Extraction of flavone from male flowers of Qinba Eucommia ulmoides and their antioxidant stability

The extraction process of flavone in male flowers of Qinba Eucommia ulmoides assisted by microwave pretreatment was studied. The flavone extraction from the different ethanol concentration,extraction time,extraction temperature and solid-to-liquid ratio were studied. And the antioxidant stability of total flavonoe was assessed by its capacity to scavenge the DPPH free radical under different treatments. The results showed that the best extraction process condition was:ethanol concentration 60%,abstracting temperature 80 ℃,abstracting time 2.5 h and the ratio of solid to extracting liquid 1∶60(g/m L). The total flavone extraction yield could reach2.983% in the optimum conditions. The temperature and metal ions(Na+,K+,Ca2+,Mg2+) did not produce a great reduction of scavenging capacity. While the Zn2 +,Cu2 +,p H and illumination had a bigger influence to the antioxidation stability of flavone in male flowers of Qinba Eucommia ulmoides.