Abstract:The anthocyanin extract of purple sweet potato was used as raw material to study its antibacterial effect on the isolated Escherichia coli.The results showed that the purple sweet potato anthocyanin had a certain inhibitory effect on the growth of Escherichia coli and was positively correlated with its concentration.The monomeric anthocyanins of purple sweet potato were prepared by high-speed countercurrent chromatography and the effects of Escherichia coli on peonidin-3-caffeoyl-feruloyl glucoside-5-glucoside were studied.Escherichia coli had a significant ability to degrade.The degradation mechanism of anthocyanin by Escherichia coli was preliminarily investigated by high performance liquid chromatography（520 nm and 280 nm）methods.It is speculated that within the time frame of this study，the role of Escherichia coli did not lead to anhydrolysis or cleavage of anthocyanins，they were not degraded into smaller molecules.The UV-absorbing aromatic ring structure in the molecule was not destroyed as a whole，but the anthocyanin color-forming group was changed to form a colorless degradation product.