Study on Flavonoids Composite Extraction from Lotus Leaf and its Radicals Scavenging Capacity

Lotus leaf flavonoids were extracted by ultrasonic and microwave.The optimal process conditions for flavonoids extraction was obtained to extract 25 minutes with 60 % alcohol when solid-to-liquid ratio was 1∶25 by ultrasonic.And then extracts were extracted 90 seconds when power was 462-watt by microwave.Extraction yield of flavones was 2.45 %.Flavonoids activities to scavenge hydroxy radicals and superoxide radicals were examined.When flavonoids(rutin as reference substance) were 125 mg/L and 3.5 mg/L,50 % hydroxy radicals and superoxide radicals were scavenged.The results showed that lotus leaf flavonoids has hydroxy radicals and superoxide radicals scavenging capacity.It provides a theoretical basis for Lotus leaf as natural antioxidant.