Cariostatic effects of chemical compounds extracted from Galla chinensis

Objectives: To evaluate the in vitro cario- static effect of chemical compounds extracted from Galla Chinensis with biofilm model. Methods: Different chemical compounds of Galla Chinesis were extracted and identified by 1H-NMR and 13C-NMR. A four-organism bacterial consortium was grown in a biofilm model on hydroxyapatite (HA) discs and glasses in a continuous culture system and exposed to repeated solution pulsing respectively. The negative control group was pulsed with 25mmol/l sucrose solution; positive control group was pulsed with sucrose solution plus 228ppm NaF. While 4.0 mg/ml GCE and 4.0 mg/ml GCE-B solution together with 25mmol/l sucrose was pulsed in the experiment group. During the experiment, the pH responses against the pulses are recorded. During the experiments the dynamic changes of pH were recorded After 10 pulses, the biofilm surface structure was observed with the Fluorescence Microscope and the population of the biofilm was enumerated. Results: GCE and GCE-A, GCE-B, GCE-C and GCE-D were extracted from Galla Chinensis. GCE is polyphenol components. Two different compounds are further extracted from GCE-B and they are identified as Gallic Acid and methyl Gallate. In the biofilm model, both of GCE and GCE-B can significantly inhibit the adherence of cariogenic bacteria to HA discs compared with the control group of 25 mM sucrose pulsed in, and can facilitate the remove of acid products. They are also found to reduce the extra-cellular polysaccharide production of biofilm. Conclusion: GCE and GCE-B are proved to have significant anticaries effect in biofilm model; they appear to be a promising source of new agents that may prevent dental caries. The identification of the two compounds from GCE-B will give us some light on the discovery of newly designed anticaries drugs.