Antioxidative and antibacterial activities of Euryale ferox Salisb. shell extracts and its compositions analysis

Four kinds of extracts were extracted from Euryale ferox Salisb. shell with different solvents,such as,ethyl acetate,ethanol,50% aqueous ethanol and hot water(70~80 ℃),respectively. The antioxidative properties of four extracts were evaluated with the method of total reducing capacity,scavenging NO2-and DPPH·activities and lipid peroxidation inhibition ability,respectively. The microbial method was used to analyze the antibacterial activity of extracts to 15 kinds of bacterials. The main compositions of extracts analyzed with HPLC method in the article. The results showed that high content polyphonic compounds were obtained in four extracts,and exhibited strong total reducing power,DPPH· scavenging activity,possessed significant lipid peroxidation inhibition activity and moderate NO2-scavenging activities. Four kinds of extracts exhibited strong antibacterial activity to three kinds of common pathogens,such as,Escherichia coli O157,Enterobacter sakazakii and Listeria monocytogenes. By standard substances qualitative,five kinds of polyphenols were determined form extracts,they were gallic acid,catechin,epicatechin,chlorogenic acid and rutin,respectively. In a conclusion,the extracts possessed strong antioxidant capacity and antibacterial activities,which may be closely related to the high content polyphenols,so,they could be potential in food antioxidant.