Effect of Extraction Conditions on the Antioxidant Activity of Diazo Cocoon Extracts

The potential medical applications of silkworm extract have been reported in numerous publications representing biomedical investigations of its possible health-benefiting effects evaluated in various model of biologically relevant systems. Testing the antioxidant properties of such extracts is interesting from a medical point of view. The extract is generally considered as a waste product with respect to the production of the silk. With the identification of its possible medical applications and various health benefits, the question arises - how the range of the used extraction parameters affects its biological activities. This study aims to determine the influence of extraction conditions 1) incubation time and temperature and 2) sonification parameters on the antioxidant activity of the obtained extracts. Several types of extracts were obtained for this purpose using: (a) sonification in ultrasonic bath at different frequencies and intensities of the ultrasound wave; (b) incubation at different temperatures in the range 60 to 100 degrees C; c) combination of ultrasound-assisted extraction with heating in water bath. The antioxidant activity of the extracts was determined by ABTS and DPPH assays. The prolong time incubation at 100 degrees C (the classic silk extraction method) was found to reduce the AOA of the obtained extract. Extracts obtained using sonification without additional heating during extraction process demonstrate good antioxidant properties. Combining ultrasound-assisted extraction with incubation at temperature below 100 degrees C yields to extracts which demonstrate very high antioxidant activity in the tested systems and offers great potential for preservation of the evaluated activity.