ABSTRACT
Objective:To study the antibacterial activity of sanguisorba tannin extract in vitro and its mechanism in the antibacterial effect on staphylococcus aureus. Methods:The antibacterial effect of sanguisorba tannin extract was studied by an Oxford-cup method and a tube double dilution method. With staphylococcus aureus as the tested bacteria, extracellular alkaline phosphatase (AKP), potassium ion, soluble protein and T-ATPase were determined. The changes in protein bands and the cell ultrastructure were respectively observed by SDS-PAGE and TEM to illustrate the antibacterial mechanism. Results:The results showed that sanguisorba tannin extract was effec-tive against the gram-positive bacteria, while the effect against the gram-negative bacteria was weak. After staphylococcus aureus was trea-ted with sanguisorba tannin extract, the contents of alkaline phosphatase (AKP), potassium ion, soluble protein, DNA, RNA and the other large molecules were increased obviously when compared with those in the control group. The concentrations of intracellular and ex-tracellular ATP were significant changed. DS-PAGE showed that staphylococcus aureus treated with sanguisorba tannin extract had no pro-tein band formation. TEM showed that the cell integrity was damaged. Conclusion:Sanguisorba tannin extract shows strong antibacterial activity, which can change the cell membrane permeability and damage the cell integrity.