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

Effects of natural products on functional constipation: analysis of active ingredient and mechanism

Constipation is a prevalent clinical ailment of the gastrointestinal system, yet its pathogenesis remains ambiguous. Despite the availability of numerous treatment modalities, they are insufficient in resolving the issue for patients. This work conducted a comprehensive review of the existing literature pertaining to the utilization of natural products for the treatment of constipation, with a focus on the efficacy of natural products in treating constipation, and to provide a comprehensive summary of their underlying mechanisms of action. Upon conducting a thorough review of the extant literature, we found that natural products can effectively treat constipation as modern synthetic drugs and compounded drugs with acetylcholinesterase (AChE) effects, rich in fiber and mucus, and the effects of increasing the tension of the ileum and gastrointestinal tract muscle, mediating signaling pathways, cytokine, excitability of the smooth muscle of the gastrointestinal tract, and regulating the homeostasis of intestinal flora. However, there is a wide variety of natural products, and there are still relatively few studies; the composition of natural products is complex, and the mechanism of action of natural products cannot be clarified. In the future, we need to further improve the detailed mechanism of natural products for the treatment of constipation.

Moringa oleifera Lam. Leaf improves constipation of rats induced by low-fiber-diet: A proteomics study

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf of Moringa oleifera Lam., a medicinal and edible herb for thousands of years in Ayurveda, is used as Pancha (na) karma (purgative) during and after the body cleansing process, to treat constipation, reduce cholesterol and body weight.

AIM OF STUDY

The aim was to investigate the diarrhea effects and possible mechanism of M. oleifera leaves in constipation rats.

MATERIALS AND METHODS

The hot water extract of M. oleifera leaves (WEMOL) was prepared and analyzed using LC-20AT HPLC system. The constipated rat model was induced by feeding with low fiber diet for 21 days. After oral administration of WEMOL for 7 days, the excretion parameter analysis, gastro-intestinal propulsion, histological analysis by HE and Alcian blue staining, and gastrointestinal hormone in rat's digestive tract through ELISA were used to evaluate the laxative effect of WEMOL. Label-free quantitation (LFQ) with LC-MS/MS, bioinformatics and Western blot were used to discover and verify the signal pathways and key proteins of WEMOL related to diarrhea.

RESULTS

The contents of isoquercitrin and astragalin were 2.7 mg/g and 1.7 mg/g, respectively in WEMOL. The stool number, weight, and water content of constipation rats were significantly reduced, indicating model had been established successfully. WEMOL (1.25 and 2.5 g/kg) increased water content of feces and the levels of Gas, MTL, NPY in gastric antrum and VIP, SP in colon of constipation rats, improved the muscle layer thickness and mucin secretion of colon. The proteomics revealed a total of 1731 differential proteins and 9 signaling pathways, WEMOL increased the expression of Vamp2, Gnai3, and Prkacb.

CONCLUSIONS

The laxative mechanism of WEMOL maybe modulate the signaling pathways mediated by 5-HT and Ach receptors, related to gastrointestinal motility and intestinal fluid secretion. It can be considered as the scientific connotation of Pancha (na) karma of M. oleifera leaves in ayurveda.

Complement C3-Deficiency-Induced Constipation in FVB/N-C3em1Hlee/Korl Knockout Mice Was Significantly Relieved by Uridine and Liriope platyphylla L. Extracts

Complement component 3 (C3) deficiency has recently been known as a cause of constipation, without studies on the therapeutic efficacy. To evaluate the therapeutic agents against C3-deficiency-induced constipation, improvements in the constipation-related parameters and the associated molecular mechanisms were examined in FVB/N-C3em1Hlee/Korl knockout (C3 KO) mice treated with uridine (Urd) and the aqueous extract of Liriope platyphylla L. (AEtLP) with laxative activity. The stool parameters and gastrointestinal (GI) transit were increased in Urd- and AEtLP-treated C3 KO mice compared with the vehicle (Veh)-treated C3 KO mice. Urd and AEtLP treatment improved the histological structure, junctional complexes of the intestinal epithelial barrier (IEB), mucin secretion ability, and water retention capacity. Also, an improvement in the composition of neuronal cells, the regulation of excitatory function mediated via the 5-hydroxytryptamine (5-HT) receptors and muscarinic acetylcholine receptors (mAChRs), and the regulation of the inhibitory function mediated via the neuronal nitric oxide synthase (nNOS) and inducible NOS (iNOS) were detected in the enteric nervous system (ENS) of Urd- and AEtLP-treated C3 KO mice. Therefore, the results of the present study suggest that C3-deficiency-induced constipation can improve with treatment with Urd and AEtLP via the regulation of the mucin secretion ability, water retention capacity, and ENS function.

Multi-strain probiotics alleviate loperamide-induced constipation by adjusting the microbiome, serotonin, and short-chain fatty acids in rats

Constipation is one of the most common gastrointestinal (GI) disorders worldwide. The use of probiotics to improve constipation is well known. In this study, the effect on loperamide-induced constipation by intragastric administration of probiotics Consti-Biome mixed with SynBalance® SmilinGut (Lactobacillus plantarum PBS067, Lactobacillus rhamnosus LRH020, Bifidobacterium animalis subsp. lactis BL050; Roelmi HPC), L. plantarum UALp-05 (Chr. Hansen), Lactobacillus acidophilus DDS-1 (Chr. Hansen), and Streptococcus thermophilus CKDB027 (Chong Kun Dang Bio) to rats was evaluated. To induce constipation, 5 mg/kg loperamide was intraperitoneally administered twice a day for 7 days to all groups except the normal control group. After inducing constipation, Dulcolax-S tablets and multi-strain probiotics Consti-Biome were orally administered once a day for 14 days. The probiotics were administered 0.5 mL at concentrations of 2 × 10⁸ CFU/mL (G1), 2 × 10⁹ CFU/mL (G2), and 2 × 10¹⁰ CFU/mL (G3). Compared to the loperamide administration group (LOP), the multi-strain probiotics not only significantly increased the number of fecal pellets but also improved the GI transit rate. The mRNA expression levels of serotonin- and mucin-related genes in the colons that were treated with the probiotics were also significantly increased compared to levels in the LOP group. In addition, an increase in serotonin was observed in the colon. The cecum metabolites showed a different pattern between the probiotics-treated groups and the LOP group, and an increase in short-chain fatty acids was observed in the probiotic-treated groups. The abundances of the phylum Verrucomicrobia, the family Erysipelotrichaceae and the genus Akkermansia were increased in fecal samples of the probiotic-treated groups. Therefore, the multi-strain probiotics used in this experiment were thought to help alleviate LOP-induced constipation by altering the levels of short-chain fatty acids, serotonin, and mucin through improvement in the intestinal microflora.

Similarities and differences in constipation phenotypes between Lep knockout mice and high fat diet-induced obesity mice

CRISPR-Cas9-mediated leptin (Lep) knockout (KO) mice exhibited prominent phenotypes for constipation, even though they were not compared with other model animals. This study compared the stool excretion, gastrointestinal motility, histological structure, mucin secretion, and enteric nerve function in Lep KO and high fat diet (HFD)-treated mice to determine if there were differences in their phenotypes for constipation. Most obesity phenotypes, including fat weight, adipocyte size, expression of lipolytic proteins (HSL, perilipin, and ATGL), and glucose concentrations, were detected similarly in the Lep KO and HFD-treated mice. They showed a similar decrease in the excretion parameters, including the stool number, weight, and water content, while the same pattern was detected in the gastrointestinal motility and intestinal length. A similar decrease in the mucosal layer thickness, muscle thickness, ability for mucin secretion, and expression of water channel (aquaporin 3 and 8) genes was detected in the mid-colon of the Lep KO and HFD-treated mice, but the alteration rate in some levels was greater in the HFD-treated group than the Lep KO mice. On the other hand, the levels of c-kit, nNOS, NSE, and PGP9.5 expression for the enteric neurons and intestitial cells of Cajal (ICC) were remarkably lower in the mid-colon of the HFD-treated mice than in the Lep KO mice, but the level of most proteins in both groups remained lower than those in the control group. A similar alteration pattern in the expression of muscarinic acetylcholine receptors (mAChRs) and serotonin receptors was detected in the Lep KO and HFD-treated mice. These results suggest that most phenotypes for obesity-induced constipation were similarly detected in the Lep KO and HFD-treated mice, but there was a difference in the regulatory function of the enteric nervous system (ENS).

Effect and mechanism of functional compound fruit drink on gut microbiota in constipation mice

Compound fruit drink (CFD) is a functional drink prepared with fruit, Chinese herbs and prebiotic fructooligosaccharide as the main ingredients. Loperamide hydrochloride was used to establish a mouse model of constipation. And the effect of CFD on the improvement of constipation and the impact on gut microbiota were studied. The results showed that CFD significantly enhanced intestinal motility in constipated mice (P < 0.05). It significantly improved serum levels of gastrointestinal regulatory-related peptides, elevated the short-chain fatty acids (SCFAs) content and alleviated colonic injury. Meanwhile, CFD also up-regulated the mRNA expression levels of AQP3, AQP9, SCF and c-Kit and the related protein expression levels. Fecal microbial results showed that the CFD medium-dose group significantly increased species richness. Furthermore, CFD increased the abundance of potentially beneficial bacteria and reduced the number of potentially pathogenic bacteria. This study indicated that CFD was a promising functional drink for effectively relieving constipation.

Dose-dependent Action of Zingiber officinale on Colonic Dysmotility and Ex Vivo Spontaneous Intestinal Contraction Modulation

Ginger (Zingiber officinale) rhizomes are commonly used in foods and employed for many ailments including gastrointestinal disorders. Our main objective was to evaluate the effect of Zingiber officinale aqueous extract (ZOAE) on gastrointestinal (GI) physiological motility and colonic dysmotility. Thereby, Wistar rats were given loperamide (LP, 3 mg/kg, b.w.) and ZOAE (75, 150, and 300 mg/kg, b.w.) or yohimbine (YOH, 2 mg/kg, b.w.). ZOAE-action on intestinal secretion was assessed using Ussing chamber technique and intestinal motility with isometric transducer. GI-transit (GIT) and gastric emptying (GE) were evaluated with the charcoal meal test and the red phenol methods. ZOAE-bioactive components were analyzed by liquid chromatography-high resolution electrospray ionization mass spectrometry (LC-HRESIMS). Constipation was induced with LP and the different indicators such as stool composition, GIT, oxidative stress biological parameters, and colonic mucosa histological alteration were performed. Anti-constipation effect of ZOAE was confirmed on stool composition, GIT (53.42% to 85.57%), GE (55.47% to 98.88%), and re-established oxidative balance. ZOAE induces an amplitude increase of spontaneous intestinal contraction with EC50 of 10.52 μg/mL. No effect of ZOAE was observed on electrogenic transport of intestinal fluid. These findings suggest that ZOAE-bioactive candidates might exert an anti-constipation action and spontaneous intestinal contraction modulation.

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.

Laxative Effects of Phlorotannins Derived from Ecklonia cava on Loperamide-Induced Constipation in SD Rats

This study investigated the laxative effects of phlorotannins (Pt) derived from Ecklonia cava (E. cave) on chronic constipation by evaluating alterations in stool parameters, gastrointestinal motility, histopathological structure, mucin secretion, gastrointestinal hormones, muscarinic cholinergic regulation, and fecal microbiota in SD rats with loperamide (Lop)-induced constipation subjected to Pt treatment. Stool-related parameters (including stool number, weight, and water contents), gastrointestinal motility, and length of intestine were significantly enhanced in the Lop+Pt-treated group as compared to the Lop+Vehicle-treated group. A similar recovery was detected in the histopathological and cytological structure of the mid-colon of Lop+Pt-treated rats, although the level of mucin secretion remained constant. Moreover, rats with Lop-induced constipation subjected to Pt treatment showed significant improvements in water channel expression, gastrointestinal hormone secretions, and expression of muscarinic acetylcholine receptors M2/M3 (mAChRs M2/M3) and their mediators of muscarinic cholinergic regulation. Furthermore, the Lop+Pt-treated group showed a significant recovery of Bifidobacteriaceae, Muribaculaceae, Clostridiaceae, and Eubacteriaceae families in fecal microbiota. Taken together, these results provide the first evidence that exposure of SD rats with Lop-induced constipation to Pt improves the constipation phenotype through the regulation of membrane water channel expression, GI hormones, the mAChR signaling pathway, and fecal microbiota.

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.

The effect of sodium carboxymethyl starch with high degree of substitution on defecation

Sodium carboxymethyl starch (CMS-Na), a kind of food additive with high degree of substitution, is also known as a prebiotic. The aim of this study was to determine the effect of CMS-Na on defecation. Constipated mouse model was prepared by loperamide. Normal rats were also used in the study. Short-chain fatty acids in rat feces were detected by gas chromatography. The bacterial communities in rat feces were identified by 16S rDNA gene sequencing. 5-hydroxytryptamine (5-HT) and tryptophan hydroxylase 1 (Tph1) were measured by ELISA. The results showed that CMS-Na increased the fecal granule counts and intestinal propulsion rate in constipated mice. The contents of water, acetic acid, propionic acid and n-butyrate in feces, Tph1 in colon and 5-HT in serum of rats were increased. In addition, CMS-Na shortened the colonic transport time in rats. The 16S rDNA gene sequencing results indicated that CMS-Na increased the relative abundance of Alloprevotella and decreased the proportion of Lactobacillus. However, the biodiversity of the normal intestinal flora was not altered. In conclusion, CMS-Na can promote defecation in constipated mice. The mechanism may be related to the regulation of Alloprevotella and Lactobacillus in colon, the increase of short-chain fatty acids, and the promotion of the synthesis of Tph1 and 5-HT.

Novel Characterization of Constipation Phenotypes in ICR Mice Orally Administrated with Polystyrene Microplastics

Indirect evidence has determined the possibility that microplastics (MP) induce constipation, although direct scientific proof for constipation induction in animals remains unclear. To investigate whether oral administration of polystyrene (PS)-MP causes constipation, an alteration in the constipation parameters and mechanisms was analyzed in ICR mice, treated with 0.5 μm PS-MP for 2 weeks. Significant alterations in water consumption, stool weight, stool water contents, and stool morphology were detected in MP treated ICR mice, as compared to Vehicle treated group. Also, the gastrointestinal (GI) motility and intestinal length were decreased, while the histopathological structure and cytological structure of the mid colon were remarkably altered in treated mice. Mice exposed to MP also showed a significant decrease in the GI hormone concentration, muscarinic acetylcholine receptors (mAChRs) expression, and their downstream signaling pathway. Subsequent to MP treatment, concentrations of chloride ion and expressions of its channel (CFTR and CIC-2) were decreased, whereas expressions of aquaporin (AQP)3 and 8 for water transportation were downregulated by activation of the mitogen-activated protein kinase (MAPK)/nuclear factor (NF)-κB signaling pathway. These results are the first to suggest that oral administration of PS-MP induces chronic constipation through the dysregulation of GI motility, mucin secretion, and chloride ion and water transportation in the mid colon.

Long-Term Administration of Anthraquinone Rhein on Induction of Constipation in Sprague-Dawley Rats via SCF/c-Kit Signaling Pathways

Background and Study Aims. It has been shown that abuse of laxatives is becoming a serious problem; therefore, a comprehensive understanding of its effect and possible mechanism on colon motility is essential to select effective treatments and avoid their abuse. Herein, we aimed to investigate the long-term stimulation of rhein on induction of constipation in rats and its underlying mechanisms. Materials and Methods. After establishing rat models of constipation, the rats were randomly divided into two equal subgroups and administered daily with normal saline (model control group) or 10 ml/kg PEG4,000 (PEG-treated group). Simultaneously, normal Sprague-Dawley (SD) rats were administered with normal saline (normal group). Physiological and fecal parameters were calculated, and intestinal transmission function was evaluated. After scarification, colonic tissues were freshly prepared for histological localization detected by immunohistochemical analysis and for the expression of stem cell factor (SCF) and c-kit proteins determined by western blot assay. Results. Following the initiation of rhein-induced rat constipation, body weight was lost slightly, the first time of black stool discharge was obviously longer, and the fecal moisture and number of fecal pellets decreased distinctly as compared with normal group. A decreased expression of SCF and c-kit was detected in model control group in comparison with normal group. Notably, compared with model control group, neither the alterations of fecal parameters and intestinal transmission function were effectively restored, nor the expression of SCF and c-kit was markedly elevated after administration of PEG4,000 for 30 d. Conclusion. Long-term stimulation of rhein can develop the constipation via SCF/c-kit signaling pathway, yet the symptoms of constipation and colon power cannot be alleviated or restored by PEG4,000. Collectively, these findings strongly suggest that long-term use of anthraquinone laxatives should be avoided for clinical treatment of constipation.

Antioxidant activity and laxative effects of tannin-enriched extract of Ecklonia cava in loperamide-induced constipation of SD rats

To investigate the role of tannin-enriched extracts of Ecklonia cava (TEE) on the regulation of oxidative balance and laxative activity in chronic constipation, we investigated alterations after exposure to TEE, on constipation phenotypes, muscarinic cholinergic regulation, and oxidative stress responses in the transverse colons of SD rats with loperamide (Lop)-induced constipation. This extract contains high levels of total condensed tannin content (326.5 mg/g), and exhibited high inhibitory activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. TEE treatment induced significant improvements in reactive oxygen species (ROS) production, superoxide dismutase (SOD) expression and nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation in primary smooth muscles of rat intestine cells (pRISMCs) and transverse colon of constipation model. Also, Lop+TEE treated groups showed alleviated outcomes for the following: most stool parameters, gastrointestinal transit, and intestine length were remarkably recovered; a similar recovery pattern was observed in the histopathological structure, mucin secretion, water channel expression and gastrointestinal hormones secretion in the transverse colon; expressions of muscarinic acetylcholine receptors M2/M3 (mAChR M2/M3) and their mediators on muscarinic cholinergic regulation were significantly recovered. Taken together, these results provide the first evidence that TEE stimulates oxidative stress modulation and muscarinic cholinergic regulation when exerting its laxative effects in chronic constipation models.

Deficiency of complement component 3 may be linked to the development of constipation in FVB/N-C3em1Hlee /Korl mice

Alterations in complement component 3 (C3) expression has been reported to be linked to several bowel diseases including Crohn's disease, inflammatory bowel disease, and ulcerative colitis; however, the association with constipation has never been investigated. In this study, we aimed to investigate the correlation between C3 regulation and constipation development using a C3 deficiency model. To achieve these, alterations in stool excretion, transverse colon histological structure, and mucin secretion were analyzed in FVB/N-C3em1Hlee /Korl (C3 knockout, C3 KO) mice with the deletion of 11 nucleotides in exon 2 of the C3 gene. The stool excretion parameters, gastrointestinal transit, and intestine length were remarkably decreased in C3 KO mice compared with wild-type (WT) mice, although there was no specific change in feeding behavior. Furthermore, C3 KO mice showed a decrease in mucosal and muscle layer thickness, alterations in crypt structure, irregular distribution of goblet cells, and an increase of mucin droplets in the transverse colon. Mucin secretion was suppressed, and they accumulated in the crypts of C3 KO mice. In addition, the constipation phenotypes detected during C3 deficiency were confirmed in FVB/N mice treated with C3 convertase inhibitor (rosmarinic acid (RA)). Similar phenotypes were observed with respect to stool excretion parameters, gastrointestinal transit, intestine length, alterations in crypt structure, and mucin secretion in RA-treated FVB/N mice. Therefore, the results of the present study provide the first scientific evidence that C3 deficiency may play an important role in the development of constipation phenotypes in C3 KO mice.

Aster tataricus alleviates constipation by antagonizing the binding of acetylcholine to muscarinic receptor and inhibiting Ca2+ influx

BACKGROUND

The dried root and rhizome of Aster tataricus (RA), is a traditional Chinese medicine has been used for more than 2000 years with the function of antitussive, expectorant and antiasthmatic. Ancient books and modern pharmacological researches demonstrated that RA may have the function of moistening intestines and relieving constipation, but there was a lack of systematic evidence. The aim of this study was to comprehensively evaluate the efficacy and possible mechanisms of ethanol extract of Aster tataricus (ATE) in treating constipation from in vivo to in vitro.

METHODS

In vivo, the ATE was studied in loperamide-induced constipation of mice. In vitro, different concentrations of ATE was tested separately or cumulatively on spontaneous and agonists-induced contractions of isolated rat duodenum strips.

RESULTS

In vivo, at doses of 0.16, 0.8 g/mL, ATE showed significantly promotion of the small intestinal charcoal transit, decrease of the amount of remnant fecal, and increase of the content of fecal water in colon. In addition, ATE could effectively relieve colonic pathological damage caused by loperamide as well. In vitro, with the cumulative concentration increase of ATE from 0.8 to 6.4 mg/mL, it could significantly decrease the contraction caused by KCl or Ach, and gradually restore to near base tension value.Meanwhile, it could also partially but significantly inhibit the contractions induced by Ach and CaCl2 on rat duodenum in a concentration related manner.

CONCLUSIONS

Taking all these findings together, it could be speculated that ATE may attenuate constipation mainly through antagonizing the binding of acetylcholine to muscarinic receptor, inhibiting Ca2+ influx and anti-inflammation.

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 Activity of the Hot-Water Extract Mixture of Hovenia dulcis Thunb. and Phyllostachys pubescens Mazel in Chronic Constipation Model SD Rats

This study examined the laxative effects of hot-water extracts of Hovenia dulcis Thunb. (HD), Phyllostachys pubescens Mazel (PM), and a 2:8 mixture of both (HP) in two chronic constipation models. For the loperamide-induced constipation model, animals were divided into an untreated group, negative control group (loperamide 4 mg/kg), positive control group (bisacodyl 4 mg/kg) group, and six treatment groups (HP 100 or 400, HD 50 or 100, and PM 100 or 400 mg/kg). For the lowfiber diet-induced constipation model, animals were divided into an untreated group (normal diet), negative control group (low-fiber diet), positive control group (Agio granule, 620 mg/kg), and the same treatment groups. Fecal number, weight, fecal water content, and intestinal transit ratio were higher in the groups treated with HP, HD, and PM than in the groups treated with loperamide or lowfiber diet. Thickness of colon mucosa and muscle layers were increased in the treated groups. Colon tension increased in the HP groups, and [Ca2+]i measurements using fura-2 as an indicator showed that HP inhibits ATP-mediated Ca2+ influx in IEC-18 cells. These results showed that the HP mixture has laxative activity by increased mucin secretion and inducing contractile activity and relaxation. It may be a useful therapeutic strategy for ameliorating in chronic constipation.

Comparative pharmacodynamic, pharmacokinetic and tissue distribution of Dahuang-Gancao decoction in normal and experimental constipation mice

Dahuang-Gancao decoction (DGD) is a classical formula, which is commonly used for reliving constipation in Chinese clinic. The aim of this study was to investigate the pharmacodynamic, pharmacokinetic and tissue distribution alternations of DGD in normal and constipation mice. DGD exhibited stronger purgative effect in constipation mice by the increased fecal excretion and reduced first defection time compared with normal mice. The C_max, AUC_0-t and MRT_0-t of rhein, aloe-emodin, rhein-8-O-β-D-glucoside, sennoside A, and glycyrrhizic acid as main bio-active components in DGD were markedly increased in constipation mice. The tissue distribution of the analytes in constipation mice were higher than those in normal mice with rhein > rhein-8-O-β-D-glucoside > aloe-emodin > glycyrrhizic acid > emodin in liver, and glycyrrhizic acid > rhein-8-O-β-D-glucoside > liquitin > sennoside A > rhein > aloe-emodin > emodin in colon. The kidney concentrations of the analytes showed a descending order of rhein > rhein-8-O-β-D-glucoside > sennoside A > glycyrrhizic acid > aloe-emodin > emodin, most of them were higher while rhein was lower in constipation mice than normal mice. The higher exposure of the anthraquinones in plasma, liver and colon may result in the stronger purgative effect in the constipation mice than normal mice. Rhein is mainly excreted through the kidney, the decreased level of rhein in constipation mice may explain the alleviated side effects. Accumulation of glycyrrhizic acid in colon may related with the moderate property of licorice. These results provided the experimental basis for understanding the therapeutic effects and metabolite profile of DGD.

Comparative Study of Constipation Exacerbation by Potassium Binders Using a Loperamide-Induced Constipation Model

Patients on dialysis are frequently administered high doses of potassium binders such as calcium polystyrene sulfonate (CPS) and sodium polystyrene sulfonate (SPS), which exacerbate constipation. Here, we compare the degree of constipation induced by CPS and SPS using a loperamide-induced constipation model to identify the safer potassium binder. Constipation model was created by twice-daily intraperitoneal administration (ip) of loperamide hydrochloride (Lop; 1 mg/kg body weight) in rats for 3 days. Rats were assigned to a control group, Lop group, Lop + CPS group or Lop + SPS group, and a crossover comparative study was performed. Defecation status (number of feces, feces wet weight, fecal water content and gastrointestinal transit time (GTT)) was evaluated. In the Lop + CPS group, GTT was significantly longer, and fecal water content was reduced. In the Lop + SPS group—although the fecal water content and GTT were unaffected—the number of fecal pellets and the fecal wet weight improved. Thus, SPS was less likely to cause constipation exacerbation than CPS. Considering the high frequency of constipation in dialysis patients with hyperkalemia, preferentially administering SPS over CPS may prevent constipation exacerbation.

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.

Physicochemical properties and laxative effects of polysaccharides from Anemarrhena asphodeloides Bge. in loperamide-induced rats

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese herbal medicine, Anemarrhena asphodeloides Bge. possesses the effects of nourishing yin, moistening dryness, clearing lungs and relieving fire. Simultaneously, it has been used to treat constipation for more than one thousand years in China. However, modern medical studies are limited and lacking on its therapeutic mechanism.

AIM OF THE STUDY

This current study was aimed to investigate the laxative activities and explore the potential mechanism of Anemarrhena asphodeloides Bge. polysaccharides (AABP) in loperamide-induced constipation rats.

MATERIALS AND METHODS

The structure of AABP was determined by using infrared spectrum, high performance gel permeation chromatography (HPGPC), and high performance liquid chromatography (HPLC). Real-time quantitative polymerase chain reaction (PCR), multitudinous methods were adopted to explore the underlining therapeutic mechanism of AABP in treating constipation, including enzyme-linked immunosorbent assay (ELISA), histopathological, immunohistochemistry and western blotting.

RESULTS

In the present study, the average molecular weight of AABP was determined as 1.11 × 10³ kDa. The primary monosaccharide compositions were analyzed including D-mannose, L-rhamnose, D-galacturonic acid, D-glucose, D-galactose and L-arabinose (1, 0.04, 0.53, 0.11, 0.33, 0.25, respectively) by high-performance liquid chromatography (HPLC). AABP significantly increased the levels of gastrin (Gas), motilin (MTL), substance P (SP), 5-hydroxytryptamine (5-HT) and vasoactive intestinal peptide (VIP), and decreased the NO content of loperamide-induced rats to ameliorate constipation in the rats. Whilst, AABP repaired the damaged colons by regulating PCNA and ICAM-1 protein expressions. Additionally, AABP up-regulated the levels of SCF, c-Kit, AQP3 and VIP as well as down-regulated the expressions of AQP8, AQP4 and PGE2.

CONCLUSION

The present findings suggested that AABP were the laxative active ingredients isolated from Anemarrhena asphodeloides Bge., which could treat constipation through regulating the gastrointestinal hormones and neurotransmitters to improve the intestinal motility and water metabolism.

Metabolomics approach to serum biomarker for laxative effects of red Liriope platyphylla in loperamide-induced constipation of SD rats

Red Liriope platyphylla (RLP) is a known herbal medicine used in the treatment of some chronic diseases including constipation, neurodegenerative disorders, diabetes and obesity. To determine and characterize putative biomarkers that predict the laxative effects induced by RLP treatment, alteration of endogenous metabolites was measured in the serum of loperamide (Lop)-induced constipation rats after administration of RLP extract (EtRLP) using ¹H nuclear magnetic resonance (¹H NMR) spectral data. The urine volume and amounts, and weights and water contents of stools were significantly recovered in the Lop + EtRLP treated group as compared to the No group, whereas body weight and food intake maintained constant levels. Also, significant recoveries in the thickness of mucosa and muscle were detected in the colon of the Lop + EtRLP treated group. Furthermore, pattern recognition showed absolutely different clustering of the serum analysis parameters when comparing the Lop treated group and Lop + EtRLP treated group. Of the 33 endogenous metabolites, 7 amino acids (alanine, arginine, glutamate, glutamine, glycine, threonine and valine) and 8 endogenous metabolites (betaine, creatine, glucose, taurine, ethanol, lactate, glycerol and succinate) were dramatically increased in the Lop + EtRLP treated SD rats. These results provide the first evidence pertaining to metabolic changes in the constipation rats treated with Lop + EtRLP. Additionally, these findings correlate with changes observed in 15 metabolites during the laxative effects of EtRLP.

Spicatoside A derived from Liriope platyphylla root ethanol extract inhibits hepatitis E virus genotype 3 replication in vitro

Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans worldwide. Although hepatitis E is self-limiting without chronic infection development, HEV infection often leads to severe liver diseases causing high mortality in pregnant women in addition to chronic hepatitis and cirrhosis in immunosuppressed patients. In this study, we investigated the effect of a Liriope platyphylla ethanol extract (LPE) on HEV replication. Interestingly, LPE suppressed replication of the genotype 3 HEV replicon. Sequential solvent fractionation revealed that the ethyl acetate (EA) fraction of LPE exerts the most potent inhibitory effects. With the aid of activity-guided fractionation and multi-step column chromatography, spicatoside A was subsequently isolated in the EA fraction of LPE and specifically shown to exert inhibitory effects on replication of the genotype 3 HEV replicon. In addition, spicatoside A interfered with replication of the HEV genotype 3 strain 47832c and expression of HEV ORF2 capsid proteins. Our findings clearly support the potential utility of spicatoside A as an effective anti-HEV agent.

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.

Synergic Laxative Effects of an Herbal Mixture of Liriope platyphylla, Glycyrrhiza uralensis, and Cinnamomum cassia in Loperamide-Induced Constipation of Sprague Dawley Rats

Constipation is an acute or chronic illness attributed to various causes, ranging from lifestyle habits to side effects of a disease. To improve the laxative effects of some traditional medicines, herbal mixtures of Liriope platyphylla, Glycyrrhiza uralensis, and Cinnamomum cassia (LGC) were evaluated for their mechanism of action and therapeutic effects in loperamide (Lop)-induced constipated Sprague Dawley rats by examining alterations in excretion parameters, histological structure, mucin secretion, and related protein levels. Food intake and water consumption were constant for all animals. We observed that the Lop+LGC-treated group had significantly greater excretion of stool and urine than was observed in the Lop+Vehicle-treated group. Administration of LGC in the constipation model restored the intestinal transit ratio to normal levels, and increased the number of goblet cells, mucosal layer, and muscle thickness. Mucin secretion was greater in the Lop+LGC-treated group than in the Lop+Vehicle-treated group, and the expression of MUC2 and AQP8 genes were also increased. In addition, reverse transcription polymerase chain reaction and Western blot revealed an increase in the muscarinic acetylcholine receptors (mAChRs) in the Lop+LGC-treated group compared to the Lop+Vehicle-treated group. Furthermore, compared with the Lop+Vehicle-treated group, treatment with LGC reduced the phosphorylation of PKC and PI3K, and expression of Gα protein, but increased levels of IP3. Our results suggest that the traditional herbal mixture of LGC induces a potent laxative effect in Lop-induced constipation through mucosal tissue changes and mucin production. We also demonstrated that the laxative effect of LGC is closely related to the expression of mAChR and its downstream signals, suggesting the possibility of developing a constipation-laxative agent using LGC.

Regulation of gastrointestinal hormones during laxative activity of gallotannin-enriched extract isolated from Galla Rhois in loperamide-induced constipation of SD rats

Regulation of gastrointestinal hormones have been reported in animal models for constipation undergoing laxative therapy when administered herbal products. We undertook to investigate whether the laxative activity of gallotannin-enriched extracts isolated from Galla Rhois (GEGR) affects the regulation of gastrointestinal hormones, by examining the concentration of four hormones and the activation of their receptors in the loperamide (Lop)-induced constipation model. Stool parameters, including number, weight and water content, were significantly recovered in the Lop+GEGR treated group, relative to the Lop+vehicle treated group; however, food intake and water consumption were maintained at a constant level. Also, a similar recovery was detected for thickness of mucosa, muscle and flat luminal surface in the Lop+GEGR treated group. Furthermore, concentration of the four gastrointestinal hormones evaluated, namely, cholecystokinin (CCK), gastrin (GAS), somatostatin (SS) and motilin (MTL), were lower in the Lop+vehicle treated group than the No treated group, but were remarkably enhanced in the Lop+GEGR treated group. Moreover, the downstream signaling pathway of MTL and SS receptors were recovered after GEGR administration. Results of the present study therefore indicate that the laxative effects of GEGR treatment may be tightly related with the regulation of gastrointestinal hormones in the Lop-induced constipation model.

Quercetin promotes gastrointestinal motility and mucin secretion in loperamide-induced constipation of SD rats through regulation of the mAChRs downstream signal

CONTEXT

Quercetin (QCT) has been known as a potential therapeutic strategy for gastrointestinal diseases because it contributes to the stabilization of mast cells, the prevention of histamine release and modulation of CaCC chloride channel.

OBJECTIVE

We investigated the laxative effect and action mechanism of QCT in Lop-induced constipation model.

MATERIALS AND METHODS

Constipation of SD rats was induced by subcutaneous injection of loperamide (Lop) (4 mg/kg weight) in 0.5% Tween 20 twice a day for three days. After 24 h, the constipation group was further treated with 1× PBS (Lop + Vehicle treated group), 10 mg/kg of QCT (Lop + LQCT treated group), 20 mg/kg of QCT (Lop + MQCT treated group) or 40 mg/kg QCT (Lop + HQCT treated group) at once. At 24 h after QCT treatment, the constipation phenotypes were measured and the transverse colon was collected from SD rats.

RESULTS

The gastrointestinal motility, the number of stools and histological structures were significantly recovered in Lop + QCT treated group compared with the Lop + Vehicle treated group. Also, above activity of epithelial cells and smooth muscle cells were regulated by the mRNA expression of the muscarinic acetylcholine receptors M2 and M3 (mAChR M2 and M3) and some mediators of their downstream signalling pathway. Finally, laxative effects of QCT on mAChR signalling pathway were significantly inhibited by the treatment of mAChR antagonist in primary smooth muscle of rat intestine cells (pRISMCs).

CONCLUSIONS

This study provides the first strong evidence that QCT can be considered an important candidate for improving chronic constipation induced by Lop treatment in animal models.

Spicatoside A in red Liriope platyphylla displays a laxative effect in a constipation rat model via regulating mAChRs and ER stress signaling

Red Liriope platyphylla extract (EtRLP) has been used as an oriental medicine for treatment of several chronic conditions, such as neurodegenerative disorders, diabetes, and obesity. To investigate the laxative activity of EtRLP, the levels of key constipation markers and their molecular regulators were examined following administration of EtRLP in constipation Sprague Dawley (SD) rats treated with loperamide (Lop). Compared with the Lop+Vehicle‑treated group, the excretion levels of urine and stool were significantly enhanced in the Lop+EtRLP‑treated group, even though feeding levels were kept constant. There was a significant improvement in histological structure, cytological ultrastructure and mucin secretion in transverse colon sections from the Lop+EtRLP‑treated group, compared with the Lop+Vehicle‑treated group. The Lop+EtRLP‑treated group exhibited a rapid recovery of the muscarinic acetylcholine receptor (mAChR) signaling pathway and of the endoplasmic reticulum (ER) stress response, compared with Lop+Vehicle‑treated group. Spicatoside A, one of the key components detected in EtRLP, recovered the levels of inositol triphosphate (IP3) and Gα in primary rat intestinal smooth muscle cells (pRISMCs). Taken together, the present results indicated that spicatoside A‑containing EtRLP had therapeutic effects against Lop‑induced constipation in SD rats via improvement of the mAChR downstream signaling pathway and the ER stress response.

Anti-ulcer effect of Gallarhois extract with anti-oxidant activity in an ICR model of ethanol/hydrochloride acid-induced gastric injury

Gallarhois (GR) is a traditional oriental herbal medicine with various pharmacological effects; however, its effect on gastric ulcer has not been previously explored. We firstly investigated the component and antioxidant activity of GR extract (EtGR) by HPLC analysis and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The results showed that EtGR consisted of gallotannin (68.7%), gallic acid (27.2%) and methyl gallate (4.1%) and that it had a high antioxidant value (IC50 value; 1.93 μg/mL). To evaluate the possible anti-gastric ulcer potential of EtGR, we investigated the effects of EtGR in the model of ethanol/hydrochloric acid (EtOH/HCl)-induced gastric ulcer. Gross and histological gastric lesions, biochemical and gene expression parameters were taken into consideration. The results showed that EtOH/HCl treatment produced mucosal injuries with morphological and histological damage, whereas EtGR co-treatment reduced the gastric injuries. EtGR treatment also decreased the contents of malonaldehyde (MDA) activity relative to the vehicle group. Moreover, EtGR decreased the levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and cyclo-oxygenase-2 (COX-2) expression. Finally, EtGR did not induce any specific toxicity in the livers or kidneys of the EtOH/HCl-induced gastric ulcer model. These results suggest that EtGR had stronger antioxidant activity and could be a new useful natural drug for gastroprotection against gastric ulcer. Moreover, these findings provide a scientific basis for the development of drugs from traditional oriental herbal medicines.

Opposite Effect of Opuntia ficus-indica L. Juice Depending on Fruit Maturity Stage on Gastrointestinal Physiological Parameters in Rat

The phytochemical composition and the effect of the green and ripe Opuntia ficus-indica juice on some gastrointestinal (GI) physiological parameters such as stomach emptying and small-intestinal motility and permeability were determined in rats administered multiple concentrations of the prickly pear juice (5, 10, and 20 mL kg^-1, b.w., p.o.). Other separate groups of rats were received, respectively; sodium chloride (0.9%, b.w., p.o.), clonidine (α-₂-adrenergic agonist, 1 mg kg^-1, b.w., i.p.), yohimbine (α-₂-adrenergic antagonist, 2 mg kg^-1, b.w., i.p.), and loperamide (5 mg kg^-1, b.w., p.o.). In vivo reverse effect of juice on GI physiological parameters was investigated using a charcoal meal test, phenol-red colorimetric method, loperamide-induced acute constipation, and castor oil-caused small-bowel hypersecretion. However, the opposite in vitro influence of juice on intestinal permeability homeostasis was assessed by the Ussing chamber system. Mature prickly pear juice administration stimulated significantly and dose dependently the GI transit (GIT; 8-26%) and gastric emptying (0.9-11%) in a rat model. Conversely, the immature prickly pear juice reduced gastric emptying (7-23%), GIT (10-28%), and diarrhea (59-88%). Moreover, the standard drugs have produced their antagonistic effects on GI physiological functions. The permeability of the isolated perfused rat small-intestine has a paradoxical response flowing prickly pear juices administration at diverse doses and maturity grade. Most importantly, the quantitative phytochemical analyses of both juices showed a different composition depending on the degree of maturity. In conclusion, the prickly pear juice at two distinct phases of maturity has different phytochemical characteristics and opposite effects on GI physiological actions in rat.

The genus Liriope: Phytochemistry and pharmacology

Liriope (Liliaceae) species have been used as folk medicines in Asian countries since ancient times. From Liriope plants (8 species), a total of 132 compounds (except polysaccharides) have been isolated and identified, including steroidal saponins, flavonoids, phenols, and eudesmane sesquiterpenoids. The crude extracts or monomeric compounds from this genus have been shown to exhibit anti-tumor, anti-diabetic, anti-inflammatory, and neuroprotective activities. The present review summarizes the results on phytochemical and biological studies on Liriope plants. The chemotaxonomy of this genus is also discussed.

Correlation between laxative effects of uridine and suppression of ER stress in loperamide induced constipated SD rats

A correlation between endoplasmic reticulum (ER) stress and laxative effects was first reported in a constipation model treated with an aqueous extract of Liriope platyphylla (AEtLP) roots. To investigate the correlation between the laxative effect of uridine (Urd) and ER stress response, alterations in the key parameters for ER stress were measured in loperamide (Lop) induced constipation Sprague Dawley (SD) rats treated with Urd. The efficacy of the laxative effect of Urd was notable on the symptoms of chronic constipation, including alteration of stool parameters and structure of the transverse colon, in Lop induced constipated SD rats. In the PERK/eIF2-ATF4 pathway of ER stress response, the levels of eukaryotic initiation factor 2 alpha (eIF2α) phosphorylation and DNA damage-inducible protein (GADD34) transcripts were significantly enhanced in the Lop+Vehicle treated group. However, the levels were restored in the Lop+Urd treated group, although few differences were detected in the decrease rate. Similar changes were observed for levels of inositol-requiring enzyme 1 beta (IRE1β) phosphorylation and X-box binding protein 1 (XBP-1) transcript in the IRE1α/XBP pathway. Furthermore, the number of ER stress-induced apoptotic cells and Bax and Bcl-2 expression were recovered in the Lop+Urd treated group compared to the Lop+Vehicle treated group. The results of the present study therefore provide first evidence that the laxative effects of Urd may be tightly correlated with the recovery of ER stress response in constipation models.

Aqueous Extracts of Herba Cistanche Promoted Intestinal Motility in Loperamide-Induced Constipation Rats by Ameliorating the Interstitial Cells of Cajal

Traditional Chinese medicine was reported to have good effects in treating functional constipation. This work attempted to prove the effects of aqueous extracts of Herba Cistanche (AEHC) on STC treatment and to determine the possible mechanisms by a loperamide-induced slow transit constipation (STC) model. HPLC was performed for identification and confirmation of the bioactive components in the AEHC. It was found that AEHC attenuated STC responses based on increased fecal quantity, moisture content, and intestinal transit rate, as well as serum levels of GAS, MTL, SS, and CGRP. The protein and mRNA levels of c-kit, a labeling of interstitial cells of Cajal (ICC), also increased. Meanwhile, only the protein level of SCF, a ligand of c-kit, increased. The analysis of our data suggested that AEHC could obviously improve the function of ICC via a signaling pathway involving PI3K, SCF, and c-kit and enhance colonic motility indices such as GAS, MTL, SS, and CGRP. It is interesting to note that AEHC appeared to be effective on constipation, so further experiments are necessary to clarify the exact mechanisms involved.

Laxative Effects of Dietary Supplementation with Sujiaonori Algal Biomaterial in Japanese Adult Women with Functional Constipation: A Case Study

Constipation is a gastrointestinal motility disorder that represents a major health problem in Japan. Approximately 26% of young Japanese adult women are reported to have this complaint. We report on the health effects of daily intake of Sujiaonori algal biomaterial (SBM) on constipation on 12 Japanese adult women. Data are from a four-week dietary intervention study on the health effects of daily Sujiaonori supplementation on cardiovascular, skin, and gastrointestinal health in which 32 adult Japanese volunteers (age range: 20-54 years) participated. They underwent clinical and laboratory investigations, and completed two study questionnaires (the brief diet history questionnaire (BDHQ) and the current health questionnaire) before and after dietary intervention. Of the 12 women volunteers with functional constipation, there were six SBM-supplemented subjects who received 3 g of Sujiaonori powder twice daily during meal, whereas the six others (controls) were from the group of those who took 3 g of a power made of 70% corn starch and 30% Japanese spinach mixture. The analysis of data on daily nutrient intake showed no significant dietary changes for nutrients (minerals, proteins, fiber, fat) and calorie intake (except alcohol intake that was reduced) in both groups. In SBM group, a significant reduction of the proportion of women with constipation was observed (p < 0.001), whereas no significant change was noted within the control group (p > 0.05). When both groups were compared, SBM was more effective than the control product; 66.7% (4/6) of SBM-supplemented women had their constipation relieved, whereas only one control (16.7%) controls benefited from dietary intervention (p < 0.001). In addition, no adverse effect was reported in the SBM group, whereas two controls reported nausea at post-survey. These results suggest that Sujiaonori contains compounds that can improve gastrointestinal function and relieve constipation.

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 the response of Korl:ICR mice to loperamide induced constipation

Animal models of constipation induced with drugs and diet have been widely employed to investigate therapeutic effects and the action mechanism of drugs against this disease. ICR mice were selected to produce this disease model through oral administration of loperamide (Lop), even though SD rats are commonly utilized in studies of constipation. To compare the responses of ICR mice obtained from three different sources to constipation inducers, alterations in stool number, histopathological structure, mucin secretion and opioid-receptor downstream signaling pathway were measured in Korl:ICR (Korea FDA source), A:ICR (USA source) and B:ICR (Japan source) injected with low and high concentrations of Lop (LoLop and HiLop). The number, weight and moisture content of stools decreased significantly in the Lop treated group of all ICR relative to the Vehicle treated group. Additionally, decreased mucosa layer thickness, muscle thickness, and mucin secretion were observed in the transverse colon of Lop treated ICR mice, while a similar number of goblet cells and crypt of lieberkuhn were detected in the same group. Furthermore, a similar change in the level of Gα expression and PKC phosphorylation was detected in the Lop treated group relative to the vehicle treated group, while some differences in the change pattern were observed in the B:ICR group. Therefore, these results of the present study provide strong additional evidence that Korl:ICR, A:ICR and B:ICR derived from different sources have a similar overall response to constipation induced by Lop injection, although there were a few differences in the magnitude of their responses.

Effects of five candidate laxatives derived from Liriope platyphylla on the 5-HT receptor signaling pathway in three cell types present in the transverse colon

The laxative effects of aqueous extract of Liriope platyphylla (AEtLP) on loperamide (Lop)‑induced constipation have been reported; however, the key compounds and the mechanism underlying these effects remain unclear. Therefore, the laxative effects of five candidates derived from L. platyphylla: Diosgenin (DG), 5-hydroxymethylfurfural (5-HMF), adenosine (AD), hydroxypropyl cellulose (HPC) and uridine (UD) were investigated by examining the alteration of G protein α (Gα) expression, protein kinase C (PKC) phosphorylation and inositol triphosphate (IP3) concentration levels in the 5-hydroxytryptamine (5‑HT; serotonin) receptor signaling pathway. Primary rat intestine smooth muscle cells (pRISMCs), intestinal epithelial cells (IEC)‑18 and B35 cells were cotreated with Lop and the five compounds in order to screen the candidates. AEtLP, prucalopride (PCP) and bisacodyl (BS) served as positive controls. In pRISMCs, Gα expression levels were recovered in the majority of candidate‑treated groups, whereas PKC phosphorylation recovery was observed only in the DG, 5‑HMF and AD treatment groups. In IEC‑18 cells, the AD treatment group mimicked the effects of PCP on PKC phosphorylation levels, whereas the DG, 5‑HMF, HPC and UD treatment groups mimicked the effects of AEtLP and BS. In B35 cells, a greater upregulation of PKC phosphorylation levels were observed in the UD treatment group compared with the PCP and BS treatment groups, whereas DG, 5‑HMF and AD treatment reduced the PKC phosphorylation levels to a greater extent than AEtLP treatment. However, effects similar to AEtLP, PCP and BS on Gα expression levels were not detected in any treatment groups in IEC‑18 and B35 cells. Furthermore, the level of IP3 was enhanced only in pRISMCs, in which all five candidates were effective, while the greatest concentration was observed in the UD treatment group. In conclusion, the results of the present study suggest that UD may be considered the compound with the greatest laxative activity, which may regulate the 5‑HT receptor signaling pathway.

Gallotannin-Enriched Extract Isolated from Galla Rhois May Be a Functional Candidate with Laxative Effects for Treatment of Loperamide-Induced Constipation of SD Rats

Several natural products containing tannins are used as traditional medicines for treatment of constipation; however, their pharmacological mechanism is not well understood. The laxative effects of gallotannin-enriched extract isolated from Galla Rhois (GEGR) were investigated using a constipation model induced by loperamide (Lop) injection. After analysis for antioxidant activity of GEGR, alterations in the excretion parameters, histological structure, mucin secretion, and related protein levels were measured in the transverse colon of Sprague Dawley (SD) rats with Lop-induced constipation following treatment with 250, 500 and 1,000 mg/ml of GEGR. The number and weight of feces increased significantly by 48–79% and 128–159%, respectively, in the Lop+GEGR treated group relative to the Lop+vehicle treated group, while food intake and water consumption were maintained at a constant level. The thickness of mucosa, muscle and flat luminal surface, as well as the number of goblet cells and crypt of lieberkuhn were enhanced in the Lop+GEGR treated group. Moreover, mucin secretion increased significantly in a dose dependent manner in the Lop+GEGR treated group. Furthermore, the downstream signaling pathway of the muscarinic acetylcholine receptors (mAChR) M2 and M3 was recovered by GEGR treatment, although the expression level varied. The levels of Gα expression and inositol triphosphate (IP3) concentration were also recovered in the Lop+GEGR treated group relative to the Lop+vehicle treated group. The results of the present study provide strong evidence that tannins distributed in various medicinal plants are important candidates for improving chronic constipation induced by Lop treatment in animal models.

Effects of the roots of Liriope Platyphylla Wang Et tang on gastrointestinal motility function

ETHNOPHARMACOLOGICAL RELEVANCE

Liriope platyphylla Wang et Tang continues to be used in Korea as a traditional medicine for the treatment of gastrointestinal (GI) disorders related to constipation and abnormal GI motility.

AIM OF THE STUDY

Because GI disorders, especially GI motility dysfunctions, are major lifelong problems, the authors investigated the effects of a water extract of the roots of L. platyphylla Wang et Tang (LPE) on the pacemaker potentials (PPTs) of interstitial cells of Cajal (ICCs) and on GI motility in male ICR mice.

MATERIALS AND METHODS

Enzymatic digestions were used to dissociate ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record PPTs generated by cultured ICCs in vitro. In vivo effects of LPE on GI motility were investigated by measuring intestinal transit rates (ITRs) of Evans blue in normal mice and in acetic acid (AA) and streptozotocin (STZ)-induced diabetic mouse models of GI motility dysfunction.

RESULTS

LPE dose-dependently depolarized PPTs in ICCs. Pretreatment with methoctramine (a muscarinic M2 receptor antagonist) did not block LPE-induced PPT depolarization. However, pretreatment with 4-DAMP (a muscarinic M3 receptor antagonist) blocked LPE-induced PPT depolarization. In addition, treatment with LY294002 (a phosphoinositide 3-kinase (PI3K) inhibitor) also blocked LPE-induced PPT depolarization. Intracellular GDPβS inhibited LPE-induced PPT depolarization, and LPE-induced PPT depolarization was found to occur in a phospholipase C (PLC)- and a protein kinase C (PKC)-dependent manner. Pretreatment with Ca(2+)free solution or thapsigargin (a Ca(2+)-ATPase inhibitor in endoplasmic reticulum) abolished PPTs, and under these conditions, LPE did not depolarize ICC PPTs. In normal mice, ITRs were significantly and dose-dependently increased by LPE (0.01-1g/kg administered intragastrically (i.g.)). In addition, LPE (i.g.) significantly recovered GI motility dysfunctions in both animal models.

CONCLUSION

LPE dose-dependently depolarizes ICC PPTs through M3 receptors via external and internal Ca(2+)regulation and via G protein-, PI3K-, PLC- and PKC- dependent pathways in vitro. Also, in vivo, LPE increased ITRs in treatment naïve mice and our two mouse models of GI dysfunction. Therefore, this study shows that LPE offers a basis for the development of a prokinetic agent that prevents or alleviates GI motility dysfunctions.

Laxative effects of Liriope platyphylla are tightly correlated with suppression of endoplasmic reticulum stress in loperamide-induced constipation of SD rats

A dysfunction of endoplasmic reticulum (ER) stress response can result in various diseases, including cancer, inflammation, diabetes and neurodegenerative disorders. To investigate whether ER stress response can play an essential role in the induction and treatment of chronic constipation, alterations in the key parameters for ER stress were measured in loperamide (Lop) induced constipation Sprague Dawley (SD) rats treated with aqueous extracts of Liriope platyphylla (AEtLP), which has been shown to have a laxative effect. Symptoms of chronic constipation including alteration of stool parameters and the transverse colon's structure were successfully induced by Lop treatment. Laxative effects such as enhancement of stools parameters, recovery of the mucosa thickness, increased muscle thickness and recovery of flat luminal surface were also observed in the Lop+AEtLP treated group. Furthermore, enhancement of eukaryotic initiation factor 2 alpha (eIF2α) phosphorylation and inositol-requiring enzyme 1 beta (IRE1β) expression, key indicators for ER stress, that were observed in the Lop+vehicle treated group were significantly recovered in the Lop+AEtLP treated group, although the phosphorylation level of c-Jun N-terminal protein kinase (JNK) remained constant. Moreover, alterations in the transcription level of the marker genes X-box binding protein 1 (XBP-1) and growth arrest and DNA damage-inducible protein (GADD34) were similar to those of eIF2α and IRE1β. However, their level was slightly or completely recovered after AEtLP treatment. Overall, this study provides the first evidence that ER stress response may be tightly correlated with chronic constipation induced by Lop treatment, as well as the laxative effects of AEtLP.

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.

Comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats and microarray analysis of drug-metabolizing genes

ETHNOPHARMACOLOGICAL RELEVANCE

Rhein is a pharmacological active component found in Rheum palmatum L. that is the major herb of the San-Huang-Xie-Xin-Tang (SHXXT), a medicinal herbal product used as a remedy for constipation. Here we have investigated the comparative pharmacokinetics of rhein in normal and constipated rats. Microarray analysis was used to explore whether drug-metabolizing genes will be altered after SHXXT treatment.

MATERIALS AND METHODS

The comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats was studied by liquid chromatography with electrospray ionization tandem mass spectrometry (LC-MS/MS). Gene expression profiling in drug-metabolizing genes after SHXXT treatment was investigated by microarray analysis and real-time polymerase chain reaction (RT-PCR).

RESULTS

A validated LC-MS/MS method was applied to investigate the comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats. The pharmacokinetic results demonstrate that the loperamide-induced constipation reduced the absorption of rhein. Cmax significantly reduced by 2.5-fold, the AUC decreased by 27.8%; however, the elimination half-life (t1/2) was prolonged by 1.6-fold. Tmax and mean residence time (MRT) were significantly prolonged by 2.8-fold, and 1.7-fold, respectively. The volume of distribution (Vss) increased by 2.2-fold. The data of microarray analysis on gene expression indicate that five drug-metabolizing genes, including Cyp7a1, Cyp2c6, Ces2e, Atp1b1, and Slc7a2 were significantly altered by the SHXXT (0.5 g/kg) treatment.

CONCLUSION

The loperamide-induced constipation reduced the absorption of rhein. Since among the 25,338 genes analyzed, there were five genes significantly altered by SHXXT treatment. Thus, information on minor drug-metabolizing genes altered by SHXXT treatment indicates that SHXXT is relatively safe for clinical application.