Pectic polysaccharide from Nelumbo nucifera leaves promotes intestinal antioxidant defense in vitro and in vivo

Extraction, characterization and intestinal anti-inflammatory and anti-oxidative activities of polysaccharide from stems and leaves of Chuanminshen violaceum M. L. Sheh & R. H. Shan

ETHNOPHARMACOLOGICAL RELEVANCE

Chuanminshen violaceum M. L. Sheh & R. H. Shan (CV) is used as a medicine with roots, which have the effects of benefiting the lungs, harmonizing the stomach, resolving phlegm and detoxifying. Polysaccharide is one of its main active components and has various pharmacological activities, but the structural characterization and pharmacological activities of polysaccharide from the stems and leaves parts of CV are still unclear.

AIM OF THE STUDY

The aim of this study was to investigate the optimal extraction conditions for ultrasound-assisted extraction of polysaccharide from CV stems and leaves, and to carry out preliminary structural analyses, anti-inflammatory and antioxidant effects of the obtained polysaccharide and to elucidate the underlying mechanisms.

MATERIALS AND METHODS

The ultrasonic-assisted extraction of CV stems and leaves polysaccharides was carried out, and the response surface methodology (RSM) was used to optimize the extraction process to obtain CV polysaccharides (CVP) under the optimal conditions. Subsequently, we isolated and purified CVP to obtain the homogeneous polysaccharide CVP-AP-I, and evaluated the composition, molecular weight, and structural features of CVP-AP-I using a variety of technical methods. Finally, we tested the pharmacological activity of CVP-AP-Ⅰ in an LPS-induced model of oxidative stress and inflammation in intestinal porcine epithelial cells (IPEC-J2) and explored its possible mechanism of action.

RESULTS

The crude polysaccharide was obtained under optimal extraction conditions and subsequently isolated and purified to obtain CVP-AP-Ⅰ (35.34 kDa), and the structural characterization indicated that CVP-AP-Ⅰ was mainly composed of galactose, galactose, rhamnose and glucose, which was a typical pectic polysaccharide. In addition, CVP-AP-Ⅰ attenuates LPS-induced inflammation and oxidative stress by inhibiting the expression of pro-inflammatory factor genes and proteins and up-regulating the expression of antioxidant enzyme-related genes and proteins in IPEC-J2, by a mechanism related to the activation of the Nrf2/Keap1 signaling pathway.

CONCLUSION

The results of this study suggest that the polysaccharide isolated from CV stems and leaves was a pectic polysaccharide with similar pharmacological activities as CV roots, exhibiting strong anti-inflammatory and antioxidant activities, suggesting that CV stems and leaves could possess the same traditional efficacy as CV roots, which is expected to be used in the treatment of intestinal diseases.

Preparation, structural characterization, and biological activities of lotus polysaccharides: A review

Lotus (Nelumbo nucifera), belonging to the family of Nelumbonaceae, is a beautiful aquatic perennial plant. It has been used as an ancient horticulture plant and famous agricultural crop for thousands of years. Modern phytochemical and pharmacological experiments have proved that polysaccharide is one of the most pivotal bioactive constituents of lotus. Hence, the systematic review covering the fundamental research advances and developing prospects of N. nucifera polysaccharides (NNPs) is an urgent demand to provide theoretical basis for their further research and application. The present review summarizes current emerging research progresses on the polysaccharides isolated from lotus, and it focuses on advanced extraction and purification methods, unique structural features, engaging biological activities, potential molecular mechanisms, as well as the relationship of structure and activity of NNPs. This review sheds light on the potential values of NNPs in affording functionally bioactive agents in food industry or therapeutically effective medicines for health care. In addition, this review will provide valuable insights for further commercial product development and promising industrial application of NNPs in both of the fundamental research communities and food or pharmaceutical industries in future.

The relationship between polysaccharide structure and its antioxidant activity needs to be systematically elucidated

Polysaccharides have a wide range of applications due to their excellent antioxidant activity. However, the low purity and unclear structure of polysaccharides have led some researchers to be skeptical about the antioxidant activity of polysaccharides. The current reports on the structure-activity relationship of polysaccharides are sporadic, so there is an urgent need to systematically summarize the antioxidant effects of polysaccharides with clear structures and the relationships between the structures to provide a scientific basis for the development and application of polysaccharides. This paper will systematically elucidate the structure-activity relationship of antioxidant polysaccharides, including the molecular weight, monosaccharide composition, glycosidic linkage, degree of branching, advanced conformation and chemical modification. For the first time, the antioxidant activity of polysaccharides is related to their chemical structure through histogram and radar map, and further studies using principal component analysis and cluster analysis. We critically discussed how the source, chemical structure and chemically modified groups of polysaccharides significantly contribute to their antioxidant activity and summarized the current research status and shortcomings of the structure-activity relationship of antioxidant polysaccharides. This review provides a theoretical basis and new perspective for further research on the structure-activity relationship of antioxidant polysaccharides and the development of natural antioxidants.

Insights into the molecular mechanisms, structure-activity relationships and application prospects of polysaccharides by regulating Nrf2-mediated antioxidant response

The occurrence and development of many diseases are closely related to oxidative stress. In this context, accumulating evidence suggests that Nrf2, as the master switch of cellular antioxidant signaling, plays a central role in controlling the expression of antioxidant genes. The core molecular mechanism of polysaccharides treatment of oxidative stress-induced diseases is to activate Keap1/Nrf2/ARE signaling pathway, promote nuclear translocation of Nrf2, and up-regulate the expression of antioxidant enzymes. However, recent studies have shown that other signaling pathways in which polysaccharides exert antioxidant effects, such as PI3K/Akt/GSK3β, JNK/Nrf2 and NF-κB, have complex crosstalk with Keap1/Nrf2/ARE, may have direct effects on the nuclear translocation of Nrf2. This suggests a new strategy for designing polysaccharides as modulators of Nrf2-dependent pathways to target the antioxidant response. Therefore, in this work, we investigate the crosstalk between Keap1/Nrf2/ARE and other antioxidant signaling pathways of polysaccharides by regulating Nrf2-mediated antioxidant response. For the first time, the structural-activity relationship of polysaccharides, including molecular weight, monosaccharide composition, and glycosidic linkage, is systematically elucidated using principal component analysis and cluster analysis. This review also summarizes the application of antioxidant polysaccharides in food, animal production, cosmetics and biomaterials. The paper has significant reference value for screening antioxidant polysaccharides targeting Nrf2.

Protective effect of Broussonetia papyrifera leaf polysaccharides on intestinal integrity in a rat model of diet-induced oxidative stress

This study aimed to investigate the effect of Broussonetia papyrifera polysaccharides (BPP) on the jejunal intestinal integrity of rats ingesting oxidized fish oil (OFO) induced oxidative stress. Polysaccharides (Mw 16,956 Da) containing carboxyl groups were extracted from Broussonetia papyrifera leaves. In vitro antioxidant assays showed that this polysaccharide possessed antioxidant capabilities. Thirty-two male weaned rats were allocated into two groups orally infused BPP solution and PBS for 26 days, respectively. From day 9 to day 26, half of the rats in each group were fed food containing OFO, where the lipid peroxidation can induce intestinal oxidative stress. OFO administration resulted in diarrhea, decreased growth performance (p < 0.01), impaired jejunal morphology (p < 0.05) and antioxidant capacity (p < 0.01), increased the levels of ROS and its related products, IL-1β and IL-17 (p < 0.01) of jejunum, as well as down-regulated Bcl-2/Bax (p < 0.01) and Nrf2 signaling (p < 0.01) of jejunum in rats. BPP gavage effectively alleviated the negative effects of OFO on growth performance, morphology, enterocyte apoptosis, antioxidant capacity and inflammation of jejunum (p < 0.05) in rats. In the oxidative stress model cell assay, the use of receptor inhibitors inhibited the enhancement of antioxidant capacity by BPP. These results suggested that BPP protected intestinal morphology, thus improving growth performance and reducing diarrhea in rats ingesting OFO. This protective effect may be attributed to scavenging free radicals and activating the Nrf2 pathway, which enhances antioxidant capacity, consequently reducing inflammation and mitigating intestinal cell death.

Ultrasonic-assisted extraction of polysaccharide from Paeoniae Radix alba: Extraction optimization, structural characterization and antioxidant mechanism in vitro

Paeoniae Radix alba is used in Traditional Chinese Medicine for the treatment of gastrointestinal disorders, immunomodulatory, cancer, and other diseases. In the current study, the yield of Paeoniae Radix alba polysaccharide (PRP) was significantly increased with optimal ultrasound-assisted extraction compared to hot water extraction. Further, an acidic polysaccharide (PRP-AP) was isolated from PRP after chromatographic separation and was characterized as a typical pectic polysaccharide with side chains of arabinogalactans types I and II. Moreover, it showed antioxidant effects on LPS-induced damage on IPEC-J2 cells determined by qRT-PCR and ELISA, including decreasing the pro-inflammatory factors' expressions and increasing the antioxidant enzymes activities, which was shown to be related to the Nrf2/Keap1 pathway modulated by PRP-AP. The metabolites change (such as itaconate, cholesterol sulfate, etc.) detected by untargeted metabolomic analysis in cells was also shown to be modulated by PRP-AP, and these metabolites were further utilized and protected cells damaged by LPS. These results revealed the cellular active mechanism of the macromolecular PRP-AP on protecting cells, and supported the hypothesis that PRP-AP has strong benefits as an alternative dietary supplement for the prevention of intestinal oxidative stress by modulating cellular metabolism.

Potential of the Novel Slot Blot Method with a PVDF Membrane for Protein Identification and Quantification in Kampo Medicines

Kampo is a Japanese traditional medicine modified from traditional Chinese medicine. Kampo medicines contain various traditional crude drugs with unknown compositions due to the presence of low-molecular-weight compounds and proteins. However, the proteins are generally rare and extracted with high-polarity solvents such as water, making their identification and quantification difficult. To develop methods for identifying and quantifying the proteins in Kampo medicines, in the current study we employ previous technology (e.g., column chromatography, electrophoresis, and membrane chromatography), focusing on membrane chromatography with a polyvinylidene difluoride (PVDF) membrane. Moreover, we consider slot blot analysis based on the principle of membrane chromatography, which is beneficial for analyzing the proteins in Kampo medicines as the volume of the samples is not limited. In this article, we assess a novel slot blot method developed in 2017 and using a PVDF membrane and special lysis buffer to quantify advanced glycation end products-modified proteins against other slot blots. We consider our slot blot analysis superior for identifying and quantifying proteins in Kampo medicines compared with other methods as the data obtained with our novel slot blot can be shown with both error bars and the statistically significant difference, and our operation step is simpler than those of other methods.

Dietary pectin attenuates Salmonella typhimurium-induced colitis by modulating the TLR2-NF-κB pathway and intestinal microbiota in mice

The role of dietary pectin on microbial-induced colitis, oxidative status, barrier function, and microbial composition, as well as the underlying mechanisms, is scarce. In this study, we aimed to investigate whether dietary pectin alleviates Salmonella typhimurium-induced colitis in mice. Male C57BL/6J mice fed an isocaloric and isofibrous diet with 7% pectin or cellulose were administered sterile water or Salmonella typhimurium to induce colitis, which is equal to a human food dose of 0.57% (5.68 g/kg). Dietary pectin alleviated Salmonella typhimurium-induced colitis and oxidative stress as shown by the reduced disease activity index score, decreased colon shortening and histological damage score, colonic hydrogen peroxide, malondialdehyde concentrations, and relative mRNA expressions of coenzyme Q-binding protein COQ10 homologue B (Coq10b), Ccl-2, Ccl-3, Ccl-8, Tnf-α, Il-1β, Ifn-γ, Ifn-β, and serum TNF-α protein level. Moreover, pectin administration ameliorated the downregulated colonic abundances of occludin, zonula occludens-1, zonula occludens-2, and the upregulated abundances of TLR2 and p-NF-κB in Salmonella-infected mice. Additionally, 16S rRNA analysis demonstrated that pectin altered the microbial beta-diversity and reduced Salmonella levels. Collectively, pectin ameliorated Salmonella typhimurium-induced colitis, oxidative stress, and tight junction, which may be related to the inactivation of TLR2-NF-κB signalling and reduced abundance of Salmonella.

Ultrasound-assisted extraction and characterization of Penthorum chinense polysaccharide with anti-inflammatory effects

Penthorum chinense has been used in both food and medication for many years, and polysaccharide of which was considered as one of the bioactive compounds. However, the extraction process of polysaccharide from P. chinense (PCP) was not well optimized. Ultrasound-assisted extractionhas been widely employed in the extraction of natural products for its compliance with the concept of green and economic chemistry. To better investigate the structure and biology activity of PCP, response surface methodology was employed to optimize the ultrasound-assisted extraction conditions of PCP. The optimum extraction for the ultrasound-assisted extraction of PCP were obtained as ratio of solvent to material 40 mL/g, ultrasonic power 380 W, and extraction time of 50 min. The yield of PCP reached 8.71% under these optimized conditions. PCP was further purified by using anion exchange chromatography and gel filtration, an acidic fraction PCP-AP-1 was hereby obtained. The results of structural elucidation indicated that PCP-AP-1 was a typical pectic polysaccharide with a molecular weight of 66360 Da, mainly composed of galacturonic acid (68.5 mol%), followed by arabinose (9.8 mol%), rhamnose (9.4 mol%), glucose (7.7 mol%), with homogalacturonan region and rhamnogalacturonan I regions. In vitro study showed that PCP-AP-1 could improve the inflammation induced by lipopolysaccharide in intestinal epithelial cells, which was probably performed through the inhibition of multiple signaling pathways including the inhibition of TLR4, NOD1/2 and NF-κB pathway, as well as the reduction of NLRP3 inflammasome. This study defined the type of polysaccharide present in P. chinense and revealed a potential of application this plant in the prevention of intestinal inflammatory diseases.

A Pectic Polysaccharide from Codonopsis pilosula Alleviates Inflammatory Response and Oxidative Stress of Aging Mice via Modulating Intestinal Microbiota-Related Gut-Liver Axis

Aging is a biological process that leads to the progressive deterioration and loss of physiological functions in the human body and results in an increase in morbidity and mortality, and aging-related disease is a major global problem that poses a serious threat to public health. Polysaccharides have been shown to delay aging by reducing oxidative damage, suppressing inflammatory responses, and modulating intestinal microbiota. Our previous studies have shown that polysaccharide CPP-1 extracted from the root of Codonopsis pilosula possesses noticeable anti-oxidant activity in vitro. Thus, in our study, we tested the anti-aging effect of CPP-1 in naturally aging mice (in vivo). Eighteen C57/BL mice (48-week-old, male) were divided into a control group, high-dose CPP-1 group (20 mg/mL), and low-dose CPP-1 group (10 mg/mL). We discovered that CPP-1 can exert a reparative effect on aging stress in the intestine and liver, including alleviating inflammation and oxidative damage. We revealed that CPP-1 supplementation improved the intestinal microbiota composition and repaired the intestinal barrier in the gut. Furthermore, CPP-1 was proved to modulate lipid metabolism and repair hepatocyte injury in the liver by influencing the enterohepatic axis associated with the intestinal microbiota. Therefore, we concluded that CPP-1 prevents and alleviates oxidative stress and inflammatory responses in the intestine and liver of aging mice by modulating the intestinal microbiota-related gut-liver axis to delay aging.

Effects of Solid Fermentation on Polygonatum cyrtonema Polysaccharides: Isolation, Characterization and Bioactivities

Polygonati Rhizoma is a widely used traditional Chinese medicine (TCM) with complex pre-processing steps. Fermentation is a common method for processing TCM to reduce herb toxicity and enhance their properties and/or produce new effects. Here, in this study, using Bacillus subtilis and Saccharomyces cerevisiae, we aimed to evaluate the potential application of solid fermentation in isolating different functional polysaccharides from Polygonatum cyrtonema Hua. With hot water extraction, ethanol precipitation, DEAE anion exchange chromatography and gel filtration, multiple neutral and acidic polysaccharides were obtained, showing different yields, content, compositions and functional groups after fermentation. Combining in vitro experiments and in vivo aging and immunosuppressed mouse models, we further compared the antioxidant and immunomodulating bioactivities of these polysaccharides and found a prominent role of a natural polysaccharide (BNP) from fermented P. cyrtonema via Bacillus subtilis in regulating intestinal antioxidant defense and immune function, which may be a consequence of the ability of BNP to modulate the homeostasis of gut microbiota. Thus, this work provides evidence for the further development and utilization of P. cyrtonema with fermentation, and reveals the potential values of BNP in the treatment of intestinal disorders.

Bioactive polysaccharides from lotus as potent food supplements: a review of their preparation, structures, biological features and application prospects

Lotus is a famous plant of the food and medicine continuum for millennia, which possesses unique nutritional and medicinal values. Polysaccharides are the main bioactive component of lotus and have been widely used as health nutritional supplements and therapeutic agents. However, the industrial production and application of lotus polysaccharides (LPs) are hindered by the lack of a deeper understanding of the structure-activity relationship (SAR), structural modification, applications, and safety of LPs. This review comprehensively comments on the extraction and purification methods and structural characteristics of LPs. The SARs, bioactivities, and mechanisms involved are further evaluated. The potential application and safety issues of LPs are discussed. This review provides valuable updated information and inspires deeper insights for the large scale development and application of LPs.

Salvia miltiorrhiza polysaccharide and its related metabolite 5-methoxyindole-3-carboxaldehyde ameliorate experimental colitis by regulating Nrf2/Keap1 signaling pathway

The roots of Salvia miltiorrhiza have been used in Traditional Chinese Medicine for thousands of years. However, tons of aerial parts of this plant are usually discarded in the production of roots preparation. To make better use of these plant resources, the polysaccharide isolated from the aerial part of S. miltiorrhiza was investigated for its potential protection against intestinal diseases. A pectic polysaccharide (SMAP-1) was isolated and characterized being composed of homogalacturonan as the main chain and rhamnogalacturonan type I as ramified region, with side chains including arabinans and possible arabinogalactan type I and II. SMAP-1 exhibited robust protective effects against dextran sodium sulfate (DSS)-induced colitis and restored colitis symptoms, colonic inflammation, and barrier functions. Anti-oxidative effects were also observed by up-regulating Nrf2/Keap1 signaling pathway. Additionally, the level of serum 5-methoxyindole-3-carboxaldehyde (5-MC) was restored by SMAP-1 identified in metabolomic analysis, being correlated with the aforementioned effects. Protection against oxidative stress on intestinal porcine enterocyte cells (IPEC-J2) by 5-MC was observed through the activation of Nrf2/Keap1 system, as also shown by SMAP-1. In conclusion, SMAP-1 could be a promising candidate for colitis prevention, and 5-MC could be the signal metabolite of SMAP-1 in protecting against oxidative stress in the intestine.

Structure characteristics of low molecular weight pectic polysaccharide and its anti-aging capability by modulating the intestinal homeostasis

Pectic polysaccharide has attracted increasing attention for their potential biological properties and applications in health industries. In this study, a low-molecular-weight pectic polysaccharide, POS4, was obtained from citrus peel. The structure of POS4 was preliminarily analyzed by gel-permeation chromatography, monosaccharide analysis, infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Results showed that the molecular weight of POS4 was 4.76 kDa and it was a galacturonic acid enriched pectic polysaccharide. The anti-aging activity in vivo showed that POS4 could notably prolong the average lifespan of fruit flies by suppressing the generation of reactive oxygen species (ROS). Further studies demonstrated that POS4 could enhance intestinal homeostasis by modulating gut microbiota in a positive way and regulating autophagy associated genes. Taken together, we proposed that galacturonic acid enriched low molecular weight pectic polysaccharide have great potential in the development of healthy foods such as anti-aging health care products.

Extraction, purification, structural characteristics, biological activities, and application of the polysaccharides from Nelumbo nucifera Gaertn. (lotus): A review

Nelumbo nucifera Gaertn. (lotus) is a widely distributed plant with a long history of cultivation and consumption. Almost all parts of the lotus can be used as foodstuff and nourishment, or as an herb. It is noteworthy that the polysaccharides obtained from lotus exhibit surprisingly and satisfying biological activities, which explains the various benefits of lotus to human health, including anti-diabetes, anti-osteoporosis, antioxidant, anti-inflammatory, anti-tumor, etc. Here, we systematically review the recent major studies on extraction and purification methods of polysaccharides from different parts (rhizome, seed, leaf, plumule, receptacle and stamen) of lotus, as well as the characterization of their chemical structure, biological activity and structure-activity relationship, and the applications of lotus polysaccharides in different fields. This article will give an updated and deeper understanding of lotus polysaccharides and provide theoretical basis for their further research and application in human health and manufacture development.

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.

Polysaccharide from aerial part of Chuanminshen violaceum alleviates oxidative stress and inflammatory response in aging mice through modulating intestinal microbiota

Aging is a biological process of progressive deterioration of physiological functions, which poses a serious threat to individual health and a heavy burden on public health systems. As population aging continues, research into anti-aging drugs that prolong life and improve health is of particular importance. In this study, the polysaccharide from stems and leaves of Chuanminshen violaceum was obtained with water extraction and alcohol precipitation, and then separated and purified with DEAE anion exchange chromatography and gel filtration to obtain CVP-AP-I. We gavaged natural aging mice with CVP-AP-I and performed serum biochemical analysis, histological staining, quantitative real-time PCR (qRT-PCR) and ELISA kit assays to analyze inflammation and oxidative stress-related gene and protein expression in tissues, and 16SrRNA to analyze intestinal flora. We found that CVP-AP-I significantly improved oxidative stress and inflammatory responses of the intestine and liver, restored the intestinal immune barrier, and balanced the dysbiosis of intestinal flora. In addition, we revealed the potential mechanism behind CVP-AP-I to improve intestinal and liver function by regulating intestinal flora balance and repairing the intestinal immune barrier to regulate the intestinal-liver axis. Our results indicated that C. violaceum polysaccharides possessed favorable antioxidant, anti-inflammatory and potentially anti-aging effects in vivo.

The comparison of preliminary structure and intestinal anti-inflammatory and anti-oxidative activities of polysaccharides from different root parts of Angelica sinensis (Oliv.) Diels

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Angelica sinensis, has been commonly used in gynecology for centuries, and is normally applied divided into different parts in various clinical applications. At present, the majority of existing studies focus on the volatile oil and ferulic acid extracted from different parts of A. sinensis, but there is a dearth of scientific information on its water-soluble polysaccharides.

AIM OF THE STUDY

The structures of polysaccharides from plants, have been reported contributing to multiple pharmacological activities such as anti-oxidative, anti-inflammatory, anti-tumor and liver protection. Therefore, the focus of this study was on its anti-oxidative and anti-inflammatory activities in vitro, which would be based on the various polysaccharides with distinct structures obtained from different parts of the A. sinensis root.

MATERIALS AND METHODS

Four parts of A. sinensis root were separated according to the Chinese Pharmacopoeia: head, body, tail and whole body. Crude polysaccharides were obtained by water extraction and ethanol precipitation method, and were further fractionated by DEAE Sepharose chromatographic column and gel filtration. The comparison of ASPs from different root parts were performed, including chemical compositions determined by colorimetric analysis, monosaccharide compositions measured by high performance liquid chromatography (HPLC), glycosidic linkage units determined by methylation and gas chromatography-mass spectrometry (GC-MS), organic functional groups determined by FT-IR, molecular weight (Mw) demarcated by gel permeation chromatography, and the viscosities and solubilities were measured according to method published in the previous report with minor modification. In vitro biological activities of APSs were compared on lipopolysaccharide (LPS)-induced inflammatory and oxidative stress models on IPEC-J2 cells.

RESULTS

Four purified polysaccharides, ASP-H-AP, ASP-B-AP, ASP-T-AP and ASP-Hb-AP from the root of A. sinensis, were obtained, and consisted of various contents of protein and the polyphenol. They were possibly pectic polysaccharides with a long homogalacturonan region as the main backbone and ramified with rhamnogalacturonan I region, but they were differed by subregions and the relative contents of glycosidic units. The Mw of four pectic polysaccharides were ranged from 67.9-267.7 kDa. The infrared spectrum also showed that the four polysaccharide fractions contained the characteristic peaks of polysaccharides. Their distinct primary structure could lead to a variety of biological activities. In vitro biological assays suggested that four polysaccharide fractions can protect IPEC-J2 cells against the LPS-induced inflammation by down-regulating inflammation factors and related genes on IPEC-J2 cells. These polysaccharides also could alleviate oxidative stress on IPEC-J2 cells by up-regulating the gene and protein expressions of antioxidant enzymes. It was concluded that ASP-H-AP possessed better anti-inflammatory and anti-oxidative effects, while those of ASP-T-AP was relatively poor among the four polysaccharide fractions.

CONCLUSION

All results indicated that the structure of pectic polysaccharides from different root parts of A. sinensis differed, which lead to their distinct anti-inflammatory and anti-oxidative activities. This may also be one of the factors why different parts of A. sinensis showed various pharmacological activities and applied independently in traditional use. In addition, it would be valuable for further studies on structure-activity relationship of polysaccharides obtained by different root parts of A. sinensis.

Polysaccharide from Salviae miltiorrhizae Radix et Rhizoma Attenuates the Progress of Obesity-Induced Non-Alcoholic Fatty Liver Disease through Modulating Intestinal Microbiota-Related Gut–Liver Axis

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide, thus treatments for it have attracted lots of interest. In this study, the Salviae miltiorrhizae Radix et Rhizoma (SMRR) polysaccharide was isolated by hot water extraction and ethanol precipitation, and then purified by DEAE anion exchange chromatography and gel filtration. With a high-fat-diet-induced obesity/NAFLD mouse model, we found that consumption of the SMRR polysaccharide could remarkably reverse obesity and its related progress of NAFLD, including attenuated hepatocellular steatosis, hepatic fibrosis and inflammation. In addition, we also reveal the potential mechanism behind these is that the SMRR polysaccharide could regulate the gut–liver axis by modulating the homeostasis of gut microbiota and thereby improving intestinal function.

In vitro digestive characteristics and microbial degradation of polysaccharides from lotus leaves and related effects on the modulation of intestinal microbiota

Polysaccharides exist as one of the most abundant components in lotus leaves, which attract increasing attention owing to their promising health-promoting benefits. In this study, the digestive and microbial degradation characteristics of lotus leaf polysaccharides (LLP) were studied by using an in vitro gastrointestinal model. The results suggested that LLP was stable in the human upper gastrointestinal tract in vitro according to its digestive stabilities at different simulated digestion stages. Conversely, the indigestible LLP (LLPI) could be remarkably utilized by intestinal microbiota in human feces during in vitro fermentation, and its fermentability was 58.11% after the in vitro fermentation of 48 h. Indeed, the microbial degradation characteristics of LLPI during in vitro fermentation by human fecal inoculum were revealed. The results showed that the content of reducing sugars released from LLPI obviously increased from 0.498 to 2.176 mg/mL at the initial fermentation stage (0–6 h), and its molecular weight sharply decreased from 4.08 × 10⁴ to 2.02 × 10⁴ Da. Notably, the molar ratios of arabinose (Ara), galactose (Gal), and galacturonic acid (GalA) in LLPI decreased from 2.89 to 1.40, from 5.46 to 3.72, and from 21.24 to 18.71, respectively, suggesting that the utilization of arabinose and galactose in LLPI by intestinal microbiota was much faster than that of galacturonic acid at the initial fermentation stage. Additionally, LLPI could remarkably regulate gut microbial composition by increasing the abundances of several beneficial microbes, including Bacteroides, Bifidobacterium, Megamonas, and Collinsella, resulting in the promoted generation of several short-chain fatty acids, especially acetic, propionic, and butyric acids. The findings from the present study are beneficial to better understanding the digestive and microbial degradation characteristics of LLP, which indicate that LLP can be used as a potential prebiotic for the improvement of intestinal health.

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LLP was stable in the human upper gastrointestinal tract in vitro.

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The indigestible LLP could be remarkably utilized by intestinal microbiota.

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Arabinose and galactose were quickly utilized at the initial fermentation stage.

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Bacteroides, Bifidobacterium, Megamonas, and Collinsella obviously increased.

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SCFAs, especially acetic, propionic, and butyric acids, remarkably promoted.