香椿废弃组织中总黄酮提取工艺优化及抗氧化活性研究

以红油香椿废弃组织为原料,采用超声波辅助溶剂浸提的方法提取黄酮类物质,并利用铁氰化钾还原法、水杨酸比色法和1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）法测定提取物的抗氧化活性。在单因素实验基础上,选择温度、液料比和超声功率为影响因子,以总黄酮得率为响应值,采用响应面法优化提取工艺。结果表明:香椿废弃组织中总黄酮最佳提取工艺为:温度59℃、液料比51 m L/g、超声功率174 W,此条件下总黄酮得率为7.94%。抗氧化活性实验结果表明:香椿废弃组织中总黄酮具有较强的清除·OH和DPPH自由基能力,IC50值分别为0.205、0.018 mg/m L,均低于相同质量浓度VC的IC50值（1.022、0.069 mg/m L）。采用超声波辅助提取技术,黄酮得率高,时间短,为香椿废弃组织中总黄酮的开发利用提供理论参考。 

Optimization of extraction process of total flavonoids from the abandoned branches of Toona Sinensis and antioxidant activities evaluation

In this study,total flavonoids were extracted from the abandoned branches of Toona Sinensis by ultrasound-assisted extraction method and their antioxidant activities were assessed by potassium ferricyanide reduction,salicylic acid colorimetric method and 1,1-diphenyl-2-picrylhydrazyl( DPPH) radical scavenging assays.Temperature,liquid-to-solid ratio and ultrasonic power were identified by single factor method as main variables that affect the extraction yield of total flavonoids. The levels of the three variables were optimized by response surface methodology.The results showed that the optimal conditions for ultrasound-assisted extraction of total flavonoids were found to be 59 ℃,a liquid-to-solid ratio of 51 m L/g and ultrasonic power of 174 W.Under the optimized conditions,the extraction yield of total flavonoids was 7.94%. The antioxidant assays showed that the extracted flavonoids presented a strong antioxidant activity to scavenge·OH and DPPH radicals with IC50 values of0.205 mg/m L and 0.018 mg/m L,respectively.These values were both lower than the IC50 values of ascorbic acid of1.022 mg/m L and 0.069 mg/m L,respectively. Ultrasound-assisted extraction not only produced high yield of flavonoids,but also greatly shortened processing time,which provided a reference for developing new processes of total flavonoids from the abandoned branches of Toona Sinensis.