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.

The physiological functions and pharmaceutical applications of inulin: A review.

Inulin (IN), a fructan-type plant polysaccharide, is widely found in nature. The major plant sources of IN include chicory, Jerusalem artichoke, dahlia etc. Studies have found that IN possessed a wide array of biological activities, e.g. as a prebiotic to improve the intestinal microbe environment, regulating blood sugar, regulating blood lipids, antioxidant, anticancer, immune regulation and so on. Currently, IN is widely used in the food and pharmaceutical industries. IN can be used as thickener, fat replacer, sweetener and water retaining agent in the food industry. IN also can be applied in the pharmaceutics as stabilizer, drug carrier, and auxiliary therapeutic agent for certain diseases such as constipation and diabetes. This paper reviews the physiological functions of IN and its applications in the field of pharmaceutics, analyzes its present research status and future research direction. This review will serve as a one-in-all resource for the researchers who are interested to work on IN.

Total glucosides of paeony (TGP) alleviates constipation and intestinal inflammation in mice induced by Sjögren's syndrome.

ETHNOPHARMACOLOGICAL RELEVANCE: Sjögren's syndrome (SS) is an autoimmune disease and can cause gastrointestinal disorders such as constipation and intestinal inflammation. As a kind of medicinal material, Paeonia lactiflora Pall has a variety of pharmacological effects, and it is also an indispensable component in many pharmaceutical preparations, which has been widely concerned by the medical and pharmaceutical circles. Total glucosides of paeony (TGP) is a mixture of biologically active compounds extracted from the root of Paeonia lactiflora Pall and has therapeutic effects on a variety of autoimmune diseases. AIM OF THE STUDY: To investigate the therapeutic effect of TGP on constipation and intestinal inflammation in mice modeled by SS, and to provide a basis for clinical research. MATERIALS AND METHODS: The SS model was set up by submandibular gland (SMG) immune induction method and then treated with TGP for 24 weeks. The fecal characteristics were observed and the fecal number and moisture content were measured. Colonic pathology was observed by H&E staining. The levels of serum P substance (SP), vasoactive intestinal peptide (VIP), interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, nuclear factor (NF)-κB, nitric oxide (NO), and nitric oxide synthase (NOS) were determined by enzyme linked immunosorbent assay (ELISA) and microplate method, respectively. Reverse transcription polymerase chain reaction (RT-PCR) was employed to analyze the mRNA expression of c-kit and stem cell factor (SCF) in colon. RESULTS: Compared with the model group, the dry and rough condition of the feces was improved, and the fecal gloss, number and moisture content significantly increased after the administration of TGP capsules. Meanwhile, TGP treatment improved colonic pathological damage, inhibited the serum concentrations of NO, NOS, IL-1ß, TNF-α, NF-κB and SP, increased serum VIP concentration, and up-regulated mRNA expression of SCF and c-kit in colon. CONCLUSIONS: TGP could obviously attenuate SS-mediated constipation and intestinal inflammation in mice by acting on some intestinal motility related factors and inflammatory factors.

An integrated metabolomics strategy to reveal dose-effect relationship and therapeutic mechanisms of different efficacy of rhubarb in constipation rats.

The ambiguity of dose-effect relationship of many traditional Chinese medicines (TCMs) has always influenced their rational use in TCM clinic. Rhubarb, a preferred representative of cathartic TCM, is currently widely used that results in a diversity of its dosage. The aim of this study was to use an integrated metabolomics strategy to simultaneously reveal dose-effect relationship and therapeutic mechanisms of different efficacy of rhubarb in constipation rats. Six doses of rhubarb (0.135, 0.27, 0.81, 1.35, 4.05, and 8.1 g/kg) were examined to elucidate the laxative and fire-purging effects by pathological sections and UPLC-Q-TOF/MSE. The results showed that there existed serious lesions in the stomach and colon of model rats. And conditions were basically improved to some extent in rhubarb-treated groups. Through relative distance calculation based on metabolomics score plots, it suggested that the effective dose threshold (EC20-EC80 range) of rhubarb was from 0.31 to 4.5 g/kg (corresponding to 3.44-50.00 g in the clinic) in rat serum and 0.29-2.1 g/kg (corresponding to 3.22-23.33 g in the clinic) in feces. Then, 33 potential biomarkers were identified in total. Functional pathway analysis revealed that the alterations of these biomarkers were associated with 15 metabolic pathways, mainly including arachidonic acid metabolism, glycerophospholipid metabolism, steroid biosynthesis, primary bile acid biosynthesis and sphingolipid metabolism. Of note, different doses of rhubarb could alleviate endogenous disorders to varying degrees through regulating multiple perturbed pathways to the normal state, which might be in a dose-dependent manner and involved in therapeutic mechanisms. To sum up, integrated serum and fecal metabolomics obtained that rhubarb ranging from 0.31 to 2.1 g/kg is safe and effective for constipation treatment. Also, our findings showed that the robust metabolomics techniques would be promising to be more accurately used in the dose-effect studies of complex TCM, and to clarify syndrome pathogenesis and action mechanisms in Chinese medicine.

Studies on antidiarrheal and laxative activities of aqueous-ethanol extract of Asphodelus tenuifolius and underlying mechanisms.

BACKGROUND: Asphodelus tenuifolius Cav. (Asphodelaceae) has traditional reputability in treatment of diarrhea and constipation but no scientific study has been reported for its gastrointestinal effects. Present study was conducted to evaluate antidiarrheal and laxative activities of the plant. METHODS: Aqueous-ethanol crude extract of Asphodelus tenuifolius (At.Cr) was subjected to phytochemical screening and liquid-liquid fractionation. In vivo studies of charcoal meal intestinal transit test, antidiarrheal activity against castor oil induced diarrhea and laxative activity were performed in mice. In vitro experiments were conducted upon rabbit jejunum preparations using standard tissue bath techniques. RESULTS: Phytochemical screening indicated presence of alkaloids, anthraquinones, flavonoids, saponins, steroids, tannins and phenols in At.Cr. In charcoal meal intestinal transit test, At.Cr increased (p < 0.001) intestinal motility at 100 mg/kg dose, but decreased (p < 0.001) it at 500 mg/kg dose, when compared to the control group. At.Cr (300-700 mg/kg) provided protection from castor oil induced diarrhea in mice, which was significant (p < 0.001) at 500 and 700 mg/kg doses, as compared to the saline treated control group. At.Cr (50 and 100 mg/kg) enhanced total and wet feces counts in normal mice, as compared to saline treated control. In jejunum preparations, At.Cr inhibited spontaneous, K+ (80 mM) and K+ (25 mM) mediated contractions, similar to verapamil. Pre-incubation of jejunum preparations with At.Cr resulted in rightward nonparallel shift in Ca+ 2 concentration response curves, similar to verapamil. The spasmolytic activity was concentrated in ethylacetate fraction. Aqueous fraction exhibited spasmogenicity upon spontaneous contractions, which was blocked in presence of verapamil, but remained unaffected by other tested antagonists. CONCLUSION: The Asphodelus tenuifolius crude extract possesses gut modulatory activity, which may normalize gut functions in diarrhea and constipation. The spasmolytic activity of the extract was found to be mediated through Ca+ 2 channel blocking action. The spasmogenic activity, found partitioned in aqueous fraction, possibly involves Ca+ 2 influx through voltage gated Ca+ 2 channels. The study supports ethnic uses of the plant in diarrhea and constipation.

Structural characterization and rheological properties of a pectin with anti-constipation activity from the roots of Arctium lappa L.

A new pectin (ALP-2) was extracted from the roots of Arctium lappa L. with the molecular weight of 1.84 × 106 Da. ALP-2 was composed of rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose and arabinose. Results of NMR revealed that the dominant linkage types of ALP-2 were →4-α-GalpA-6-OMe-(1→, →2-α-Rha-(1→, →5-α-Araf-(1→ and →3,6-ß-Galp-(1→. The ELISA results indicated ALP-2 was a typical pectin with HG chain and RG-I chain. The rheological experiments showed that ALP-2 fluid exhibited shear thinning behavior. The viscosity of ALP-2 was mainly affected by concentration, temperature, and pH. The ALP-2 fluid with elastic properties at high frequencies could be used as a thickener in the food industry. Moreover, ALP-2 with the dosages of 200 mg/kg and 400 mg/kg exhibited strong anti-constipation activity in vivo. ALP-2 treated groups could improve small intestinal movement rate and increase the weight of feces significantly in constipation mice. Therefore, ALP-2 could be considered as the active component for functional food or therapeutic agent in constipation therapy.

Extracts of black garlic exhibits gastrointestinal motility effect.

In this studied, extracts of black garlic on the improvement of gastrointestinal function, antioxidant activity, total polyphenols, total flavonoids and total polysaccharides were evaluated. Results showed that the black garlic n-butanol fraction extract (BA) had significantly increased effect within small intestine in vitro, while the ethyl acetate fractions had no significant effect on small intestine in vitro. Increase of 5-HT4 content effectively stimulated the gastrointestinal peristalsis, which enhanced its gastrointestinal tract emptying, and promoted defecation. As for antioxidant activity test, the water extract was more effective in SOD activity test, DPPH radical scavenging rates, ferric reducing antioxidant power and reducing power. In addition, the water fraction was simulated by gastric acid digestion and hydrolysis, and the small intestine was isolated after acid hydrolysis (AW). It was found that the water fraction extract after acid hydrolysis did significantly improve the intestinal contraction rate. In short, extract of black garlic could effectively promote gastrointestinal motility and promote defecation. The active compounds were highly polar ingredients since water extract of black garlic exhibits most significant effect on improving gastrointestinal function.

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.

Enteromorpha and polysaccharides from enteromorpha ameliorate loperamide-induced constipation in mice.

Slow-transit constipation(STC)is a disease characterized by functional gastrointestinal disorder. Common laxatives used in clinical practice against constipation such as Senna have side effects. Enteromorpha(EP)is a common marine alga, and the polysaccharide extracted from EP has been reported possessing anti-cancer and anti-inflammation effects. The aim of this study is to investigate the effects of EP and Polysaccharides from Enteromorpha (PEP) on loperamide induced constipated mice model and illustrating mechanism of action. We investigated the effect of EP and PEP on fecal water content, defecation frequency and gastrointestinal transit (GI) time of loperamide-induced STC mice. In addition, serum Nitric Oxide (NO) content and vasoactive intestinal peptide receptor1 (VIPR1) as well as serotonin receptor (5-HT4) expression in the distal colon were analyzed. Furthermore, we determined the role of EP and PEP on microbiota distribution using stool genomic 16S rRNA sequencing. EP and PEP significantly enhanced intestinal motility function, and alleviated constipation associated intestinal inflammation. Moreover, EP and PEP significantly decreased serum NO concentration, down-regulated VIPR1 expression and up-regulated 5-HT4 expression in distal colon. Genomic stool DNA MiSeq Sequencing Analysis of microbiota community structures and distribution revealed that intestinal microecological changes caused by constipation recovered after both EP and PEP treatment. Our results indicate that EP and PEP are potent natural products which could be suggested in constipation therapy strategies.

Fiber Compounds and Human Health.

BACKGROUND: It is known that insufficient consumption of fiber in Western societies is directly linked to certain diseases. The required daily fiber intake can be obtained from foods such as fruits and vegetables, whole grains, legumes, nuts and others, or by eating foods enriched with fiber as a functional ingredient. OBJECTIVE: This review studies certain fiber compounds such as oligosaccharides (namely α-galactosides and fructans), arabinoxylans and ß-glucans. RESULTS: The European regulatory body governing nutrition and health claims aims to protect consumers' right to receive truthful information about food by verifying statements on "nutrition", "content", "health claims" and "reducing the risk of disease". Some of these foods and functional ingredients can be considered as "novel foods". CONCLUSIONS: This paper describes the state of the art of certain fiber compounds and their effect on human health; the different requirements for fiber components used as functional or novel food ingredients; and the response of the European authorities to the use of this ingredient and its related health claims in terms of food labelling. After EFSA approval, these claims can be used in food labelling as an added value for consumer health, which may also improve their success in the market.

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 (5­HT; 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 candidate­treated groups, whereas PKC phosphorylation recovery was observed only in the DG, 5­HMF and AD treatment groups. In IEC­18 cells, the AD treatment group mimicked the effects of PCP on PKC phosphorylation levels, whereas the DG, 5­HMF, 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, 5­HMF 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 IEC­18 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 5­HT receptor signaling pathway.

Toxicological implications and laxative potential of ethanol root extract of Morella serrata in loperamide-induced constipated Wistar rats.

CONTEXT: Morella serrata L. (Myricaceae) is commonly used in South Africa to treat several diseases including constipation. OBJECTIVES: This study investigated toxicological implications and laxative potential of the ethanol root extract of the plant. MATERIALS AND METHODS: While normal control animals were placed on sterile placebo, the loperamide-constipated rats were treated with the extract at 75, 150 and 300 mg/kg doses for 7 days, and their feeding patterns and faecal properties were monitored. Gastrointestinal transit ratio and the toxicity profile of the tested doses were thereafter evaluated. RESULTS: The significantly increased faecal volume (192.08%), feed (63.63%), water intake (55.97%) and improved intestinal motility (95.05%) in the constipated rats following treatment with the extract (at 300 mg/kg) suggested laxative potential of the extract. The 1.5-2.0-fold normalization of the platelets, erythrocytes and leukocytes counts in the extract-treated constipated rats suggests its non-haematotoxic tendency. Furthermore, the extract (at the highest investigated dose) reversed the attenuation in the concentrations of the electrolytes (0.5-2-fold), total protein (62.12%) and albumin (55.88%) in the constipated animals as well as attenuated activities of hepatic enzymes (0.5-3.0-fold) and levels of urea (126.67%), creatinine (40.32%), cholesterol (3-fold) and triglycerides (9-fold). These further support its non-toxic and therapeutic attributes against constipation. CONCLUSION: Overall, the effect exhibited by M. serrata in this study competed well with Senokot (standard drug) and proved that it may be relatively safe and with excellent laxative potential, thus, supporting its pharmacological applications in South Africa.

Plantago ovata: Clinical study of overuse.

The objective of the study was to undertake evidence-base study to evaluate clinical manifestation of the over-estimated use of herbal drug Plantago ovata and to compare it with placebo for the efficacy and adverse effects. The patients of both genders were included. Blood urea, creatinine, ALT, Serum B12, CP, ESR and liver function tests were performed. The data was statistically analyzed in both groups for differential symptomatology. In anorexia test verses control results showed that Plantago ovata husk and placebo showed the affected ratio as 81 percent and 50 percent, correspondingly. Whereas in clinical performance of heart burning, pain in epigastrium, low libido, body pain, dyspepsia, fever, burning sensation in palm and sole in test drug showed affected response as adverse effect 90%, 88% and as control drug, 36%, 29%, 22%, 25%, 38%, 30%, 33%, 57%, respectively. The results were highly marked in test drug i.e. in comparison with placebo. This is clearly evident from data analysis that effect observed in test arm is far more superior hence null hypothesis was rejected clearly. Similarly serological and biochemical reports study i.e. (ALT, Vit. B1 and Vit A) revealed that there is no hepatotoxic and neurotoxic effect found in both the drugs.

Toxicity and antioxidant capacity of Frangula alnus Mill. bark and its active component emodin.

In the present study toxicity of Frangula alnus Mill. bark, widely used as laxative, was investigated. Human peripheral blood lymphocytes (HPBLs) were treated with F. alnus bark extract or emodin (emodin is bark component with laxative property), and cytotoxicity, genotoxicity and parameters of oxidative stress were assessed. Also, polyphenol content of bark extract and antioxidant activity of the extract and emodin measured by DPPH, ABTS and FRAP methods were examined. The bark extract (500 µg/ml) produced cell death and DNA damage, while level of ROS changed at 250 µg/ml. Emodin induced cell death and DNA damage at 150 µg/ml and 200 µg/ml, respectively, and the increase of ROS was observed at 25 µg/ml. These results suggest that both, bark extract and emodin, are cyto/genotoxic to HPBLs and that oxidative stress is involved in the mechanism of their toxicity. The results on antioxidant activity showed that, unlike emodin, bark extract possess moderate antioxidant capacity (44.6%, 46.8% and 2.25 mmol Fe(2+)/g measured by DPPH, ABTS and FRAP assay, respectively) that can be related to relatively high phenolic content (116.07 mg/g). However, due to toxicological properties use of F. alnus bark as well as emodin-containing preparations should be taken with caution.

Dual effectiveness of Flaxseed in constipation and diarrhea: Possible mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: This study was planned to assess pharmacological basis for the medicinal use of Flaxseed in constipation and diarrhea. MATERIALS AND METHODS: The oil and mucilage of Flaxseeds were studied for their laxative, and antidiarrheal activities in mice. The mechanisms of laxative and antidiarrheal activities were further studied using the isolated tissue preparations (rabbit jejunum and guinea-pig ileum) immersed in Tyrode׳s solution maintained at 37°C and aerated with carbogen gas. Isotonic responses were measured on spontaneously contracting isolated jejunum and guinea-pig ileum preparations. RESULTS: Oral administration of Flaxseed oil (30 and 70mg/kg, orally) and mucilage (1 and 2.5g/kg, orally) caused dose-dependent increase in wet feces in mice. The spasmogenic effect of Flaxseed oil was partially blocked by pyrilamine (p<0.05) and atropine (p<0.01) in isolated rabbit jejunum whereas atropine completely blocked the effect of Flaxseed mucilage on isolated guinea-pig ileum. When studied for its antidiarrheal effect, Flaxseed oil reduced the castor oil-induced diarrheal score by 49.35% and 84.41% and intestinal secretions by 19% and 33.62% at the oral doses of 100 and 300mg/kg respectively. In isolated rabbit jejunum preparations, Flaxseed oil produced a dose-dependent inhibition of both spontaneous and low K(+) (25mM) -induced contractions in rabbit jejunum. The inhibitory effect against low K(+) was most sensitive to tetra-ethylammonium chloride, a non-specific K(+) channel blocker, followed by glibenclamide, a partial ATP-dependent K(+) channels blocker and 4-Aminopyridine, a voltage gated K(+)-channel blocker. CONCLUSIONS: Our results indicate that Flaxseed oil and mucilage exhibit laxative activity, mediated primarily through cholinergic pathway with weak histaminergic effect component evident in Flaxseed oil, which also showed antidiarrheal activity, mediated possibly through K(+) channels activation. Thus this study rationalizes the medicinal use of Flaxseed in both the constipation and diarrhea with sound mechanistic basis.

Determination of bioactive components in Chinese herbal formulae and pharmacokinetics of rhein in rats by UPLC-MS/MS.

Rhein (4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid, cassic acid) is a pharmacological active component found in Rheum palmatum L. the major herb of San-Huang-Xie-Xin-Tang (SHXXT), a medicinal herbal product used as a remedy for constipation. Here we have determined multiple bioactive components in SHXXT and investigated the comparative pharmacokinetics of rhein in rats. A sensitive and specific method combining liquid chromatography with electrospray ionization tandem mass spectrometry has been developed and validated to simultaneously quantify six active compounds in the pharmaceutical herbal product SHXXT to further study their pharmacokinetics in rats. Multiple reaction monitoring (MRM) was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. There were no significant matrix effects in the quantitative analysis and the mean recovery for rhein in rat plasma was 91.6%±3.4%. The pharmacokinetic data of rhein demonstrate that the herbal formulae or the single herbal extract provide significantly higher absorption rate than the pure compound. This phenomenon suggests that the other herbal ingredients of SHXXT and rhubarb extract significantly enhance the absorption of rhein in rats. In conclusion, the herbal formulae (SHXXT) are more efficient than the single herb (rhubarb) or the pure compound (rhein) in rhein absorption.

The laxative effect of emodin is attributable to increased aquaporin 3 expression in the colon of mice and HT-29 cells.

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a stimulant laxative and used to treat constipation. Aquaporin 3 (AQP3) plays an important role in regulating water transfer in the colon. In the study, we investigated whether the laxative effect of emodin is associated with the regulation of AQP3 in the colon. Our results showed that treatment with emodin increased the fecal water content in the colon of mice and evaluation index of defecation in a dose-dependent manner. More interestingly, emodin significantly increased the AQP3 protein and mRNA expression both in the colon of mice and in human intestinal epithelial cells (HT-29). Mechanistically, emodin obviously up-regulated the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A catalytic subunits α (PKA C-α) and phosphorylated cAMP response element-binding protein (p-CREB Ser133) expression in HT-29 cells. These results suggest that the laxative effect of emodin is associated with the increased expression of AQP3 by up-regulating PKA/p-CREB signal pathway.

Rheinanthrone, a metabolite of sennoside A, triggers macrophage activation to decrease aquaporin-3 expression in the colon, causing the laxative effect of rhubarb extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Aquaporin-3 (AQP3) is expressed in mucosal epithelial cells in the colon and is important for regulating fecal water content. We examined the role of AQP3 in the laxative effect of rhubarb extract. METHODS: After orally administering rhubarb extract or its major component (sennoside A) to rats, the fecal water content, AQP3 expression and prostaglandin E2 (PGE2) concentrations in the colon were examined. The mechanism by which sennoside A decreases the expression of AQP3 was examined using the human colon cancer HT-29 cells and macrophage-derived Raw264.7 cells. RESULTS: During diarrhea by rhubarb extract administration, the PGE2 levels in the colon increased while the AQP3 expression significantly decreased. Similar changes were also observed when sennoside A was administered. When sennoside A or its metabolites, rheinanthrone and rhein were added to Raw264.7 cells, a significant increase in the PGE2 concentration was observed only in cells treated with rheinanthrone. Fifteen minutes after adding PGE2 to the HT-29 cells, the AQP3 expression decreased to approximately 40% of the control. When pretreated with indomethacin, sennoside A neither decreased the AQP3 expression nor induced diarrhea. CONCLUSIONS: Sennoside A may decrease AQP3 expression in the colon to inhibit water transport from the luminal to the vascular side, leading to a laxative effect. The decreases in the levels of AQP3 are caused by rheinanthrone, which is a metabolite of sennoside A, this metabolite activates the macrophages in the colon and increases the secretion of PGE2; PGE2 acts as a paracrine factor and decreases AQP3 expression in colon mucosal epithelial cells.

Identification of E. dysenterica laxative peptide: a novel strategy in the treatment of chronic constipation and irritable bowel syndrome.

Plants have contributed over the years to the discovery of various pharmacological products. Amongst the enormous diversity of herbs with remarkable medicinal use and further pharmacological potential, here in this report we evaluated pulp extracts from Eugenia dysenterica fruits and further identified the active principle involved in such laxative activity in rats. For protein isolation, fruits were macerated with an extraction solution following precipitation with (NH(4))(2)SO(4) (100%). After dialysis, the peptide was applied onto a reversed-phase semi-preparative HPLC column, and the major fraction was eluted with 26% and 66% acetonitrile. The evaluation of molecular masses by MALDI-TOF and Tris/Tricine SDS-PAGE of HPLC fractions showed the presence of a major peptide with approximately 7 kDa. The N-terminal amino acid peptide sequence was determined and showed no similarity to other proteins deposited in the Data Bank. Peptide from E. dysenterica was able to enhance rats' intestinal motility by approximately 20.8%, probably being responsible for laxative activity. Moreover, these proteins were non-toxic to mammals, as observed in histopathology and hemolytic analyses. In conclusion, results here reported indicate that, in the near future, proteins synthesized by E. dysenterica fruits could be utilized in the development of novel biotechnological pharmaceutics with laxative properties for use in chronic constipation and irritable bowel syndrome treatment.

Laxative activities of Mareya micrantha (Benth.) Müll. Arg. (Euphorbiaceae) leaf aqueous extract in rats.

BACKGROUND: Mareya micrantha (Benth.) Müll. Arg. (Euphorbiaceae) is a shrub that is commonly used in Côte d'Ivoire (West Africa) for the treatment of constipation and as an ocytocic drug. The present study was carried out to investigate the laxative activity of Mareya micrantha in albino's Wistar rats. METHODS: Rats were divided in 5 groups of 5 animals each, first group as control, second group served as standard (sodium picosulfate) while group 3, 4 and 5 were treated with leaf aqueous extract of Mareya micrantha at doses of 100, 200 and 400 mg/kg body weight (b.w.), per os respectively. The laxative activity was determined based on the weight of the faeces matter. The effects of the leaves aqueous extract of Mareya micrantha and castor oil were also evaluated on intestinal transit, intestinal fluid accumulation and ions secretion. RESULTS: Phytochemicals screening of the extract revealed the presence of flavonoids, alkaloids, tannins, polyphenols, sterols and polyterpenes. The aqueous extract of Mareya micrantha applied orally (100, 200 and 400 mg/kg; p.o.), produced significant laxative activity and reduced loperamide induced constipation in dose dependant manner. The effect of the extract at 200 and 400 mg/kg (p.o.) was similar to that of reference drug sodium picosulfate (5 mg/kg, p.o). The same doses of the extract (200 and 400 mg/kg, p.o.) produced a significant increase (p < 0.01) of intestinal transit in comparison with castor oil (2 mL) (p < 0.01). Moreover, the extract induced a significant enteropooling and excretion of Cl-, Na+, K+ and Ca2+ in the intestinal fluid (p < 0.01). CONCLUSIONS: The results showed that the aqueous extract of Mareya micrantha has a significant laxative activity and supports its traditional use in herbal medicine.