Propolis extracted by different methods:flavonoid content determination and area differentiation evaluation

Two ethanol and supercritical carbon dioxide( CO2) extraction methods were used to produce propolis extracts from 9 districts and 16 varieties propolis samples in this study. The yield and total flavonoid content of propolis extracts were determined correspondingly. In addition,the propolis area differentiation was evaluated by data statistical analysis. By comparing two extraction methods,the results showed that the total flavonoid content of propolis extracts produced by the supercritical CO2extraction method was significantly lower than that produced by the ethanol extraction method. The propolis area differentiation results showed that the propolis grown in Hebei and Yunnan regions had generally higher yields and total flavonoid contents,the propolis developed at Hubei,Shandong,Hunan and Hainan areas had moderate yields and total flavonoid contents,and the propolis grown in Heilongjiang region had generally lower yield and total flavonoid content. Moreover,the total flavonoid contents of propolis extracts from different varieties grown in Henan and Sichuan regions showed significant differences. Therefore,this research suggested that the propolis production enterprises fixed the raw materials collecting area,variety and extraction method in order to guarantee the propolis product quality stability.