Antioxidant properties of water and ethanol extracts from hot air-dried and freeze-dried daylily flowers

摘要

Daylily (Hemerocallis fulva Linn.) flowers were hot air-dried and freeze-dried after harvest. Water and ethanol extracts were prepared from these dried flowers and their antioxidant properties were evaluated using total antioxidant activity, reducing capacity, metal chelating activity, and DPPH and superoxide anion radical scavenging activities, comparing with standards. Extracts from daylily flowers exhibited strong antioxidant activity. Ethanol was more efficienct to extract antioxidants than water and that freeze-drying preserved higher activities than air-drying. Ethanol extract from freeze-dried daylily flowers showed the highest antioxidant activity and phenol content.