Search Results (52)

Mao Jian Green Tea flavonoids (MJGT_F) contain luteolin, luteolin-7-O-glucoside, eriodictyol, and eriodictyol-7-O-glucoside, among which the first three components have hypoglycemic effects; however, the overall hypoglycemic potential of MJGT_F remains unclear. This study demonstrated that MJGT_F inhibited α-glucosidase in vitro and improved metabolic parameters in a dose-dependent manner in T2DM (type 2 diabetes mellitus) rats (reducing blood glucose, triglyceride, total cholesterol, low-density lipoprotein, insulin, and the homeostatic model assessment of insulin resistance; increasing high-density lipoprotein, insulin sensitivity index, and glucagon-like peptide-1). High-dose MJGT_F (MJGT_F_H) showed optimal efficacy. Mechanistically, MJGT_F_H activated the AMPK pathway, evidenced by a significant increase in the p-AMPK/AMPK ratio and downregulation of hepatic gluconeogenic enzymes G6Pase and PEPCK. These coordinated effects collectively suggest enhanced hepatic glucose utilization and suppression of glucose overproduction. MJGT_F_H also modulated gut microbiota by enriching beneficial taxa (e.g., Akkermansia muciniphila, 11.17-fold vs. metformin) and reducing pathogens like Enterobacteriaceae. These findings highlight MJGT_F’s dual regulatory roles in glucose metabolism and microbiota, supporting its potential for diabetes management. Full article

Infectious wounds pose formidable clinical challenges due to hypoxia, exacerbated inflammation, and persistent microbial colonization. To address this, we developed a bioinspired multifunctional hydrogel (PTDPs) through the in situ freeze-thaw co-assembly of polyvinyl alcohol (PVA), tea polyphenols (TP), polydopamine (PDA), and marine-derived self-assembling peptides (AAPs). The resultant PTDP hydrogel formed an intricate hydrogen-bonded network that enhanced mechanical robustness and substrate adhesion. TP and PDA synergistically confer potent antioxidant properties: TP scavenges radicals via phenolic hydroxyl groups while PDA enhances responsiveness to diverse radicals in hypoxic environments. Integrated with AAPs’ pro-regenerative functions and PDA’s broad-spectrum antimicrobial efficacy, this system generates therapeutic synergy. Characterization revealed outstanding physicochemical properties including tunable plasticity, high swelling ratios, and sustained hydration retention. In vitro studies demonstrated potent antioxidant activity, efficient inhibition of Staphylococcus aureus and Escherichia coli proliferation, and cytocompatibility facilitating endothelial cell migration/proliferation. In murine full-thickness infected wound models, the PTDP hydrogel significantly accelerated wound closure, enhanced neovascularization, and improved collagen deposition, underscoring its potential as an innovative therapeutic platform for infected and chronic wounds with strong translational prospects. Full article

Microbial contamination is the leading cause of foodborne diseases and spoilage in food and personal care products. Previous studies by our group have demonstrated that vine tea extract (VTE) and dihydromyricetin (DMY) inhibit the growth of Escherichia coli. In this study, we further explored the inhibitory mechanisms of VTE and DMY against E. coli through a label-free proteomics approach. The proteomic analysis detected 130 and 81 differentially expressed proteins (DEPs) in E.coli following VTE and DMY treatment, respectively. The analysis indicated that VTE and DMY inhibit bacterial growth through multiple-target mechanisms. Specifically, they inhibit E. coli growth by disrupting the cationic antimicrobial peptide resistance pathway, amino acid biosynthesis and metabolism, and nucleotide metabolism. Additionally, VTE disrupts various secondary metabolic pathways, while DMY interferes with E. coli ribosome assembly and function, and disrupts cell membrane lipid homeostasis by interfering with fatty acid metabolism. RT-qPCR validation confirmed transcriptional alterations in genes encoding key target proteins. Molecular docking results indicated that DMY may affect bacterial protein synthesis, cationic antimicrobial peptide resistance, and transcriptional regulation by binding to target proteins such as RplB, RplV, LpxA, and YafC. In conclusion, this study systematically deciphered the multi-target inhibitory mechanisms of VTE and DMY against E. coli, providing a theoretical basis for developing plant-derived antimicrobial agents. Full article

Insect odorant-binding proteins (OBPs) are promising molecular targets for developing novel pest management strategies by modulating chemoreception-driven behaviors. The tea gray geometrid Ectropis grisescens (Lepidoptera, Geometridae) is a major pest in tea plantations, causing substantial economic losses in China. In this study, we identified 18 OBPs from E. grisescens antennal transcriptome. All of the encoded proteins possessed N-terminal signal peptides and conserved cysteine residues, behaviors which are characteristic of insect OBPs. Phylogenetic analysis categorized these proteins into plus-C, minus-C, and classic OBP subfamilies. MEME motif analysis identified conserved sequence features potentially involved in odor detection. Tissue- and sex-specific expression profiling showed that EgriGOBP1-2, OBP3, OBP8, and OBP13 were highly expressed in the antennae of both sexes, suggesting roles in olfactory communication. Among them, EgriGOBP1-2, OBP3, and OBP13 exhibited similar expression levels between males and females, while other EgriOBPs were predominantly expressed in the legs, wings, or other tissues, indicating additional physiological functions beyond chemoreception. To investigate functional specificity, we selected antenna-enriched EgriGOBP2 for ligand-binding analysis. Fluorescence binding assays demonstrated that EgriGOBP2 exhibited broad binding affinity toward 8 of 12 host volatiles and 11 of 12 plant essential oil-derived volatiles. These combined findings lay the foundation for mechanistic studies of chemical recognition in E. grisescens and provide insights into the development of ecologically friendly pest control alternatives. Full article

Background/Objectives: The kidney plays a crucial role in regulating normal blood pressure and is one of the major organs affected by hypertension. The present study aimed to investigate the hypotensive and renoprotective effects of four specific green tea peptides extracted from green tea dregs on spontaneously hypertensive rats (SHRs) and to investigate the underlying mechanisms. Methods: Four specific green tea peptides (40 mg/kg) were gavaged to SHRs for 4 weeks, and blood pressure, renal function, renal pathological changes, renal tissue fibrosis indexes, and inflammation indexes were examined in SHRs to analyze the role of the four green tea peptides in alleviating hypertension and its renal injury. Results: The results showed that the four TPs significantly reduced systolic and diastolic blood pressure (20–24% and 18–28%) in SHR compared to the model group. Meanwhile, gene levels and protein expression of renal fibrosis-related targets such as phospho-Smad2/3 (p-Smad2/3) (26–47%), Sma- and Mad-related proteins 2/3 (Smad2/3) (19–38%), transforming growth factor-β1 (TGF-β1) (36–63%), and alpha-smooth muscle actin (alpha-SMA) (58–86%) were also significantly reduced. In addition, the reduced expression levels of medullary differentiation factor 88 (MyD88) (14–36%), inducible nitric oxide synthase (iNOS) (58–73%), and nuclear factor-κB p65 (NF-kB p65) (35–78%) in kidneys also confirmed that TPs attenuated renal inflammation in SHR. Therefore, green tea peptides could attenuate the fibrosis and inflammatory responses occurring in hypertensive kidneys by inhibiting the Ang II/TGF-β1/SMAD signaling pathway and MyD88/NF-κB p65/iNOS signaling pathway. Conclusions: The results showed that green tea peptides may be effective candidates for lowering blood pressure and attenuating kidney injury. Full article

Summer green tea often suffers from an inferior flavor, attributed to its bitterness and astringency. In this study, an integrated shaking and piling process was performed to improve the flavor of summer green tea. The results demonstrated a significant improvement in the sweet and kokumi flavors, accompanied by a reduction in umami, astringency, and bitterness following the treatment. Additionally, the yellowness and color saturation were also enhanced by the treatment. A total of 146 non-volatile metabolites (NVMs) were identified during the study. The elevated levels of sweet-tasting amino acids (L-proline, L-glutamine, and L-threonine), soluble sugars, and peptides (such as gamma-Glu-Gln and glutathione) contributed to the enhanced sweetness and kokumi. Conversely, the decreased levels of ester-catechins, flavonoid glycosides, and procyanidins resulted in a reduction in umami, astringency, and bitterness. Furthermore, the decreased levels of certain NVMs, particularly ascorbic acid and saponarin, played a crucial role in enhancing the yellowness and color saturation of the summer green tea. Our findings offered a novel theoretical framework and practical guidelines for producing high-quality summer green tea. Full article

Herbivore-induced plant volatiles (HIPVs) serve as powerful defense mechanisms that help plants mitigate pest-induced stress. Geraniol is a HIPV released by tea leaves in response to damage inflicted by tea green leafhoppers. In order to investigate whether the release of geraniol is a defensive mechanism of tea plants against infestation by tea green leafhoppers, our study explored the effects of geraniol on tea green leafhoppers, including the selectivity of tea green leafhoppers’ response to geraniol, survival and reproductive parameters, as well as alterations in endophytes and the transcriptome. The findings indicated that while geraniol did not exhibit strong repellent or lethal effects on tea green leafhoppers, it significantly reduced the egg-laying and hatching rates. Through 16S rRNA microbial sequencing, we found that geraniol treatment significantly altered the composition of endophytic microbial communities in tea green leafhoppers, potentially affecting their metabolic functions. Transcriptome analysis further showed that genes associated with energy metabolism, such as glutamate dehydrogenase, were significantly upregulated in response to geraniol, suggesting that tea green leafhoppers may enhance energy metabolism to counteract geraniol-induced stress. Additionally, the downregulation of antimicrobial peptide-related signaling pathways suggests that geraniol may weaken the immune capacity of tea green leafhoppers, potentially reducing their resistance to pathogens. These findings indicate that the strategic application of geraniol could be a promising approach to controlling tea green leafhopper populations. This study enhances our understanding of the insect-resistant mechanisms of HIPVs and provides new insights into environmentally sustainable pest management strategies for tea plantations. Full article

Phytosulfokine (PSK) is a tyrosine-sulfated pentapeptide found throughout the plant kingdom, playing key roles in plant growth, development, and responses to biotic and abiotic stresses. However, there is still a lack of a comprehensive analysis of the CsPSK gene family in Camellia sinensis. In this study, we conducted a genome-wide identification and characterized 14 CsPSK genes in tea plants, which are unevenly distributed across seven chromosomes. CsPSK genes encode proteins ranging from 75 to 124 amino acids in length, all belonging to the PSK-α type and containing conserved PSK domains. A synteny analysis revealed that the expansion of the CsPSK gene family is primarily attributed to whole-genome duplication, with homology to Arabidopsis thaliana PSK genes. A promoter region analysis identified cis-regulatory elements related to hormone and stress responses. An expression profile analysis showed that CsPSK genes are highly expressed in roots, stems, flowers, and leaves, and are induced by both biotic and abiotic stresses. Furthermore, an RT-qPCR assay demonstrated that the expression levels of CsPSK8, CsPSK9, and CsPSK10 are significantly upregulated following Discula theae-sinensis infection. These findings establish a basis for further research into the role of the CsPSK gene family in tea plant disease resistance and underlying molecular mechanisms, offering valuable perspectives for developing novel antimicrobial peptides. Full article

Otitis media (OM) is a frequent disease with incidence rate of 5300 cases per 100,000 people. Recent studies showed that polymicrobial biofilm formation represents a significant pathogenic mechanism in recurrent and chronic forms of OM. Biofilm enables bacteria to resist antibiotics that would typically be recommended in guidelines, contributing to the ineffectiveness of current antimicrobial strategies. Given the challenges of successfully treating bacterial biofilms, there is an growing interest in identifying novel and effective compounds to overcome antibacterial resistance. The objective of this review was to provide an overview of the novel compounds with antibiofilm effects on bacterial biofilm formed by clinical isolates of OM. The systematic review included studies that evaluated antibiofilm effect of novel natural or synthetic compounds on bacterial biofilm formed from clinical isolates obtained from patients with OM. The eligibility criteria were defined using the PICOS system: (P) Population: all human patients with bacterial OM; (I) Intervention: novel natural or synthetic compound with biofilm effect; (C) Control standard therapeutic antimicrobial agents or untreated biofilms, (O) Outcome: antibiofilm effect (biofilm inhibition, biofilm eradication), (S) Study design. The PRISMA protocol for systematic reviews and meta-analysis was followed. From 3564 potentially eligible studies, 1817 duplicates were removed, and 1705 were excluded according to defined exclusion criteria. A total of 41 studies with available full texts were retrieved by two independent authors. Fifteen articles were selected for inclusion in the systematic review which included 125 patients with OM. A total of 17 different novel compounds were examined, including N-acetyl-L-cysteine (NAC), tea tree oil, xylitol, eugenol, Aloe barbadensis, Zingiber officinale, Curcuma longa, Acacia arabica, antisense peptide nucleic acids, probiotics Streptococcus salivarius and Streptococcus oralis, Sodium 2-mercaptoethanesulfonate (MESNA), bioactive glass, green synthesized copper oxide nanoparticles, radish, silver nanoparticles and acetic acid. Staphylococcus aureus was the most commonly studied pathogen, followed by Pseudomonas aeruginosa and Haemophilus influenzae. Biofilm inhibition only by an examined compound was assessed in six studies; biofilm eradication in four studies, and both biofilm inhibition and biofilm eradication were examined in five studies. This systematic review indicates that some compounds like NAC, prebiotics, nanoparticles and MESNA that have significant effects on biofilm are safe and could be researched more extensively for further clinical use. However, a lack of data about reliable and efficient compounds used in therapy of different types of otitis media still remains in the literature. Full article

Modern functional foods are designed to provide health benefits beyond basic nutrition. They are enriched with bioactive ingredients like probiotics, vitamins, minerals, and antioxidants. These foods support overall health, enhance immune function, and help prevent chronic diseases. Milk proteins and tea are known to influence satiety and regulate body weight. Studies have shown that green tea polyphenols, namely, (−)-epigallocatechin gallate (EGCG), and whey proteins, predominantly lactoferrin (LF) from milk, play a role in regulating satiety. This study aims to investigate the effect of conjugating EGCG with apo-lactoferrin (Apo-LF) and assessing these effects on satiety through monitoring glucagon-like peptide-1 (GLP-1) regulation in a human colon (NCI-H716) cell line. Apo-LF-EGCG conjugates were synthesized and characterized in terms of structural and functional properties. The effect on GLP-1 regulation was assessed by real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) to monitor gene and protein expressions, respectively. The results revealed that the protein–polyphenol interaction occurs through the complex formation of hydrogen bonds at the O-H and carbonyl groups of EGCG. The conjugates also showed a significant up-regulation of gene and protein expression levels of GLP-1 while also preventing EGCG from degradation, thereby preserving its antioxidant properties. The Apo-LF-EGCG conjugates increase satiety via increasing GLP-1 secretion in human colon cells while simultaneously retaining the antioxidant properties of EGCG. Therefore, these conjugates show potential for use as dietary supplements to enhance satiety. Full article

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. Full article

In dead biological tissues such as human hair, the ability of antioxidants to minimise autoxidation is determined by their chemical reactions with reactive oxygen species. In order to improve our understanding of factors determining such antioxidant properties, the mechanistic chemistry of four phenolic antioxidants found in tea and rosemary extracts (epicatechin, epigallocatechin gallate, rosmarinic and carnosic acids) has been investigated. The degradation of N-acetyl alanine by photochemically generated hydroxyl radicals was used as a model system. A relatively high concentration of the antioxidants (0.1 equivalent with respect to the substrate) tested the ability of the antioxidants to intercept both initiating hydroxyl radicals (preventive action) and propagating peroxyl radicals (chain-breaking action). LC-MS data showed the formation of hydroxylated derivatives, quinones and hydroperoxides of the antioxidants. The structure of the assignment was aided by deuterium exchange experiments. Tea polyphenolics (epicatechin and epigallocatechin gallate) outperformed the rosemary compounds in preventing substrate degradation and were particularly effective in capturing the initiating radicals. Carnosic acid was suggested to act mostly as a chain-breaking antioxidant. All of the antioxidants except for rosmarinic acid generated hydroperoxides which was tentatively ascribed to the insufficient lability of the benzylic C-H bond of rosmarinic acid. Full article

Microcin E492 (MccE492) is an antimicrobial peptide and proposed virulence factor produced by some Klebsiella pneumoniae strains, which, under certain conditions, form amyloid fibers, leading to the loss of its antibacterial activity. Although this protein has been characterized as a model functional amyloid, the secondary structure transitions behind its formation, and the possible effect of molecules that inhibit this process, have not been investigated. In this study, we examined the ability of the green tea flavonoid epigallocatechin gallate (EGCG) to interfere with MccE492 amyloid formation. Aggregation kinetics followed by thioflavin T binding were used to monitor amyloid formation in the presence or absence of EGCG. Additionally, synchrotron radiation circular dichroism (SRCD) and transmission electron microscopy (TEM) were used to study the secondary structure, thermal stability, and morphology of microcin E492 fibers. Our results showed that EGCG significantly inhibited the formation of the MccE492 amyloid, resulting in mainly amorphous aggregates and small oligomers. However, these aggregates retained part of the β-sheet SRCD signal and a high resistance to heat denaturation, suggesting that the aggregation process is sequestered or deviated at some stage but not completely prevented. Thus, EGCG is an interesting inhibitor of the amyloid formation of MccE492 and other bacterial amyloids. Full article

Tea plants are highly susceptible to the adverse effects of a high-temperature climate, which can cause reduced yield and quality and even lead to plant death in severe cases. Therefore, reducing the damage caused by high-temperature stress and maintaining the photosynthetic capacity of tea plants is a critical technical challenge. In this study, we investigated the impact of small oligopeptides (small peptides) and surfactants on the high-temperature-stress tolerance of tea plants. Our findings demonstrated that the use of small peptides and surfactants enhances the antioxidant capacity of tea plants and protects their photosynthetic system. They also induce an increase in gibberellin (GA) content and a decrease in jasmonic acid (JA), strigolactone (SL), auxin (IAA), and cytokinin (CTK) content. At the same time, small peptides regulate the metabolic pathways of diterpenoid biosynthesis. Additionally, small peptides and surfactants induce an increase in L-Carnosine and N-Glycyl-L-Leucine content and a decrease in (5-L-Glutamyl)-L-Amino Acid content, and they also regulate the metabolic pathways of Beta-Alanine metabolism, Thiamine metabolism, and Glutathione metabolism. In summary, small peptides and surfactants enhance the ability of tea plants to resist high-temperature stress. Full article

A variety of phytocompounds contained in medical plants have been used as medication, including Kampo (traditional Japanese) medicine. Phytochemicals are one category of the chemical compounds mainly known as antioxidants, and recently, their anti-inflammatory effects in preventing chronic inflammation have received much attention. Here, we present a narrative review of the health-promotion and disease-prevention effects of phytochemicals, including polyphenols, the latter of which are abundant in onions, oranges, tea, soybeans, turmeric, cacao, and grapes, along with the synergetic effects of vitamin D. A phenomenon currently gaining popularity in Japan is finding non-disease conditions, so-called ME-BYO (mibyou) and treating them before they develop into illnesses. In addition to lifestyle-related diseases such as metabolic syndrome and obesity, dementia and frailty, commonly found in the elderly, are included as underlying conditions. These conditions are typically induced by chronic inflammation and might result in multiple organ failure or cancer if left untreated. Maintaining gut microbiota is important for suppressing (recently increasing) intestinal disorders and for upregulating immunity. During the COVID-19 pandemic, the interest in phytochemicals and vitamin D for disease prevention increased, as viral and bacterial infection to the lung causes fatal inflammation, and chronic inflammation induces pulmonary fibrosis. Furthermore, sepsis is a disorder inducing severe organ failure by the infection of microbes, with a high mortality ratio in non-coronary ICUs. However, antimicrobial peptides (AMPs) working using natural immunity suppress sepsis at the early stage. The intake of phytochemicals and vitamin D enhances anti-inflammatory effects, upregulates immunity, and reduces the risk of chronic disorders by means of keeping healthy gut microbiota. Evidence acquired during the COVID-19 pandemic revealed that daily improvement and prevention of underlying conditions, in terms of lifestyle-related diseases, is very important because they increase the risk of infectious diseases. This narrative review discusses the importance of the intake of phytochemicals and vitamin D for a healthy lifestyle and the prevention of ME-BYO, non-disease conditions. Full article