Abstract: Abstract： Objective To investigate the influence of different concentrations of allicin in apoptosis of A549 cells induced by porphyromonas gingivalis (P.gingivalis). Methods The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of allicin in inhibiting P.gingivalis were investigated by broth dilution methods. The tetrazolium salts (MTT) assay was used to detect the viability of A549 cells infected by P.gingivalis and treated with different concentrations of allicin (64 mg/L, 96 mg/L and 128 mg/L). The flow cytometry FITC/PI staining was used to detect apoptotic rates of A549 cells treated by P.gingivalis and/or allicin for 24 h. Results The values of MIC and MBC of allicin for inhibiting P.gingivalis were 64 mg/L and 128 mg/L respectively. MTT assay showed that the cell viability was significantly increased with the increased concentration of allicin in a concentration- dependent manner (P < 0.05). There was no significant difference in cell viability between allicin (128 mg/L) group and control group, which showed that allicin was no significant cytotoxicity in A549 cells. Flow cytometry assay showed that the apoptotic rates from high to low were P.gingivalis group > P. gingivalis + allicin group > allicin group > control group with significant differences (P < 0.01). The apoptosis of A549 cells induced by P.gingivalis was significantly inhibited by allicin (P < 0.01). Conclusion Allicin can inhibit P.gingivalis infection in lung epithelial cells. There is a good prospect in the application of allicin in the treatment of pulmonary infection in patients with periodontitis.

Key words: porphyromonas gingivalis, allicin, apoptosis, microbial sensitivity tests, A549 cells