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

Fu brick tea polysaccharides: A state-of-the-art mini-review on extraction, purification, characteristics, bioactivities and applications

Fu brick tea (FBT), a post-fermented dark tea, is highly esteemed for its abundant nutritional and medicinal values. Fu brick polysaccharides (FBTPs) are acidic heteropolysaccharides primarily composed of galactose and galacturonic acid, which are crucial components of FBT. FBTPs exhibit multiple bioactivities, including immunomodulatory, antioxidant, anti-inflammatory, regulatory effects on intestinal microbiota, anti-obesity, among others. Owing to their significant marketing potential and promising development prospects, FBTPs have attracted considerable attention from researchers worldwide. However, the specific mechanisms and underlying structure-function relationships of FBTPs are not well understood. Consequently, this review aims to provide comprehensive and cutting-edge information on the extraction, purification, structural characteristics, and biological activities of FBTPs, with an emphasis on exploring how their structural characteristics influence biological activities and therapeutic potential. We found that different materials and extraction techniques could result in differences in the structure-activity relationship of FBTPs. Furthermore, monosaccharide composition and molecular weight could also significantly impact the bioactivities of FBTPs, such as lipid-lowering effects and immunomodulatory activity. This review would further facilitate the applications of FBTPs as therapeutic agents and functional foods, thereby laying a solid foundation for their further development and utilization.

Combined Analysis of Grade Differences in Lapsang Souchong Black Tea Using Sensory Evaluation, Electronic Nose, and HS-SPME-GC-MS, Based on Chinese National Standards

Tea standard samples are the benchmark for tea product quality control. Understanding the inherent differences in Chinese national standards for Lapsang Souchong black tea of different grades is crucial for the scientific development of tea standardization work. In this study, Lapsang Souchong black tea of different grades that meet Chinese national standards was selected as the research object. The aroma characteristics were comprehensively analyzed through sensory evaluation, electronic nose, and HS-SPME-GC-MS (headspace solid-phase microextraction gas chromatography-mass spectrometry). The findings indicate that the higher-grade Lapsang Souchong has a higher evaluation score. The results of electronic nose analysis indicate that the volatiles with differences in tea of different grades were mainly terpenoids and nitrogen oxides. The results of HS-SPME-GC-MS analysis show that the odor characteristics of the super-grade samples are mainly floral and fruity, and these substances mainly include D-Limonene, 3,7-dimethyl-1,6-octadien-3-ol and 3-Hydroxymandelic acid, and ethyl ester. The primary aroma characteristics of the first-grade samples are floral, sweet, woody, and green, with key contributing compounds including 2-Furanmethanol, 1-Octen-3-ol, and 5-ethenyltetrahydro-α,α,5-trimethyl-cis-, 4,5-di-epi-aristolochene. The main aroma characteristics of the second-grade samples are green, herbal scent, and fruity, and the main substances include 3,7-dimethyl-1,6-octadien-3-ol, 2,3-dimethylthiophene, Dihydroactinidiolide, and Naphthalene-1-methyl-7-(1-methylethyl)-. It is worth noting that the second-grade samples contain a large amount of phenolic substances, which are related to the smoking process during processing. This study lays a solid foundation for the preparation of tea standard samples and the construction of the tea standard system.

Physical activity combined with tea consumption could further reduce all-cause and cancer-specific mortality

The study aimed to comprehensively assess the separate and combined effects of physical activity (PA) and tea consumption on all-cause mortality and cancer-specific mortality among 21,350 participants from The National Health and Nutrition Examination Survey (NHANES) between 2009 and 2018. PA and tea consumption were evaluated through self-reported questionnaires and dietary recall interviews at baseline, with mortality data from the National Death Index. Cox regression analyses yielded hazard ratios (HR) and 95% confidence intervals (CI). Results indicated that both tea consumption and PA independently reduced all-cause mortality. In the physically active group, tea consumption further decreased mortality risk, while this effect was not significant in the inactive group. Jointly, the highest tea consumers who exercised the most exhibited the lowest mortality risk compared to non-tea drinkers who exercised the least. Tea consumption alone does not significantly impact cancer-specific mortality; it is only in physically active group that tea consumption significantly lowers the risk of cancer-specific mortality. These findings underscore the potential benefits of regular tea consumption and PA in promoting longevity and reducing premature death risks.

Dark Tea Wine Protects Against Metabolic Dysfunction-Associated Steatotic Liver Disease In Vivo Through Activating the Nrf2/HO-1 Antioxidant Signaling Pathway

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a complex and multifactorial disease. Dark tea exhibits great potential for various bioactivities for metabolic health. In this study, we aimed to evaluate therapeutic effects and the underlying mechanisms of dark tea wine (DTW) on MASLD with obesity. A rat model of MASLD was established by high-fat diet and administered with different doses of DTW as an intervention. The biomarkers of lipid metabolism and oxidative stress in rats were tested. The weight of organs and adipose tissues and the expressions of nuclear factor erythroid 2-like 2 (Nrf2) and heme oxygenase-1 (HO-1) were investigated based on the pathology and western blot analysis. We found that DTW enhanced antioxidant capacity via activating the Nrf2/HO-1 signaling pathway, further markedly triggering inhibition of weight gain, reduction of lipid dysfunction, and improvement of pathological characteristics to ameliorate MASLD induced by high-fat diet. These results suggest that DTW is a promising functional supplement for prevention and treatment of MASLD and obesity.

Functional Peptides from Yak Milk Casein: Biological Activities and Structural Characteristics

The average content of casein in yak milk is 40.2 g/L. Casein can be degraded by enzymatic digestion or food processing to produce abundant degradation peptides. International researchers have studied the degradation peptides of yak milk casein by using multiple techniques and methods, such as in vitro activity tests, cellular experiments, proteomics, bioinformatics, etc., and found that the degradation peptides have a wide range of functional activities that are beneficial to the human body, such as angiotensin-converting enzyme (ACE) inhibitory, antioxidant, anti-inflammatory, antidiabetic, antimicrobial, anticancer, and immunomodulatory activities, etc., and it has been proved that the types and strengths of functional activities are closely related to the structural characteristics of the peptides. This paper describes the characteristics of yak milk proteins, the functional activities, and mechanism of action of degraded peptides. Based on the types of functional activities of yak milk casein degradation peptides, we classified and elucidated the effects of structural factors, such as peptide molecular weight, peptide length, amino acid sequence, physicochemical properties, electrical charge, hydrophobicity, spatial conformation, chain length, and the type of enzyme on these activities. It reveals the great potential of yak milk casein degradation peptides as functional active peptide resources and as auxiliary treatments for diseases. It also provides important insights for analyzing yak casein degradation peptide activity and exploring high-value utilization.

Dynamic changes in the non-volatile and flavour compounds in withered tea leaves of three different colour cultivars based on multi-omics

In this study, metabolomics and proteomics were performed to investigate the fluctuations of non-volatile compounds and proteins in tea leaves from three tea cultivars with varying colours during withering. A total of 2798 compounds were detected, exhibiting considerable variations in amino acids, phenylpropanoids, and flavonoids. The ZH1 cultivar displayed increased levels of amino acids but decreased levels of polyphenols, which might be associated with the up-regulation of enzymes responsible for protein degradation and subsequent amino acid production, as well as the down-regulation of enzymes involved in phenylpropanoid and flavonoid biosynthesis. The FUD and ZH1 cultivars had elevated levels of flavanols and flavanol-O-glycosides, which were regulated by the upregulation of FLS. The ZJ and ZH1 cultivars displayed elevated levels of theaflavin and peroxidase. This work presents a novel investigation into the alterations of metabolites and proteins between tea cultivars during withering, and helps with the tea cultivar selection and manufacturing development.

Plant growth-promoting rhizobacteria (PGPR) improve the growth and quality of several crops

Plant growth-promoting rhizobacteria (PGPR) are known to have the effect of promoting plant growth. In this paper, three PGPR strains were selected from the previous work, which had plant growth-promoting activities such as phosphate solubilization, nitrogen fixation, phosphorus mobilization, etc. These strains named FJS-3(Burkholderia pyromania), FJS-7(Pseudomonas rhodesiae), and FJS-16(Pseudomonas baetica), respectively, were prepared into solid biological agents. Three widely planted commercial crops (tea plant, tobacco, and chili pepper) were selected for PGPR growth promotion verification. The results showed that the new shoots of tea seedlings under PGPR treatment were much more than the control. We also used tobacco, another important crop in Guizhou, to test the growth-promoting effect of individual bacteria, and the results showed that each of them could promote the growth of tobacco plants, and FJS-3(Burkholderia pyrrocinia) had the best effect. In addition, we carried out experiments on tobacco and pepper using multi-strain PGPR, the tobacco plants' height, fresh, and root weight increased by 30.15 %, 37.36 %, and 54.5 %, respectively, and the pepper plants' increased by 30.10 %, 56.38 % and 43.18 %, respectively, which both showed significantly better effects than that of a single strain. To further test the field performance, field trials were carried out in a mature Longjing43 tea plantation in Guizhou. There were four treatments: no fertilization (T1), combined application of PGPR biological agent and compound fertilizer (T2), only application of PGPR (T3), and only application of compound fertilizer (T4). In terms of yield, grouped with or without PGPR, there was a 15.38 % (T2:T4) and 92.31 % (T3:T1) increase between them, respectively. The tea's yield and tea flavor substances such as tea polyphenols, caffeine, and theanine were detected, and the T2 showed the most significant positive effect on both sides. Especially, an important indicator of Matcha green tea is the color, chlorophyll content was then tested, and PGPR application increased it and improved the appearance. All these results demonstrated that the PGPR we screened could significantly promote plant growth and quality improvement, and had good application potential in crop planting, which could contribute to environmental protection and economic growth.

Defense against oxidative stress in Caenorhabditis elegans by dark tea

Dark tea, rich in nutricines including tea polyphenols and free amino acids, is a kind of post-fermented tea. The potential application of nutricines against oxidative damage and senescence, which drives animal health maintenance and disease prevention, has attracted considerable interest. In this study, the effect of dark tea and its effects on longevity and defense against oxidative stress was investigated in the Caenorhabditis elegans (C. elegans) model. Under normal conditions, dark tea extended the lifespan without significant impairment of propagation. It also improved the motility, alleviated the fat accumulation and apoptosis. Additionally, orally administered dark tea could significantly decrease the level of reactive oxygen species (ROS) and resulted in a superior lifespan in H2O2-induced oxidative stressed C. elegans. In antioxidant assays in vitro, dark tea was found to be rich in strong hydroxyl, DPPH and ABTS+ free radical scavenging capacity. Interestingly, mRNA sequence analyses further revealed that dark tea may catalyze intracellular relevant oxidative substrates and synthesize antioxidants through synthetic and metabolic pathways. These results suggest that dark tea is worth further exploration as a potential dietary supplement for the maintenance of animal health and the prevention of related diseases.