Abstract: The antibacterial effects of Chinese wild blueberry extracts and its different fractions on Staphyloccocus aureus (AB91093,ATCC26001) in vitro were investigated.Methanol:water:formic acid (85:15:0.5) was used to extract Chinese wild blueberry,and the extract was separated using C-18 Sep-Pak cartridge to afford mixture of organic acids and sugar,phenolics and anthocyanins.The content of total sugar,phenolics and anthocyanins in the fractions were determined and their antibacterial effect against S.aureus were investigated respectively.Moreover,their influence on bacteria cell membrane integrity was studied.The contents of total sugar,phenolics and anthocyanins in the extract were 4.76%,7.88 mg/g and 124.45 mg/100 g,respectively.Anthocyanins showed the highest antibacterial effects among blueberry extracts,its MIC and MBC were 0.21 mg/mL and 0.26 mg/mL,respectively.The damage of S.aureus cell membrane integrity was the same as their antibacterial effect.Blueberry extract was the best followed by anthocyanins,the mixture of organic acids and sugar.

Key words: wild blueberry, sugar, phenolics, anthocyanins, Staphyloccocus aureus