Abstract
The present study investigated the preventive effect of polyphenols in Liubao tea (PLT) on carbon tetrachloride (CCl&sub4;)-induced liver injury in mice. The mice were initially treated with PLT, followed by induction of liver injury using 10 mL/kg CCl&sub4;. Then liver and serum indices, as well as the expression levels of related messenger RNAs (mRNAs) and proteins in liver tissues were measured. The results showed that PLT reduces the liver quality and indices of mice with liver injury. PLT also downregulates aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides (TGs), and malondialdehyde (MDA), and upregulates superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the sera of mice with liver injury. PLT also reduces serum levels of interleukin-6 (IL-6), interleukin-12 (IL-12), tumor necrosis factor- α (TNF- α ), and interferon- γ (IFN- γ ) cytokines in mice with liver injury. Pathological morphological observation also shows that PLT reduces CCl&sub4;-induced central venous differentiation of liver tissues and liver cell damage. Furthermore, qPCR and Western blot also confirm that PLT upregulates the mRNA and protein expressions of Gu/Zn-SOD, Mn-SOD, catalase (CAT), GSH-Px, and nuclear factor of κ -light polypeptide gene enhancer in B-cells inhibitor- α (I κ B- α ) in liver tissues, and downregulates the expression of cyclooxygenase 2 (COX-2) and nuclear factor κ -light-chain-enhancer of activated B cells (NF- κ B). Meanwhile, PLT also raised the phosphorylated (p)-NF- κ B p65 and cytochrome P450 reductase protein expression in liver injury mice. The components of PLT include gallic acid, catechin, caffeine, epicatechin (EC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and epicatechin gallate (ECG), which possibly have a wide range of biological activities. Thus, PLT imparts preventive effects against CCl&sub4;-induced liver injury, which is similar to silymarin.