Sugiura Minoru, Ohshima Makoto, Ogawa Kazunori, Yano Masamichi
Department of Citrus Research, National Institute of Fruit Tree Science, Shimizu, Shizuoka, Japan.
Biol Pharm Bull. 2006 Mar;29(3):588-91. doi: 10.1248/bpb.29.588.
Fruits and vegetables contain numerous antioxidants such as carotenoids, vitamins, and phenolic phytochemicals. Recent studies have demonstrated that antioxidants may reduce the risk for diabetes or its complications. In this study, we investigated the effects of the chronic administration of Satsuma mandarin fruit on an antioxidant defense system in streptozotocin (STZ)-induced diabetic rat liver. After a ten-week administration of Satsuma mandarin, antioxidant enzymes and glutathione levels in the liver were evaluated. The superoxide dismutase (SOD), catalase, and glutathione-peroxidase (GPx) activities, and glutathione level in the STZ-induced diabetic rats liver decreased significantly compared with those in the age-matched normal rats. The glutathione-reductase (GR) activities did not differ significantly between these two groups. In contrast, the SOD, GR, and glutathione levels in the Satsuma mandarin (1% or 3%) diet-fed STZ-diabetic rat livers were significantly higher than those in the normal diet-fed STZ-diabetic rat livers. In addition, although the serum alanine aminotransferase and gamma-glutamyl-aminotransferase concentrations of normal diet-fed STZ-diabetic rats were significantly higher than those of the age-matched normal rats, these increments of serum liver enzymes were diminished by the chronic administration of Satsuma mandarin. These results suggest that Satsuma mandarin may act as a suppressor against liver cell damage and inhibit the progression of liver dysfunction induced by chronic hyperglycemia.
水果和蔬菜含有多种抗氧化剂，如类胡萝卜素、维生素和酚类植物化学物质。最近的研究表明，抗氧化剂可能会降低患糖尿病或其并发症的风险。在本研究中，我们调查了长期给予温州蜜柑果实对链脲佐菌素（STZ）诱导的糖尿病大鼠肝脏抗氧化防御系统的影响。在给予温州蜜柑十周后，评估肝脏中的抗氧化酶和谷胱甘肽水平。与年龄匹配的正常大鼠相比，STZ诱导的糖尿病大鼠肝脏中的超氧化物歧化酶（SOD）、过氧化氢酶和谷胱甘肽过氧化物酶（GPx）活性以及谷胱甘肽水平显著降低。这两组之间的谷胱甘肽还原酶（GR）活性没有显著差异。相比之下，喂食温州蜜柑（1%或3%）饮食的STZ糖尿病大鼠肝脏中的SOD、GR和谷胱甘肽水平显著高于喂食正常饮食的STZ糖尿病大鼠肝脏中的水平。此外，尽管喂食正常饮食的STZ糖尿病大鼠的血清丙氨酸氨基转移酶和γ-谷氨酰转移酶浓度显著高于年龄匹配的正常大鼠，但长期给予温州蜜柑可减少这些血清肝酶的升高。这些结果表明，温州蜜柑可能作为肝细胞损伤的抑制剂，并抑制慢性高血糖诱导的肝功能障碍的进展。
