Dendrobium officinale polysaccharide attenuates cognitive impairment in circadian rhythm disruption mice model by modulating gut microbiota.

Dendrobium officinale polysaccharide (DOP) has received an increasing amount of attention as it could alleviate AD-related cognitive impairment via the regulation of microglial activation. However, the modulatory mechanism of DOP on circadian rhythm disruption (CRD) and related cognitive impairment needs further investigation. In our study, the circadian rhythm disruption mice showed a deficit in recognition and spatial memory. DOP treatment reshaped the perturbation of gut microbiota caused by CRD, including up-regulated the abundance of Akkermansia and Alistipes, down-regulated the abundance of Clostridia. In addition, DOP restored histopathological changes, reduced inflammatory cells infiltration and strengthened mucosal integrity. Mechanistically, DOP ameliorated intestinal barrier dysfunction by up-regulating tight junction protein expression, which in turn improved the invasion of lipopolysaccharide to blood and brain. The change of these contributes to inhibiting the NF-κB activation and neuroinflammation, and thus attenuating hippocampus neuronal damage and the deposition of Aß. Meanwhile, our results revealed that DOP could reverse the levels of metabolites derived related to cognitive function improvement, and these metabolites were closely associated with the key microbiota. Therefore, we speculated that DOP has the potential to provide neuroprotection against cognitive impairment by modulating the gut microbiota.

Tea Polyphenols as Prospective Natural Attenuators of Brain Aging.

No organism can avoid the process of aging, which is often accompanied by chronic disease. The process of biological aging is driven by a series of interrelated mechanisms through different signal pathways, including oxidative stress, inflammatory states, autophagy and others. In addition, the intestinal microbiota play a key role in regulating oxidative stress of microglia, maintaining homeostasis of microglia and alleviating age-related diseases. Tea polyphenols can effectively regulate the composition of the intestinal microbiota. In recent years, the potential anti-aging benefits of tea polyphenols have attracted increasing attention because they can inhibit neuroinflammation and prevent degenerative effects in the brain. The interaction between human neurological function and the gut microbiota suggests that intervention with tea polyphenols is a possible way to alleviate brain-aging. Studies have been undertaken into the possible mechanisms underpinning the preventative effect of tea polyphenols on brain-aging mediated by the intestinal microbiota. Tea polyphenols may be regarded as potential neuroprotective substances which can act with high efficiency and low toxicity.

The Modulatory Effect of Cyclocarya paliurus Flavonoids on Intestinal Microbiota and Hypothalamus Clock Genes in a Circadian Rhythm Disorder Mouse Model.

Circadian rhythm disruption is detrimental and results in adverse health consequences. We used a multi-omics profiling approach to investigate the effects of Cyclocarya paliurus flavonoid (CPF)-enriched diets on gut microbiota, metabolites, and hypothalamus clock genes in mice with induced circadian rhythm disruption. It was observed that CPF supplementation altered the specific composition and function of gut microbiota and metabolites induced by circadian rhythm disruption. Analysis showed that the abundance of Akkermansia increased, while the abundance of Clostridiales and Ruminiclostridium displayed a significant downward trend after the CPF intervention. Correlation analysis also revealed that these gut microbes had certain correlations with the metabolites, suggesting that CPFs help the intestinal microbiota to repair the intestinal environment and modulate the release of some beneficial metabolites. Notably, single-cell RNA-seq revealed that CPF supplementation significantly regulated the expression of genes associated with circadian rhythm, myelination, and neurodegenerative diseases. Altogether, these findings highlight that CPFs may represent a promising dietary therapeutic strategy for treating circadian rhythm disruption.

RNA-Seq Transcriptomic Analysis of Green Tea Polyphenols Modulation of Differently Expressed Genes in Enterococcus faecalis Under Bile Salt Stress.

Enterococcus faecalis (E. faecalis) belongs to lactic acid bacteria which can be used as a probiotic additive and feed, bringing practical value to the health of humans and animals. The prebiotic function of tea polyphenols lays a foundation for green tea polyphenols (GTP) to repair the adverse changes of E. faecalis under stress conditions. In this study, RNA-sequence analysis was used to explore the protective effect of GTP on E. faecalis under bile salt stress. A total of 50 genes were found to respond to GTP under bile salts stress, containing 18 up-regulated and 32 down-regulated genes. The results showed that multiple genes associated with cell wall and membrane, transmembrane transport, nucleotide transport and metabolism were significantly differentially expressed (P < 0.05), while GTP intervention can partly alleviate the detrimental effects of bile salt on amino acid metabolism and transport. The present study provides the whole genome transcriptomics of E. faecalis under bile salt stress and GTP intervention which help us understand the growth and mechanism of continuous adaptation of E. faecalis under stress conditions.

A Natural Plant Source-Tea Polyphenols, a Potential Drug for Improving Immunity and Combating Virus.

The coronavirus disease 2019 (COVID-19) is still in a global epidemic, which has profoundly affected people's lives. Tea polyphenols (TP) has been reported to enhance the immunity of the body to COVID-19 and other viral infectious diseases. The inhibitory effect of TP on COVID-19 may be achieved through a series of mechanisms, including the inhibition of multiple viral targets, the blocking of cellular receptors, and the activation of transcription factors. Emerging evidence shows gastrointestinal tract is closely related to respiratory tract, therefore, the relationship between the state of the gut-lung axis microflora and immune homeostasis of the host needs further research. This article summarized that TP can improve the disorder of flora, reduce the occurrence of cytokine storm, improve immunity, and prevent COVID-19 infection. TP may be regarded as a potential and valuable source for the design of new antiviral drugs with high efficiency and low toxicity.

Tea polyphenols-loaded nanocarriers: preparation technology and biological function.

Tea polyphenols (TP) have various biological functions including anti-oxidant, anti-bacterial, anti-apoptotic, anti-inflammatory and bioengineered repair properties. However, TP exhibit poor stability and bioavailability in the gastrointestinal tract. Nanoencapsulation techniques can be used to protect TP and to uphold their original characteristics during processing, storage and digestion, improve their physiochemical properties and enhance their health promoting effects. Nano-embedded TP show higher antioxidant, antibacterial and anticancer properties than TP, allowing TP to play a better role in bioengineering restoration after embedding. In this review, recent advances in nanoencapsulation of TP with biopolymeric nanocarriers (polysaccharides and proteins), lipid-based nanocarriers and innovative developments in preparation strategies were mainly discussed. Additionally, the strengthening biological functions of stability and bioavailability, antioxidant, antibacterial, anticancer activities and bioengineering repair properties activities after the nano-embedding of TP have been considered. Finally, further studies could be conducted for exploring the application of nanoencapsulated systems in food for industrial applications.

Omics Analyses of Intestinal Microbiota and Hypothalamus Clock Genes in Circadian Disturbance Model Mice Fed with Green Tea Polyphenols.

Green tea polyphenols (GTP) have similar activities as prebiotics, which effectively regulate the structure of intestinal flora and affect their metabolic pathways. The intestinal flora is closely related to the host's circadian rhythm, and the supplementation with GTP may be an effective way to improve circadian rhythm disorders. In this study, we established a mouse model of circadian rhythm disturbance of anthropogenic flora to investigate the regulation mechanism of GTP on the host circadian rhythms. After 4 weeks of GTP administration, the results showed that GTP significantly alleviated the structural disorder of intestinal microbiota, thus effectively regulating related metabolites associated with brain nerves and circadian rhythms. Moreover, single-cell transcription of the mouse hypothalamus suggested that GTP up-regulated the number of astrocytes and oligodendrocytes and adjusted the expression of core clock genes Csnk1d, Clock, Per3, Cry2, and BhIhe41 caused by circadian disruption. Therefore, this study provided evidence that GTP can improve the physiological health of hosts with the circadian disorder by positively affecting intestinal flora and related metabolites and regulating circadian gene expression.

The interaction effect between tea polyphenols and intestinal microbiota: Role in ameliorating neurological diseases.

Tea polyphenols (TP) are one of the most functional and bioactive substances in tea. The interactions between TP and intestinal microbiota suggest that probiotics intervention is a useful method to ameliorate neurological diseases. Now, numerous researches have suggested that TP plays a significant role in modulating intestinal bacteria, especially in the area of sustaining a stable state of intestinal microbial function and abundance. Furthermore, homeostatic intestinal bacteria can enhance the immunity of the host. The close reciprocity between intestinal microbiota and the central nervous system provides a new chance for TP to modulate neural-related diseases depending on intestinal microbiota. Therefore, based on the bidirectional relationship between the brain and the intestines, this review provides a new clue to solve insomnia symptoms and related neurological diseases that will enable us to better study the bidirectional effects of TP and intestinal microbiota on the improvement of host health. PRACTICAL APPLICATIONS: This review provides a new clue to solve insomnia symptoms and related neurological diseases that will enable us to better study bidirectional effects of TP and intestinal microbiota on the improvement of host health.

The role of the intestinal microbiota in the pathogenesis of host depression and mechanism of TPs relieving depression.

Depression is a prevalent neuropsychiatric disease with a high recurrence rate, affecting over 350 million people worldwide. Intestinal flora disorders and gut-brain-axis (GBA) dysfunction may cause mental disorders. Alterations in the intestinal flora composition could increase the permeability of the gut barrier, activate systemic inflammation and immune responses, regulate the release and efficacy of monoamine neurotransmitters, alter the activity and function of the hypothalamic-pituitary-adrenal (HPA) axis, and modify the abundance of the brain-derived neurotrophic factor (BDNF); all of these showed a close correlation with the occurrence of depression. In addition, the disturbance of the intestinal flora is related to circadian rhythm disorders, which aggravate the symptoms of depression. Tea polyphenols (TPs) have been found to have antidepressant effects. Therefore, the close reciprocity between the intestinal flora and circadian rhythm provides a new opportunity for TPs to regulate depression relying on the intestinal flora. In this review, we discussed the relationship between intestinal flora dysbiosis and the pathogenesis of depression and the mechanism of TPs relieving depression via the GBA.

Antimicrobial Effect of Tea Polyphenols against Foodborne Pathogens: A Review.

ABSTRACT: Food contamination by foodborne pathogens is still widespread in many countries around the world, and food safety is a major global public health issue. Therefore, novel preservatives that can guarantee safer food are in high demand. Contrary to artificial food preservatives, tea polyphenols (TPs) are getting wide attention as food additives for being "green," "safe," and "healthy." TPs come from many sources, and the purification technology is sophisticated. Compared with other natural antibacterial agents, the antibacterial effect of TPs is more stable, making them excellent natural antibacterial agents. This review includes a systematic summary of the important chemical components of TPs and the antibacterial mechanisms of TPs against various foodborne pathogens. The potential applications of TPs are also discussed. These data provide a theoretical basis for the in-depth study of TPs.

The interaction between tea polyphenols and host intestinal microorganisms: an effective way to prevent psychiatric disorders.

Tea polyphenols (TP) are the most bioactive components in tea extracts. It has been reported that TP can regulate the composition and the function of the intestinal flora. Meanwhile, intestinal microorganisms improve the bioavailability of TP, and the corresponding metabolites of TP can regulate intestinal micro-ecology and promote human health more effectively. The dysfunction of the microbiota-gut-brain axis is the main pathological basis of depression, and its abnormality may be the direct cause and potential influencing factor of psychiatric disorders. The interrelationship between TP and intestinal microorganisms is discussed in this review, which will enable us to better evaluate the potential preventive effects of TP on psychiatric disorders by modulating host intestinal microorganisms.

Nanotechnology improves delivery efficiency and bioavailability of tea polyphenols.

Tea polyphenols (TPP) have shown various biological activities. However, due to their poor stability in the gastrointestinal (GI) tract, TPP exhibit low absorption and bioavailability which limit their applications in food fields. Recently, several studies have focused on the utilization of nanotechnology to solve these problems. In this review, we introduced the embedding materials and methods of TPP-loaded nanoparticles and the potential mechanisms for improving bioavailability, such as to protect TPP from pH stress, enzymes and ions of the GI tract, and increase of the permeability. Furthermore, future challenges and application prospects of nanoparticles as carriers for the delivery of TPP were also discussed. PRACTICAL APPLICATIONS: Nanotechnology is currently an emerging field in food science, which can be employed to increase the systemic delivery and bioavailability of phytochemicals. Due to the improved bioavailability, TPP-loaded nanoparticles can be developed as potential functional food. A better understanding of the nano-embedding technology and the potential mechanisms will allow us to better utilize nanomaterials to increase the bioavailability of TPP and expand their applications.

Oolong Tea Polyphenols Ameliorate Circadian Rhythm of Intestinal Microbiome and Liver Clock Genes in Mouse Model.

Our present study focused on the regulating effect of oolong tea polyphenols (OTPs) on the circadian rhythm of liver and intestinal microbiome. OTP significantly alleviated the disrupted diurnal oscillation and phase shift of the specific intestinal microbiota and liver clock genes in mice induced by constant dark (CD) treatment. Transcriptomics revealed that 1114 genes in the control group and 647 genes in the CD group showed circadian rhythm while 723 genes were rhythmic in the CD-OTP group. The Gene Ontology (GO) database provided significant differences in differentially expressed genes (DEGs) in response to OTP treatment. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched the most DEGs after OTP intervention including "Focal adhesion" (9 DEGs) and "PI3K-Akt signaling pathway" (9 DEGs). The present study provided a global view that OTP may alleviate the circadian rhythm disorder of the host, contributing to the improvement of microecology and health.

Omics Analyses of Gut Microbiota in a Circadian Rhythm Disorder Mouse Model Fed with Oolong Tea Polyphenols.

Microbiome has been revealed as a key element involved in maintaining the circadian rhythms. Oolong tea polyphenols (OTP) has been shown to have potential prebiotic activity. Therefore, this study focused on the regulation mechanisms of OTP on host circadian rhythms. After 8 weeks of OTP administration, a large expansion in the relative abundance of Bacteroidetes with a decrease in Firmicutes was observed, which reflected the positive modulatory effect of OTP on gut flora. In addition, Kyoto Encyclopedia of Genes and Genomes pathways of ATP-binding cassette transporters, two-component system, and the biosynthesis of amino acids enriched the most differentially expressed genes after OTP treatment. Of the differentially expressed proteins identified, most were related to metabolism, genetic information processing, and environmental information processing. It underscores the ability of OTP to regulate circadian rhythm by enhancing beneficial intestinal microbiota and affecting metabolic pathways, contributing to the improvement of host microecology.

Transcriptomic and proteomic effects of (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3"Me) treatment on ethanol-stressed Saccharomyces cerevisiae cells.

Saccharomyces cerevisiae (S. cerevisiae) is the main fermentation strain in brewing industry. However, the accumulation of ethanol during the fermentation inhibits the growth of S. cerevisiae. Polyphenols are important bioactive ingredients in oolong tea, and epigallocatechin-3-O-(3"-O-methyl)-gallate (EGCG3"Me) has exhibited ameliorate effect on alcohol intoxication. Therefore, in the current work, we used RNA-seq transcriptomics and iTRAQ proteomic analysis to study the effect of EGCG3"Me on ethanol-stressed S. cerevisiae. After EGCG3"Me intervention (0.8%, w/v), 178 up-regulated and 172 down-regulated genes were identified, meanwhile, 190 differentially expressed proteins (DEPs) were identified. In addition, KEGG pathways for metabolic pathways, biosynthesis of secondary metabolites and microbial metabolism were among the most DEPs after EGCG3"Me intervention. The integrated transcriptomic and proteomic analysis indicated EGCG3"Me may alleviate ethanol-induced damage on the cell wall and cell membrane of S. cerevisiae, and facilitate the redox balance and glycolysis. This study provides new insights into the mechanisms underlying the molecular response to ethanol in S. cerevisiae by the treatment of EGCG3"Me.

RNA-seq transcriptomic analysis of green tea polyphenols regulation of differently expressed genes in Saccharomyces cerevisiae under ethanol stress.

Saccharomyces cerevisiae has been widely used to produce alcoholic beverages and bio-fuels; however, its performance is remarkably compromised by the increased ethanol concentration during the fermentation process. In this study, RNA-sequence analysis was used to investigate the protective effect of green tea polyphenols (GTP) on S. cerevisiae cells from ethanol-induced damage. GO and KEGG analysis showed that to deal with the stress of ethanol, large amounts of genes related to cell wall, cell membrane, basic metabolism and redox regulation were significantly differentially expressed (P < 0.05), while these undesired changes could be partly relieved by administration of GTP, suggesting its potential to enhance the ethanol tolerance of S. cerevisiae. The present study provided a global view of the transcriptomic changes of S. cerevisiae in response to the accumulation of ethanol and the treatment of GTP, which might deepen our understanding about S. cerevisiae and the fermentation process, and thus benefit the development of the bioethanol production industry.

A metagenomic analysis of the modulatory effect of Cyclocarya paliurus flavonoids on the intestinal microbiome in a high-fat diet-induced obesity mouse model.

BACKGROUND: As a result of a low bioavailability, the majority of Cyclocarya paliurus flavonoids (CPF) remain in the large intestine where they accumulate to exert a modulatory effect on the intestinal micro-ecology. Therefore, the present study investigated the modulatory effect of CPF on intestinal microbiota. RESULTS: CPF dramatically ameliorated the obesity-induced gut dysbiosis. A significant decrease (P < 0.05) was observed in the ratio of Firmicutes/Bacteroidetes after CPF treatment for 8 weeks. Moreover, Kyoto Encyclopedia of Genes and Genomes pathways of biosynthesis of amino acids, the two-component system and ATP-binding cassette transporters enriched the most differentially expressed genes after CPF intervention. CONCLUSION: The results of the present study indicate that CPF might have prebiotic-like activity and could be used as a functional food component with potential therapeutic utility to prevent obesity-related metabolic disorders by manipulating the gut flora and affecting certain metabolic pathways, thus contributing to the improvement of human health. © 2019 Society of Chemical Industry.

A transcriptome analysis of the ameliorate effect of Cyclocarya paliurus triterpenoids on ethanol stress in Saccharomyces cerevisiae.

Saccharomyces cerevisiae (S. cerevisiae) plays a critical role in ethanol fermentation. However, during the fermentation, yeast cells are exposed to the accumulation of ethanol, which significantly affect the cell growth and the target product yield. In the present work, we employed RNA-sequence (RNA-seq) to investigate the ameliorate effect of Cyclocarya paliurus (C. paliurus) triterpenoids on S. cerevisiae under the ethanol stress. After C. paliurus triterpenoids intervention (0.3% v/v), 84 differentially expressed genes (DEGs) were identified, including 39 up-regulated and 45 down-regulated genes. The addition of triterpenoids decreased the filamentous and invasive growth of cells, and benefit to the redox balance and glycolysis. This study offers a global view through transcriptome analysis to understand the molecular response to ethanol in Sc131 by the treatment of C. paliurus triterpenoids, which may be helpful to enhance ethanol tolerance of S. cerevisiae in the fermentation of Chinese fruit wine.

A metagenomics approach to the intestinal microbiome structure and function in high fat diet-induced obesity mice fed with oolong tea polyphenols.

To investigate the modulatory effect of oolong tea polyphenols (OTP) on intestinal microbiota, OTP was prepared by column chromatography and its influence on the gut flora structure was analyzed by high-throughput sequencing with a human flora-associated high fat diet (HFD) induced obesity mouse model. We observed a robust increase in bacterial biodiversity and the abundance of genera known to be butyrate- and acetate-producing bacteria. A large increase in Bacteroidetes with a decrease in Firmicutes was observed after the administration of OTP for 4 weeks, and the corresponding decrease in the Firmicutes/Bacteroidetes ratio reflected the positive modulatory effect of OTP on the intestinal microbiota. In addition, KEGG pathways for the biosynthesis of amino acids, carbon metabolism, and the ribosome were among the most differentially expressed genes after OTP intervention. The current study revealed that OTP rich in tea catechins, especially O-methylated derivatives, may have prebiotic-like activity and can be used as a functional food component with potential therapeutic utility to prevent obesity-related metabolic disorders by manipulating the intestinal microbiota.

The modulatory effect of (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) on intestinal microbiota of high fat diet-induced obesity mice model.

(-)-Epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) has exhibited multiple beneficial effects on the prevention of obesity in oolong tea. However, its absorption is relatively low, and the potential to be fully utilized is not completely elucidated. Therefore, with human flora-associated (HFA) mice model, the effect of EGCG3″Me on high fat diet-induced obesity was investigated by high-throughput sequencing. The shifts in relative abundance of the dominant taxa at the phylum, family and genus levels showed the dramatically effects of EGCG3″Me. Despite significant inter-individual variation, a large increase in Bacteroidetes with concomitant decrease of Firmicutes was observed after the administration of EGCG3″Me for 8weeks, with a corresponding decrease in the Firmicutes/Bacteroidetes ratio, which reflect the modulatory effect of EGCG3″Me on intestinal microbiota. The results showed that EGCG3″Me may have prebiotic-like activity and can be used as a functional food component with potential therapeutic utility in manipulating intestinal microbiota, contributing to the prevention of gut dysbiosis.