Efficient Preparation of Black Tea Extract (BTE) with the High Content of Theaflavin Mono- and Digallates and the Protective Effects of BTE on CCl₄-Induced Rat Liver and Renal Injury

Abstract

Theaflavins (TFs), formed by the dimerization of green tea catechins during “fermentation” to prepare black tea, possess antioxidant and anti-inflammatory effects. Reported efficacious effects of black tea (∼2% of TFs) or related products come from catechins unless TFs are assayed. The present study aimed to target the preparation of black tea extract (BTE) enriched with theaflavin mono- and digallates majorly from dry tea leaves in aqueous media versus traditional fermentation of fresh leaves. We further investigated the protective function of the produced BTE on rat liver and kidney injury induced by CCl4 and its underlying molecular mechanisms. The results showed that BTE suppressed the activation level of hepatic stellate cells (HSCs), and the secretion of collagen was induced by CCl4. The relative expression levels of TGF-β, p-ERK1/ERK1, p-ERK2/ERK2, p-Smad1/Smad1, and p-Smad2/Smad2 were reduced to 56, 68, 56, 44, and 32%, respectively, compared with those of CCl4-treated rats. Therefore, BTE enriched with TFs prevented rat hepatic fibrosis through the TGF-β/Smad/ERK signaling pathway and kidney injury by inhibiting the expression of TGF-β and proinflammatory cytokines in rats. We predict the broad application of TFs and related products because of their strong antioxidant and inhibitory effects on chronic inflammation.

Vine Tea (Ampelopsis grossedentata) Extract Attenuates CCl4‐Induced Liver Injury by Restoring Gut Microbiota Dysbiosis in Mice

“…[ 33 ] Studies show that the regular intake of flavonoid‐rich tea can prevent the development of liver diseases, indicating their outstanding potential in liver disease treatment. [ 14,34 ]…”

“…[33] Studies show that the regular intake of flavonoid-rich tea can prevent the development of liver diseases, indicating their outstanding potential in liver disease treatment. [14,34] In the present study, we extracted VTE from dried Vine tea leaves and identified the major components of VTE by HPLC-MS/MS analysis (Figure 1). Among these components, dihydromyricetin of Ampelopsis grossedentata was found to prevent nonalcoholic fatty liver disease by improving mitochondrial respiratory capacity and redox homeostasis.…”

Red-fleshed apple flavonoid extract alleviates CCl4-induced liver injury in mice

“…Ma et al found that silymarin intervention improved liver steatosis and hepatic lobular inflammation ( 46 ). Another study found that black tea extract prevents liver fibrosis in rats by regulating the TGF-β/Smad/ERK signaling pathway ( 47 ). Thus, flavonoids have high medicinal value.…”

Cyanidin Alleviated CCl4-Induced Acute Liver Injury by Regulating the Nrf2 and NF-κB Signaling Pathways

“…Numerous studies have indicated that oxidative stress and inflammatory responses are the main pathogenic factors in CCl 4 -induced liver injury [ 21 , 22 ]. In brief, when CCl 4 enters hepatocytes, it is metabolized by the cytochrome 450 enzyme family (CYP family), leading to the generation of the trichloromethyl radical (CCl 3 • ) and the trichloromethyl peroxide radical (Cl 3 COO • ).…”