Hypolipidemic effects of crude green tea polysaccharide on rats, and structural features of tea polysaccharides isolated from the crude polysaccharide

Green Tea Ameliorates Depression-Like Behavior and Cognitive Impairment Induced by High-Fat Diet and Chronic Mild Stress

Depression often develops in young individuals and is linked to complications like cognitive impairment. Conventional antidepressants show limited efficacy in restoring cognitive function and may cause adverse effects. Green tea, a safe and health-promoting beverage, offers various health benefits. This study investigated the effects of long-term green tea consumption on stress-induced depression-like behavior and mild cognitive impairment in animal models. We established a rodent model of mild depression and studied the effects of green tea on depression-like behavior and cognitive impairment through comprehensive evaluation, including behavioral assessments, neurotransmitter quantification, gene and protein expression analysis, blood metabolite profiling, and gut microbiota characterization. Results demonstrated significant improvements in mood, long-term memory, and sterol and glycerophospholipid metabolism. Green tea repaired the intestinal barrier and upregulated genes vital for tight junctions and mucin production. It also enhanced gut microbiota composition, reducing the Firmicutes-to-Bacteroidetes ratio and promoting beneficial bacteria such as NK4A136, Muribaculum, and Gordonibacter. These microbiota changes improved liver lipid metabolism and alleviated depressive symptoms. Green tea effectively mitigates depression-like behavior and cognitive deficits by modulating the gut-liver-brain axis.

A low-protein soybean-free diet improves carcass traits and meat quality and modulates the colonic microbiota in Daweizi pigs

Introduction

Soybean meal is an excellent protein source and is widely used in pig feed. However, the Americas account for more than 80% of global soybean production, so European and Asia swine production largely depends on soybean imports. The use of safe and functional unconventional feed sources can effectively alleviate worldwide protein shortage problems.

Methods

Here, we formulated a low-protein soybean-free diet (LPNS) for growing and fattening pigs using rice, potatoes, tea, and other unconventional feed sources. Thirty-six healthy Daweizi pigs (average body weight 23.60 ± 1.34 kg) were raised under the same conditions and randomly assigned to two dietary treatments: (1) Con group, corn-soybean base meal; (2) LPNS group. When the average weight of pigs in the group reached 85 kg, two pigs per pen were randomly selected and euthanized for collection of the colonic digesta and carcass traits and for meat quality determination.

Results

Compared with the corn-soybean based diet, the LPNS diet decreased the average daily gain (ADG) and feed conversion ratio (FCR) of Daweizi pigs but had a lower cost per kilogram of gain. In addition, the LPNS diet significantly increased leanness and decreased the fat-skin rate and bone rate of Daweizi pigs. The cooking loss of meat decreased, and unsaturated fatty acids such as C22:6 and n-3 PUFA significantly increased in the LPNS group. Moreover, the purine content in the meat substantially decreased with the LPNS diet. The 16S rDNA analysis revealed that the LPNS diet greatly modified the composition of the colonic microbiota community, with a decrease in the Firmicutes/Bacteroidetes ratio and an increase in the abundance of Lactobacillus spp.

Discussion

The use of functional herbs along with a low-protein diet helped to regulate fat and purine metabolism in fatty-type pigs. The LPNS diet formulated with unconventional-feed sources not only helps reduce the feed cost in swine production but also improves the carcass traits and meat quality of pigs, which is more suitable for small-scale pig farming.

Characterization of tea polysaccharides from Tieguanyin oolong tea and their hepatoprotective effects via AMP-activated protein kinase-mediated signaling pathways

In the present study, we succeeded in extracting tea polysaccharide (TPS) from Tieguanyin oolong tea, and the TPS was characterized. TPS is an acidic heteropolysaccharide containing rhamnose, arabinose, galactose, glucose (Glc), xylose, mannose, galacturonic acid, and guluronic acid. We found that TPS supplementation partially reversed the elevated levels of serum alanine aminotransferase, total cholesterol, and low-density lipoprotein cholesterol in high-fat diet (HD)-induced nonalcoholic fatty liver disease (NAFLD) mice (p < 0.05), and hepatic steatosis and impaired Glc tolerance were also ameliorated. After HD intervention, the activity of Adenosine 5'-monophosphate-activated protein kinase (AMPK) and its downstream genes, including Sirtuin 1 (SIRT1), sterol regulatory element-binding protein-1c (SREBP1c), acetyl-coenzyme A carboxylase 1 (ACC1), and adipose triglyceride lipase (ATGL), was significantly inhibited (p < 0.05). TPS can increase the expression of these genes. The hepatoprotective effects of TPS in AMPK-/- mice almost completely disappeared. Moreover, the expression levels of SIRT1, SREBP1c, ACC1, and ATGL did not significantly change after TPS supplementation (p > 0.05). Therefore, our findings suggest that TPS protects the liver from hepatic glucolipid metabolism disorders in HD-induced NAFLD mice by activating AMPK-mediated signaling pathways.

Structural characteristics and biological activity of a water-soluble polysaccharide HDCP-2 from Camellia sinensis

Large-leaf Yellow tea (LYT) is a traditional beverage from Camellia Sinensis (L.) O. Kuntze in China and has unusual health-regulating functions. This investigation explored the structural characteristics of a polysaccharide extracted from LYT, which possesses anti-inflammatory activity. The polysaccharide HDCP-2, obtained through ethanol fractional precipitation and then DEAE-52 anion exchange column, followed by DPPH radical scavenging screening, exhibited a yield of 0.19 %. The HPGPC method indicated that the molecular weight of HDCP-2 is approximately 2.9 × 104 Da. Analysis of the monosaccharide composition revealed that HDCP-2 consisted of mannose, glucose, xylose, and galacturonic acid, and their molar ratio is approximately 0.4:0.5:1.2:0.7. The structure motif of HDCP-2 was probed carefully through methylation analysis, FT-IR, and NMR analysis, which identified the presence of β-d-Xylp(1→, →2, 4)-β-d-Xylp(1→, →3)-β-d-Manp(1→, α-d-Glcp(1→ and →2, 4)-α-d-GalAp(1→ linkages. A CCK-8 kit assay was employed to evaluate the anti-inflammatory action of HDCP-2. These results demonstrated that HDCP-2 could inhibit the migration and proliferation of the MH7A cells and reduce NO production in an inflammatory model induced by TNF-α. The abundant presence of xylose accounted for 39 % of the LYT polysaccharide structure, and its distinctive linking mode (→2, 4)-β-d-Xylp(1→) appears to be the primary contributing factor to its anti-inflammatory effect.

Aloe polysaccharides ameliorate obesity-associated cognitive dysfunction in high-fat diet-fed mice by targeting the gut microbiota and intestinal barrier integrity

Aloe polysaccharides (APs) display cognition-improving properties, but the underlying mechanisms remain unclear. Herein, AP supplementation for 24 weeks significantly improved cognitive behavioral disturbances caused by a high-fat diet. Moreover, APs notably reshaped the structure of the gut microbiota, which was manifested by increasing the relative abundance of Alloprevotella, Alistipes, Romboutsia, Turicibacter, Prevotellaceae_UCG-001, and Akkermansia while reducing the abundance of Parasutterella, Staphylococcus, Helicobacter, Enterococcus, and Erysipelatoclostridium. Notably, the gut barrier damage and LPS leakage caused by HF were recovered by APs. Additionally, with the improvement of intestinal barrier integrity, oxidative stress and inflammation in the brain and jejunum were significantly ameliorated. Furthermore, the expression of genes associated with cognitive impairment and the intestinal tract barrier was up-regulated (CREB, BDNF, TrkB, ZO-1 and occludin), while the expression of genes associated with inflammatory factors was down-regulated (IL-1β, IL-6, and TNF-α). Finally, we observed a significant correlation among cognition-related genes, gut microbiota, oxidative stress, and inflammation in the HF-AP group. Together, our findings suggest that altered gut microbiota composition and improved gut barrier integrity may be important targets for potentially improving high-fat diet-induced cognitive impairment.

Recent insights into the physicochemical properties, bioactivities and their relationship of tea polysaccharides

Tea polysaccharides (TPS) is receiving global concern in past years due to their therapeutic effects in many diseases such as obesity and diabetes. Many publications imply that the unique physicochemical properties and bioactivities of TPS are prerequisites for its use as a biofilm, drug carrier and emulsifier. Despite numerous healthy benefits, studies on the in-deep structure-activity relationship of TPS still not well explored and explained yet. The main reasons for the research limitation are attributed mainly to the unbreakable advanced structural research technology and the formation of TPS conjugates. The present review also summarizes some similar parameters in primary structure of TPS with better bioactivities, discusses the relationships between their physicochemical properties and bioactivities, and suggests that function-specific TPS would be obtained in the future if the links between preparation methods, physicochemical properties and bioactivities of TPS could be well understood and established.

Purification, structural characteristics and anti-atherosclerosis activity of a novel green tea polysaccharide

A new homogeneous polysaccharide (TPS3A) was isolated and purified from Tianzhu Xianyue fried green tea by DEAE-52 cellulose and Sephacryl S-500 column chromatography. Structural characterization indicated that TPS3A mainly consisted of arabinose, galactose, galacturonic acid and rhamnose in a molar ratio of 5.84: 4.15: 2.06: 1, with an average molecular weight of 1.596 × 104 kDa. The structure of TPS3A was characterized as a repeating unit consisting of 1,3-Galp, 1,4-Galp, 1,3,6-Galp, 1,3-Araf, 1,5-Araf, 1,2,4-Rhap and 1-GalpA, with two branches on the C6 of 1,3,6-Galp and C2 of 1,2,4-Rhap, respectively. To investigate the preventive effects of TPS3A on atherosclerosis, TPS3A was administered orally to ApoE-deficient (ApoE-/-) mice. Results revealed that TPS3A intervention could effectively delay the atherosclerotic plaque progression, modulate dyslipidemia, and reduce the transformation of vascular smooth muscle cells (VSMCs) from contractile phenotype to synthetic phenotype by activating the expression of contractile marker alpha-smooth muscle actin (α-SMA) and inhibiting the expression of synthetic marker osteopontin (OPN) in high-fat diet-induced ApoE-/- mice. Our findings suggested that TPS3A markedly alleviated atherosclerosis by regulating dyslipidemia and phenotypic transition of VSMCs, and might be used as a novel functional ingredient to promote cardiovascular health.

Dynamic Formation of Green Tea Cream and the Identification of Key Components Using the "Knock-Out/Knock-In" Method

The composition of green tea cream is extremely complex, and identification of key components is a prerequisite for elucidating its microstructure formation mechanism. This study examined the dynamic changes in the content of components and properties of colloid particles during the formation process of tea cream by chemical analysis and dynamic laser scattering (DLS). A "knock-out/knock-in" method was developed and used to further explore the relationship between the interaction of these components and the microstructure formation of tea cream. The results revealed that polysaccharides, proteins, epigallocatechin gallate (EGCG), and caffeine were the main components involved in tea cream formation. These components participated in the formation process in the form of polysaccharide-protein and EGCG-caffeine colloidal particles. Consequently, there were synchronized dynamic changes in the levels of polysaccharides, proteins, EGCG, and caffeine. The "knock-out/knock-in" experiment revealed that the interactions between EGCG or caffeine and macro-molecule components were not the key factors in tea cream microstructure formation. However, it was found that the complexation between EGCG and caffeine played a crucial role in the formation of tea cream. The findings suggested that decreasing the concentrations of EGCG and caffeine could be useful in controlling tea cream formation during tea beverage processing and storage.

Structural Characterization of a Low Molecular Weight HG-Type Pectin From Gougunao Green Tea

Tea is a popular beverage with a long history of safe and healthy use. Tea polysaccharide is a bioactive component extracted from tea, which has attracted more and more attention in recent decades. In this article, an acidic polysaccharide Gougunao tea polysaccharide (GPS) was isolated from Gougunao green tea by hot water extraction and ethanol precipitation. After purification by a diethylaminoethyl (DEAE) Sepharose Fast Flow column and a Sephacryl S-400 column, several homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) fractions were obtained. Fraction GPS2b with the highest yield was selected for structural characterization by methylation and nuclear magnetic resonance (NMR) analysis. GPS2b was found to be an HG-type pectic polysaccharide (degree of methyl esterification [DE], 51.6%) with low molecular weight (Mw, 36.8 kDa). It was mainly composed of →4)-α-GalpA- (1→ and →4)-α-GalpA-6-OMe-(1→. In addition, a minor highly branched RG-I domain was identified in this fraction. The investigation of structural features of tea polysaccharides can provide insights to understand their structure-bioactivity relationship.

Chemical characterization of Tianshan green tea polysaccharides and its protective effects on cell oxidative injury

The purpose of this study was to analyze the chemical characterization of Tianshan green tea polysaccharides (TSPS), and evaluate its antioxidant activity by chemical-based and cellular-based antioxidant models in vitro. The results showed that the TSPS were composed of mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, arabinose, and fucose with a molar ratio of 14.5:33.5:10.5:6.5:111.5:22.3:59.5:51: 1.0, and an average molecular weight of 19.49 kDa. TSPS exhibited excellent antioxidant ability to DPPH radical, hydroxyl radical, and ABTS radical, and enhanced the ferric-reducing power (FRAP). The antioxidation model of LO2 and HepG2 cells was established, and found that TSPS had no significant toxicity to either of the two cells at the range of 0.1-5 mg/mL, but clearly protected cells from H₂ O₂ -induced apoptosis and significantly reduced intracellular ROS level. In addition, the activities of antioxidant-associated enzymes were detected in LO2 cells, which suggested that TSPS could significantly improve the activities of SOD and CAT enzyme when the concentration was higher than 0.5 mg/mL. Furthermore, TSPS activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway by promoting Nrf2 nuclear translocation and inhibited the expression of Kelch-like ECH-associated protein 1 (Keap-1) and enhanced the expression of heme oxygenase-1 (HO-1). PRACTICAL APPLICATIONS: Tianshan green tea, a local variety in Fujian Province, belongs to unfermented tea. Polysaccharide is considered as the most promising component in Tianshan green tea. This study showed that TSPS had excellent antioxidant activity and had no significant toxicity to cells, which provides a scientific foundation and new idea for its further development and application in functional foods.

Hypolipidemic, anti-inflammatory, and anti-atherosclerotic effects of tea before and after microbial fermentation

BACKGROUND

Microbial fermentation significantly affects the flavor and efficacy of tea. It is generally believed that fermented tea is more effective in lowering lipids, while unfermented tea can more effectively inhibit inflammation. However, there is not sufficient evidence to support this claim. To systematically compare the hypolipidemic, anti-inflammatory, and anti-atherosclerotic effects of tea before and after microbial fermentation, hyperlipidemic rats and inflammatory injury cells were treated with Monascus purpureus-fermented pu-erh tea water extract (MPT) and sun-dried green tea water extract (SGT), respectively.

RESULTS

MPT, with higher levels of theabrownins, flavonoids, gallic acid (GA), and lovastatin, was more effective in reducing serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and inflammatory cytokines (TNF-α, IL-1β, and IL-6), while SGT, with higher levels of tea polyphenols, amino acids, (-)-epigallocatechin gallate (EGCG), and theaflavins, was more effective in increasing serum high-density lipoprotein cholesterol (HDL-C) in hyperlipidemic rats. The foam cells on the arterial wall of the rats in the MPT group were visibly less, and the thrombosis time was longer than that in the SGT group. Cell experiments showed that MPT was more effective in protecting endothelial cells from damage than SGT.

CONCLUSION

Surprisingly, Monascus purpureus-fermented pu-erh tea not only had better hypolipidemic and anti-atherosclerotic effects than its raw material (sun-dried green tea), but also was superior in anti-inflammatory effects to the latter, which was possibly attributable to the great changes in functional ingredients during microbial fermentation.

Effects of polysaccharides from Yingshan Yunwu tea on meat quality, immune status and intestinal microflora in chickens

The present study was aimed to investigate the effects of the addition of Yingshan Yunwu green tea polysaccharide conjugates (GTPC) on meat quality, immune response and gut microflora in chickens. A total of 200 chickens with average initial body weight were randomly allotted to 4 groups. Intestinal samples were collected at the end of experiment for bacterial culture and microbial community analysis by 16S rDNA gene sequencing using Illumina MiSeq. Chicken breast muscle and serum were also sampled for analysis of meat quality and immune function. The results showed that dietary GTPC addition increased (P < 0.05) chicken breast muscle pH and redness-greenness (a*) value and decreased (P < 0.05) the values of lightness (L*), yellowness-blueness (b*), hardness, toughness and adhesiveness. In addition, dietary supplementation of GTPC increased (P < 0.05) the weight of thymus and bursa and serum concentrations of IgA and IgG. Furthermore, of the 10 bacterial phyla, the predominant taxa across all sampling time-points were Bacteroidetes, Firmicutes, Proteobacteria, and Deferribacteres, representing >97% of all sequences. GTPC increased the abundance of Bacteroidetes and Lactobacillus, and decreased the abundance of Proteobacteria. These findings provided some references of the application of GTPC in the poultry industry.

Health Functions and Related Molecular Mechanisms of Tea Components: An Update Review

Tea is widely consumed all over the world. Generally, tea is divided into six categories: White, green, yellow, oolong, black, and dark teas, based on the fermentation degree. Tea contains abundant phytochemicals, such as polyphenols, pigments, polysaccharides, alkaloids, free amino acids, and saponins. However, the bioavailability of tea phytochemicals is relatively low. Thus, some novel technologies like nanotechnology have been developed to improve the bioavailability of tea bioactive components and consequently enhance the bioactivity. So far, many studies have demonstrated that tea shows various health functions, such as antioxidant, anti-inflammatory, immuno-regulatory, anticancer, cardiovascular-protective, anti-diabetic, anti-obesity, and hepato-protective effects. Moreover, it is also considered that drinking tea is safe to humans, since reports about the severe adverse effects of tea consumption are rare. In order to provide a better understanding of tea and its health potential, this review summarizes and discusses recent literature on the bioactive components, bioavailability, health functions, and safety issues of tea, with special attention paid to the related molecular mechanisms of tea health functions.

Tea Polysaccharides as Potential Therapeutic Options for Metabolic Diseases

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 sinensis L.). 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.

Review of herbal medications with the potential to cause bleeding: dental implications, and risk prediction and prevention avenues

Medicinal plant products have been used in health care since time immemorial. During the past three decades, the use of herbal supplements has been on the rise in the USA. A number of these products have been shown to possess the potential to interfere with blood clotting. This paper is a review of blood-thinning herbal supplements commonly used in the USA, accompanied by discussion of the dental implications of their use along with suggestions for prediction and prevention of the risk of bleeding. Twenty herbal supplements belonging to four pharmacological groups are identified and reviewed. While the majority (45%) of the supplements reviewed possesses antiplatelet properties, the remaining are dispersed among anticoagulant (15%), a combination of antiplatelet and anticoagulant (15%), and other diverse groups (25%). The literature reveals that most of the available information on blood-thinning herbs is based on in vitro experiments, animal studies, and individual clinical case reports. Some herbal effects are also speculated based on theoretical grounds. These observations, together with the deficiency of the law regulating herbal supplements, indicate limitations of the literature and the regulatory mechanisms related to these products, further implying the need for additional research and improved regulation. While emphasizing the dental implications of the findings reported in the literature, suggestions were made for prediction and prevention of the risk of bleeding caused by herbal medications, based on the concepts of predictive, preventive, and personalized medicine.

Antioxidant Activities and Repair Effects on Oxidatively Damaged HK-2 Cells of Tea Polysaccharides with Different Molecular Weights

This study aims at investigating the antioxidant activity and repair effect of green tea polysaccharide (TPS) with different molecular weights (Mw) on damaged human kidney proximal tubular epithelial cells (HK-2). Scavenging activities on hydroxyl radical (·OH) and ABTS radical and reducing power of four kinds of TPS with Mw of 10.88 (TPS0), 8.16 (TPS1), 4.82 (TPS2), and 2.31 kDa (TPS3) were detected. A damaged cell model was established using 2.6 mmol/L oxalate to injure HK-2 cells. Then, different concentrations of TPSs were used to repair the damaged cells. Index changes of subcellular organelles of HK-2 cells were detected before and after repair. The four kinds of TPSs possessed radical scavenging activity and reducing power, wherein TPS2 with moderate Mw presented the strongest antioxidant activity. After repair by TPSs, cell morphology of damaged HK-2 cells was gradually restored to normal conditions. Reactive oxygen species production decreased, and mitochondrial membrane potential (Δψm) of repaired cells increased. Cells of G1 phase arrest were inhibited, and cell proportion in the S phase increased. Lysosome integrity improved, and cell apoptotic rates significantly reduced in the repaired group. The four kinds of TPSs with varying Mw displayed antioxidant activity and repair effect on the mitochondria, lysosomes, and intracellular DNA. TPS2, with moderate Mw, showed the strongest antioxidant activity and repair effect; it may become a potential drug for prevention and treatment of kidney stones.

Tea Polysaccharides Inhibit Colitis-Associated Colorectal Cancer via Interleukin-6/STAT3 Pathway

The interleukin-6 (IL-6)/signal transducer and activator of transcription (STAT)-3 signaling pathway regulates proliferation and survival of intestinal epithelial cells and has profound impact on the tumorigenesis of colitis-associated cancer (CAC). Tea polysaccharides (TPS) are the major nutraceutical component isolated from tea-leaves and are known to possess antioxidant, anti-inflammatory, and antitumor bioactivities. Here, we investigated the antitumor activities of TPS on CAC using the azoxymethane/dextran sulfate sodium (AOM/DSS) mouse model and IL-6-induced colorectal cancer cell line (CT26) and determined whether TPS exerted its antitumor effects through the IL-6/STAT3 pathway. Results demonstrated that TPS significantly decreased the tumor incidence, tumor size, and markedly inhibited the infiltration of pro-inflammatory cells and the secretion of pro-inflammatory cytokines via balancing cellular microenvironment. Furthermore, we found that TPS suppressed the activation of STAT3 and transcriptionally regulated the expressions of downstream genes including MMP2, cyclin Dl, survivin, and VEGF both in vivo and in vitro. Thus, it was concluded that TPS attenuated the progress of CAC via suppressing IL-6/STAT3 pathway and downstream genes' expressions, which indicated that TPS may be a hopeful antitumor agent for the prevention and treatment of colon cancer.