An Investigation of Inhibitory Agent against Acid Production of Oral Bacteria

以细菌素C3603、碘乙酸和阿扎霉素为对照，研究了MLI（暂定名）对口腔微生物产酸的抑制作用。从放线菌菌株的培养上清中部分纯化了MLI。MLI明显抑制变形链球菌群（血清型a-g）和干酪乳杆菌从葡萄糖产生乳酸，这种作用不是由于其抗菌作用。另一方面，C3603、碘乙酸和阿扎霉素也抑制乳酸产生，但观察到抗菌作用。MLI对变形链球菌产生的甲酸、乙酸等代谢产物无明显抑制作用，但对乳酸脱氢酶（LDH）活性有明显的抑制作用，且随MLI浓度的增加而增加，当MLI浓度为2.5g/ml时，LDH活性抑制率接近95%。然而，C3603和碘乙酸没有。采用制备型硅胶薄层层析法对MLI进行分析，将MLI分离成4个斑点，分别为A、B、C、D，其RF值不同。只有D斑提取物对乳酸产生有抑制作用，但无抑菌活性。然后将D组分上高效液相色谱柱，观察到3个峰。这3个峰的抑制作用正在研究中。

Inhibitory action of MLI(tentative name) against acid production of oral microoganisms was studied with bacteriocin C3603, iodoacetic acid and azalomycin as controls. MLI was partially purified from culture supernatant of Actinomyces sp. strain. MLI markedly suppressed lactic acid production from glucose by Streptococcus mutans group(serotype a-g) and Lactobacillus casei, and this effect was not due to its antibacterial action. On the other hand, C3603, iodoacetic acid and azalomycin also suppressed lactic acid production, but antibacterial actions were observed. MIL did not suppress productions of formic acid, acetic acid and the other metabolic substances tested by S.mutans group.MLI remarkably inhibited lactate dehydrogenase(LDH) activity depending upon MLI concentration, and nearly 95% inhibition of LDH activity was observed when 2.5 g/ml of MLI was added into the reaction mixture. However, C3603 and iodoacetic acid did not. MLI was analyzed by thin layer chromatography using preparative kiesel gel, and was separated into 4 spots of A,B,C,D showing different RF values, respectively. Only extract from D spot showed inhibition of lactic acid production without antibacerial activity. Then, fraction D was applied to high performans liquid chromatographic column, and 3 peaks were observed. Inhibitory actions of these 3 peaks are under the progress.