Polysaccharides extracted from Rheum tanguticum ameliorate radiation-induced enteritis via activation of Nrf2/HO-1

Rhapontin activates nuclear factor erythroid 2-related factor 2 to ameliorate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced gastrointestinal dysfunction in Parkinson's disease mice

BACKGROUND

Parkinson's disease (PD)-a progressive neurodegenerative disorder-is characterized by motor and gastrointestinal dysfunction. The exploration of novel therapeutic strategies for PD is vital.

AIM

To investigate the potential mechanism of action of rhapontin-a natural compound with known antioxidant and anti-inflammatory properties-in the context of PD.

METHODS

Network pharmacology was used to predict the targets and mechanisms of action of rhapontin in PD. Behavioral tests and tyrosine hydroxylase immunofluorescence analysis were used to assess the effect of rhapontin on symptoms and pathology in MPTP-induced mice. Interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, and IL-10 levels in tissues were measured using an enzyme-linked immunosorbent assay (ELISA). Additionally, nuclear factor erythroid 2-related factor 2 (NRF2) activation was confirmed using western blotting.

RESULTS

NRF2 was predicted to be the key transcription factor underlying the therapeutic effects of rhapontin in PD, and its anti-PD action may be associated with its anti-inflammatory and antioxidant properties. Rhapontin ameliorated the loss of dopaminergic neurons and gastrointestinal dysfunction in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice by activating NRF2. Additionally, rhapontin treatment significantly decreased pro-inflammatory cytokines (IL-6, TNF-α, IL-1β) in the substantia nigra, striatum, and colon, whereas it increased anti-inflammatory cytokine (IL-10) levels only in the colon, indicating the involvement of gut-brain axis in its neuroprotective potential. Finally, NRF2 was identified as a key transcription factor activated by rhapontin, particularly in the colon.

CONCLUSION

We elucidated the effects of rhapontin in MPTP-induced PD mouse models using a combination of network pharmacology analysis, behavioral assessments, immunofluorescence, ELISA, and Western blotting. Our findings revealed the multifaceted role of rhapontin in ameliorating PD through its anti-inflammatory and antioxidant properties, particularly by activating NRF2, paving the way for future research into targeted therapies for PD.

Prevention and treatment of radiation injury by traditional Chinese medicine: A review

Nuclear radiation exposure events and tumor radiotherapy are highly susceptible to a range of psychological, physiological and other health problems, which can seriously affect patients' quality of life. It has been shown that 87.5 % of tumor patients are exposed to varying degrees of radiation injury during radiotherapy. The treatment of radiation injury (RI) in modern medicine is limited to drug therapy, cell therapy, etc. Among them, the most chemical drugs cause many adverse reactions including fatigue, nausea, vomiting, etc., and there are very few drugs dedicated to the treatment of RI. Traditional Chinese medicine (TCM) is a rich natural medicinal resource, which has a wide range of pharmacological activities, multiple targets of action and minimal toxic side effects. Many studies have demonstrated that TCM and its compound preparations have enormous potential in the treatment of radiation induced comprehensive diseases. However, TCM is limited in clinical application due to its slow onset of action, complex active ingredients, and low bioavailability. Therefore, the article reviews the application, molecular mechanisms, and new dosage forms of TCM in the prevention and treatment of RI. On this basis, we will focus on discussing the development advantages and application prospects of the combination of traditional Chinese and Western medicine to achieve highly efficient treatment of RI. This review aims to provide scientific and effective drug delivery strategies and basic theoretical support for the clinical effective treatment of RI with TCM, and further promote the innovative development of TCM.

Mid-infrared spectroscopic identification of the right-baked rhubarb for ulcerative colitis therapy

Clinical and experimental evidences have confirmed the significant therapeutic effects of rhubarb on ulcerative colitis (UC), but the strong purgative function of rhubarb also aggravates UC symptoms such as bloody diarrhea. Stir-baking to scorch is a traditional Chinese medicinal processing method that can eliminate the adverse purgative function while keep or even enhance the UC therapeutic function of rhubarb. However, the under-baked rhubarb still have the undesirable purgative function, but the over-baked rhubarb may lose the required medicinal functions. Therefore, the determination of the right endpoint is the primary quality concern about the baking process of rhubarb. In this research, typical anthraquinone compounds and mid-infrared (MIR) spectra were recruited to determine the best baking degree of rhubarb for UC therapy. Raw rhubarb slices were baked at 180 °C with rotation to prepare the rhubarbs with different baking degrees. The right-baked rhubarb was defined according to the UC therapeutic responses as well as the traditional color criterion. Referring to the typical anthraquinone compounds in rhubarb slices and extracts, the baking degree of rhubarb may be assessed by the conversion ratio of anthraquinone glycosides to anthraquinone aglycones. MIR spectra showed the gradual decompositions of organic compounds including anthraquinone glycosides and tannins during the baking process. Rhubarbs with different baking degrees can be distinguished clearly by MIR-based principal component analysis. In conclusion, the ratio of anthraquinone glycosides to anthraquinone aglycones may be a reasonable chemical indicator of the right-baked rhubarb. Meanwhile, MIR spectroscopy can identify the right-baked rhubarb simply and rapidly.

Gut microbiota modulation, prebiotic and bioactive characteristics of date pomace polysaccharides extracted by microwave-assisted deep eutectic solvent

This study investigated the characteristics of polysaccharides from date pomace using microwave-assisted deep eutectic solvents. The impact on the gut microbiota and probiotics growth was examined in vitro. The study also examined its antioxidant properties, ability to inhibit enzymes linked to diabetes and high blood pressure, impact on cell growth, and physical properties. The isolated MPS had an average molecular weight of 8073.38 kDa and contained mannose, galacturonic acid, galactose, glucose, and fructose in specific proportions. At a concentration of 1000 mg/L, MPS showed strong antioxidant activity, with significant scavenging rates in various tests such as DPPH (57.0 ± 1.05 %) and ABTS (66.4 ± 2.48 %). MPS displayed 77 %, 80 %, and 43 % inhibition for α-amylase, α-glucosidase, and ACE-inhibition, respectively. MPS displayed significant antiproliferative effects, achieving 100 % and 99 % inhibition against Caco-2 and MCF-7 cells at 2500 mg/L, respectively. MPS showed broad-spectrum antibacterial properties against both Gram-positive and Gram-negative foodborne bacteria. Gemmiger formicilis, Blautia species, Collinsella aerofaciens, and Bifidobacterium longum showed strong positive correlations, suggesting increased SCFA production. Network analysis indicated species correlations, with 86 % showing negative correlations with Escherichia and Enterococcus saccharolyticus. MPS was abundant in Firmicutes, Actinobacteria, and Proteobacteria phyla. Date pomace could serve as a dietary fiber source, promoting better health.

Amomum subulatum fruits protect against radiation-induced esophagitis by regulating antioxidant status and inflammatory responses

Radiation esophagitis (RE) is an inimical event that requires proper management while carrying out radiotherapy for thoracic cancers. The present study investigates the protective effect of dry fruits of the culinary and folkloric spice Amomum subulatum against experimental thoracic radiation-induced esophagitis. C57BL/6 mice were subjected to 25 Gy whole thorax irradiation and administered with 250 mg/kg body weight of methanolic extract of A. subulatum dry fruits (MEAS) orally for four consecutive weeks. Changes in tissue antioxidant activities, oxidative stress parameters, expression of antioxidant, inflammation, and fibrosis-related genes were observed. Administration of MEAS boosted antioxidant status, thereby reducing radiation-induced oxidative stress in the esophagus. PCR (polymerase chain reaction) results showed decreased expression of apoptosis, inflammation, and fibrosis-associated genes as well as increased expression of vital cytoprotective and antioxidant genes in MEAS-treated mice, manifesting its protective effect against radiation-induced oxidative stress, inflammatory responses, and fibrosis in the esophagus. Further, histopathology, immunohistochemistry (Cyclooxygenase-2), and Masson's Trichrome staining ascertained the protective effect of MEAS in alleviating radiation-induced esophageal injury. The synergistic effect of bioactive phytochemicals in MEAS with potent antioxidant and anti-inflammatory efficacies might have contributed to its mitigating effect against RE. Taken together, our results ascertained the radioprotective potential of MEAS, suggesting its possible nutraceutical application as a radiation countermeasure.

Mesenchymal Stem Cell-Derived Exosomes are Effective for Radiation Enteritis and Essential for the Proliferation and Differentiation of Lgr5+ Intestinal Epithelial Stem Cells by Regulating Mir-195/Akt/β-Catenin Pathway

BACKGROUND

Radiation enteritis (RE) is a common complication of abdominal or pelvic radiotherapy, which when severe, could be life-threatening. Currently, there are no effective treatments. Studies have shown that mesenchymal stem cells (MSCs)-derived exosomes (MSC-exos) exhibit promising therapeutic effects in inflammatory diseases. However, the specific role of MSC-exos in RE and the regulatory mechanisms remain elusive.

METHODS

In vivo assay was carried out by injecting MSC-exos into the total abdominal irradiation (TAI)-induced RE mouse model. For in vitro assay, Lgr5-positive intestinal epithelial stem cells (Lgr5+ IESC) were extracted from mice, followed by irradiation along with MSC-exos treatment. HE staining was performed to measure histopathological changes. mRNA expression of inflammatory factors TNF-α and IL-6 and stem cell markers LGR5, and OCT4 were quantified by RT-qPCR. EdU and TUNEL staining was performed to estimate cell proliferation and apoptosis. MiR-195 expression in TAI mice and radiation-induced Lgr5+ IESC was tested.

RESULTS

We found that the injection of MSC-exos inhibited inflammatory reaction, increased stem cell marker expression, and maintained intestinal epithelial integrity in TAI mice. Furthermore, MSC-exos treatment increased the proliferation and simultaneously suppressed apoptosis in radiation-stimulated Lgr5+ IESC. MiR-195 expression increased by radiation exposure was decreased by MSC-exos therapy. MiR-195 overexpression facilitated the progress of RE by counteracting the effect of MSC-exos. Mechanistically, the Akt and Wnt/β-catenin pathways inhibited by MSC-exos were activated by miR-195 upregulation.

CONCLUSION

MSC-Exos are effective in treating RE and are essential for the proliferation and differentiation of Lgr5+ IESCs. Moreover, MSC-exos mediates its function by regulating miR-195 Akt β-catenin pathways.

Exploring Natural Products as Radioprotective Agents for Cancer Therapy: Mechanisms, Challenges, and Opportunities

Radiotherapy is an important cancer treatment. However, in addition to killing tumor cells, radiotherapy causes damage to the surrounding cells and is toxic to normal tissues. Therefore, an effective radioprotective agent that prevents the deleterious effects of ionizing radiation is required. Numerous synthetic substances have been shown to have clear radioprotective effects. However, most of these have not been translated for use in clinical applications due to their high toxicity and side effects. Many medicinal plants have been shown to exhibit various biological activities, including antioxidant, anti-inflammatory, and anticancer activities. In recent years, new agents obtained from natural products have been investigated by radioprotection researchers, due to their abundance of sources, high efficiency, and low toxicity. In this review, we summarize the mechanisms underlying the radioprotective effects of natural products, including ROS scavenging, promotion of DNA damage repair, anti-inflammatory effects, and the inhibition of cell death signaling pathways. In addition, we systematically review natural products with radioprotective properties, including polyphenols, polysaccharides, alkaloids, and saponins. Specifically, we discuss the polyphenols apigenin, genistein, epigallocatechin gallate, quercetin, resveratrol, and curcumin; the polysaccharides astragalus, schisandra, and Hohenbuehelia serotina; the saponins ginsenosides and acanthopanax senticosus; and the alkaloids matrine, ligustrazine, and β-carboline. However, further optimization through structural modification, improved extraction and purification methods, and clinical trials are needed before clinical translation. With a deeper understanding of the radioprotective mechanisms involved and the development of high-throughput screening methods, natural products could become promising novel radioprotective agents.

AP2a-Mediated Upregulation of miR-125a-5p Ameliorates Radiation-Induced Oxidative Stress Injury via BRD4/Nrf2/HO-1 Signaling

Radiation therapy is widely used to restrain tumor progression, but it is always accompanied by damage to healthy tissues. We aimed to probe the impact and mechanism of activator protein 2a (AP2a) and miR-125a-5p in radiation-induced oxidative stress injury. Human umbilical vein endothelial cells (HUVECs) were treated with X rays to induce radiation injury in vitro. Cell viability was measured using MTT assays. Flow cytometry assay was employed to detect the apoptosis rate. Oxidative stress markers were evaluated by detection kits. Gene or protein levels were determined by RT-qPCR or Western blotting. Validation of the interaction of miR-125a-5p with BRD4 and AP2a was conducted by dual luciferase assay or ChIP. MiR-125a-5p and AP2a were decreased in irradiated HUVECs, whereas BRD4 was increased. MiR-125a-5p overexpression or BRD4 silencing alleviated the cell viability decline, apoptosis, and oxidative stress injury caused by radiation treatment. MiR-125a-5p repressed the BRD4 level. The protective effects of miR-125a-5p overexpression in the radiation-induced oxidative injury were impeded by BRD4 overexpression. Moreover, AP2a bound to the promoter of miR-125a-5p. MiR-125a-5p inhibition reversed the effects of AP2a overexpression on radiational oxidative injury by modulating Nrf2/HO-1 signaling. AP2a transcriptionally activated miR-125a-5p ameliorated oxidative stress injury of HUVECs caused by radiation through Nrf2/HO-1 signaling.

Advances in health-promoting effects of natural polysaccharides: Regulation on Nrf2 antioxidant pathway

Natural polysaccharides (NPs) possess numerous health-promoting effects, such as liver protection, kidney protection, lung protection, neuroprotection, cardioprotection, gastrointestinal protection, anti-oxidation, anti-diabetic, and anti-aging. Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway is an important endogenous antioxidant pathway, which plays crucial roles in maintaining human health as its protection against oxidative stress. Accumulating evidence suggested that Nrf2 antioxidant pathway might be one of key regulatory targets for the health-promoting effects of NPs. However, the information concerning regulation of NPs on Nrf2 antioxidant pathway is scattered, and NPs show different regulatory behaviors in their different health-promoting processes. Therefore, in this article, structural features of NPs having regulation on Nrf2 antioxidant pathway are overviewed. Moreover, regulatory effects of NPs on this pathway for health-promoting effects are summarized. Furthermore, structure-activity relationship of NPs for health-promoting effects by regulating the pathway is preliminarily discussed. Otherwise, the prospects on future work for regulation of NPs on this pathway are proposed. This review is beneficial to well-understanding of underlying mechanisms for health-promoting effects of NPs from the view angle of Nrf2 antioxidant pathway, and provides a theoretical basis for the development and utilization of NPs in promoting human health.

Nattokinase attenuates bisphenol A or gamma irradiation-mediated hepatic and neural toxicity by activation of Nrf2 and suppression of inflammatory mediators in rats

Nattokinase (NK), a protease enzyme produced by Bacillus subtilis, has various biological effects such as lipid-lowering activity, antihypertensive, antiplatelet/anticoagulant, and neuroprotective effects. Exposure to environmental toxicants such as bisphenol A (BPA) or γ-radiation (IR) causes multi-organ toxicity through several mechanisms such as impairment of oxidative status, signaling pathways, and hepatic and neuronal functions as well as disruption of the inflammatory responses. Therefore, this study is designed to evaluate the ameliorative effect of NK against BPA- or IR-induced liver and brain damage in rats. Serum ammonia level and liver function tests were measured in addition to brain oxidative stress markers, amyloid-beta, tau protein, and neuroinflammatory mediators. Moreover, relative quantification of brain nuclear factor-erythroid 2-related factor-2 (Nrf2)/heme oxygenase-1 (HO-1) genes, as well as apoptotic markers in brain tissue, was carried out in addition to histopathological examination. The results showed that NK improved liver functions, impaired oxidative status, the cholinergic deficits, and minified the misfolded proteins aggregates. Furthermore, NK alleviated the neuroinflammation via modulating NF-κB/Nrf2/HO-1 pathway and glial cell activation in addition to their antiapoptotic effect. Collectively, the current results revealed the protective effect of NK against hepatic and neurotoxicity derived from BPA or IR.

Fecal fermentation characteristics of Rheum tanguticum polysaccharide and its effect on the modulation of gut microbial composition

Background

Rheum tanguticum is utilized as one of the well known traditional Chinese medicine for the treatment of gastrointestinal diseases. Recently, R. tanguticum polysaccharides (RP) have received increasing attention due to their diversely pharmacological activities. Usually, the pharmacological activities of polysaccharides are closely correlated to their metabolic properties from the stomach to the intestine. However, the digestive behavior and fecal fermentation characteristics of RP are unknown, which need to be fully investigated.

Methods

In this study, an in vitro simulated gastrointestinal model was carried out for the investigation of the digestive behavior and fecal fermentation characteristics of RP. The possible changes in physicochemical properties of RP, such as molecular weight, monosaccharide composition, reducing sugar released, chemical composition, pH value, and short chain fatty acids, were determined during in vitro simulated digestion and human fecal fermentation, and its effect on the modulation of gut microbial composition was also evaluated.

Results

The results revealed that RP was indigestible under the in vitro simulated digestion conditions according to its stabilities in physicochemical properties. Conversely, the indigestible RP (RPI) could be notably utilized by colonic microbiota in human feces after the in vitro fermentation, especially, at the initial fermentation stage (0–6 h). The fecal fermentation characteristics of RPI were revealed. Results showed that the content of reducing sugars obviously increased from 0.177 to 0.778 mg/mL at the initial stage of fermentation, and its molecular weight notably declined from 2.588 × 10⁵ to 0.828 × 10⁵ Da at the end stage of fermentation. Notably, the utilization of arabinose and galactose in RPI by colonic bacteria was faster than that of galacturonic acid. Besides, RPI could obviously modulate gut microbial composition via promoting the relative abundances of several beneficial bacteria, such as genera Bacteroides, Bifidobacterium, and Megamonas, resulting in the promoted production of several short-chain fatty acids, such as acetic, propionic, and butyric acids.

Conclusions

Results from this study showed that RP was indigestible in the human upper gastrointestinal tract in vitro, but could be easily utilized by colonic microbiota in human feces at the initial stage of fermentation. RP could be used as potential prebiotics for the improvement of intestinal health.

Valorization of Polysaccharides From Benincasa hispida: Physicochemical, Moisturizing, and Antioxidant Skincare Properties

Benincasa hispida Cogn. (B. hispida) is a popular vegetable in China, and studies have been reported on B. hispida polysaccharides (BPS) preparation. However, few studies have been reported on its physicochemical and skincare properties. In this study, we analyzed the physicochemical properties of BPS, free radical scavenging capability, moisturizing and antioxidant activities in vitro and in vivo, respectively. Our results show that BPS was an inhomogeneous acidic polysaccharide that could scavenge a variety of free radicals. Also, BPS had a good moisturizing and antioxidant capability both in vitro and in vivo. Specifically, BPS could alter some key antioxidant enzyme activities and pro-inflammatory factor levels via activating the NRF2/HO-1 pathway, thereby preventing H2O2-induced reactive oxygen species (ROS) production and apoptosis of HDF-1 cells. Our results suggest that BPS exhibited favorable moisturizing and anti-aging properties and might be an attractive candidate for the development of anti-aging skincare products.

Screening of radiation gastrointestinal injury biomarkers in rat plasma by high-coverage targeted lipidomics

INTRODUCTION

In the event of radiological accidents and cancer radiotherapies in clinic, the gastrointestinal (GI) system is vulnerable to ionizing radiation and shows GI injury. Accessible biomarkers may provide means to predict, evaluate, and treat GI tissue damage. The current study investigated radiation GI injury biomarkers in rat plasma.

MATERIAL AND METHODS

High-coverage targeted lipidomics was employed to profile lipidome perturbations at 72 h after 0, 1, 2, 3, 5 and 8 Gy (⁶⁰Co γ-rays at 1 Gy/min) total-body irradiation in male rat jejunum. The results were correlated with previous plasma screening outcomes.

RESULTS

In total, 93 differential metabolites and 28 linear dose-responsive metabolites were screened in the jejunum. Moreover, 52 lipid species with significant differences both in jejunum and plasma were obtained. Three lipid species with linear dose-response relationship both in jejunum and plasma were put forth, which exhibited good to excellent sensitivity and specificity in triaging different exposure levels.

DISCUSSION

The linear dose-effect relationship of lipid metabolites in the jejunum and the triage performance of radiation GI injury biomarkers in plasma were studied for the first time.

CONCLUSION

The present study can provide insights into expanded biomarkers of IR-mediated GI injury and minimally invasive assays for evaluation.

Protective effects of Brownea grandiceps (Jacq.) against ϒ-radiation-induced enteritis in rats in relation to its secondary metabolome fingerprint

Radiation enteritis is the most common complication of radiotherapy in patients with pelvic malignancies. Thus, the radioprotective activity of the total hydro-alcoholic extract (BGE) and the ethyl acetate soluble fraction (EAF) of Brownea grandiceps leaves was evaluated against ϒ-radiation-induced enteritis in rats. (BGE) and (EAF) were characterized using HPLC-PDA-ESI-MS/MS analysis. The total phenolic and flavonoid contents were also quantified. In vivo administration of (BGE) (400 mg/kg) and (EAF) (200 & 400 mg/kg) prevented intestinal injury and maintained the mucosal integrity of irradiated rats through increasing villi length and promoting crypt regeneration. Also, (EAF) showed more potent antioxidant activity than (BGE) through reduction of MDA level and enhancement of GSH content and catalase enzyme activity. (BGE) and (EAF) down-regulated intestinal NF-κB expression leading to diminished expression of downstream inflammatory cytokine TNF-α. Moreover, (EAF) markedly reduced the expression of profibrotic marker TGF-β1. Seventy-nine compounds were tentatively identified, including flavonoids, proanthocyanidins, polar lipids and phenolic acids. (EAF) showed significantly higher total phenolic and flavonoid contents, as compared to (BGE). Results revealed remarkable radioprotective activity of (BGE) and (EAF), with significantly higher activity for (EAF). The chemical constituents of (BGE) and (EAF) strongly supported their radioprotective activity. To the best of our knowledge, the present study describes for the first time the radioprotective activity of B. grandiceps leaves in relation to its secondary metabolome fingerprint; emphasizing the great promise of B. grandiceps leaves, especially (EAF), to be used as natural radio-protective agent.

Characterization and Heterologous Expression of UDP-Glucose 4-Epimerase From a Hericium erinaceus Mutant with High Polysaccharide Production

Hericium erinaceus is an important medicinal fungus in traditional Chinese medicine because of its polysaccharides and other natural products. Compared terpenoids and polyketides, the analysis of synthetic pathway of polysaccharides is more difficult because of the many genes involved in central metabolism. In previous studies, A6180, encoding a putative UDP-glucose 4-epimerase (UGE) in an H. erinaceus mutant with high production of active polysaccharides, was significantly upregulated. Since there is no reliable genetic manipulation technology for H. erinaceus, we employed Escherichia coli and Saccharomyces cerevisiae to study the function and activity of A6180. The recombinant overexpression vector pET22b-A6180 was constructed for heterologous expression in E. coli. The enzymatic properties of the recombinant protein were investigated. It showed that the recombinant A6180 could strongly convert UDP-α-D-glucose into UDP-α-D-galactose under optimal conditions (pH 6.0, 30°C). In addition, when A6180 was introduced into S. cerevisiae BY4742, xylose was detected in the polysaccharide composition of the yeast transformant. This suggested that the protein coded by A6180 might be a multifunctional enzyme. The generated polysaccharides with a new composition of sugars showed enhanced macrophage activity in vitro. These results indicate that A6180 plays an important role in the structure and activity of polysaccharides. It is a promising strategy for producing polysaccharides with higher activity by introducing A6180 into polysaccharide-producing mushrooms.