Comparison of the main compounds in Fuding white tea infusions from various tea types

Tea Administration Facilitates Immune Homeostasis by Modulating Host Microbiota

Tea, derived from the young leaves and buds of the Camellia sinensis plant, is a popular beverage that may influence the host microbiota. Its consumption has been shown to promote the growth of beneficial bacterial species while suppressing harmful ones. Simultaneously, host bacteria metabolize tea compounds, resulting in the production of bioactive molecules. Consequently, the health benefits associated with tea may stem from both the favorable bacteria it nurtures and the metabolites produced by these microbes. The gut microbiota plays a vital role in mediating the systemic immune homeostasis linked to tea consumption, functioning through complex pathways that involve the gut-lung, gut-brain, and gut-liver axes. Recent studies have sought to establish connections between tea, its bioactive compounds, and immune regulation via the gut microbiota. In this paper, we aim to summarize the latest research findings in this field.

Exogenous tannic acid relieves imidacloprid-induced oxidative stress in tea tree by activating antioxidant responses and the flavonoid biosynthetic pathway

Pesticide stress on plants is receiving increased scrutiny due to its effect on plant secondary metabolism and nutritional quality. Tannic acid (TA) is a natural polyphenolic compound showing excellent antioxidant properties and is involved in alleviating stress. The present study thoroughly investigated the effects and mechanism of exogenous TA on relieving imidacloprid (IMI) stress in tea plants. Our research found that TA(10 mg/L) activated the antioxidant defense system, enhanced the antioxidant ability, reduced the accumulation of ROS and membrane peroxidation, and notably promoted tea plant tolerance to imidacloprid stress. Additionally, TA boosted photosynthetic capacity, strengthened the accumulation of nutrients. regulated detoxification metabolism, and accelerated the digestion and metabolism of imidacloprid in tea plants. Furthermore, TA induced significant changes in 90 important metabolites in tea, targeting 17 metabolic pathways through extensively targeted metabolomics. Specifically, TA activated the flavonoid biosynthetic pathway, resulting in a 1.3- to 3.1-fold increase in the levels of 17 compounds and a 1.5- to 63.8-fold increase in the transcript level of related genes, such as ANR, LAR and CHS in this pathway. As a potential tea health activator, TA alleviates the oxidative damage caused by imidacloprid and improves the yield and quality of tea under pesticide stress.

Metabolomic and transcriptomic analyses reveal comparisons against liquid-state fermentation of primary dark tea, green tea and white tea by Aspergillus cristatus

Liquid-state fermentation (LSF) of tea leaves is a promising way to obtain tea-based nutraceutical products rich in various bioactive compounds. In the study, the changes of bioactive compounds, tea pigments and complex metabolites from LSF of primary dark tea, green tea and white tea infusions with Aspergillus cristatus were determined. Chemical analyses revealed that soluble sugars, monosaccharide composition, total polyphenols, total flavonoids, free amino acids, soluble proteins and tea pigments were changed in different ways. An untargeted metabolomic analysis and ribonucleic acid sequencing (RNA-seq) based transcriptomic analysis were performed to investigate the metabolic differentiation and clarify the key differentially expressed genes (DEGs, fold change >2 and p < 0.05), showing that amino acid metabolism, carbohydrate metabolism and lipid metabolism were the most enriched pathways during A. cristatus fermentation of primary dark tea, green tea and white tea infusions. In addition, glycerophospholipid metabolism, linoleic acid metabolism and phenylalanine metabolism were greatly accumulated in the fermentation of primary dark tea and white tea infusions; Pyruvate metabolism, glycolysis/gluconeogenesis, fatty acid degradation, tyrosine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis and valine and leucine, isoleucine degradation were greatly accumulated in the fermentation of primary dark tea and green tea infusions; Starch and sucrose metabolism was greatly accumulated in the fermentation of green tea and white tea infusions; Galactose metabolism was significantly enhanced in the fermentation of primary dark tea infusion; Amino sugar and nucleotide sugar metabolism, sphingolipid metabolism and alanine, aspartate and glutamate metabolism were significantly enhanced in the fermentation of green tea infusion. Besides, some other pathways involving aminobenzoate degradation, biosynthesis of cofactors, pyrimidine metabolism, benzoxazinoid biosynthesis and phenazine biosynthesis, tropane, piperidine and pyridine alkaloid biosynthesis and flavone and flavonol biosynthesis also differed from each other. These findings support that A. cristatus plays a vital role in the biochemical and genetic regulation of metabolite profile, and could be considered a potential prospect for better use of A. cristatus on different kinds of tea materials.

Biological Activities and Polyphenol Content of Qi Cha Tea®, a Functional Beverage of White Tea Containing Botanicals and Dry Botanical Extracts with European Health Claims

Infusions of Camellia sinensis leaves have been known for their health benefits. The Bio Concentrate Assets® (ABC) method is a method of enriching organic infusion leaves (from Camellia sinensis) with organic dry and concentrated extracts using organic acacia gum, and its application to white tea has provided Qi cha tea®. In the present study, the content of tea polyphenols and caffeine, and the biochemical properties of Qi cha tea® and its botanical constituents (elderberry, tulsi, Echinacea purpurea, orange peel, lemongrass, and acacia gum) were assessed. Antioxidant and cell viability activities were determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and MTT (3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay in human Caco-2 and HCT-116 cell lines, and ascorbic acid and tamoxifen, respectively. The caffeine and polyphenol composition of Qi cha tea® was modified with less caffeine and gallic acid and more epigallocatechin gallate (EGCG) than the original white tea. The majority of the tested botanical samples including Qi cha tea® at 50 µg/mL show similar antioxidant activities, with the exception of Echinacea purpurea. The greatest effect was found for white tea. The antioxidant power of the Qi cha tea® (90% at 50 µg/mL for pressurized liquid extraction (PLE) was divided by approximately a factor of two (61% at 50 µg/mL for pressurized liquid extraction products (PLEP)), which corresponds to the 48.3% (mass/mass) white tea original content in the Qi cha tea®. Qi cha tea® shows the lowest cytotoxic activity in the viability of the two cell lines when compared to white tea. The application of the ABC method to Qi cha tea® using various botanicals and dry extract with acacia gum as blinder has allowed the development of a new innovative functional health beverage that complies with European health claims.

Variations of main quality components of matcha from different regions in the Chinese market

Matcha has a unique aroma of seaweed-like, which is popular with Chinese consumers. In order to effectively understand and use matcha for drinks and tea products, we roundly analyzed the variation of main quality components of 11 matcha samples from different regions in the Chinese market. Most of matcha samples had lower ratio of tea polyphenols to amino acids (RTA), and the RTA of 9 samples of matcha was less than 10, which is beneficial to the formation of fresh and mellow taste of matcha. The total volatile compounds concentrations by HS-SPME were 1563.59 ~ 2754.09 mg/L, among which terpenoids, esters and alcohols were the top three volatile components. The total volatile compounds concentrations by SAFE was 1009.21 ~ 1661.98 mg/L, among which terpenoids, heterocyclic compounds and esters ranked the top three. The 147 volatile components with high concentration (&gt;1 mg/L) and no difference between samples are the common odorants to the 11 samples of matcha. The 108 distinct odorants had differences among the matcha samples, which were important substances leading to the different aroma characteristics. Hierarchical cluster analysis (HCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) showed that 11 samples of matcha were well clustered according to different components. Japanese matcha (MT, MY, ML, MR, MJ) could be clustered into two categories. The aroma composition of Guizhou matcha (GM1, GM2) was similar to that of Japanese matcha, 45 volatile components (decanal, pyrazine, 3,5-diethyl-2-methyl-, 1-hexadecanol, etc. were its characteristic aroma components. The aroma characteristics of Shandong matcha and Japanese matcha (ML, MR, MJ) were similar, 15 volatile components (γ-terpinene, myrtenol, cis-3-hexenyl valerate, etc.) were its characteristic aroma components. While Jiangsu matcha and Zhejiang matcha have similar aroma characteristics due to 225 characteristic aroma components (coumarin, furan, 2-pentyl-, etc). In short, the difference of volatile components formed the regional flavor characteristics of matcha. This study clarified the compound basis of the flavor difference of matcha from different regions in the Chinese market, and provided a theoretical basis for the selection and application of matcha in drinks and tea products.

Green and white teas as health-promoting foods

Tea is one of the most consumed beverages around the world and as such, it is constantly the object of novel research. This review focuses on the research performed during the last five years to provide an updated view of the current position of tea regarding human health. According to most authors, tea health benefits can be traced back to its bioactive components, mostly phenolic compounds. Among them, catechins are the most abundant. Tea has an important antioxidant capacity and anti-inflammatory properties, which make this beverage (or its extracts) a potential aid in the fight against several chronic diseases. On the other hand, some studies report the possibility of toxic effects and it is advisable to reduce tea consumption, such as in the last trimester of pregnancy. Additionally, new technologies are increasing researchers' possibilities to study the effect of tea on human gut microbiota and even against SARS CoV-2. This beverage favours some beneficial gut microbes, which could have important repercussions due to the influence of gut microbiota on human health.

The anti-obesity and health-promoting effects of tea and coffee

This paper reviews provenance, chemical composition and properties of tea (Camelia sinensis L.) and coffee (Coffee arabica, L. and Coffeacaniphora, L.), their general health effects, as well as the currently available knowledge concerning their action on fat storage, physiological mechanisms of their effects, as well as their safety and recommended dosage for treatment of obesity. Both tea and coffee possess the ability to promote health and to prevent, to mitigate and to treat numerous disorders. This ability can be partially due to presence of caffeine in both plants. Further physiological and medicinal effects could be explained by other molecules (theaflavins, catechins, their metabolites and polyphenols in tea and polyphenol chlorogenic acid in coffee). These plants and plant molecules can be efficient for prevention and treatment of numerous metabolic disorders including metabolic syndrome, cardiovascular diseases, type 2 diabetes and obesity. Both plants and their constituents can reduce fat storage through suppression of adipocyte functions, and support of gut microbiota. In addition, tea can prevent obesity via reduction of appetite, food consumption and food absorption in gastrointestinal system and through the changes in fat metabolism.

The contribution ratio of various characteristic tea compounds in antioxidant capacity by DPPH assay

Tea is a worldwide health beneficial beverage for its antioxidant ability. 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay is a common method to measure the antioxidant capacity of tea compounds, yet the contribution ratio of various characteristic tea compounds is still unclear. high-performance liquid chromatography (HPLC) was used to examine the content of polyphenol compounds in 24 tea samples from four tea categories (green tea, white tea, oolong tea, and black tea). Based on the results of DPPH and HPLC, contribution ratio of each tea compound was analyzed by the Pearson correlation analysis and the partial least squares regression (PLSR). The Pearson correlation analysis showed that the order of correlation between the area of 13 peaks and the antioxidant ability of tea samples was x8 > x6 > x3 > x13 > x10 > x7 > x2 > x5 > x11 > x9 > x4 > x12 > x1; the regression equation fit by PLSR was Y = 47.258 - 0.760x1 + 0.287x2 - 1.484x3 - 0.569x4 + 0.674x5 + 2.257x6 + 1.698x7 + 1.389x8 - 0.188x9 + 0.467x10 + 0.297x11 + 1.314x12 + 0.963x13. We identified nine common peaks by reference standard substances: the x3 was gallic acid (GA), x4 was theobromine, x5 was catechuic acid (CA), x6 was epigallocatechin (EGC), x8 was epigallocatechin gallate (EGCG), x9 was caffeine, x10 was epicatechin (EC), x12 was epicatechin gallate (ECG), and x13 was gallocatechin gallate (GCG). Based on the study of spectrum-effect correlation, we obtain a better understanding of the antioxidant activity of complex tea polyphenols component. PRACTICAL APPLICATIONS: Identify the contribution of specific chemical compound to antioxidant activity by the coefficients in PLSR equation and provide a deeper insight into the joint effect of multiple ingredients of tea. Further, we can infer the DPPH free radical scavenging ability of a new kind of tea by the PLSR equation without chemical detection.