干燥方式对明月草叶片中黄酮类化合物抗氧化活性的影响

Effect of Drying Methods on the Antioxidant Activity of Flavonoids Extracted from the Leaves of Angelica keiskei koidzumi

以明月草叶片为原料,对叶片进行自然晾干、热风干燥及真空冷冻干燥三种干燥处理,以乙醇为浸提试剂,采用溶剂浸提法对明月草中的黄酮类化合物进行提取,比较三种干燥处理方式对提取物抗氧化性的影响。结果表明:在80℃下,65%的乙醇按1:25的料液比浸提3h时,黄酮类化合物的提取率可达1.73%;随着不同干燥方式明月草叶片中提取黄酮类化合物浓度的提高,其还原力及清除DPPH自由基和超氧阴离子的能力也逐步提升;浓度在2mg/mL时,清除DPPH自由基的能力,真空冷冻干燥样品达到最高92%;浓度在10mg/mL时,清除超氧阴离子的能力,真空冷冻干燥样品达到最高66%;浓度在0.5mg/mL时,还原力真空冷冻干燥样品达到最高0.970。因此,真空冷冻干燥法是保持明月草叶片黄酮抗氧化活性的较好方式。

In the study,the leaves of Angelicakeiskeikoidzumi were dried by three methods,including shade drying,hot air drying,and vacuum freeze-drying,to study the effects of drying methods on the antioxidant activity of their ethanol extracts.The results showed that the extraction rate of flavonoids reached up to 1.73% when extracted with 65%ethanol at 80℃for 1 hat 1：25 ratio.With the increase of the concentration of the extracts,their reducing power and the ability to scavenge DPPH radicals and superoxide anion increased gradually.Vacuum freeze-drying contributed the highest DPPH radical scavenging ability of 92% at extract concentration 2 mg/mL,the greatest superoxide anion scavenging ability of66% at extract concentration 10 mg/mL,and strongest reducing power of 0.970 at extract concentration0.5 mg/mL.