Nostoc sphaeroides Kütz Polysaccharide Improved Constipation and Promoted Intestinal Motility in Rats

Improvement of functional dyspepsia with Suaeda salsa (L.) Pall via regulating brain-gut peptide and gut microbiota structure

PURPOSE

The traditional Chinese herbal medicine Suaeda salsa (L.) Pall (S. salsa) with a digesting food effect was taken as the research object, and its chemical composition and action mechanism were explored.

METHODS

The chemical constituents of S. salsa were isolated and purified by column chromatography, and their structures were characterized by nuclear magnetic resonance. The food accumulation model in mice was established, and the changes of the aqueous extract of S. salsa in gastric emptying and intestinal propulsion rate, colonic tissue lesions, serum brain-gut peptide hormone, colonic tissue protein expression, and gut microbiota structure were compared.

RESULTS

Ten compounds were isolated from S. salsa named as naringenin (1), hesperetin (2), baicalein (3), luteolin (4), isorhamnetin (5), taxifolin (6), isorhamnetin-3-O-β-D-glucoside (7), luteolin-3'-D-glucuronide (8), luteolin-7-O-β-D-glucuronide (9), and quercetin-3-O-β-D-glucuronide (10), respectively. The aqueous extract of S. salsa can improve the pathological changes of the mice colon and intestinal peristalsis by increasing the rate of gastric emptying and intestinal propulsion. By adjusting the levels of 5-HT, CCK, NT, SS, VIP, GT-17, CHE, MTL, and ghrelin, it can upregulate the levels of c-kit, SCF, and GHRL protein, and restore the imbalanced structure of gut microbiota, further achieve the purpose of treating the syndrome of indigestion. The effect is better with the increase of dose.

CONCLUSION

S. salsa has a certain therapeutic effect on mice with the syndrome of indigestion. From the perspective of "brain-gut-gut microbiota", the mechanism of digestion and accumulation of S. salsa was discussed for the first time, which provided an experimental basis for further exploring the material basis of S. salsa.

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.

Improvement of loperamide-hydrochloride-induced intestinal motility disturbance by Platycodon grandiflorum polysaccharides through effects on gut microbes and colonic serotonin

Constipation is a common gastrointestinal symptom characterized by intestinal motility disorder. The effects of Platycodon grandiflorum polysaccharides (PGP) on intestinal motility have not been confirmed. We established a rat model of constipation induced by loperamide hydrochloride to elucidate the therapeutic effect of PGP on intestinal motility disorder and to explore the possible mechanism. After PGP treatment (400 and 800 mg/kg) for 21 d, PGP clearly relieved gastrointestinal motility, including fecal water content, gastric emptying rate, and intestinal transit rate. Moreover, the secretion of motility-related hormones, gastrin and motilin, were increased. Enzyme-linked immunosorbent assay, western blot, immunohistochemistry, and immunofluorescence results confirmed that PGP significantly increased the secretion of 5-hydroxytryptamine (5-HT) and the expression of related proteins, such as tryptophan hydroxylase 1, 5-HT4 receptor, and transient receptor potential ankyrin 1. 16S rRNA gene sequencing showed that PGP significantly increased the relative abundance of Roseburia, Butyricimonas, and Ruminiclostridium, which were positively correlated with 5-HT levels. However, the relative abundance of Clostridia_UCG-014, Lactobacillus, and Enterococcus were decreased. PGP improved intestinal transport by regulating the levels of 5-HT, which interacts with the gut microbiota and the intestinal neuro-endocrine system, further affecting constipation. Overall, PGP is a potential supplement for the treatment of constipation.

Dysregulation of the Enteric Nervous System in the Mid Colon of Complement Component 3 Knockout Mice with Constipation Phenotypes

Complement component 3 (C3) contributes to neurogenesis, neural migration, and synaptic elimination under normal and disease conditions of the brain, even though it has not been studied in the enteric nervous system (ENS). To determine the role of C3 in the regulatory mechanism of ENS during C3 deficiency-induced constipation, the changes in the markers of neuronal and interstitial cells of Cajal (ICCs), the markers for excitatory and inhibitory transmission of ENS, and expression of C3 receptors were analyzed in the mid colon of C3 knockout (KO) mice at 16 weeks of age. Prominent constipation phenotypes, including the decrease in stool parameters, changes in the histological structure, and suppression of mucin secretion, were detected in C3 KO mice compared to wildtype (WT) mice. The expression levels of the neuron specific enolase (NSE), protein gene product 9.5 (PGP9.5), and C-kit markers for myenteric neurons and ICCs were lower in the mid colon of C3 KO mice than WT mice. Excitatory transmission analysis revealed similar suppression of the 5-hydroxytryptamine (5-HT) concentration, expression of 5-HT receptors, acetylcholine (ACh) concentration, ACh esterase (AChE) activity, and expression of muscarinic ACh receptors (mAChRs), despite the mAChRs downstream signaling pathway being activated in the mid colon of C3 KO mice. In inhibitory transmission analysis, C3 KO mice showed an increase in the nitric oxide (NO) concentration and inducible nitric oxide synthase (iNOS) expression, while neuronal NOS (nNOS) expression, cholecystokinin (CCK), and gastrin concentration were decreased in the same mice. Furthermore, the levels of C3a receptor (C3aR) and C3bR expression were enhanced in the mid colon of C3 KO mice compared to the WT mice during C3 deficiency-induced constipation. Overall, these results indicate that a dysregulation of the ENS may play an important role in C3 deficiency-induced constipation in the mid colon of C3 KO mice.

Effects of Nostoc sphaeroids Kütz polysaccharide on renal fibrosis in high-fat mice

In this study, we investigated the effects of Nostoc sphaeroids Kütz polysaccharide (NSKP) on renal fibrosis in high‐fat mice. ApoE^−/− male mice were randomly divided into four groups: control (Cont) group, high‐fat diet (HFD) group, HFD+0.4 g/kg BW NSKP, and HFD+0.8 g/kg BW NSKP (NSKP groups). The Cont was fed a standard diet. The HFD group was fed HFD. Every day, NSKP groups were fed HFD, as well as given 0.4 g/kg BW or 0.8 g/kg BW NSKP. After 22 weeks, the serum biochemical indices (TC, TG, LDL‐C, HDL‐C, GLU, BUN, and SCR) were measured. For the kidney, the histopathological sections were observed and analyzed, and inflammatory factors and markers of renal fibrosis were measured. For the NSKP groups, the serum TC, TG, LDL‐C, BUN, and SCR were decreased, HDL‐C significantly increased compared with the HFD group. The protein expressions of TNF‐α, IL‐1β, and TGF‐β1 were significantly downregulated. The α‐SMA in renal cortex was decreased, and the mRNA expression of Col‐I and Col‐IV in renal collagen fibers was downregulated. To sum up, NSKP reduced the blood lipid of HFD mice, downregulated the inflammation of kidney, inhibited the expression of collagen fiber, and improved the renal fibrosis caused by long‐term lipid metabolism disorder.

Preclinical experimental models for assessing laxative activities of substances/products under investigation: a scoping review of the literature

Constipation is a common gastrointestinal problem worldwide. Its impact on health can range from an unpleasant problem to being seriously troublesome. When lifestyle modification fails to deal with constipation, laxatives are the mainstay of therapy. There are several types of laxatives currently available; however, there still remains a need for better laxatives because certain currently available laxatives are not appropriate for or accessible to some patients. Preclinical experiments to study the laxative potential of substances/products of interest are vital to improving that situation. The selection of appropriate experimental models for assessing the laxative activities of substances/products under investigation is crucial to achieving valid and meaningful results. This article provides a scoping review of the literature, outlining, and summarizing models currently being used in preclinical experiments assessing the laxative activities of substances/products under investigation. The review includes both screening models, e.g., the isolated organ bath system, in vivo fecal assessment and intestinal transit assay, and confirmation models, e.g., in vivo constipation models. Chemical substances/drugs used to induce constipation in in vivo constipation models, e.g., loperamide, diphenoxylate, montmorillonite, and clonidine, as well as standard laxative agents used as a positive control in experimental models, e.g., bisacodyl, carbachol, lactulose, sodium picosulfate, castor oil, phenolphthalein, and yohimbine, are described in detail. The purpose of this article is to assist researchers in the design and implementation of preclinical experimental models for assessing laxative activities of substances/products under investigation to achieve valid and meaningful preclinical results prior to experimentation in humans.