to a mammalian kidney model, Madin-Darby canine kidney (MDCK) tubule cells, grown in culture and as cysts in a collagen matrix.

KEY RESULTS

Naringenin inhibited Dictyostelium growth, but not development. Screening of a library of random gene knockout mutants identified a mutant lacking TRPP2 (polycystin-2) that was resistant to the effect of naringenin on growth and random cell movement. TRPP2 is a divalent transient receptor potential cation channel, where mutations in the protein give rise to type 2 autosomal dominant polycystic kidney disease (ADPKD). Naringenin inhibited MDCK cell growth and inhibited cyst growth. Knockdown of TRPP2 levels by siRNA in this model conferred partial resistance to naringenin such that cysts treated with 3 and 10 μM naringenin were larger following TRPP2 knockdown compared with controls. Naringenin did not affect chloride secretion.

CONCLUSIONS AND IMPLICATIONS

The action of naringenin on cell growth in the phylogenetically diverse systems of Dictyostelium and mammalian kidney cells, suggests a conserved effect mediated by TRPP2 (polycystin-2). Further studies will investigate naringenin as a potential new therapeutic agent in ADPKD.

Distinct action of flavonoids, myricetin and quercetin, on epithelial Cl⁻ secretion: useful tools as regulators of Cl⁻ secretion

Epithelial Cl⁻ secretion plays important roles in water secretion preventing bacterial/viral infection and regulation of body fluid. We previously suggested that quercetin would be a useful compound for maintaining epithelial Cl⁻ secretion at a moderate level irrespective of cAMP-induced stimulation. However, we need a compound that stimulates epithelial Cl⁻ secretion even under cAMP-stimulated conditions, since in some cases epithelial Cl⁻ secretion is not large enough even under cAMP-stimulated conditions. We demonstrated that quercetin and myricetin, flavonoids, stimulated epithelial Cl⁻ secretion under basal conditions in epithelial A6 cells. We used forskolin, which activates adenylyl cyclase increasing cytosolic cAMP concentrations, to study the effects of quercetin and myricetin on cAMP-stimulated epithelial Cl⁻ secretion. In the presence of forskolin, quercetin diminished epithelial Cl⁻ secretion to a level similar to that with quercetin alone without forskolin. Conversely, myricetin further stimulated epithelial Cl⁻ secretion even under forskolin-stimulated conditions. This suggests that the action of myricetin is via a cAMP-independent pathway. Therefore, myricetin may be a potentially useful compound to increase epithelial Cl⁻ secretion under cAMP-stimulated conditions. In conclusion, myricetin would be a useful compound for prevention from bacterial/viral infection even under conditions that the amount of water secretion driven by cAMP-stimulated epithelial Cl⁻ secretion is insufficient.

Metabolomics approach to serum biomarker for loperamide-induced constipation in SD rats

Loperamide has long been known as an opioid-receptor agonist useful as a drug for treatment of diarrhea resulting from gastroenteritis or inflammatory bowel disease as well as to induce constipation. To determine and characterize putative biomarkers that can predict constipation induced by loperamide treatment, alteration of endogenous metabolites was measured in the serum of Sprague Dawley (SD) rats treated with loperamide for 3 days using ¹H nuclear magnetic resonance (¹H NMR) spectral data. The amounts and weights of stool and urine excretion were significantly lower in the loperamide-treated group than the No-treated group, while the thickness of the villus, crypt layer, and muscle layer was decreased in the transverse colon of the same group. The concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatinine (Cr) were also slightly changed in the loperamide-treated group, although most of the serum components were maintained at a constant level. Furthermore, pattern recognition of endogenous metabolites showed completely separate clustering of the serum analysis parameters between the No-treated group and loperamide-treated group. Among 35 endogenous metabolites, four amino acids (alanine, glutamate, glutamine and glycine) and six endogenous metabolites (acetate, glucose, glycerol, lactate, succinate and taurine) were dramatically decreased in loperamide-treated SD rats. These results provide the first data pertaining to metabolic changes in SD rats with loperamide-induced constipation. Additionally, these findings correlate the changes in 10 metabolites with constipation.

Aqueous extracts of Liriope platyphylla induced significant laxative effects on loperamide-induced constipation of SD rats

Background

Liriope platyphylla has long been reported as a therapeutic drug for treatment of various human chronic diseases including inflammation, diabetes, neurodegenerative disorders, obesity, and atopic dermatitis. To investigate the laxative effects of L. platyphylla, alterations in excretion parameters, histological structure, mucin secretion, and related protein levels were investigated in rats with loperamide (Lop)-induced constipation after treatment with aqueous extract of L. platyphylla (AEtLP).

Methods

Alterations on constipation phenotypes were measured in rats with Lop-induced constipation after treatment with AEtLP using excretion parameter analysis, histological analysis, RT-PCR, western blot and transmission electron microscope (TEM) analysis.

Results

The amounts of stool and urine excretion were significantly higher in the Lop + AEtLP-treated group than in the Lop + vehicle-treated group, whereas food intake and water consumption were maintained at constant levels. AEtLP treatment also induced an increase in villus length, crypt layer, and muscle thickness in the constipation model. Total mucin secretion was higher in the Lop + AEtLP-treated group than in the Lop + vehicle-treated group, although mucin secretion per crypt was very similar among all groups. Furthermore, RT-PCR and western blot revealed a dramatic reduction of key factors level on the muscarinic acetylcholine receptors (mAChRs) signaling pathway in the Lop + AEtLP-treated group relative to the Lop + vehicle-treated group. Especially, the accumulation of lipid droplets in enterocytes of crypts following Lop treatment was improved to the level of the No-treated group in response to AEtLP treatment.

Conclusion

These results suggest that AEtLP improves constipation induced by Lop treatment through an increase in crypt layer and stimulation of lipid droplet secretions. These data are the first to show that the laxative effects of AEtLP are closely related to the down-regulation of mAchRs and their downstream signals.

Cellular mechanism underlying formaldehyde-stimulated Cl- secretion in rat airway epithelium

BACKGROUND

Recent studies suggest that formaldehyde (FA) could be synthesized endogeneously and transient receptor potential (TRP) channel might be the sensor of FA. However, the physiological significance is still unclear.

METHODOLOGY/PRINCIPAL FINDINGS

The present study investigated the FA induced epithelial Cl(-) secretion by activation of TRPV-1 channel located in the nerve ending fiber. Exogenously applied FA induced an increase of I(SC) in intact rat trachea tissue but not in the primary cultured epithelial cells. Western blot and immunofluorescence analysis identified TRPV-1 expression in rat tracheal nerve ending. Capsazepine (CAZ), a TRPV-1 specific antagonist significantly blocked the I(SC) induced by FA. The TRPV-1 agonist capsaicin (Cap) induced an increase of I(SC), which was similar to the I(SC) induced by FA. L-703606, an NK-1 specific inhibitor and propranolol, an adrenalin β receptor inhibitor significantly abolished the I(SC) induced by FA or Cap. In the ion substitute analysis, FA could not induce I(SC) in the absence of extracelluar Cl(-). The I(SC) induced by FA could be blocked by the non-specific Cl(-) channel inhibitor DPC and the CFTR specific inhibitor CFTR(i-172), but not by the Ca(2+)-activated Cl(-) channel inhibitor DIDS. Furthermore, both forskolin, an agonist of adenylate cyclase (AC) and MDL-12330A, an antagonist of AC could block FA-induced I(SC).

CONCLUSION

Our results suggest that FA-induced epithelial I(SC) response is mediated by nerve, involving the activation of TRPV-1 and release of adrenalin as well as substance P.

Kiwifruit modulation of gastrointestinal motility

Disorders of gastrointestinal motility are common, resulting in a decreased quality of life of individuals, and an economic burden. Gastrointestinal motility is categorized according to location within the gastrointestinal tract: stomach, small intestine, and colon, with the colon being the dominant compartment in determining overall gastrointestinal transit. Constipation results from gastrointestinal dysmotility and is a significant chronic health issue globally. Clinical studies in a range of adult populations consistently indicate that kiwifruit are a highly effective dietary option to promote laxation. This, together with emerging evidence for the putative effects of kiwifruit in beneficially promoting gastric emptying and digesta mixing, suggests that kiwifruit are physiologically active throughout the gastrointestinal tract. Although the mechanisms of this action remain unknown, the unique behavior of kiwifruit fiber during digestion and the potential action of bioactive components in kiwifruit may contribute to the effectiveness of kiwifruit in modulating gastrointestinal motility.

Laxative effects and mechanism of action of Brazilian green propolis

BACKGROUND

Brazilian green propolis is reported to have wide range of biological properties including antibacterial, anti-inflammatory, anti-influenza, and antioxidant activities. In the digestive system, a protective effect of propolis on gastric ulcer has been reported, but a laxative effect has not yet been reported. We investigated the effect and the mechanism of action of water and ethanol extracts of Brazilian green propolis.

METHODS

We examined the laxative effect of propolis on stool frequency by administering orally an ethanol extract of propolis (EEP) or a water extract of propolis (WEP) at 10, 50, 100, or 500 mg/kg to normal mice. We then investigated the effects of propolis using constipation model mice induced by two types of drugs, loperamide (a μ opioid receptor agonist) and clonidine (an α-2 adrenergic receptor agonist). We also investigated the effects of WEP on gastrointestinal transit and contractional tension of the ileum to uncover the mechanism of action of WEP.

RESULTS

Treatment with WEP, but not with EEP, significantly increased the weight of stools (p<0.01 at 500 mg/kg). WEP treatment significantly restored stool frequency and stool weight in clonidine-induced constipation model mice, but not in loperamide-induced constipation model mice. WEP treatment did not affect gastro-intestinal transit, but significantly increased the contractional tension of the isolated ileum of guinea pigs. This increase was inhibited by an acetylcholine receptor antagonist (atropine), but not by a 5-HT receptor antagonist (GR113808).

CONCLUSION

These findings indicate that WEP has laxative effects both in normal mice and in clonidine-induced constipation model mice. The laxative effects of WEP might be mediated by increased contractional tension of the ileum exerted at least in part via activation of an acetylcholine receptor.