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The tea plant accumulates elevated levels of fluoride (F) from environmental sources. Drinking tea containing high F levels poses a potential threat to human health. Selenium (Se) was applied by foliar spray to investigate its effects on F accumulation and physiology in tea plant. Foliar application of different forms of Se, i.e., Na 2 SeO 3 , Kappa-selenocarrageenan, Selenomethionine and Nanoselenium, reduced F content in tea leaves by 10.17 %-44.28 %, 16.12 %-35.41 %, 22.19 %-45.99 % and 22.24 %-43.82 %, respectively. Foliar spraying Se could increase F accumulation in pectin through increasing pectin content and pectin demethylesterification to bind more F in the cell wall, which decreased the proportion of water-soluble fluoride in tea leaves. Application of Se significantly decreased the contents of chromium (39.6 %-72.0 %), cadmium (48.3 %-84.4 %), lead (2.2 %-44.4 %) and copper (14.1 %-44.6 %) in tea leaves. Foliar spraying various forms of Se dramatically increased the Se content and was efficiently transformed into organic Se accounting for more than 80 % in tea leaves. All Se compounds increased peroxidase activity by 3.3 %-35.5 % and catalase activity by 2.6 %-99.4 %, reduced malondialdehyde content by 5.6 %-37.1 %, and increased the contents of chlorophyll by 0.65 %-31.8 %, carotenoids by 0.24 %-27.1 %, total catechins by 1.6 %-21.0 %, EGCG by 4.4 %-17.6 % and caffeine by 9.1 %-28.6 %. These results indicated that Se application could be served as a potential efficient and safe strategy diminishing the concentration of F in tea leaves., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Fuzhuan brick tea (FBT) is a traditional popular beverage in the border regions of China. Nowadays, FBT has been attracted great attention due to its uniquely flavor and various health-promoting functions. An increasing number of efforts have been devoted to the studies on health benefits and chemistry of FBT over the last decades. However, FBT was still received much less attention than green tea, oolong tea and black tea. Therefore, it is necessary to review the current encouraging findings about processing, microorganisms, chemical constituents, health benefits and potential risk of FBT. The fungus fermentation is the key stage for processing of FBT, which is involved in a complex and unique microbial fermentation process. The fungal community in FBT is mainly dominated by "golden flower" fungi, which is identified as Aspergillus cristatus . A great diversity of novel compounds is formed and identified after a series of biochemical reactions during the fermentation process of FBT. FBT shows various biological activities, such as antioxidant, anti-inflammatory, anti-obesity, anti-bacterial, and anti-tumor activities. Furthermore, the potential risk of FBT was also discussed. It is expected that this review could be useful for stimulating further research of FBT.

Fuzhuan brick tea (FBT), one of the unique dark teas, has various health-promoting functions. In the present study, one polysaccharide fraction, namely FBTPS-2-1, was extracted and purified from FBT, and its structure and potential immunostimulatory activity were investigated. The results showed that FBTPS-2-1,one of typical heteropolysaccharides, was mainly composed of Gal, Ara, and Glc with little molar content of Man, Rha, GalA, and GlcA in molar ratio of 46.59:22.13:13.57:8.20:6.02:2.12:1.38 and molecular weight of 748 kDa. The backbone of FBTPS-2-1 contained →4)-β-d-Gal p -(1→4)-β-d-Gal p -(1→, →4)-β-d-Gal p -(1→4)-α-d-Glc p -(1→, →4)-α-d-Glc p -(1→4)-α-d-Glc p -(1→, →4)-α-d-Glc p -(1→4)-β-d-Gal p -(1→, →3)-β-d-Gal p -(1→4)-β-d-Gal p -(1→, →3,6)-β-d-Gal p -(1→3)-β-d-Gal p -(1→ and →3,6)-β-d-Gal p -(1→3,6)-β-d-Gal p -(1→. The linkages of branches in FBTPS-2-1 were mainly composed of α-l-Ara f -(1→3,6)-β-d-Gal p -(1→, →5)-α-l-Ara f -(1→3,6)-β-d-Gal p -(1→, →6)-β-d-Gal p -(1→3,6)-β-d-Gal p -(1→, α-l-Ara f -(1→3,5)-α-l-Ara f -(1→, →3,5)-α-l-Ara f -(1→5)-α-l-Ara f -(1→, α-d-Gal p -(1→3,5)-α-l-Ara f -(1→ and →5)-α-l-Ara f -(1→6)-β-d-Gal p -(1→. Furthermore, FBTPS-2-1 could increase the phagocytosis of macrophages and promote the secretion of NO and a variety of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, indicating noticeable immune enhancement activity. Thus, FBTPS-2-1 could serve as a potentially functional food to improve human health by modulating the host immunoreaction.

The flower of tea (Camellia sinensis L.) plant has been paid an increasing attention in the last twenty years, since it was found that tea flowers contained representative constituents similar to those of tea leaves, such as catechins, caffeine and amino acids. Tea flower is theoretically valuable although it has been considered as an industrial waste over a long period of time. This review summarizes the research findings conducted until now on physiological genetics, chemical composition, health benefits and toxicology of tea flowers, aiming to foresee their future applications. A lot of genes are involved in flower development and the synthesis and transmission of various chemicals in tea flowers. The chemical composition of tea flower consists mainly of catechins, polysaccharides, proteins, amino acids and saponins and thus tea flower possesses various health benefits such as antioxidant, anti-inflammatory, immunostimulating, antitumor, hypoglycemic, anti-obesity and anti-allergic activities. Moreover, tea flower contains a protease that can elevate the free amino acids content in the tea infusion by almost two folds. More importantly, the enzymatic activity of the protease is much higher than that of the commercially available proteases. Additionally, aqueous extracts of tea flower are demonstrated to safe to animals. Thus, the potential uses of tea flowers in food and medical fields are warranted., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

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.

An increasing amount of evidence suggests that the gut microbiota composition and structure contribute to the pathophysiology of metabolic syndrome (MS), which has been put forward as a new target in the treatment of diet-induced MS. In this work, we aimed to investigate effects of Fuzhuan brick tea polysaccharides (FBTPS) on MS and gut microbiota dysbiosis in high-fat diet (HFD) fed mice and to further investigate whether its attenuation of MS is related to the modulation of gut microbiota. The results showed that FBTPS intervention could significantly attenuate metabolic syndrome in HFD-induced mice. Based on results of sequencing, FBTPS treatment could increase the phylogenetic diversity of HFD-induced microbiota. FBTPS intervention could significantly restore the HFD-induced increases in relative abundances of Erysipelotrichaceae, Coriobacteriaceae, and Streptococcaceae. Spearman's correlation analysis showed that 44 key OTUs were negatively or positively associated with MS. Our results suggested that FBTPS could serve as a novel candidate for prevention of MS in association with the modulation of gut microbiota.

In the present study, digestion under saliva, simulated gastric and small intestinal conditions and fermentation in vitro of polysaccharides from the flowers of Camellia sinensis (TFPS) by human gut microbiota were investigated. The results indicated that human saliva and simulated gastric and intestinal juices had no effect on TFPS, while TFPS could be utilized by human fecal microbiota, which was proved from the decreased molecular weight and lower content of total or reducing sugars after fermentation under anaerobic conditions. It was found that pH in the fermentation system decreased, and the production of short-chain fatty acids was significantly enhanced. Furthermore, in vitro fermentation of TFPS altered the composition of gut microbiota, specifically in elevating the ratio of Bacteroidetes to Firmicutes and enriching Prevotella. The present results suggest that TFPS has the potential to be developed as functional foods to modify gut microbiota.

Background: Brick tea usually contains very high fluoride, which may affect human health. Biosorbents have received much attention for selective removal of fluoride because of low cost, environmental friendliness, and relative safeness., Results: In the present study, a highly selective fluoride tea waste based biosorbent, namely, aluminum (Al) oxide decorated tea waste (Tea-Al), was successfully prepared. The Tea-Al biosorbent was characterized by energy-dispersive spectrometry, Fourier transform infrared spectroscopy, powder X-ray diffraction and X-ray photoelectron spectroscopic analysis. The Tea-Al sample exhibited remarkably selective adsorption for fluoride (52.90%), but a weaker adsorption for other major constituents of brick tea infusion, such as catechins, polyphenols and caffeine, under the same conditions. Fluoride adsorption by Tea-Al for different times obeyed the surface reaction and adsorption isotherms fit the Freundlich model. In addition, the fluoride adsorption mechanism appeared to be an ion exchange between hydroxyl and fluoride ions., Conclusion: Results from this study demonstrated that Tea-Al is a promising biosorbent useful for the removal of fluoride in brick tea infusion. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

Tea has a long history of medicinal and dietary use. Tea polysaccharide (TPS) is regarded as one of the main bioactive constituents of tea and is beneficial for health. Over the last decades, considerable efforts have been devoted to the studies on TPS: extraction, structural feature and bioactivity of TPS. However, it has been received much less attention compared with tea polyphenols. In order to provide new insight for further development of TPS in functional foods, in present review we summarize the recent literature, update the information and put forward future perspectives on TPS covering its extraction, purification, quantitative determination techniques as well as physicochemical characterization and bioactivities., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

[Display omitted] • Tea polysaccharide (TPS) is an acid polysaccharide with various structural features. • TPS modulate gut microbiota composition and metabolites as a potential prebiotic. • The health-promoting effects of TPS by targeting gut microbiota are discussed. • Future perspective and challenges of TPS studies were proposed. Tea has been used medicinally and dietarily for thousands of years. Tea polysaccharides (TPS), considered one of the main bioactive components of tea, show diverse health benefits. Yet it has received far less attention than tea polyphenols. During recent decades, considerable researches have been dedicated to TPS, including extraction, structural characteristics, and potential bioactivity. Recent studies suggested that the biological effects of dietary TPS are subjected to gut microbiota (GM) modulation. Thus, this review focuses on recent research advance on the structure characteristics of TPS, TPS degradation in the gut, TPS modulation on the diversity of GM and production of short chain fatty acids (SCFAs), and the health benefits of TPS through targeting GM. Furthermore, some future research directions were also proposed. The purpose of this review is to enhance our understanding the health-promoting properties of TPS and to promote further researches on the TPS. [ABSTRACT FROM AUTHOR]