大蒜素抗变异链球菌的致龋效果

目的研究大蒜素对口腔变异链球菌生长及其菌斑生物膜粘附的抑制作用。方法二倍稀释法梯度稀释测最小抑菌浓度(minimum inhibitory concentration,MIC),将MIC以上2个梯度浓度对应的培养物涂布于BHI培养基上进行次代培养获得最低杀菌浓度(minimum bactericidal concentration,MBC);酶标仪测A值观察不同浓度大蒜素抑菌效应;抑制产酸试验观察抑制细菌产酸效应;结晶紫法研究亚抑菌浓度提取物对变异链球菌粘附能力及生物膜总量的影响;采用激光共聚焦荧光显微镜(laser scanning confocal microscopy,LSCM)观察常态牙菌斑生物膜生长过程中及药物处理后牙菌斑生物膜中死菌和活菌的构成,研究其对牙菌斑生物膜结构和活性的影响。结果抑菌试验中,得到大蒜素MIC为12.8 mg/L,MBC为25.8 mg/L。MIC及亚抑菌浓度抑菌试验显示均有一定的抑菌性,抑制率为2.17%～67.12%,并且抑菌性与浓度梯度成正相关。产酸试验显示24 h内大蒜素明显抑制细菌产酸(P0.01),细菌粘附试验结果显示大蒜素在MIC时生物膜的生成速度最慢,生物膜的总量最低(P0.01)。共聚焦荧光显微镜可见大蒜素组随药物浓度增加,菌斑生物膜较薄,绿色的活菌及团块明显减少,抑制生物膜的生长。结论大蒜素对变异链球菌生长、产酸与粘附有一定抑制作用。

The anti-caries effect of allicin against Streptococcus mutans

Abstract: Objective To study the inhibition of allicin against Streptococcus mutans and its plaque biofilm adhesion. Methods The minimum inhibitory concentration (MIC) was measured using double-dilution method. The cultures corresponding to the two gradient concentrations higher than the MIC were applied to the BHI medium for subculturing to obtain the minimum bactericidal concentration (MBC). The A value measured with enzyme-labeled instrument was used to observe the antibacterial effect of different concentrations of allicin. The inhibition of acid production by bacteria was observed through inhibition of acid-producing effect. The adhesion and total amount of biofilm of S. mutans were tested with crystal violet staining. The vitality and structure of S. mutans in the biofilm was observed by using scanning electron microscopy. Results The MIC and MBC of allicin were 12.8 mg/L and 25.8 mg/L respectively. The MIC and subbacterial concentration inhibition experiments showed a certain antibacterial activity of allicin, which was positively correlated with the concentration gradient. Inhibition of acid production showed that allicin significantly inhibited bacterial acid production within 24 hours compared to the control group. Conclusion Allicin has an anti-caries effect on Streptococcus mutans by inhibiting the adhesion of the pathogen and the formation of its biofilm.