Extraction of isoflavonoids from Pueraria by combining ultrasound with microwave vacuum

This study proposes a new method to quickly extract and dry isoflavonoids from Pueraria Lobala Ohwi (Pueraria) by combining ultrasound and microwave technologies. The time required to extract isoflavonoids at comparable levels of production by ultrasound disruption was 20 times shorter than by conventional reflux extraction. Moreover, test results for drying the extracted substance from Pueraria show that the microwave-vacuum method is 10 times faster than the conventional two-step vacuum approach. Finally, different instrumental analyses of isoflavonoids obtained from Pueraria using the proposed new method show that extraction by ultrasound disruption and microwave-vacuum drying affects neither the structure nor the composition of the extracted substance. (C) 2008 Published by Elsevier B.V.