浒苔多酚的抗氧化及改善胰岛素抵抗作用

Antioxidant Activity of Enteromorpha prolifera Polyphenols and Their Effect on Improving Insulin Resistance

摘要:

本文提取分离了浒苔多酚并对其抗氧化及改善胰岛素抵抗（IR）作用进行了研究。测定浒苔多酚对DPPH?的清除率以评价其体外抗氧化能力；测定IR-HepG2细胞的葡萄糖消耗量以评价在体外细胞水平改善IR的能力；通过DIO小鼠实验，评价其在小鼠体内抗氧化、改善IR的能力。结果表明：所得组份EP1具有较好的抗氧化作用，其体外DPPH清除IC50为1.08 mg/mL，与模型组相比，EP1能显著提高小鼠肝脏抗氧化酶SOD、CAT活性达25.04%、36.28%，降低血清MDA水平可达42.92%；EP1可显著改善HepG2细胞及DIO小鼠的IR状态（p<0.05），其抑制HOMA-IR指数幅度可达16.8%；EP1还能抑制DIO小鼠的肥胖程度，降低脂肪比例（p<0.05）；而另一组份EP2的抗氧化及改善胰岛素抵抗作用均不及EP1。综上，浒苔多酚EP1具有较好的抗氧化能力，能明显改善IR状态，其机制可能与其发挥抗氧化作用抑制机体ROS水平有关。

Abstract:

Enteromorpha prolifera polyphenols (EPs) were extracted and separated, and their antioxidant activity and effect on insulin resistance (IR) were investigated in this paper. The 2,2-diphenyl-1-picrylhydrazyl (DPPH?) radical scavenging assay was used to evaluate the in vitro antioxidant capacities of EPs; the capability of EPs for reducing IR was evaluated in vitro by measuring the glucose consumption of IR-HepG2 cells. Experiments with diet-induced obese (DIO) mice were used to evaluate the in vivo antioxidant activities of EPs and their effects on IR in vivo. The results showed that the fraction EP1 had good DPPH? radical scavenging ability with an IC50 value of 1.08 mg/mL. Compared to the control group, EP1 significantly increased the liver SOD and CAT activities in mice by 25.04% and 36.28%, respectively, and decreased the serum malondialdehyde (MDA) level by 42.92%. EP1 improved IR states of HepG2 cells and DIO mice significantly (p<0.05), reduced the homeostatic model assessment (HOMA)-IR index by 16.8%, and decreased the degree of obesity and reduce the fat percentage in DIO mice significantly（p<0.05）. On the other hand, EP2 was inferior to EP1 in terms of antioxidant activity and IR-improving effect. In summary, EP1 has good in vitro and in vivo antioxidant capacities, and can improve IR state significantly, which may be associated with its antioxidant activity by suppressing levels of reactive oxygen species (ROS).