Valorization of Polysaccharides Obtained from Dark Tea: Preparation, Physicochemical, Antioxidant, and Hypoglycemic Properties

A glucuronogalactomannan isolated from Tetrastigma hemsleyanum Diels et Gilg: Structure and immunomodulatory activity

A novel acidic glucuronogalactomannan (STHP-5) was isolated from the aboveground part of Tetrastigma hemsleyanum Diels et Gilg with a molecular weight of 3.225 × 105 kDa. Analysis of chain conformation showed STHP-5 was approximately a random coil chain. STHP-5 was composed mainly of galactose, mannose, and glucuronic acid. Linkages of glycosides were measured via methylation analysis and verified by NMR. In vitro, STHP-5 induced the production of nitric oxide (NO) and secretion of IL-6, MCP-1, and TNF-α in RAW264.7 cells, indicating STHP-5 had stimulatory activity on macrophages. STHP-5 was proven to function as a TLR4 agonist by inducing the secretion of secreted embryonic alkaline phosphatase (SEAP) in HEK-Blue™-hTLR4 cells. The TLR4 activation capacity was quantitatively measured via EC50, and it showed purified polysaccharides had stronger effects (lower EC50) on activating TLR4 compared with crude polysaccharides. In conclusion, our findings suggest STHP-5 may be a novel immunomodulator.

Optimization of Composite Enzymatic Extraction, Structural Characterization and Biological Activity of Soluble Dietary Fiber from Akebia trifoliata Peel

In order to reduce the waste of Akebia trifoliata peel and maximize its utilization, in this study, on the basis of a single-factor experiment and the response surface method, the optimum technological conditions for the extraction of soluble dietary fiber from Akebia trifoliata peel with the compound enzyme method were obtained. The chemical composition, physical and chemical properties, structural characterization and biological activity of the purified soluble dietary fiber (AP-SDF) from the Akebia trifoliata peel were analyzed. We discovered that that the optimum yield was 20.87% under the conditions of cellulase addition 600 U/g, enzymolysis time 100 min, solid-liquid ratio 1:24 g/mL and enzymolysis temperature 51 °C. At the same time, AP-SDF was a porous network structure cellulose type I acidic polysaccharose mainly composed of arabinoxylan (36.03%), galacturonic acid (27.40%) and glucose (19.00%), which possessed the structural characteristic peaks of the infrared spectra of polysaccharides and the average molecular weight (Mw) was 95.52 kDa with good uniformity. In addition, the AP-SDF exhibited high oil-holding capacity (15.11 g/g), good water-holding capacity and swelling capacity, a certain antioxidant capacity in vitro, hypoglycemic activity in vitro for α-glucosidase inhibition and hypolipidemic activity in vitro for the binding ability of bile acids and cholesterol. These results will provide a theoretical basis for the development of functional products with antioxidant, hypoglycemic and hypolipidemic effects, which have certain application value in related industries.

Ultrasound-assisted complex enzyme extraction, structural characterization, and biological activity of polysaccharides from Ligustrum robustum

Ligustrum robustum is one of the traditional teas in China with a long history of drinking and medicinal use. Through Response surface optimization, the yield of polysaccharides extracted by ultrasonic-assisted complex enzyme (UAE-EN) method was increased to 14.10 ± 0.56 %. Neutral homogeneous polysaccharide (LRNP) and acidic homogeneous polysaccharide (LRAP-1, LRAP-2, LRAP-3) from L. robustum were purified. The molecular weights of them were 5894, 4256, 4621 and 3915 Da. LRNP was composed of glucose (Glc), galactose (Gal), arabinose (Ara) with molar percentage of 24.97, 42.38 and 30.80. Structure analysis revealed that the backbone of LRNP consisted of 1,5-linked α-Araf, 1,4-linked β-Galp, 1,6-linked β-Galp, and 1,4-linked β-Glcp with the branches of 1,2-linked α-Araf, 1,3-linked α-Araf, 1,3-linked β-Glcp and 1,6-linked β-Galp residues, some terminal residues of α-Araf, β-Glcp and α-Galp were also included. In vitro experiments showed that the four polysaccharides possessed excellent antioxidant, antitumor and hypoglycemic activities. LRNP possessed the protective effect against oxidative stress. The studies provide a basis for further exploitation of L. robustum.

Valorization of cell wall polysaccharides extracted from Liubao brick tea residues: chemical, structural, and hypoglycemic properties

BACKGROUND

Tea dregs, typically generated during the production of instant tea or tea beverages, have conventionally been regarded as waste material and routinely discarded. Nevertheless, contemporary research endeavors are concentrating on discovering efficient methods for utilizing the potential of this discarded resource.

RESULTS

In this study, we employed a sequential extraction method using chemical chelating agents to extract and isolate four distinct cell wall polysaccharides, designated as CWTPS-1 through CWTPS-4, from the tea dregs of Liubao brick tea. A comprehensive investigation into their physicochemical, structural, and hypoglycemic properties was conducted. The analysis of chemical composition and physicochemical characteristics revealed that all four CWTPSs were characterized as acidic polysaccharides, albeit with varying chemical compositions and physicochemical attributes. Specifically, the xyloglucan fractions, CWTPS-3 and CWTPS-4, were found to be rich in glucose and xylose, displaying a more uniform molecular weight distribution, greater structural stability, and a more irregular surface compared to the others. Moreover, they exhibited a higher diversity of monosaccharide residues. Importantly, our research unveiled that all four CWTPSs exhibited the capacity to modulate key glucose-regulated and antioxidant enzyme activities within HepG2 cells via the IRS-1-PI3K/AKT signaling pathway, thereby ameliorating cellular insulin resistance. Furthermore, our correlation analysis highlighted significant associations between monosaccharide composition and neutral sugar content with the observed hypoglycemic activity of CWTPSs.

CONCLUSION

This study highlights the potential of utilizing tea dregs as a valuable resource, making a significant contribution to the advancement of the tea industry. Furthermore, CWTPS-4 exhibits promising prospects for further development as a functional food ingredient or additive. © 2024 Society of Chemical Industry.

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.

Preparation, Characterization, and Antioxidant Properties of Selenium-Enriched Tea Peptides

The research on the activity of selenium (Se)-enriched agricultural products is receiving increasing attention since Se was recognized for its antioxidant activities and for its enhancement of immunity in trace elements. In this study, antioxidant Se-containing peptides, namely, Se-TAPepI-1 and Se-TAPepI-2, were optimally separated and prepared from Se-enriched tea protein hydrolysates by ultrafiltration and Sephadex G-25 purification, and subsequently, their physicochemical properties, oligopeptide sequence, and potential antioxidant mechanism were analyzed. Through the optimization of enzymatic hydrolysis conditions, the Se-enriched tea protein hydrolyzed by papain exhibited a better free radical scavenging activity. After separation and purification of hydrolysates, the two peptide fractions obtained showed significant differences in selenium content, amino acid composition, apparent morphology, peptide sequence, and free radical scavenging activity. Therein, two peptides from Se-TAPepI-1 included LPMFG (563.27 Da) and YPQSFIR (909.47 Da), and three peptides from Se-TAPepI-2 included GVNVPYK (775.42 Da), KGGPGG (552.24 Da), and GDEPPIVK (853.45 Da). Se-TAPepI-1 and Se-TAPepI-2 could ameliorate the cell peroxidation damage and inflammation by regulating NRF2/ARE pathway expression. Comparably, Se-TAPepI-1 showed a better regulatory effect than Se-TAPepI-2 due to their higher Se content, typical amino acid composition and sequence, higher surface roughness, and a looser arrangement in their apparent morphology. These results expanded the functional activities of tea peptide and provided the theoretical basis for the development of Se-containing peptides from Se-enriched tea as a potential natural source of antioxidant dietary supplements.

Amelioration Effects and Regulatory Mechanisms of Different Tea Active Ingredients on DSS-Induced Colitis

The potential biological function of tea and its active components on colitis has attracted wide attention. In this study, different tea active ingredients including tea polyphenols (TPPs), tea polysaccharides (TPSs), theabrownin (TB), and theanine (TA) have been compared in the intervention of dextran sulfate sodium (DSS)-induced colitis in mice. Specifically, TPP showed the greatest effect on colitis since it reduced 60.87% of disease activity index (DAI) compared to that of the DSS-induced colitis group, followed by the reduction of 39.13% of TPS and 28.26% of TB on DAI, whereas there was no obvious alleviative effect of TA on colitis. TPP, TPS, and TB could regulate the composition and abundance of gut microbiota to increase the content of short-chain fatty acids (SCFAs) and enhance intestinal barrier function. Further evidence was observed that TPP and TPS regulated the activation of Nrf2/ARE and the TLR4/MyD88/NF-κB P65 pathway to alleviate the colitis. Results of cell experiments demonstrated that TPP showed the greatest antiapoptosis and mitochondrial function protective capability among the tea ingredients via inhibiting the Cytc/Cleaved-caspase-3 signaling pathway. In summary, the superior anticolitis activity of TPP compared to TPS and TB is primarily attributed to its unique upregulation of the abundance of Akkermansia and its ability to regulate the mitochondrial function.

Lipid-Lowering Effects of a Novel Polysaccharide Obtained from Fuzhuan Brick Tea In Vitro

Lipid accumulation causes diseases such as obesity and abnormal lipid metabolism, thus impairing human health. Tea polysaccharide is one of the natural, active substances that can lower lipid levels. In this paper, an oleic-acid-induced HepG2 cell model was established. The lipid-lowering effects of a novel group of Fuzhuan brick tea polysaccharides (FTPs)-obtained from Fuzhuan brick tea-were examined in vitro. The monosaccharide composition of FTP3 was Glc, Gal, Ara, Man, Rha, GalAc, GlcAc, and Xyl with a molar ratio of 23.5:13.2:9.0:5.5:5.4:2.7:1.3:1.0, respectively. A molecular weight of 335.68 kDa was identified for FTP3. HepG2 cells treated with FTP3 achieved a prominent lipid-lowering effect compared with cells treated with oleic acid. Images of the Oil Red O staining treatment showed that FTP3-treated groups had significantly fewer red fat droplets. TC and TG levels were lower in FTP3-treated groups. FTP3 alleviated lipid accumulation in HepG2 cells, activated AMPK, and decreased the SREBP-1C and FAS protein expressions associated with fatty acid synthesis. FTP3 holds promising potential for its lipid-lowering effects.

Possible Mechanisms of Dark Tea in Cancer Prevention and Management: A Comprehensive Review

Tea is one of the most popular drinks in the world. Dark tea is a kind of post-fermented tea with unique sensory characteristics that is produced by the special fermentation of microorganisms. It contains many bioactive substances, such as tea polyphenols, theabrownin, tea polysaccharides, etc., which have been reported to be beneficial to human health. This paper reviewed the latest research on dark tea's potential in preventing and managing cancer, and the mechanisms mainly involved anti-oxidation, anti-inflammation, inhibiting cancer cell proliferation, inducing cancer cell apoptosis, inhibiting tumor metastasis, and regulating intestinal flora. The purpose of this review is to accumulate evidence on the anti-cancer effects of dark tea, the corresponding mechanisms and limitations of dark tea for cancer prevention and management, the future prospects, and demanding questions about dark tea's possible contributions as an anti-cancer adjuvant.

Lentinula edodes Sing Polysaccharide: Extraction, Characterization, Bioactivities, and Emulsifying Applications

In the present work, the optimization of extraction, emulsifying properties, and biological activities of polysaccharides from Lentinula edodes Sing (LES) were studied. The results showed LES polysaccharides extracted by hot water or ultrasonication are a group of β-glucan. Among all the samples, the one extracted by hot water showed the best emulsifying capacity. In addition, the results demonstrated that LES polysaccharide had strong scavenging activities in vitro on DPPH and ABTS radicals, which reached the highest level for the one extracted by 90 min ultrasonication (p < 0.05). Overall, Lentinula edodes Sing polysaccharides (LESPs) may have potential applications as emulsifying agents in food industries.

Effects and Stress-Relieving Mechanisms of Dark Tea Polysaccharide in Human HaCaT Keratinocytes and SZ95 Sebocytes

A new skincare application scenario for dark tea, a unique and post-fermented tea popular in the health food industry, was developed in this paper. The effects of dark tea polysaccharide (DTP) on stress-induced skin problems and its mechanism of action were investigated by modeling cortisone-induced stress injury in human HaCaT keratinocytes and SZ95 sebaceous gland cells. The results showed a reduced cortisol conversion induced by cortisone under the action of DTP with a concentration of 200 μg/mL, probably by inhibiting the expression of the HSD11B1 enzyme. DTP was also able to suppress the cortisone-induced elevation of lipid levels in SZ95 sebocytes at this concentration. In addition, the composition and structure of DTP were verified by ultrafiltration, ultraviolet-visible spectrophotometry (UV-VIS), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and infrared spectroscopy. In brief, DTP has a unique and significant stress-relieving effect, which provides new ideas for the development of new ingredients for the skin care industry.

Microanalysis Characterization and Immunomodulatory Effect for Selenium-Enriched Polysaccharide from Morchella esculenta (L.) Pers

Morchella esculenta (L.) Pers., referred to as Morel, is a medicinal and edible homologous fungus, which contains many bioactive substances. In Morel, polysaccharides are the most abundant and have various bioactivities. In the present work, two novel polysaccharides, Se-MPS and MPS, were prepared and purified from selenium-enriched (Se-enriched) and common Morel mycelia, respectively, and their structural and immunomodulatory properties were evaluated. The results show that Se-enriched treatment significantly changed the polysaccharides' chemical composition, molecular weight, and sugar chain configuration. In addition, the Se-enriched treatment also improved the polysaccharides' fragmentation and thermal stability. Importantly, Se-enriched Morel polysaccharide (Se-MPS) could significantly enhance phagocytosis of RAW 264.7 macrophage cells and, remarkably, activate their immune response via activating the TLR4-TRAF6-MAPKs-NF-κB cascade signaling pathway, finally exerting an immunomodulatory function. Based on these findings, selenium-enriched Morel polysaccharide appears to have more potential for development and utilization in functional foods or medicines than ordinary Morel polysaccharide.

Ultrasound-Assisted Deep Eutectic Solvent Extraction of Polysaccharides from Anji White Tea: Characterization and Comparison with the Conventional Method

Deep eutectic solvent as a new green and safe solvent system has attracted more and more attention in recent years. In this study, three deep eutectic solvents (DES) were combined with ultrasound irradiation to extract tea polysaccharides (TPs) from Anji white tea, which was compared with conventional hot water extraction (HW). The physicochemical, structural, and biological properties of TPs extracted by ultrasound-assisted DES and hot water (HWP) were further investigated. Results showed that the DES system composed of choline chloride and 1,6-hexanediol (CH) with the molar ratio of 1:2 exhibited the optimal extraction yield (19.18%) and in vitro antioxidant activities for TPs (CHP). Furthermore, compared to the HWP, the CHP had a higher extraction yield and total carbohydrate content and a lower molecular weight. Monosaccharide composition analysis displayed that the molecular structure of CHP exhibited more arabinose but less glucose, mannose, galacturonic acid, and glucuronic acid than HWP. Little difference was observed in the preliminary structural characteristics between HWP and CHP from Fourier transform infrared analysis. Besides, CHP possessed better α-glucosidase inhibitory and hypoglycemic activity in L6 cells than HWP. Therefore, the ultrasound-assisted DES extraction method can be a promising strategy for extracting TPs with excellent bioactivities for future applications in functional foods.

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

Structural characterization of a pectic polysaccharide from laoshan green tea and its inhibitory effects on the production of NO, TNF-α and IL-6

A novel pectic polysaccharide, named GTPS3-1, was isolated and purified from Laoshan green tea polysaccharide (GTPS) through DEAE Sepharose Fast Flow and Sephacryl S-300 columns, its structure was characterized and its anti-inflammatory activity was explored. GTPS3-1, with a molecular weight of 26.05 kDa, was mainly composed of galacturonic acid, galactose, rhamnose and arabinose in a molar ratio of 4.72:2.5:1.68:1 on the basis of monosaccharide composition. Structural analysis results revealed that GTPS3-1 was a highly branched pectin consisting of →3)-Galp-(1→, →2)-Rhap-(1→, →3,5)-Araf-(1→, →3)-Rhap-(1→, GalpA-(1→, →3,4)-Galp-(1→, →4)-GalpA-(1→, →5)-Araf-(1→, →2,4)-Rhap-(1→, Rhap-(1→ and Araf-(1→ according to FT-IR, methylation and NMR analyses. In addition, GTPS3-1 inhibited the production of NO, TNF-α and IL-6 in a dose-dependent manner, which resulted in the amelioration of inflammatory injury in LPS-induced RAW 264.7 cells. These results would provide a theoretical basis for practical application of the novel polysaccharide as an anti-inflammatory adjuvant.

Advances in the Utilization of Tea Polysaccharides: Preparation, Physicochemical Properties, and Health Benefits

Tea polysaccharide (TPS) is the second most abundant ingredient in tea following tea polyphenols. As a complex polysaccharide, TPS has a complex chemical structure and a variety of bioactivities, such as anti-oxidation, hypoglycemia, hypolipidemic, immune regulation, and anti-tumor. Additionally, it shows excellent development and application prospects in food, cosmetics, and medical and health care products. However, numerous studies have shown that the bioactivity of TPS is closely related to its sources, processing methods, and extraction methods. Therefore, the authors of this paper reviewed the relevant recent research and conducted a comprehensive and systematic review of the extraction methods, physicochemical properties, and bioactivities of TPS to strengthen the understanding and exploration of the bioactivities of TPS. This review provides a reference for preparing and developing functional TPS products.

Valorization of Polysaccharides From Benincasa hispida: Physicochemical, Moisturizing, and Antioxidant Skincare Properties

Benincasa hispida Cogn. (B. hispida) is a popular vegetable in China, and studies have been reported on B. hispida polysaccharides (BPS) preparation. However, few studies have been reported on its physicochemical and skincare properties. In this study, we analyzed the physicochemical properties of BPS, free radical scavenging capability, moisturizing and antioxidant activities in vitro and in vivo, respectively. Our results show that BPS was an inhomogeneous acidic polysaccharide that could scavenge a variety of free radicals. Also, BPS had a good moisturizing and antioxidant capability both in vitro and in vivo. Specifically, BPS could alter some key antioxidant enzyme activities and pro-inflammatory factor levels via activating the NRF2/HO-1 pathway, thereby preventing H2O2-induced reactive oxygen species (ROS) production and apoptosis of HDF-1 cells. Our results suggest that BPS exhibited favorable moisturizing and anti-aging properties and might be an attractive candidate for the development of anti-aging skincare products.

Preparation, Physicochemical and Hypoglycemic Properties of Natural Selenium-Enriched Coarse Tea Glycoproteins

Various functional components in tea have been well developed, but less research has been explored on glycoproteins in tea. In this paper, three types of glycoprotein fractions, namely tea selenium-binding glycoprotein1-1 (TSBGP1-1), TSBGP2-1, and TSBGP3-1, respectively, were extracted and purified from selenium-enriched coarse green tea. Chemical analysis revealed that three fractions were glycoproteins, but their selenium content, molecular weight, and monosaccharide composition were significantly different. Fourier transforms infrared (FT-IR) analysis indicated that three fractions contained characteristic absorption peaks of glycoproteins but differed in secondary structural composition. Thermogravimetric (TG) analysis showed that the thermal stability of the three fractions was dramatically distinct. The in vitro hypoglycemic activity showed that TSBGPs significantly activated the insulin receptor substrate 2 (IRS2)/protein kinase B (Akt) pathway in LO2 cells, then enhanced glucose metabolism and inhibited gluconeogenesis, and finally ameliorated insulin resistance (IR) and glucose metabolism disorders. Furthermore, Pearson correlation analysis reveals that the hypoglycemic activity was significantly correlated with Se, protein, monosaccharide composition (especially glucose), molecular weight, and secondary structure. Our results show that Se-enriched tea glycoprotein is a desirable candidate for developing anti-diabetic food, and TSBGP-2 and TSBGP-3 had a better regulation effect. Our results can provide a research reference for the extraction, physicochemical property, and function of selenium-enriched plant glycoproteins.