Tea Drinking Alleviates Diabetic Symptoms via Upregulating Renal Water Reabsorption Proteins and Downregulating Renal Gluconeogenic Enzymes in db/db Mice

Abstract

Scope: Tea, made from the plant Camellia sinensis, is known to have anti‐diabetes effects and different mechanisms of action are proposed. Kidney is a vital organ in managing water reabsorption and glucose metabolism, and is greatly influenced by diabetes. The present study investigates the effects of tea administration on water reabsorption and gluconeogenesis in the kidney of diabetic mice. Methods and results: Db/db mice are given tea infusion as drinking fluid when they begin to exhibit hyperglycemia. It is found that green tea or black tea infusion potently elevates renal proteins vital for water reabsorption, including protein kinase C‐α, aquaporin 2, and urea transporter‐A1, as well as increases trafficking of these proteins to apical plasma membrane where they exert water reabsorption function. The treatment also downregulates renal gluconeogenic enzymes, including glucose‐6‐phosphatase‐α and phosphoenolpyruvate carboxykinase. Associated with these biochemical changes are the rectified polyuria, polydipsia, polyphagia, and hyperglycemia, all symptoms of diabetes. Conclusions: For the first time, the present study demonstrates that tea has robust effects in enhancing kidney water reabsorption proteins and downregulating gluconeogenic enzymes in db/db mice. It remains to be investigated whether such beneficial effects of tea occur in humans.

Potential of green tea EGCG in neutralizing SARS-CoV-2 Omicron variant with greater tropism toward the upper respiratory tract

“…Now it is a popular beverage worldwide, especially in adults starting to focus on health concerns, because it does not have significant caloric content and yet possibly possesses multiple health-promoting effects, such as body weight control, metabolic syndrome alleviation, prevention of cancer, diabetes mellitus, and cardiovascular, neurodegenerative or infective diseases ( Yang et al, 2002 ; Yang et al, 2016 ; Zhang et al, 2019 ; Z. Zhang et al, 2021 , Zhang et al, 2021 ; Zhao et al, 2020 ). Some green teas contain unusually high quantities of catechins (up to 35% of dry weight pending on the cultivar) including epicatechin, epicatechin gallate, epigallocatechin, and EGCG ( Datta et al, 2022 ; Yang et al, 2002 ).…”

“…Some green teas contain unusually high quantities of catechins (up to 35% of dry weight pending on the cultivar) including epicatechin, epicatechin gallate, epigallocatechin, and EGCG ( Datta et al, 2022 ; Yang et al, 2002 ). Among these, EGCG is the most abundant (over 50% in most cases) ( Yang et al, 2002 ; Zhao et al, 2020 ) and is the best-documented in terms of antioxidant and prooxidant activities as well as its redox-associated biological functions ( Datta et al, 2022 ; Dong et al, 2016 ; Yang & Hong, 2013 ).…”

“…3 ), given its capacity for i) downregulating GRP78 expression, ii) changing GRP78 from the active monomer to inactive dimeric and oligomeric forms (Z. Zhang, Zhang, et al, 2021 ), and iii) promoting remission of diabetes and hyperinsulinemia ( Bose et al, 2008 ; Yang et al, 2016 ; Zhao et al, 2020 ).

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Potential protective mechanisms of green tea polyphenol EGCG against COVID-19

“…Mounting evidence demonstrates that EGCG is helpful in controlling blood glucose in diabetic subjects ( Chen et al, 2009 ; Kao, Chang, Lee, & Chen, 2006 ; Sae-tan, Grove, & Lambert, 2011 ; Wolfram et al, 2006 ; Yang, Zhang, Zhang, Huang, & Wang, 2016 ; Zhao, Wu, Wang, Yang, & Zhang, 2020 ). Moreover, several studies in animal models and humans have shown that EGCG suppresses RAGE signaling pathway; specifically, 1) treatment with EGCG (10 mg/kg and 50 mg/kg, i.p.)…”

The Effects of Green Tea on Diabetes and Gut Microbiome in db/db Mice: Studies with Tea Extracts vs. Tea Powder

“…The possible mechanisms of actions of tea preparations in mitigating metabolic diseases have been studied extensively. These include a decrease in micronutrient absorption, promotion of catabolism by EGCG through metabolic regulators such as AMP-activated protein kinase (AMPK), enhancement of thermogenesis and increase in renal water reabsorption [ 8 , 11 , 12 , 13 , 14 ]. The beneficial health effects of green tea polyphenols and EGCG have also been suggested to be mediated through their modulation of gut microbiota [ 15 ].…”