| Background:Dental caries is one of the most common infectious diseases in the world,a biofilm-mediated,sugar-driven,multifactorial dynamic disease[1].The fourth national oral epidemiological survey showed that children who are gradually rising have a tendency to suffer from convulsions.Although the pathobiological pathology is complex,it is also believed that the formation of dental plaque biofilm is one of the important causes of dental caries[2-3].Plaque biofilm produce anaerobic and acidic environments,leading to the formation and development of dental caries[4].Therefore,eradicating dental biofilms and controlling bacterial acid production is an effective method to control dental caries.Streptococcus mutans is an important cariogenic bacteria in the oral cavity.Its cariogenic factors are the adherence of teeth,sugar formation,and strong acid and acid production capacity[5].Therefore,the search for a safe and effective antimicrobial agent to inhibit the growth of bacteria and the formation of biofilm has always been a research focus in the field of caries prevention and treatment.The phytochemicals demonstrate direct bactericidal or bacteriostatic effects,such as:?1?prevention of bacterial adherence to mucosal surfaces of the pharynx,skin,and teeth surface;?2?inhibition of glycolytic enzymes and pH drop;?3?reduction of biofilm and plaque formation;and?4?cell surface hydrophobicity.Collectively,findings from numerous studies suggest that phytochemicals could be used as drugs for elimination of infections with minimal side effects.Garlic has the pharmacological effects of lowering blood pressure[6],lowering blood fat[7],anti-tumor[8],anti-bacterial anti-inflammatory[9],preventing atherosclerosis[10],regulating body immunity[11],etc.Garlic contains various biologically active ingredients such as allicin,alliinase,allicin,S-allyl sulfur,diallyl sulfide and allyl trisulfide.The antimicrobial agent found in garlic is Allicin,however this is only found in the freshly crushed cloves rather than the intact plant.When the garlic clove is broken,the contact between the enzyme allicin alkyl-sulfonate-lyase and allicin leads to formation of allicin.Methods:The minimum inhibitory concentration?MIC?was measured by double-dilution method with gradient dilution method,the culture corresponding to the two gradient concentrations above the MIC is applied to the BHI medium for subculture to obtain the minimum bactericidal concentration?MBC?;The OD value of enzyme-labeled instrument was used to observe the antibacterial effect of different concentrations of allicin;The inhibition of acid production was observed to inhibit the acid-producing effect of bacteria;The adhesion and total amount of the biofilm of S.mutans was tested with crystal violet staining.The vitality and structure of S.mutans in the biofilm was observed by using scanning electron microscopy.Result:In the inhibition experiment,the minimum inhibitory concentration was 12.8ug/mL,the minimum bactericidal concentration was 25.8 ug/mL.The minimum inhibitory concentration and the subbacterial concentration inhibition experiment showed a certain antibacterial activity,and the antibacterial activity was positively correlated with the concentration gradient.Inhibition of acid production in 24h showed that allicin significantly inhibited bacterial acid production compared to the control group?P<0.01?.The results of bacterial adhesion test showed that allicin produced the slowest biofilm and the lowest total amount of biofilm in MIC?P<0.01?.Laser scanning confocal microscopy showed that with the increase of the concentration of allicin,the plaque biofilm was thinner,and the green viable bacteria and clumps decreased significantly,which inhibited the growth of biofilm.Conclusion:Allicin has an anti-caries effect on Streptococcus mutans by inhibiting the adhesion of the pathogen and the formation of its biofilm. |
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