Bacterial, short-chain fatty acid and gas profiles of partially hydrolyzed guar gum in vitro fermentation by human fecal microbiota

Probiotics and Prebiotics Intervention in Respiratory and Digestive Infections Linked to Covid-19

Probiotics and prebiotics have been suggested as natural agents against viral infections and dysbiosis and may encourage clinical applications. This review aims to analyze the main and recent advances related to viral infections such as Covid-19 and its gastrointestinal complications, antiviral immunity generated and possible preventive role that probiotics and/or prebiotics can play in controlling and promoting antiviral immunity. The literature search was performed through a critical analysis of relevant publications reported in PubMed and Scopus databases on clinical trials and assays conducted in vitro on colon cells and in vivo on mice. Some studies using probiotics and prebiotics for the prevention of viral infection in different age groups are discussed. Covid-19 patients have been shown to suffer from gastrointestinal complications in addition to respiratory symptoms due to interactions between the respiratory system and the gastrointestinal tract infected with SARS-CoV-2. Unfortunately, therapies used to prevent (or treat) symptoms of Covid-19 have proven to be of limited effectiveness. In addition, the lack of access to coronavirus vaccines around the world and vaccine hesitancy continue to hamper control of Covid-19. It is therefore crucial to find alternative methods that can prevent disease symptoms. Evidence-based efficacy of certain probiotics (Lactobacillus and Bifidobacterium) that may be useful in viral infections was shown with immunomodulatory properties (pro-inflammatory mediators reduction), promoting antiviral immunity (antibodies production, virus titers) and controlling inflammation (anti-inflammatory effect), as well as viral clearance and antimicrobial potential against opportunistic bacteria (anti-dysbiosis effect). But, available data about clinical application of probiotics in Covid-19 context remain limited and relevant scientific investigation is still in its early stages. Also, evidence for prebiotics potential in this field is limited, since the exact mechanism involved in systemic immune modulation by these compounds is till now unknown. Thus, further research is necessary to explore in the viral infection context the mechanism by which gut and lung interact in the presence of probiotics and prebiotics through more animal and clinical experiments.

Cashew gum fractions protect intestinal mucosa against shiga toxin-producing Escherichia coli infection: Characterization and insights into microbiota modulation

Diarrheal diseases remain a major public health concern, particularly in regions with poor sanitation. Polysaccharides extracted from natural gums have been investigated as functional agents for intestinal health, and their fractionation enables the production of oligosaccharides with potential prebiotic activity. This study aimed to produce cashew gum (CG) fractions through Smith degradation (CGD48) and partial hydrolysis (CGD24) and to evaluate their ability to modulate and protect the intestinal microbiota. Balb/c mice were administered CG (1200 mg/kg), CGD24 (800 mg/kg), or CGD48 (800 mg/kg) for 10 and 26 days, followed by infection with Shiga toxin-producing Escherichia coli (STEC) (5 × 1010 CFU/mL) for three days. Characterization assays confirmed the fragmentation of CG. Both CGD24 and CGD48 promoted the growth of beneficial bacteria with and without infection and reduced STEC colonization. Furthermore, they preserved mucin levels in the cecum and large intestine and maintained baseline levels of superoxide dismutase (SOD), suggesting protection of the intestinal mucosa. These findings indicate that CG fractions exhibit microbiota-modulating and protective effects against STEC, highlighting their therapeutic potential and the need for further studies to elucidate the underlying mechanisms.

In vitro fermentation of Auricularia auricula polysaccharides and their regulation of human gut microbiota and metabolism

Auricularia auricula is abundant in polysaccharides that received increasing attention due to their variety biological activities and prebiotic potential. In order to explore the role of A. auricula polysaccharides (AAP) in regulating human gut microbiota and metabolic health, this study employed metagenomic and metabolomic analyses to examine the impact of AAP on the gut microbiota via in vitro fecal fermentation experiments. After in vitro fermentation, the data indicated that gut microbiota utilized AAP to produce rich short-chain fatty acids (SCFAs) including acetic acid, propionic acid, butyric acid and modulate gut microbiota structure, such as increasing the proportion of Bacteroidetes to Firmicutes, elevating the abundance of beneficial bacteria, including Bacteroides, especially the Parabacteroides, and inhibiting the abundance of harmful bacteria such as Bilophila, Morganella, and Escherichia-Shigella. Furthermore, the metabolomic analysis indicated that AAP utilization by gut microbes substantially alters the metabolic profile, in which 26 potential biological biomarkers were found and affects tryptophan, bile acids, purines, and butyric acid pathways to promote host health. In conclusion, this research indicated that AAP has a prebiotic potential, which can regulate the gut microbiota and promote host health. Moreover, this study provided scientific evidence for using AAP as a functional food with prebiotic effect.

Ginsenosides and gut microbiota: differential effects on healthy individuals and irritable bowel syndrome subtypes

Background

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with poorly understood mechanisms. Variations in gut microbiota composition are observed in different IBS subtypes. Ginsenosides have shown potential in alleviating IBS symptoms, but their interactions with gut microbiota in different IBS subtypes are not well studied.

Methods

In this study, we investigated the effects of ginsenosides on the gut microbiota of both healthy participants and participants suffering from IBS characterized by diarrhea (IBS-D) or constipation (IBS-C), using in vitro fermentation alongside 16S rRNA sequencing and bioinformatics analyses.

Results

The analysis demonstrated that there were no statistically significant alterations in α- or β-diversity between the ginsenosides-treated and control groups across all models. However, the microbial composition assessment revealed the presence of 51 shared genera, with notable variations in composition and a significant enrichment of specific taxa. Specifically, the LEfSe analysis revealed that, following ginsenosides treatment, the healthy model groups exhibited significant enrichment of Stenotrophomonas and Achromobacter, while the IBS-D model groups demonstrated significant enrichment of Pseudomonas and Stenotrophomonas.

Conclusions

The results elucidate the distinctive microbial signatures associated with ginsenosides treatment across both healthy and IBS-D groups, underscoring the potential therapeutic efficacy of ginsenosides in modulating gut microbiota. This study highlights the necessity for further investigation into targeted microbiome therapies for IBS, which may facilitate the development of more personalized and efficacious treatment strategies for gastrointestinal health.

Effects of fructooligosaccharides and Lactobacillus reuteri on the composition and metabolism of gut microbiota in students

Fructooligosaccharides (FOSs) and Lactobacillus reuteri have shown great potential in treating gastrointestinal diseases by regulating gut microbiota and metabolites. However, the synergistic effect between these two remains unclear. In this study, an in vitro fermentation model was constructed to investigate the regulatory effects of FOSs and L. reuteri on the gut microbiota of healthy student populations. After 24 hours of fecal fermentation, the results indicated that the experimental group added with FOSs had increased relative abundances of Bifidobacterium and Lactobacillus, while it exhibited lower relative abundances of Escherichia-Shigella and Bacteroides. Conversely, the groups added with L. reuteri had higher relative abundances of Bacillus and unclassified_c_Bacilli. The results of microbial metabolism revealed that the addition of FOSs produced a large amount of acetic acid, but reduced the contents of propionic acid, butyric acid, isobutyric acid, and isovaleric acid, along with reducing the production of H2, H2S and NH3. In contrast, the addition of L. reuteri had no significant effect on metabolism. Compared to the single additions, the combination of FOSs and L. reuteri had its advantages and had a more balanced microbial structure and metabolic regulation similar to the addition of FOSs alone. Additionally, correlation analysis revealed a negative correlation between gas production and Bifidobacterium, Lactobacillus, and Bacillus, and a positive correlation with Escherichia-Shigella and Bacteroides. Moreover, the formation of acetic acid was positively correlated with Bifidobacterium and negatively correlated with Escherichia-Shigella. These findings demonstrated that the combination of FOSs and L. reuteri can effectively synergistically regulate the fecal microbiome of students. This study can provide a theoretical reference for the precise development of functional foods. However, the regulatory mechanisms need further in-depth investigation.

Low molecular weight galactomannan alleviates diarrhea induced by senna leaf in mice via intestinal barrier improvement and gut microbiota modulation

Low molecular weight galactomannan (LMGM), a soluble dietary fibre derived from guar gum, is recognized for its prebiotic functions, including promoting the growth of beneficial intestinal bacteria and the production of short-chain fatty acids, but the mechanism of alleviating diarrhea is not fully understood. This study established an acute diarrhea mouse model using senna leaf decoction and evaluated the therapeutic effects of LMGM by monitoring diarrhea scores, loose stool prevalence, intestinal tissue pathology and gene expression, and gut microbiota composition and metabolisms. The results indicated that LMGM significantly reduced diarrhea scores and loose stool prevalence within two hours post-treatment. Hematoxylin and eosin staining and quantitative real-time polymerase chain reaction analysis revealed that LMGM improved intestinal epithelial structure and up-regulated the expression of zonula occludens 1, occludin, mucin 2, aquaporin 3, and aquaporin 4 in ileum, jejunum, and colon tissues. Moreover, LMGM increased the abundance of beneficial bacteria such as Lactobacillaceae and Lachnospiraceae, and decreased Prevotellaceae in the cecum. Furthermore, LMGM promoted short-chain fatty acid production and reduced ammonia nitrogen and skatole concentrations in the intestinal content. The study suggests that LMGM could serve as a functional prebiotic for diarrhea alleviation, potentially by enhancing the intestinal barrier, modulating water transportation, and regulating the microbiota composition.

Characteristics of the effects of Polygonati Rhizoma on gut microbiota and metabolites in vitro associated with poor dietary habits in pregnant women

Poor dietary habits have been associated with dysbiosis and microbial imbalance in pregnant women. Such imbalances can pose health risks during pregnancy. This study aimed to explore the impact of Polygonati Rhizoma on the gut microbiota of pregnant women through In vitro simulated fermentation. Interestingly, significant differences in microbial community richness and structure were found between the control and the treatment with Polygonati Rhizoma. Analysis of composition and variability indicated that the treatment with Polygonati Rhizoma group showed higher levels of Lactobacillus and Bifidobacterium, but lower levels of Parabacteroides and Lachnoclostridium. The study also investigated specific genera differences between groups using the co-occurrence network analysis and their correlations with microbial metabolites by the redundancy analysis (RDA), Mantel-test network heatmap, and heatmap highlighting the relationships among gut microbiota, short-chain fatty acids (SCFAs), and gases in the absence or presence of Polygonati Rhizoma supplementation. Functional predictions from BugBase phenotype prediction indicated changes in potentially pathogenic and aerobic bacteria in Polygonati Rhizoma supplementation. Overall, the findings provide valuable insights into the influence of Polygonati Rhizoma on the gut microbiota in pregnant women associated with poor dietary habits.

In vitro gastrointestinal digestion and fecal fermentation behaviors of pectin from feijoa (Acca sellowiana) peel and its impact on gut microbiota

This study investigated the digestion and fermentation characteristics of pectin from feijoa peel (FPP) and its effect on gut microbiota via in vitro simulated digestion and fecal fermentation. The gastrointestinal results showed that the molecular weight (Mw) of FPP kept stable with small production of reducing sugar and free monosaccharides, indicating that FPP was basically not degraded during digestion. However, during the fecal fermentation, the Mw of FPP significantly decreased with the release of free monosaccharides, which were further utilized by gut microbiota. The content of reducing sugar showed a trend of increasing at first and then decreasing. The production of gases and short-chain fatty acids (SCFAs) increased with the utilization of FPP, along with the pH decrease in fecal culture. Meanwhile, FPP regulated the composition of gut microbiota by suppressing enteropathogenic bacteria (genera Escherichia-Shigella and Fusobacterium) and promoting beneficial bacteria (genera Lactiplantibacillus and Bifidobacterium). Significantly positive correlation was found between SCFAs and bacteria including Lactiplantibacillus and Bifidobacterium. These results suggested that FPP had potential prebiotic functions to promote human intestinal health.

In Vitro Digestion and Fermentation of Cowpea Pod Extracts and Proteins Loaded in Ca(II)-Alginate Hydrogels

Antioxidants derived from food by-products are known for their bioactive properties and impact on human health. However, the gastrointestinal behavior is often poor due to their degradation during digestion. The development of Ca(II)-alginate beads supplemented with biopolymers and enriched with cowpea (Vigna unguiculata) extract could represent a novel environmentally friendly technological solution to produce functional ingredients in the food industry. The present study evaluates the impact of in vitro digestion/fermentation by analyzing global antioxidant response (GAR), production of short-chain fatty acids (SCFAs) as a modulation of gut microbiota, and behavior of proton transverse relaxation times by low-field nuclear magnetic resonance (as an indicator of gelation state and characterization of microstructure). Results revealed that guar gum and cowpea protein preserved a high GAR of total phenolic compounds and antioxidant capacity by ABTS and FRAP methods after digestion/fermentation, promoting an adequate protection of the bioactives for their absorption. Alginate-based beads have great potential as prebiotics, with the guar gum-containing system contributing the most to SCFAs production. Finally, the overall higher mobility of protons observed in the intestinal phase agrees with structural changes that promote the release of phenolic compounds during this stage. Beads are excellent carriers of bioactive compounds (cowpea phenolic compounds and peptides) with potential capacities.

Characteristics of stachyose-induced effects on gut microbiota and microbial metabolites in vitro associated with obesity in children

Childhood obesity presents a serious health concern associated with gut microbiota alterations. Dietary interventions targeting the gut microbiota have emerged as promising strategies for managing obesity in children. This study aimed to elucidate the impact of stachyose (STS) supplementation on the gut microbiota composition and metabolic processes in obese children. Fecal samples were collected from 40 obese children (20 boys and 20 girls) aged between 6 and 15 and in vitro fermentation was conducted with or without the addition of STS, respectively, followed by 16S rRNA amplicon sequencing and analysis of short-chain fatty acids (SCFAs) and gases. Notably, our results revealed that STS supplementation led to significant alterations in gut microbiota composition, including an increase in the abundance of beneficial bacteria such as Bifidobacterium and Faecalibacterium, and a decrease in harmful bacteria including Escherichia-Shigella, Parabacteroides, Eggerthella, and Flavonifractor. Moreover, STS supplementation resulted in changes in SCFAs production, with significant increases in acetate levels and reductions in propionate and propionate, while simultaneously reducing the generation of gases such as H2S, H2, and NH3. The Area Under the Curve (AUC)-Random Forest algorithm and PICRUSt 2 were employed to identify valuable biomarkers and predict associations between the gut microbiota, metabolites, and metabolic pathways. The results not only contribute to the elucidation of STS's modulatory effects on gut microbiota but also underscore its potential in shaping metabolic activities within the gastrointestinal environment. Furthermore, our study underscores the significance of personalized nutrition interventions, particularly utilizing STS supplementation, in the management of childhood obesity through targeted modulation of gut microbial ecology and metabolic function.

Food carbohydrates in the gut: structural diversity, microbial utilization, and analytical strategies

Carbohydrates, which are a vital dietary component, undergo digestion and gut fermentation through microbial enzymes to produce beneficial short-chain fatty acids. Certain carbohydrates selectively modulate the gut microbiota, impacting host health. Carbohydrate-active enzymes within the gut microbiota significantly contribute to carbohydrate utilization and microbial diversity. Despite their importance, the structural complexity of carbohydrates poses analytical challenges. However, recent advancements, notably, mass spectrometry, have allowed for their characterization and functional analysis. This review examines the intricate relationship between dietary carbohydrates and the gut microbiota, highlighting the crucial role of advanced analytical techniques in understanding their diversity and implications. These advancements provide valuable insights into carbohydrate bioactivity. Integrating high-throughput analysis with next-generation sequencing provides deeper insights into gut microbial interactions, potentially revealing which carbohydrate structures are beneficial for gut health.

The Regulatory Effect of Huangshui Polysaccharides on Intestinal Microbiota and Metabolites during In Vitro Fermentation

Huangshui polysaccharides (HSPs) have attracted extensive attention recently for their biological activity and physicochemical property. This research investigated the extraction, structural characterization, and prebiotic activity of three different HSPs (HSP40-0, HSP60-0, and HSP80-0) in vitro to reveal the scientific support for the high-value utilization of Huangshui. HSPs were heteropolysaccharide with diverse structures and surface morphologies. Comprehensive analysis was conducted through 16S rRNA gene sequencing and metabolite profiling techniques, and results showed that HSPs had different potentials to regulate the gut microbiota due to their different structures; for instance, both HSP40-0 and HSP80-0 could notably increase the relative abundance of Bacteroidota, whereas HSP60-0 could increase the relative abundance of Phascolarctobacterium. In addition, HSPs upregulated beneficial differential metabolites, especially short-chain fatty acids (SCFAs). Fermentation products containing these metabolites exhibited anti-inflammatory effects on LPS-treated Caco-2 cells. This study will provide reference for exploring the relationship between the natural polysaccharide structure and the prebiotic activity and widen the application of Huangshui.