RESUMO
Objeetive:To screen the different extracts from Geranium strictipes with anticaries activity,and to study the effect of the active extract on the production of acid and polysaccharides of oral cariogenic bacteria.Methods:Chlorhexidine and Galla Chinensis were used as the positive controls.Tube double dilution method was used to study the extracts of Geranium strictipes on the growth of Streptococcus mutans (S.mutans) and Actinomyce viscosus (A.viscosus).First,the activity of 5 extracts fom Geranium strictipes against S.mutans,A.viscosus was detected.Their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were obtained.The effects of 4 lower concentrations(＜ MIC) of the active extract on the production of oral bacterial acid polysaccharides were examined.Results:The effect of n-butanol extraction part of Geranium strictipes was the strongest among all the extracts against the two kinds of bacteria in the inhibition of bacteria growth,bacterial acid production and polysaccharides production,but weaker than that of Chlorhexidine and Galla Chinensis.Conclusion:N-butanol extraction part of Geranium strictipes may be a natural and effective anti-caries agent.