Antioxidant activity and laxative effects of tannin-enriched extract of Ecklonia cava in loperamide-induced constipation of SD rats. Kim Ji Eun,Choi Yun Ju,Lee Su Jin,Gong Jeong Eun,Lee Young Ju,Sung Ji Eun,Jung Young Suk,Lee Hee Seob,Hong Jin Tae,Hwang Dae Youn PloS one 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. 10.1371/journal.pone.0246363
    Astragaloside IV alleviates mouse slow transit constipation by modulating gut microbiota profile and promoting butyric acid generation. He Qiulan,Han Changpeng,Huang Liang,Yang Haojie,Hu Jiancong,Chen Huaxian,Dou Ruoxu,Ren Donglin,Lin Hongcheng Journal of cellular and molecular medicine Gut microbiota and short-chain fatty acids (SCFAs) are associated with the development of various human diseases. In this study, we examined the role of astragaloside IV in modulating mouse gut microbiota structure and the generation of SCFAs, as well as in slow transit constipation (STC). An STC model was established by treating mice with loperamide, in which the therapeutic effects of astragaloside IV were evaluated. The microbiota community structure and SCFA content were analysed by 16S rRNA gene sequencing and gas chromatography-mass spectrometry, respectively. The influence of butyrate on STC was assessed using a mouse model and Cajal cells (ICC). Astragaloside IV promoted defecation, improved intestinal mobility, suppressed ICC loss and alleviated colonic lesions in STC mice. Alterations in gut microbiota community structure in STC mice, such as decreased Lactobacillus reuteri diversity, were improved following astragaloside IV treatment. Moreover, astragaloside IV up-regulated butyric acid and valeric acid, but decreased isovaleric acid, in STC mouse stools. Butyrate promoted defecation, improved intestinal mobility, and enhanced ICC proliferation by regulating the AKT-NF-κB signalling pathway. Astragaloside IV promoted intestinal transit in STC mice and inhibited ICC loss by regulating the gut microbiota community structure and generating butyric acid. 10.1111/jcmm.15586
    Emodin down-regulates expression of TRPV1 mRNA and its function in DRG neurons in vitro. Sui Feng,Huo Hai-Ru,Zhang Chang-Bin,Yang Na,Guo Jian-You,Du Xin-Liang,Zhao Bao-Sheng,Liu Hong-Bin,Li Lan-Fang,Guo Shu-Ying,Jiang Ting-Liang The American journal of Chinese medicine Emodin is a principle ingredient isolated from rhubarb rhizome, which is commonly used for constipation or pain-related diseases in traditional Chinese medicine (TCM) practice. The transient receptor potential vanilloid 1 ion channel proteins (TRPV1) are abundantly expressed in the peripheral sensory neurons and are assumed to act as a kind of nociceptor involved in the perception of pain and development of hyperalgesia. The aim of this study was to further unravel the analgesic mechanisms of rhubarb through investigating the effects of its main constitutive ingredient emodin on the expression of TRPV1 mRNA as well as on its calcium- mediating functions in vitro. The primary DRG neurons with a high purity and viability were obtained, and the TRPV1 mRNA expression levels were examined by using real-time RT-PCR and the elevated amplitudes of intracellular [Ca(2+)]i in the DRG neurons evoked by TRPV1 agonist capsaicin were examined by confocal microscopy. The results showed that emodin could significantly down-regulate both the mRNA expression of TRPV1 and the capsaicin-evoked intracellular fluorescent intensity in the DRG neurons under both 37 degrees C and 39 degrees C in vitro. Concomitantly, all of the changes induced by emodin could not be blocked by pretreatment of the primary neurons with capsazepine, an antagonist of TRPV1. In conclusion, we established that the mRNA expression level of TRPV1 and its calcium-mediating function in naive DRG neurons could be down-regulated by emodin through perhaps the non-TRPV1 channel pathways, and this might be the molecular mechanisms for rhubarb to inhibit hyperalgesia induced by inflammatory stimuli. 10.1142/S0192415X1000824X
    Simultaneous determination of ten compounds in rat plasma by UPLC-MS/MS: Application in the pharmacokinetic study of Ma-Zi-Ren-Wan. Hu Dong-Dong,Han Quan-Bin,Zhong Linda Li-Dan,Li Yan-Hong,Lin Cheng-Yuan,Ho Hing-Man,Zhang Man,Lin Shu-Hai,Zhao Ling,Huang Tao,Mi Hong,Tan Hong-Sheng,Xu Hong-Xi,Bian Zhao-Xiang Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Ma-Zi-Ren-Wan (MZRW) is a classic Chinese formula which has been used to treat human constipation in China for over 2000 years. In order to make good and rational use of this formula in the future, this paper presents the first attempt to track the pharmacokinetic features of MZRW in rat using rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Ten chemical components of MZRW, namely, rhein, emodin, aloe emodin, hesperidin, naringin, amygdalin, albiflorin, paeoniflorin, magnolol and honokiol, were simultaneously determined in rat plasma after a single oral administration (10g/kg body weight) of MZRW to rats. Geniposide and liquiritin were used as internal standards. The separation was performed on a Waters ACQUITY BEH C18 column (100mm×2.1mm, 1.7μm). The detection was conducted by multiple-reaction monitoring (MRM) in negative ionization mode. Two highest abundant MRM transitions without interference were optimized for each analyte. This method was well validated in terms of linearity, precision, accuracy, recovery, matrix effect and stability. All calibration curves had good linearity (r(2)>0.995) over the concentration range from 3.9 to 125.0ng/mL for emodin, 3.9-500.0ng/mL for amygdalin, 2.0-4000.0ng/mL for naringin and hesperidin, 3.9-2000.0ng/mL for magnolol, 7.8-2000.0ng/mL for rhein and 3.9-4000.0ng/mL for albiflorin, paeoniflorin, aloe emodin and honokiol. The intra-day and inter-day precision (relative standard deviation) was within 15%, the accuracy (relative error) ranged from -13.6% to 15.1%, and the lower limit of quantification in plasma ranged between 2.0ng/mL and 7.8ng/mL. Extraction recovery, matrix effect and stability were satisfactory. The validated method was successfully applied to a pharmacokinetic study of these ten compounds after oral administration of MZRW to rats. The pharmacokinetic parameters of each compound can facilitate clinical studies in the future. 10.1016/j.jchromb.2015.07.003
    A Purified Anthraquinone-Glycoside Preparation From Rhubarb Ameliorates Type 2 Diabetes Mellitus by Modulating the Gut Microbiota and Reducing Inflammation. Cui Hong-Xin,Zhang Ling-Shuai,Luo Yang,Yuan Ke,Huang Zhi-Yong,Guo Ying Frontiers in microbiology L. is widely used in traditional Chinese medicine for the treatment of constipation. Here, the therapeutic effects and underlying mechanisms of purified anthraquinone-glycoside preparation from rhubarb (RAGP) on the type 2 diabetes mellitus (T2DM) rats were investigated. After 6 weeks of metformin and RAGP treatment, the weight returned to normal. Fasting blood glucose (FBG), glycated serum protein (GSP), insulin concentration and HOMA-IR index had significantly decreased, and glucagon-like peptide-1 (GLP-1) concentrations had increased. Histological abnormalities in the pancreas and ileum had improved. These effects were associated with enhanced intestinal integrity, thereby reducing the absorption of lipopolysaccharide (LPS) and inflammation. To investigate whether RAGP ameliorated insulin resistance effects on the gut microbiota, we performed 16s rDNA sequencing of ileal gut contents. This showed an amelioration of gut dysbiosis, with greater abundance of probiotic and short-chain fatty acid-producing bacteria, and lower abundance of the Lachnospiraceae NK4A136 group and LPS-producing . The mechanism of the hypoglycemic effect of RAGP involves regulation of the gut microbiota, activation of the GLP-1/cAMP pathway to ameliorate insulin resistance. Thus, this study provides a theoretical basis for the use of RAGP to treat T2DM, and it may be a novel approach to restore the gut microbiota. 10.3389/fmicb.2019.01423
    Determination of bioactive components in Chinese herbal formulae and pharmacokinetics of rhein in rats by UPLC-MS/MS. Hou Mei-Ling,Chang Li-Wen,Lin Chi-Hung,Lin Lie-Chwen,Tsai Tung-Hu Molecules (Basel, Switzerland) 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. 10.3390/molecules19044058
    [Effect of vasoactive intestinal peptide on defecation and VIP-cAMP-PKA-AQP3 signaling pathway 
in rats with constipation]. Zhou Yongxue,Wang Yujin,Zhang Hong,Yan Shuguang,Wang Bin,Xie Pei Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences OBJECTIVE:To observe the effect of vasoactive intestinal peptide (VIP) on the metabolism of intestinal fluid and cyclic AMP protein kinase A signaling pathway (cAMP-PKA) and water channel protein 3 (AQP3) in rats with constipation, and to explore the mechanism of VIP in the treatment of constipation.
 Methods: A total of 45 healthy adult rats were randomly divided into a control group, a model group, a model +VIP group. After 4 weeks of VIP treatment, the first black stool time were examined with the ink gastric method; the water content in feces was calculated; the morphological changes in colonic tissues were observed by HE staining. The expression of VIP and AQP3 protein levels in colon tissues were detected by Western blot; and the cAMP, PKA, AQP3 mRNA expression levels were detected by quantitative real time polymerase chain reaction (qPCR). 
 Results: Compared with the control group, the first black stool time was prolonged, the water content of fecal decreased significantly (both P<0.01); part of the colon mucosa epithelial cells were destructed; the goblet cell volume decreased and quantity was reduced; the contents of AQP3 and VIP in colon tissues were significantly decreased, and the cAMP, PKA and AQP3 mRNA levels were decreased in the model group (all P<0.05). Compared with the model group, the first black stool time in the model +VIP group was shortened, the fecal water content increased significantly (both P<0.05); the mucosal epithelium integrity improved, the number of goblet cells increased; the content of AQP3 and VIP in colon tissues was increased, and the cAMP, PKA, and AQP3 mRNA levels were elevated (all P<0.05).
 Conclusion: Intravenous injection of VIP can regulate intestinal fluid metabolism and improve the symptoms of constipation in rats, which might be related to the regulation of VIP-cAMP-PKA-AQP3 signaling pathway. 10.11817/j.issn.1672-7347.2016.11.010
    Pharmacological basis for the medicinal use of muskmelon base (Pedicellus Melo.) for abdominal distention and constipation. Gao Yuan,Cai Run-Lan,Xie Chen,Lin Yu-Lin,Zhang Lei,Qi Yun Journal of ethnopharmacology ETHNOPHARMACOLOGICAL RELEVANCE:Muskmelon base (Pedicellus Melo.) has a long history (Ming Dynasty) as a Chinese traditional medicine. According to traditional use, it was prepared as rectal suppositories for treating abdominal distention and constipation. The present study was carried out on the pharmacological basis for the medicinal use of muskmelon base. AIM OF THE STUDY:The objective of this study was to determine the pharmacological basis for the medicinal use of the ethanol extract from muskmelon base (EMB) for abdominal distention and constipation. MATERIALS AND METHODS:In this study, we report the gastrointestinal prokinetic action of EMB following single rectal or large intestinal administration. Laxative activity, gastric emptying and small intestinal transit tests were examined in ICR mice. SD rats were used to determine changes in large intestinal transit and contractile effects of the proximal colon in vivo. Guinea pigs were used to evaluate the contractile effects of the proximal colon and the possible mechanism or mechanisms on proximal colon activity ex vivo. Moreover, the acute toxicity of EMB was evaluated. RESULTS:In the in vivo experiments, the acute toxicity test showed that the maximum tolerated dose (MTD) of EMB was 400 mg/kg. A laxative effect was observed in mice at different dosages (6.5, 13 and 26 mg/kg). EMB showed a dose-dependent acceleration of gastric emptying (13 and 26 mg/kg). It also promoted both small intestinal (6.5, 13 and 26 mg/kg) and large intestinal (4, 8 and 16 mg/kg) transit activity. In the SD rat model, single rectal administration of EMB (8 and 16 mg/kg) showed a significant increase in both the frequency and amplitude of proximal colon smooth muscle contractility. These increases in amplitude and frequency peaked 30-60 min after EMB administration and corresponded with the results of the laxative activity test. The ex vivo experiments showed that varying doses of EMB (11.5, 23 and 46 mg/kg) had a direct prokinetic effect that was sensitive to atropine. CONCLUSIONS:Our results show that EMB is a low dosage, fast acting drug with a large therapeutic window (4-400 mg/kg) and shows significant gastrointestinal prokinetic action after single rectal or large intestinal administration. This gastrointestinal prokinetic effect was stronger in the intestines than in the stomach. This effect was sensitive to atropine, suggesting that EMB acts mainly through cholinergic mechanisms. 10.1016/j.jep.2012.04.025
    Deciphering the correlations between aging and constipation by metabolomics and network pharmacology. Liu Xiaojie,Zhao Di,Zhao Sijun,Li Zhenyu,Wang Yulan,Qin Xuemei Aging From the points of view of phenomena and experience, aging and constipation are inextricably correlated. However, experimental support and underlying mechanisms are still lacking. The purpose of this study is to explore the relationships between aging and constipation from the perspectives of fecal metabolites and network pharmacology. The behavioral analyses of aging and constipation were carried out on both aging rats and constipation rats. We found that aging rats exhibited not only significant aging behaviors but also significant constipation behaviors, while constipation rats exhibited both significant constipation and aging behaviors. Additionally, fecal metabolomics was carried out and found that 23 metabolites were aging-related and 22 metabolites were constipation-related. Among them, there were 16 differential metabolites in common with 11 metabolic pathways. Network pharmacology was applied to construct the target-pathway network of aging and constipation, revealing that pathway in cancer was the most associated signaling pathway. The current findings will provide not only a novel perspective for understanding aging and constipation, but a theoretical association and understanding the traditional Chinese medicine theory and the Western medicine theory about aging and constipation, as well as support for the clinical research and development of medicine related to constipation in the elderly. 10.18632/aging.202340
    The synergism mechanism of Rhubarb Anthraquinones on constipation elucidated by comparative pharmacokinetics of Rhubarb extract between normal and diseased rats. Gong Xiao-Hong,Li Yan,Zhang Ruo-Qi,Xie Xiao-Fang,Peng Cheng,Li Yun-Xia European journal of drug metabolism and pharmacokinetics In the study, it was hypothesized that Rhubarb Anthraquinones synergistically enhanced the purgative effect on constipation rat from the direct and indirect pathway at the same time. A validated HPLC method was successfully applied to elucidate the synergism mechanism from pharmacokinetics aspect after oral administration of Rhubarb extract with a dose of 0.25 g to normal and constipation rats. Comparison of the pharmacokinetic data of normal and constipation rats showed that there were significant differences (p < 0.05) in the main pharmacokinetic parameters. The C max and AUC of emodin in constipation rats were about ten times that of normal rats, while the t 1/2 was remarkably decreased (p < 0.05). However, a significant decrease (p < 0.05) in AUC value for aloe-emodin and rhein was observed in model group compared with normal group. The results may be attributed to the direct action of aloe-emodin and rhein on intestinal cell membranes and the indirect action of emodin on bowel movement through the adjustment by nervous system. 10.1007/s13318-014-0216-7