Microwave assisted extraction of flavonoids from cultivated Epimedium sagittatum: Extraction yield and mechanism, antioxidant activity and chemical composition

A microwave assisted extraction procedure has been optimized to isolate flavonoids from cultivated Epimedium sagittatum. And microwave assisted extraction was compared with two conventional extraction methods (i.e., heating extraction and agitated bed extraction) in terms of extraction yield and mechanism, antioxidant activity and chemical composition. Scanning electron micrographs illustrated that microwave irradiation resulted in disruptions of leaf samples, which might enhance mass transfer between extractant and intracellular ingredients and especially facilitate the exudation of flavonoids into extractant. Antioxidant activities of flavonoid extracts obtained by microwave assisted extraction were higher than those by conventional extraction methods. Flavonoid extracts achieved by microwave assisted extraction, heating extraction and agitated bed extraction contained different amount of epimedins A, B, C and icariin. Compared to conventional extraction methods, microwave assisted extraction presents distinctive advantages in superior extraction yield, higher antioxidant capacities of extracts and higher percentage of marker compounds, and consequently shows great potential for becoming an alternative technique for effective utilization of cultivated E. sagittatum resources. (C) 2013 Elsevier B.V. All rights reserved.