【作者】 谢倩；

【导师】 周学东；

【作者基本信息】 四川大学 ， 口腔临床医学， 2005， 博士

【摘要】 龋病是在以细菌为主的多种因素影响下,牙体硬组织发生的进行性破坏的一种疾病。龋病的预防一直是国内外的研究重点。现有的龋病预防措施都存在一些不足。我国天然药物资源丰富,历史悠久,有着巨大的开发潜力。本课题组在国内外首次开展中药防龋的系列研究,前期研究通过对多味中药的抗龋筛选实验发现五倍子(Galla Chinesis)具有与化学制剂洗必泰、氟化钠相近的抗龋效能。在不影响各实验菌株生长的较低浓度下也可有效抑制细菌产酸,产胞外多糖及早期对羟磷灰石的黏附等致龋毒力因子,具有抑制致龋菌生长、调节细菌代谢的作用。在体外生物膜模型中,五倍子水提物具有抑制细菌对羟磷灰石表面的黏附及牙体硬组织脱矿的作用,并与氟化钠的作用相当。但是对于五倍子防龋的活性成分及其防龋机制还缺乏进一步的认识,因此,本研究拟通过化学方法,结合体外系列筛选实验和口腔生物膜模型,对天然药物五倍子防龋有效部位(活性成分)进行分离追踪,综合评估其防龋效能;筛选出防龋有效成分,并对其进行结构鉴定。为进一步研究五倍子防龋有效成分的作用机制提供实验基础 方法 在前期研究的基础上,利用溶剂提取法提取五倍子生药中的多酚类物质,(前期研究证实此类提取物具有抗龋活性)。并对五倍子多酚性化合物以葡聚糖凝胶sephadex LH-20(Amersham Biosiences安玛更多还原

【Abstract】 Dental caries is fundamentally a microbial disease, which involves the hard tissue of tooth. The prevention of dental caries have been extensively studied worldwide, however none of the existed preventive ways of dental caries is exclusive. There are many theories and prescribes in ancient Chinese natural medicine dealing with dental caries, which facilitate the study of preventing dental caries by herbal medicine. In our previous study, we find out the water extract of Galla Chinesis has significant anticaries effects in vitro and in biofilm model. But what is the effective anticaries component of Galla Chinesis and how they affect the metabolism and growth of cariogenic bacteria and oral biofilm remains obscure till now. The purples of this study is to investigate the chemical components of Galla Chinesis and their anticaries effect, to trace out and identify the most effective component and to evaluate the anticaries efficacy of the active component in biofilm model.Methods: Based on our previous study, the polyphenol components of Galla Chinesis (GCE) was extracted. Then the GCE was further fractioned using a Sephadex LH-20 column for GCE-A, GCE-B, GCE-C and GCE-D. A series of in vitro anticarious experiments, the inhibition of growth, acid production,glucan generation and initial adherence, have been carried out using the Galla Chinesis extracts. According to the results of these experiments the effective components of Galla Chinesis were found out and their chemical structures are identified using !H-NMR and 13C-NMR. A four-organism bacterial consortium was grown in a biofilm model on hydroxyapatite (HA) discs and bovine enamel blocks 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. After 10 pulses, the biofilm surface structure was observed with the Fluorescence Microscope and the population of the biofilm was enumerated. And the change of enamel structure was also checked under a polarized microscope.Results: GCE and GCE-A, GCE-B, GCE-C and GCE-D were extracted from Galla Chinensis. GCE and GCE-B are proved has the highest anticaries efficacy. Two different compounds are further extracted from GCE-B and they are identified as Gallic Acid and Methyl Gallate. GCE and GCE-B are proved to be effective in vitro anticaries experiments. 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. The enamel lesion of GCE pulsed group is also shallower than the negative control.Conclusion: GCE and GCE-B are successfully extracted from Galla Chinensis and two chemical compounds fractioned from GCE-B are identified in the present study. GCE and GCE-B are proved to havesignificant anticaries effect in vitro and 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.更多还原