Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
Division of Physiology, School of Medical Sciences, University of Phayao, Phayao 56000, Thailand.
Molecules. 2021 Mar 28;26(7):1907. doi: 10.3390/molecules26071907.
pulp (CP) is a by-product of coffee processing. CP contains polyphenols that have exhibited beneficial effects, including antioxidant and lipid-lowering effects, as well as enhanced insulin sensitivity, in in vitro and in vivo models. How polyphenols, as found in CP aqueous extract (CPE), affect type 2 diabetes (T2D) has not been investigated. Thus, the present study examined the potential antidiabetic, antioxidant, and renoprotective effects of CPE-rich polyphenols, using an experimental model of T2D in rats induced by a high-fat diet and a single low dose of streptozotocin. The T2D rats received either 1000 mg/kg body weight (BW) of CPE, 30 mg/kg BW of metformin (Met), or a combination treatment (CPE + Met) for 3 months. Plasma parameters, kidney morphology and function, and renal organic transport were determined. Significant hyperglycemia, hypertriglyceridemia, insulin resistance, increased renal lipid content and lipid peroxidation, and morphological kidney changes related to T2D were restored by both CPE and CPE + Met treatments. Additionally, the renal uptake of organic cation, H-1-methyl-4-phenylpyridinium (MPP), was reduced in T2D, while transport was restored by CPE and CPE + Met, through an up-regulation of antioxidant genes and protein kinase Cα deactivation. Thus, CPE has antidiabetic and antioxidant effects that potentially ameliorate kidney function in T2D by preserving renal organic cation transport through an oxidative stress pathway.
咖啡加工副产物——咖啡果皮（CP）含有多酚，具有抗氧化和降低血脂的作用，以及增强胰岛素敏感性等有益作用，在体外和体内模型中都得到了证实。然而，CP 中的多酚对 2 型糖尿病（T2D）的影响尚未得到研究。因此，本研究使用高脂肪饮食和单次低剂量链脲佐菌素诱导的 T2D 大鼠实验模型，研究了 CP 富多酚对糖尿病的潜在治疗作用，包括抗氧化和肾脏保护作用。T2D 大鼠接受 1000mg/kg 体重的 CP、30mg/kg 体重的二甲双胍（Met）或 CP+Met 联合治疗 3 个月。测定了血浆参数、肾脏形态和功能以及肾脏有机转运。CP 和 CP+Met 治疗均可恢复 T2D 大鼠的显著高血糖、高三酰甘油血症、胰岛素抵抗、肾脏脂质含量和脂质过氧化增加以及与 T2D 相关的形态学肾脏变化。此外，T2D 大鼠的有机阳离子 H-1-甲基-4-苯基吡啶（MPP）摄取减少，而 CP 和 CP+Met 治疗可通过上调抗氧化基因和蛋白激酶 Cα失活来恢复这种摄取，从而改善肾脏功能。因此，CP 具有抗糖尿病和抗氧化作用，通过氧化应激途径保护肾脏有机阳离子转运，从而可能改善 T2D 患者的肾脏功能。
