Gang Chen1, Ming-Liang Tan2, Kai-Kai Li3, Ping-Chung Leung3, Chun-Hay Ko4. 1. School of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing 400067, China; Chongqing Key Laboratory of Nature Medicine Research, Chongqing Key Lab of Catalysis & Functional Organic Molecules, Chongqing Technology and Business University, Chongqing 400067, China. Electronic address: gangch_tcm@163.com. 2. School of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing 400067, China; Chongqing Key Laboratory of Nature Medicine Research, Chongqing Key Lab of Catalysis & Functional Organic Molecules, Chongqing Technology and Business University, Chongqing 400067, China. 3. Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. 4. Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. Electronic address: gohey@cuhk.edu.hk.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Green tea is a Chinese materia medica with the main functions of "inducing urination and quenching thirst". Green tea polyphenols (GTP) are generally acknowledged as the main active fraction with multiple pharmacological functions in green tea. However, the effect of GTP on hyperuricemia is not clear till now. AIM OF STUDY: The present study was carried out to investigate the effect of GTP on serum level of uric acid in potassium oxonate (PO)-induced hyperuricemic mice, and explore the underlying mechanisms from two aspects of production and excretion of uric acid. MATERIALS AND METHODS: PO and GTP were intragastricly administered to mice for consecutive 7 days. Serum level of uric acid, and xanthine oxidase (XOD) activity in serum and liver were examined. Simultaneously, expression of XOD protein in liver was analyzed by Western blot assay. Expressions of urate transporters including urate-anion transporter (URAT) 1, organic anion transporter (OAT) 1 and 3 in kidney were analyzed by immunohistochemistry staining method. RESULTS: 300 and 600 mg/kg GTP significantly decreased serum level of uric acid of hyperuricemic mice in a dose-dependent manner (p<0.05 or p<0.01). Besides, 300 and 600 mg/kg GTP markedly reduced XOD activity in serum and liver of hyperuricemic mice (both p<0.01). Furthermore, 300 and 600 mg/kg GTP clearly reduced XOD expression in liver, as well as reduced URAT1 expression and increased OAT1 and OAT3 expressions in kidney of hyperuricemic mice (p<0.05 or p<0.01). CONCLUSIONS: These results demonstrated that GTP had the effect of lowering uric acid through decreasing the uric acid production and increasing uric acid excretion. Our study suggested that GTP would be a promising candidate as a novel hypouricaemic agent for further investigation.
ETHNOPHARMACOLOGICAL RELEVANCE: Green tea is a Chinese materia medica with the main functions of "inducing urination and quenching thirst". Green tea polyphenols (GTP) are generally acknowledged as the main active fraction with multiple pharmacological functions in green tea. However, the effect of GTP on hyperuricemia is not clear till now. AIM OF STUDY: The present study was carried out to investigate the effect of GTP on serum level of uric acid in potassium oxonate (PO)-induced hyperuricemicmice, and explore the underlying mechanisms from two aspects of production and excretion of uric acid. MATERIALS AND METHODS:PO and GTP were intragastricly administered to mice for consecutive 7 days. Serum level of uric acid, and xanthine oxidase (XOD) activity in serum and liver were examined. Simultaneously, expression of XOD protein in liver was analyzed by Western blot assay. Expressions of urate transporters including urate-anion transporter (URAT) 1, organic anion transporter (OAT) 1 and 3 in kidney were analyzed by immunohistochemistry staining method. RESULTS: 300 and 600 mg/kg GTP significantly decreased serum level of uric acid of hyperuricemicmice in a dose-dependent manner (p<0.05 or p<0.01). Besides, 300 and 600 mg/kg GTP markedly reduced XOD activity in serum and liver of hyperuricemicmice (both p<0.01). Furthermore, 300 and 600 mg/kg GTP clearly reduced XOD expression in liver, as well as reduced URAT1 expression and increased OAT1 and OAT3 expressions in kidney of hyperuricemicmice (p<0.05 or p<0.01). CONCLUSIONS: These results demonstrated that GTP had the effect of lowering uric acid through decreasing the uric acid production and increasing uric acid excretion. Our study suggested that GTP would be a promising candidate as a novel hypouricaemic agent for further investigation.
Authors: Félix Vargas; Paola Romecín; Ana I García-Guillén; Rosemary Wangesteen; Pablo Vargas-Tendero; M Dolores Paredes; Noemí M Atucha; Joaquín García-Estañ Journal: Front Physiol Date: 2018-04-24 Impact factor: 4.566