International Joint Research Center of Shaanxi Province for Food and Health Sciences, Provincial Research Station of Se-Enriched Foods in Hanyin County of Shaanxi Province, College of Food Engineering and Nutritional Science, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Shaanxi Normal University, Xi'an 710119, China.
Yinchuan Market Supervision Administration, Yinchuan 750001, China.
Molecules. 2023 May 4;28(9):3880. doi: 10.3390/molecules28093880.
Ultrasound-microwave combined extraction (UMCE), gradient ethanol precipitation, chemical characterization, and antioxidant and hypoglycemic activities of leaf polysaccharides (LLP) were systematically studied. The optimal conditions for UMCE of LLP achieved by response surface method (RSM) were as follows: microwave time of 16 min, ultrasonic time of 20 min, particle size of 100 mesh, and ratio of liquid to solid of 55:1. Three novel polysaccharide fractions (LLP, LLP, LLP) with different molecular weights were obtained by gradient ethanol precipitation. Polysaccharide samples exhibited scavenging capacities against ABTS and DPPH radicals and inhibitory activities against α-glucosidase and α-amylase. Among the three fractions, LLP possessed relatively high antioxidant and hypoglycemic activities in vitro, which showed a potential for becoming a nutraceutical or a phytopharmaceutical for prevention and treatment of hyperglycemia or diabetes.
系统研究了超声-微波协同提取（UMCE）、梯度乙醇沉淀、化学特性以及叶多糖（LLP）的抗氧化和降血糖活性。通过响应面法（RSM）得到 LLP 的 UMCE 最佳条件为：微波时间 16 分钟，超声时间 20 分钟，粒径 100 目，液固比 55:1。通过梯度乙醇沉淀得到三种不同分子量的新型多糖级分（LLP、LLP 和 LLP）。多糖样品对 ABTS 和 DPPH 自由基具有清除能力，对α-葡萄糖苷酶和α-淀粉酶具有抑制活性。在这三种级分中，LLP 在体外具有相对较高的抗氧化和降血糖活性，有望成为预防和治疗高血糖或糖尿病的营养保健品或植物药。
