1. Antioxidant and Antiapoptotic Polyphenols from Green Tea Extract Ameliorate CCl4-Induced Acute Liver Injury in Mice.
- Author
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Diao, Jian-xin, Ou, Jin-ying, Dai, Huan, Li, Hai-ye, Huang, Wei, Hua, He-yu, Xie, Ting, Wang, Ming, and Yang, Yun-gao
- Subjects
ANIMAL experimentation ,ANTIOXIDANTS ,APOPTOSIS ,ASPARTATE aminotransferase ,BIOLOGICAL models ,HIGH performance liquid chromatography ,LIVER failure ,MICE ,OXIDOREDUCTASES ,POLYPHENOLS ,SERUM ,WESTERN immunoblotting ,DNA-binding proteins ,GREEN tea ,ALANINE aminotransferase ,ACUTE diseases ,CASPASES ,IN vitro studies - Abstract
Objective: To investigate the phenolic composition, antioxidant properties, and hepatoprotective mechanisms of polyphenols from green tea extract (GTP) in carbon tetrachloride (CCl
4 )-induced acute liver injury mouse model. Methods: High-performance liquid chromatography was used to analyze the chemical composition of the extract. Antioxidant activity of GTP was assessed by O2 ∙- , OH∙ , DPPH∙ , and ferric-reducing antioxidant power (FRAP) assay in vitro. Sixty Kunming mice were divided into 6 groups including control, model, low-, medium-, and high-doses GTP (200, 400, 800 mg/kg) and vitamin E (250 mg/kg) groups, 10 in each group. GTP and vitamin E were administered at a level of abovementioned doses twice per day for 7 days prior to exposure to a single injection of CCl4 . Hepatoprotective effects of GTP were evaluated in a CCl4 -induced mouse model of acute liver injury, using commercial enzyme linked immunosorbent assay kits, histopathological observation, terminal deoxynucleotidyl transferase-mediated dUTPNick-end labeling (TUNEL) assay and Western blot. Results: GTP contained 98.56 µg gallic acid equivalents per milligram extract total polyphenols, including epicatechingallate, epigallocatechin gallate, epicatechin, and epigallocatechin. Compared with the model group, low-, medium-, or high doses GTP significantly decreased serum levels of alanine aminotransferase and aspartate transaminase (P<0.01). Histopathological observation confirmed that pretreatment of GTP prevented swelling and necrosis in CCl4 -exposed hepatocytes. Hepatoprotective effects of low-, medium-, and high-dose GTP were associated with eliminating free radicals and improving superoxide dismutase, catalase, and glutathione peroxidase activity in the liver. Additionally, low-, medium-, and high-dose GTP decreased cell apoptosis in the CCl4 -exposed liver (P<0.01). Phosphorylated nuclear factor kappa-B (NF-κB), p53, Bcl-2 associated x protein/B-cell lymphoma/leukemia-2 gene, cytochrome C, and cleaved caspase-3 levels were downregulated compared with the model group (P<0.01). Conclusion: GTP achieves hepatoprotective effects by improving hepatic antioxidant status and preventing cell apoptosis through caspase-3-dependent signaling pathways. [ABSTRACT FROM AUTHOR]- Published
- 2020
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