Green extraction, chemical composition, and in vitro antioxidant activity of theabrownins from Kangzhuan dark tea

Liu, Yi; Liu, Hongyan; Xiao, Yang; Zhu, Fan; Wu, Ding‐Tao; Li, Hua-Bin; Gan, Ren‐You

doi:10.1016/j.crfs.2022.10.019

Cited by 12 publications

(4 citation statements)

References 37 publications

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“…The possible reason for this may be the high content of L-serine and TBs, etc., which were significantly elevated during long-term storage. Previous studies have indicated the antioxidant potential of TBs [ 50 ]. In summary, the antioxidative activity of organic green tea is closely related to the changes in the content of phenolic compounds, such as tea polyphenols, luteoloside, carotenoids, chlorophyll-b, anthocyanin, and TBs, etc.…”

Section: Resultsmentioning

confidence: 99%

The Flavor Characteristics, Antioxidant Capability, and Storage Year Discrimination Based on Backpropagation Neural Network of Organic Green Tea (Camellia sinensis) during Long-Term Storage

Wen,

Han,

Wang

et al. 2024

Foods

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The storage period of tea is a major factor affecting tea quality. However, the effect of storage years on the non-volatile major functional components and quality of green tea remains largely unknown. In this study, a comparative analysis of organic green teas with varying storage years (1–16 years) was conducted by quantifying 47 functional components, using electronic tongue and chromatic aberration technology, alongside an evaluation of antioxidative capacity. The results indicated a significant negative correlation between the storage years and levels of tea polyphenols, total amino acids, soluble sugars, two phenolic acids, four flavonols, three tea pigments, umami amino acids, and sweet amino acids. The multivariate statistical analysis revealed that 10 functional components were identified as effective in distinguishing organic green teas with different storage years. Electronic tongue technology categorized organic green teas with different storage years into three classes. The backpropagation neural network (BPNN) analysis demonstrated that the classification predictive ability of the model based on the electronic tongue was superior to the one based on color difference values and 10 functional components. The combined analysis of antioxidative activity and functional components suggested that organic green teas with shorter storage periods exhibited stronger abilities to suppress superoxide anion radicals and hydroxyl radicals and reduce iron ions due to the higher content of eight components. Long-term-stored organic green teas, with a higher content of substances like L-serine and theabrownins, demonstrated stronger antioxidative capabilities in clearing both lipid-soluble and water-soluble free radicals. Therefore, this study provided a theoretical basis for the quality assessment of green tea and prediction of green tea storage periods.

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Section: Resultsmentioning

confidence: 99%

The Flavor Characteristics, Antioxidant Capability, and Storage Year Discrimination Based on Backpropagation Neural Network of Organic Green Tea (Camellia sinensis) during Long-Term Storage

Wen,

Han,

Wang

et al. 2024

Foods

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“…It should be noted that the research on TB is still preliminary, and its specific structure has not been clearly defined because of its complex chemical composition. 47 Despite the excellent bioactivities of TB in weight loss and lipid reduction, TB does not exhibit strong antioxidant and anti-inflammatory activities like TPP and TPS, which could be reflected in the lower decrease of ROS level than TPP and TPS and inapparent regulation of Nrf2/ARE and TLR4/NF-κB p65. 48 These differences may lead to the lower activity of TB than TPP and TPS on amelioration of colitis.…”

Section: ■ Discussionmentioning

confidence: 99%

“…Consistently, our finding demonstrated that TPP showed a significantly higher activity of alleviating the apoptosis and mitochondrial damage than TPS and TB by regulating the expression of Bcl-2 and the Cytc/Cleaved-caspase3 signaling pathway. It should be noted that the research on TB is still preliminary, and its specific structure has not been clearly defined because of its complex chemical composition . Despite the excellent bioactivities of TB in weight loss and lipid reduction, TB does not exhibit strong antioxidant and anti-inflammatory activities like TPP and TPS, which could be reflected in the lower decrease of ROS level than TPP and TPS and inapparent regulation of Nrf2/ARE and TLR4/NF-κB p65 .…”

Section: Discussionmentioning

confidence: 99%

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

Wei,

Wang

et al. 2023

J. Agric. Food Chem.

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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.

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“…During the fermentation process of dark tea, theaflavins are oxidized and polymerized to form thearubigins, then further formatted to theabrownin; at this stage, the concentration of theaflavins and thearubigins have decreased whereas the concentration of TB has significantly increased [ 19 ]. Studies have also shown that TB can effectively reduce skeletal muscle insulin resistance, accelerate fatty acid oxidation and mitochondrial biosynthesis, and inhibit the production of advanced glycation end products (AGEs) [ 20 ]. It can also significantly lower fasting blood sugar levels by promoting liver glycogen synthesis [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Theabrownin from Dark Tea Ameliorates Insulin Resistance via Attenuating Oxidative Stress and Modulating IRS-1/PI3K/Akt Pathway in HepG2 Cells

Liu,

Wang,

Zhu

et al. 2023

Nutrients

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Dark tea has great potential in regulating glycolipid metabolism, and theabrownin (TB) is considered to be the characteristic and bioactive constituent of dark tea. This study evaluated the ability of TB1 (fermented for 7 days) and TB2 (fermented for 14 days) isolated from dark tea to reverse insulin resistance (IR) in HepG2 cells. The results indicated that TB significantly ameliorated oxidative stress by improving mitochondrial function. In addition, TB improved glycogen synthesis and glucose consumption, and inhibited gluconeogenesis and fatty acid synthesis, by regulating GSK3β (Glycogen synthase kinase 3β), G6Pase (Glucose-6-phosphatase), GCK (Glucokinase), PEPCK1 (Phosphoenolpyruvate carboxy kinase 1), SREBP-1C (sterol regulatory element-binding protein 1C), FASN (fatty acid synthase), and ACC (Acetyl-CoA carboxylase). Additionally, the results of Western blot and real-time PCR experiments demonstrated that TB modulated glucolipid metabolism through the IRS-1 (Insulin receptor substrate 1)/PI3K (phosphatidylinositol-3 kinase)/Akt (protein kinase B) signaling pathway. Treatment with the PI3K inhibitor demonstrated a favorable correlation between PI3K activation and TB action on glycolipid metabolism. Notably, we observed that TB2 had a greater effect on improving insulin resistance compared with TB1, which, due to its prolonged fermentation time, increased the degree of oxidative polymerization of TB.

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Green extraction, chemical composition, and in vitro antioxidant activity of theabrownins from Kangzhuan dark tea

Cited by 12 publications

References 37 publications

The Flavor Characteristics, Antioxidant Capability, and Storage Year Discrimination Based on Backpropagation Neural Network of Organic Green Tea (Camellia sinensis) during Long-Term Storage

The Flavor Characteristics, Antioxidant Capability, and Storage Year Discrimination Based on Backpropagation Neural Network of Organic Green Tea (Camellia sinensis) during Long-Term Storage

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

Theabrownin from Dark Tea Ameliorates Insulin Resistance via Attenuating Oxidative Stress and Modulating IRS-1/PI3K/Akt Pathway in HepG2 Cells

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