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Sialylated immunoglobulin G (IgG) is a vital glycoprotein in breast milk with the ability to promote the growth of Bifidobacteriumin gut microbiota and relieve inflammatory bowel disease (IBD) symptoms in vitro. Here, it was found that the microcapsules with sialylated IgG could protect and release sialylated IgG with its structure and function in the intestine. Furthermore, the sialylated IgG microcapsules alleviated the clinical symptoms (body weight, feed quantity, and colon length loss), decreased disease activity index score, suppressed the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IFN-γ, and MCP-1) and endotoxin (lipopolysaccharide), and enhanced the intestinal mucosal barrier (Claudin1, Muc2, Occludin, and ZO-1) in dextran sulfate sodium (DSS)-induced colitis mice. Additionally, the sialylated IgG microcapsules improved the gut microbiota by increasing the relative abundance of critical microbe Bifidobacterium bifidumand promoted the production of short-chain fatty acids (SCFAs). Correlation analysis indicated that the key microbes were strongly correlated with pro-inflammatory factors, clinical symptoms, tight junction protein, and SCFAs. These findings suggest that the sialylated IgG microcapsules have the potential to be used as a novel therapeutic approach for treating IBD.

Western diet (rich in highly refined sugar and fat) can induce a range of metabolic dysfunctions in animals and humans, including neuroinflammation and cognitive function decline. Neuroinflammation and cognitive impairment, two critical pathological characteristics of Alzheimer’s disease, have been closely associated with microbial alteration via the gut-brain axis. Thus, the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid (AA-2βG) isolated from the fruits of Lycium barbarumon preventing the high-fructose diet (HFrD) induced neuroinflammation in mice. It was found that AA-2βG prevented HFrD-induced cognitive deficits. AA-2βG also predominantly enhanced the gut barrier integrity, decreased lipopolysaccharide entry into the circulation, which subsequently countered the activation of glial cells and neuroinflammatory response. These beneficial effects were transmissible by horizontal fecal microbiome transplantation, transferring from AA-2βG fed mice to HFrD fed mice. Additionally, AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillusand Akkermansia, potentially beneficial intestinal bacteria. The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut. As a potential functional food ingredient, AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.

Theasinensin A (TSA), a dimer of epigallocatechin gallate, has been preliminarily demonstrated to have hypoglycemia and anti-inflammatory effects. However, little information is available on its potential mechanisms of anti-diabetes. Therefore, the present study aimed to investigate the influence of TSA on glucose and lipid metabolism and gut microbiota in high-fat-diet/streptozotocin-induced diabetic mice. As result, TSA improved polydipsia, polyphagia and impaired glucose tolerance of diabetic mice, declined the fasting blood glucose and hepatic triglyceride level, and enhanced the expression at mRNA level of insulin receptor substrate, phosphoinositide 3-kinase, protein kinase B and glucagon-like peptide 1 receptor (GLP-1R) in the diabetic liver. Moreover, TSA could restore the disorder of gut microbiota of diabetic mice. High-dose (100 mg/kg) TSA showed better beneficial effects from the blood biochemical parameters, hepatic function and gut microbiota. In general, high-dose TSA significantly modulated gut microbiota by increasing the relative abundance of Akkermansiaand decreasing the relative abundances of Acetatifactor, Anaerotruncus, Pseudoflavonifactor, Oscillibacterand Clostridiumclusters. The results indicated that TSA could exert an anti-diabetes effect in diabetic mice through restoring glucose homeostasis, declining hepatic steatosis, activating insulin and GLP-1 signaling pathways, and ameliorating gut microbiota dysbiosis.

β-Carotene, a typical non-oxygenated carotenoid, is the most efficient source of retinol (VA). The low bio-availability of β-carotene lead to large accumulation in colon; however, the relationship between β-carotene and gut microflora remains unclear. This study intends to explore the interaction between β-carotene and gut microflora using an in vitrofermentation model. After 24 h fermentation, the degradation rate of β-carotene was (64.28 ± 6.23)%, which was 1.46 times that of the group without gut microflora. Meanwhile, the production of VA was nearly 2 times that of the group without gut microflora, indicating that the gut microflora can metabolize β-carotene into VA. β-Carotene also influences the production of short-chain fatty acids (SCFAs), the production of total SCFAs in 0.5 mg/mL β-carotene (BCM) group was (44.00 ± 1.16) mmol/L, which was 2.26 times that of the blank control (BLK) group. Among them, the production of acetic acid in BCM group was (19.06 ± 0.82) mmol/L, which was 2.64 time that of the BLK group. Furthermore, β-carotene significantly affected the structure and composition of gut microflora, increasing the abundance of Roseburia, Parasutterellaand Lachnospiraceae, and decreasing the abundance of Dialister, Collinsellaand Enterobacter(P< 0.05). This study provides a new way to understand how β-carotene works in human body with gut microflora.

Recent studies indicated a strong relationship between carotenoids and gut microflora. However, their structure–activity relationship remains unclear. This study evaluated the interaction between four typical carotenoids (β-carotene, lutein, lycopene, and astaxanthin) and gut microflora using an in vitrofermentation model. After 24 h of fermentation, the retention rates of the four carotenoids were 1.40, 1.38, 1.46, and 5.63 times lower than those of their without gut microflora control groups, respectively. All four carotenoid treated groups significantly increased total short-chain fatty acids (SCFAs) production. All carotenoid supplements significantly promoted the abundance of Roseburiaand Parasutterellaand inhibited the abundance of Collinsella, while β-carotene, lutein, lycopene, and astaxanthin significantly promoted the abundance of Ruminococcus, Sutterella, Subdoligranulum, and Megamonas, respectively. Furthermore, xanthophylls have a more significant impact on gut microflora than carotenes. This study provides a new way to understand how carotenoids work in the human body with the existing gut microflora.

Polysaccharides from Fuzhuan brick tea (FBTPS), one of most important bioactive components in tea, showed various health-promoting functions. Our previous work demonstrated that the crude FBTPS (CFBTPS) could modulate the gut microbiota. However, which purified fraction in CFBTPS contributing to the modulation of gut microbiota remains unclear. Thus, the fermentation characteristics and probiotic activity of a purified fraction (FBTPS-2-1) of CFBTPS were evaluated in this work. The results showed that gut microbiota could utilize FBTPS-2-1 to produce short-chain fatty acids including acetic, propionic, n-butyric and n-valeric acids. FBTPS-2-1 could modulate the structure and metabolic pathways of gut microbiota. FBTPS-2-1 could increase the health-promoting gut microbiota such as Prevotellaceae and Bifidobacteriaceae, and decreased the harmful bacteria such as Enterobacteriaceae and Fusobacteriaceae. The results of metagenomics showed that Prevotella copriand Megamonas funiformiswere the dominant bacteria after fermentation of FBTPS-2-1. Furthermore, FBTPS-2-1 could regulate the biosynthesis and metabolism pathways of gut microbiota. Thus, the enrichment of food with FBTPS-2-1 is expected as a potential strategy for promoting human health due to modulation of gut microbiota.

Fuzhuan brick tea (FBT), one of the unique dark teas, has various health-promoting functions. In the present study, one polysaccharide fraction, namely FBTPS-2-1, was extracted and purified from FBT, and its structure and potential immunostimulatory activity were investigated. The results showed that FBTPS-2-1,one of typical heteropolysaccharides, was mainly composed of Gal, Ara, and Glc with little molar content of Man, Rha, GalA, and GlcA in molar ratio of 46.59:22.13:13.57:8.20:6.02:2.12:1.38 and molecular weight of 748 kDa. The backbone of FBTPS-2-1 contained →4)-β-d-Galp-(1→4)-β-d-Galp-(1→, →4)-β-d-Galp-(1→4)-α-d-Glcp-(1→, →4)-α-d-Glcp-(1→4)-α-d-Glcp-(1→, →4)-α-d-Glcp-(1→4)-β-d-Galp-(1→, →3)-β-d-Galp-(1→4)-β-d-Galp-(1→, →3,6)-β-d-Galp-(1→3)-β-d-Galp-(1→ and →3,6)-β-d-Galp-(1→3,6)-β-d-Galp-(1→. The linkages of branches in FBTPS-2-1 were mainly composed of α-l-Araf-(1→3,6)-β-d-Galp-(1→, →5)-α-l-Araf-(1→3,6)-β-d-Galp-(1→, →6)-β-d-Galp-(1→3,6)-β-d-Galp-(1→, α-l-Araf-(1→3,5)-α-l-Araf-(1→, →3,5)-α-l-Araf-(1→5)-α-l-Araf-(1→, α-d-Galp-(1→3,5)-α-l-Araf-(1→ and →5)-α-l-Araf-(1→6)-β-d-Galp-(1→. Furthermore, FBTPS-2-1 could increase the phagocytosis of macrophages and promote the secretion of NO and a variety of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, indicating noticeable immune enhancement activity. Thus, FBTPS-2-1 could serve as a potentially functional food to improve human health by modulating the host immunoreaction.

Sialylated immunoglobulin G (IgG) is an important immunoglobulin in breast milk, but its effect on adult gut microbiota is not yet clear due to digestion by pepsin. Based on our previous IgG protecting study, effects of sialylated IgG on gut microbiota were investigated by in vitroanaerobic fermentation in the present study. It was found that the addition of sialylated IgG could significantly promote the growth of Bifidobacterium. Meanwhile, three bifidobacterial species B. bifidumCCX 19061, Bembidion breveCCX 19041, and B. longumsubsp. infantisCCX 19042 were isolated. Furthermore, B. breveCCX 19041 and B. longumsubsp. infantisCCX 19042 showed co-culture growth property with B. bifidumCCX 19061 in a sialylated IgG-based medium, which was also supported by changes of free monosaccharides and N-glycan structure. These findings suggest that the increase of Bifidobacterium in vitrofermentation is attributed to the commensal relationship of the three bifidobacterial species by utilizing sugars released from sialylated IgG.

Tea polysaccharides (TPS) are regarded as some of the main bioactive constituents of tea made from the leaves and buds of the tea plant (Camellia sinensisL.). An increasing number of studies have demonstrated that TPS can reduce the risk of type 2 diabetes, obesity, and other metabolic diseases. However, the potential mechanisms responsible for antidiabetic and antiobesogenic activities of TPS remain unclear. Therefore, the cellular and physiological mechanisms that underlie the antidiabetic and antiobesogenic effects, including antioxidant and anti-inflammation effects, inhibition of digestive enzymes, prevention of macronutrient absorption, and expression of gene and protein, were summarized in this review. Furthermore, the gastrointestinal functions of TPS and the role of gut microbiota in the prevention and treatment of metabolic diseases were discussed. It is expected that the present review will be helpful for enhancing our knowledge about the health-promoting effects of TPS on metabolic diseases and stimulating further works on TPS.

Kudingcha made from the leaves of Ilex kudingchaand chlorogenic acid have antiobesity and intestinal microbiota modulating effects. However, the effects of kudingcha dicaffeoylquinic acids (diCQAs) on obesity and intestinal microbiota are still poorly understood. In the present study, the effects of kudingcha diCQAs on adipose accumulation and intestinal microbiota were investigated in high-fat-diet-fed mice. As a result, kudingcha diCQAs decreased the liver and adipose tissue masses, concentrations of serum inflammatory factors, and hepatic expressions of lipid synthesis related genes and increased the expressions of genes involved in lipid degradation in the liver. Kudingcha diCQAs also exhibited considerable effects on intestinal microbiota. They increased the relative abundances of Bifidobacteriumand Akkermansiaand affected the function of the microbial community including bile acid biosynthesis. Kudingcha diCQAs had antiobesity potential, possibly acting through affecting intestinal microbiota. Furthermore, the effects of kudingcha diCQAs on fat accumulation and intestinal microbiota had a dose-dependent manner.

The protein–polyphenol layer by layer (LbL) assembled polymer composite microcapsule is a considerable delivery system that can be used to improve the bioactive stability and effectiveness of natural compounds in various applications. In the present study, three kinds of polyphenols were loaded in the sequence of (−)-epigallocatechin gallate (EGCG), 3,4-O-dicaffeoylquinic acid (3,4-diCQA), and tannin acid (TA) to prepare a BSA–polyphenol LbL membrane. The composition of IgG-(BSA-EGCG/3,4-diCQA/TA)nmicrocapsules and their stability and releasing ability in the gastrointestinal tract were evaluated. In addition, by binding of these three kinds of polyphenols to BSA, the thermal denaturation temperature and ordered secondary structure of the BSA–polyphenol microcapsules were increased, and the time of scavenging activity on 2,2′-azinobis(3-ethylbenzothiazolin-6-sulfonic acid) free radicals was significantly prolonged. These findings suggest that (BSA-EGCG/3,4-diCQA/TA)nmicrocapsules can not only protect IgG in food processing and stomach digestion but also release it in the small intestinal tract for bioactive delivery.

Theaflavins (TFs) and theasinensins (TSs) are the key components formed from the enzymatic oxidation of tea catechins, contributing significantly to the biological activities and taste of black and Oolong teas. In this study, we aimed to reveal the catechin conversion and the enzymatic synthesis of TFs and TSs under reaction temperatures and pH values using polyphenol oxidase (PPO) from potato tuber (Solanum tuberosumL.). The results indicated that different temperatures, pH values and durations had significant effects on the conversion of catechins and the formation of TFs and TSs. During the reaction, the most of catechin substrates was consumed at 60–90 min after reaction initiation, and large amounts of the products TFs (0.04–0.41 mg/mL) and TSs (0.51–1.52 mg/mL) were obtained. The content of TSs was significantly higher and the maximum content of TSs was more than three times that of TFs. Reaction at a lower temperature (20 °C) is suitable for producing dimers, especially for TFs. Higher pH value resulted in higher catechin consumption and higher TSs content, while the maximum of TFs was obtained at pH 5.0. The present results provided a theoretical basis and practical guidance for the targeted processing of tea catechin dimers in vitro.

Based on the use of multi-walled carbon nanotubes (MWCNTs) in matrix solid-phase dispersion (MSPD) extraction, a novel, rapid and reliable method was developed for the analysis of 11 photoinitiators used in food packaging ink followed by quantitation by gas chromatography-tandem mass spectrometry. The use of MWCNTs was compared with that of the adsorbents C18 silica and diatomaceous earth (DE) in the MSPD procedure. The extracts obtained using MWCNTs were better than those obtained using C18 and DE. Using the newly developed method, recoveries ranged from 70.9% to 121.4%, the RSDs were between 0.1% and 3.5%, and the LOQs ranged from 0.002–0.008 mg kg−1. This method was used to test the degree of migration of the photoinitiators into food, showing that the migration into tea powder increased with increasing initial concentration of the pollutants, while this phenomenon was not found in milk powder. The ability of the photoinitiators to migrate into food matrices was shown to be closely related to their molecular weight and to their molecular conformation, as well as the particular characteristics of the food matrix.

Sialylated immunoglobulin G (IgG) is a kind of glycoproteins in breast milk with the property of anti-inflammation. Our previous work showed that sialylated IgG could significantly promote the growth of Bifidobacteriumin the gut microbiota of healthy volunteers. Nevertheless, whether sialylated IgG can benefit patients with inflammatory bowel disease (IBD) as prebiotics remains unclear. Therefore, its prebiotic effect on the gut microbiota of IBD patients was investigated by in vitrofermentation in this study. The results showed that sialylated IgG could significantly enhance the diversity, richness and composition of gut microbiota in IBD samples compared with non-sialylated IgG. In detail, sialylated IgG not only improved the growth of three common genera (Romboutsia, Prevotellaand Akkermansia) with low relative abundance in IBD samples but also increased the genera (Bifidobacterium, Actinomyces, Atopobiumand Citrobacter) with low relative abundance both in healthy and IBD fecal samples. Correspondingly, the contents of short-chain fatty acids for fermentation group of fecal sample from IBD patients with sialylated IgG as the carbon source were higher than those for fermentation group of fecal sample from IBD patients with non-sialylated IgG as the carbon source. In addition, the metabolic pathway results confirmed that sialylated IgG upregulated the functional genes related to hydrolysis, absorption and utilization of carbohydrates. The transcriptome sequencing results further showed that sialylated IgG could induce particular gene expression of Bifidobacterium bifidumto modulate the gut microbiota of IBD patients. Thus, as a kind of natural dietary component, sialylated IgG has potential applications in treating IBD.

The intracellular polysaccharides of Aspergillus cristatus(IPSs) from Fuzhuan brick tea have been demonstrated to improve immune function linked to modulating the gut microbiota. Herein, to further investigate the efficacy of IPSs to maintain gut homeostasis, the protection of the purified fraction of IPSs (IPSs-2) on the mice with colitis induced by dextran sulfate sodium (DSS) and the underlying mechanisms were explored in this study. The results revealed that IPSs-2 alleviated the typical symptoms of colitis and suppressed the excessive inflammatory mediators, regulating the genes related to inflammatory responses in the colon at the mRNA level. Meanwhile, IPSs-2 treatment reinforced the intestinal barrier function by ameliorating the DSS-induced histological injury, facilitating the differentiation of goblet cells to enhance Mucin-2 generation, and enhancing the expression of tight junction proteins to alleviate colitis. In addition, IPSs protected against colitis by promoting the production of short-chain fatty acids (SCFAs), the activation of SCFAs receptors, and the leverage of the gut microbiota viathe enrichment of Bacteroides, Parabacteroides, Faecalibacterium, Flavonifractor_plautii, and Butyricicoccus, linking with reducing inflammation and repairing intestinal barrier function. Overall, our research revealed the therapeutic potential of IPSs-2 as a prebiotic for attenuating inflammatory bowel disease and provided a rationale for future investigation.

In the present study, we found that anthocyanins from Lycium ruthenicumMurray (ACN) potently ameliorated a high-fructose diet (HFrD)-induced neuroinflammation in mice. ACN improved the integrity of the intestinal barrier and suppressed the toll-like receptor 4 (TLR4) signaling pathway to ameliorate the neuroinflammation, which was verified by Tlr4–/–mice. Furthermore, ACN could modulate the HFrD-induced dysbiosis of gut microbiota. The fecal microbiota transplantation from ACN-induced mice was sufficient to attenuate the neuroinflammation, while the amelioration of neuroinflammation by ACN was blocked upon gut microbiota depletion. In addition, ACN-induced increment of the relative abundance of Lactobacillusmight be responsible for the alleviation of the neuroinflammation, which was further confirmed in the promoting effect of ACN on the growth of Lactobacillusin vitro. Overall, these results provided the evidence of a comprehensive cross-talk mechanism between ACN and neuroinflammation in HFrD-fed mice, which was mediated by reducing gut microbiota dysbiosis and maintaining the intestinal barrier integrity.

An analytical method using gel permeation chromatography (GPC) coupled with gas chromatography-mass spectrometry (GC-MS) was established for the determination of 10 photo-initiators – benzophenone (BP), 2-methyl benzophenone (2-MBP), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), 3-methyl benzophenone (3-MBP), 4-methyl benzophenone (4-MBP), ethyl 4-dimethylaminobenzoate (EDB), 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651), o-methyl-benzoyl benzoate (OMBB), 2-ethylhexyl-4-dimethylamino benzoate (EHA) and 2-isopropylthioxanthone (ITX) – in plastic food packaging. The plastic samples were treated with ultrasound in cyclohexane/ethyl acetate (1 : 1, v/v). The extract was cleaned up by gel permeation chromatography. The final solution was subjected to GC-MS using an external standard method for quantitation in selected ion monitoring mode. The 10 target photo-initiators showed linear recovery relationships over the concentrations of 0.005 to 0.2 mg L−1, with r2> 0.999. The recoveries from spiked samples (0.07 × 10−3, 0.17 × 10−3and 0.33 × 10−3mg dm−2of standard) for each of the 10 photo-initiators ranged from 77.0% to 120.6%, with relative standard deviations (RSDs) of 0.5–13.9%. The limits of detection (LOD) were from 0.03 × 10−3mg dm−2to 0.12 × 10−3mg dm−2. The developed extraction method is simple and yields a sufficiently pure test sample, while the analytical method meets the sensitivity and precision requirements for photo-initiator detection. This method could be routinely used to determine the levels of photo-initiator residues in plastic food packaging.

There is growing evidence that prevention of metabolic syndrome (MS) by dietary fibers is intricately linked to gut microbiota. In the present work, the mice were fed a high-fat diet (HFD) and orally treated with yeast β-glucan to further examine the effects of β-glucan on MS and gut microbiota and the potential relationship between gut microbiota and its activity. After intervention for 10 weeks, it was found that the treatment of yeast β-glucan could significantly improve the HFD-induced MS. Furthermore, pro-inflammatory cytokines in plasma including IL-6 and IL-1β were decreased. Yeast β-glucan could regulate the diversity and composition of HFD-induced gut microbiota. Moreover, the relative abundances of Lactobacillusand Lactococcus, having significant positive correlation with metabolic changes, were decreased by β-glucan, which might play a critical role in attenuation of MS. Our findings suggest that yeast β-glucan shows promising application as a prebiotic for preventing MS and regulating gut microbiota.