Study on the effect of Xinjiang Yili black bee propolis extract of Enterococcus faecalis

NADILA Ailijiang; NIU Qiao-li; SHI Chen-li; ZHAO Jin

doi:10.15956/j.cnki.chin.j.conserv.dent.2025.03.003

Abstract：AIM:To investigate the antibacterial effect of Xinjiang Yili black bee propolis extract on the planktonic and biofilm state of Enterococcus faecalis,as well as its efficacy and safety in vivo.METHODS:In vitro experiment:The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)were determined by liquid dilution method,and the growth curve was measured.The minimum biofilm inhibition concentration(MBIC50)and the minimum biofilm clearance concentration(MBRC50)were determined by crystal violet staining.The surface morphology of Enterococcus faecalis biofilm was observed by scanning electron microscopy(SEM).In vivo experiment:A rat model of periapical inflammation was established,and the bacteria in the root canal of the rats were collected and measured by colony count before and after medication.The development of periapical inflammation in each group was compared by Micro CT bone quantitative analysis.The weight increase of rats in each group was recorded during the experiment,and the effects of propolis extract of Xinjiang Yili on the growth and development of rats were observed.Major organs of the rats were subjected to hematoxylin and eosin(HE)staining to observe changes in tissue structure and evaluate the toxicity of the extract to the cells of major organs.RESULTS:In vitro experiment:The MIC and MBC of propolis extract on Enterococcus faecalis were 0.938mg/mL and 1.875 mg/mL respectively.The MBIC50 was 1.875 mg/mL and the MBRC50 was 3.75 mg/mL.The SEM results showed that the amount of Enterococcus faecalis biofilm formation was inversely proportional to the concentration of propolis liquid compared with the control group.In vivo experiment:Compared with the blank group,the bacteria quantity in the root canal of propolis group was significantly reduced at the age of 10 weeks;The periapical lesion volume of propolis group and calcium hydroxide group was significantly smaller than that of blank group,and the difference was statistically significant(P<0.05).The growth trend of body weight was similar in all groups.HE staining sections of major organs were uniform,and no significant changes in histological structure were observed.CONCLUSION:The propolis extract of Yili can safely and effectively inhibit the growth of Enterococcus faecalis and its biofilm formation,which provides a new idea for the treatment of refractory periapical inflammation.