藜麦多糖及糖醛酸单元抗氧化与降糖活性研究

Study on the Antioxidant and Hypoglycemic Activities of Quinoa Polysaccharide and Its Uronic Acid Units

摘要: [目的]本研究旨在探究藜麦多糖及其组成单糖的体外抗氧化与降糖活性，为藜麦多糖的功能性开发提供科学依据。[方法]通过DPPH自由基和羟自由基清除实验评估藜麦多糖的抗氧化活性，利用α-淀粉酶抑制实验评价其降糖活性。随后，对葡萄糖醛酸、半乳糖醛酸等单糖进行量效关系验证。[结果]藜麦多糖在4 mg∙mL⁻¹时，DPPH自由基清除率为13.26%，羟自由基清除率为12.71%，且在16 mg∙mL⁻¹时α-淀粉酶抑制率高达87.44%。单糖中，葡萄糖醛酸和半乳糖醛酸表现出显著的抗氧化和降糖能力。在2 mg∙mL⁻¹时，半乳糖醛酸的羟自由基清除率高达98.32%，α-淀粉酶抑制率为55.14%；葡萄糖醛酸的DPPH自由基清除率为10.27%，α-淀粉酶抑制率为48.24%。量效关系实验表明，两种单糖的活性随浓度增加而显著增强。[结论]藜麦多糖及其组成单糖在体外具有显著的抗氧化及降糖作用，尤其是葡萄糖醛酸和半乳糖醛酸表现出极高的生物活性。

Abstract: [Objective] This study investigates the in vitro antioxidant and hypoglycemic activities of quinoa polysaccharides and their constituent monosaccharides, aiming to provide a scientific foundation for the functional development of quinoa polysaccharides. [Methods] The antioxidant activity of quinoa polysaccharides was evaluated using DPPH radical and hydroxyl radical scavenging assays. Hypoglycemic activity was assessed via α-amylase inhibition assays. Additionally, the dose-effect relationships of monosaccharides, including glucuronic acid and galacturonic acid, were examined. [Results] At a concentration of 4 mg∙mL⁻¹, quinoa polysaccharides demonstrated a DPPH radical scavenging rate of 13.26% and a hydroxyl radical scavenging rate of 12.71%. At 16 mg∙mL⁻¹, the α-amylase inhibition rate reached 87.44%. Among the monosaccharides, glucuronic acid and galacturonic acid exhibited remarkable antioxidant and hypoglycemic activities. Specifically, at 2 mg∙mL⁻¹, galacturonic acid achieved a hydroxyl radical scavenging rate of 98.32% and an α-amylase inhibition rate of 55.14%. Glucuronic acid showed a DPPH radical scavenging rate of 10.27% and an α-amylase inhibition rate of 48.24%. Dose-effect experiments revealed that the activities of these two monosaccharides increased significantly with concentration. [Conclusion] Quinoa polysaccharides and their constituent monosaccharides, particularly glucuronic acid and galacturonic acid, exhibit significant antioxidant and hypoglycemic effects in vitro. These findings highlight the potential of quinoa polysaccharides and their monosaccharides as functional ingredients for applications in health and nutrition.