Changes of total polyphenol content and electron donating ability of Aster glehni extracts with different microwave-assisted extraction conditions

摘要

Aster glehni was extracted by microwave-assisted extraction(MAE) and reflux extraction(RE) methods and their extraction efficiencies were compared. A considerable reduction in extraction time was achieved by MAE. When 70 percent methanol, 50 percent methanol, 70 percent ethanol, or 50 percent ethanol was used, MAE extract contained nearly same amounts of soluble solid and total polyphenol contents as obtained by RE. The optimum MAE conditions for the extraction of Aster glehni were 120-150 watts of microwave energy and 4-8 minutes of extraction time. No significant changes were found in electron donating ability(EDA) over the variation of microwave energy or extraction time. The use of diluted methanol or ethanol resulted in improving extraction yield(24 percent), total polyphenol content(2.6 percent) and EDA(60 percent).