Studies on the practical use of soybean peptides for oral health promotion in the elderly

为了验证膳食摄入大豆肽可能有利于促进老年人口腔健康的假设，我们研究了大豆肽对口腔病原微生物生长的影响。大豆肽“hinut - r”（平均链长3-4）抑制牙周炎病原放线菌聚集菌的生长。它还能抑制白色念珠菌和光秃念珠菌的早期生长，这两种念珠菌可引起机会性口腔感染。通过凝胶过滤层析得到Hinute-R的两个组分。与Hinute-R和分子量约为2000道尔顿的分数II相比，分子量约为10000道尔顿的分数I对光斑草生长的抑制效果显著。从大豆蛋白的消化物中分离出的抗氧化肽LLPHH，在2.5 mg/ml和12.5 mg/ml浓度下，分别使C. glabrata的生长降低23%和42%。大豆肽对人体细胞无毒性作用。这些结果支持大豆肽对抗感染能力差的老年受试者的潜力。在项目的第二部分中，我们证明了吸痰法对于获取老年受试者唾液蛋白谱的信息是有用的，这些老年受试者不能进食或容易吐出唾液。作为我们临床试验的初步研究，我们调查了需要护理的老年人唾液成分与口腔状况之间的关系。在被调查的成分中，P物质是一种引起咳嗽反射并参与吞咽功能的内源性物质，与存在的牙齿数量呈正相关。这一信息可能对进一步使用大豆肽的临床试验有用。

In order to investigate the hypothesis that dietary consumption of soybean peptides may be beneficial for oral health promotion in the elderly, we studied their effects on growth of oral pathogenic microorganisms. The soybean peptides "Hinute-R" (average chain length 3-4) inhibited the growth of Aggregatibacter actinomycetemcomitans, an etiologic agent of periodontitis. It also inhibited the growth in early stage of Candida albicans and Candida glabrata, which can cause opportunistic oral infections. Two fractions were obtained from Hinute-R by gel filtration chromatography. The fraction I, showing a molecular weight of approximately 10,000 daltons, was remarkably effective in inhibiting the growth of C. glabrata when compared to Hinute-R and fraction II having a molecular weight of approximately 2,000 daltons. The presence of LLPHH, anti-oxidative peptide isolated from digests of a soybean protein, at 2.5 and 12.5 mg/ml reduced the growth of C. glabrata by 23% and 42%, respectively. No toxicity of soybean peptides was observed against human cells. These results support the potential of soybean peptides for elderly subjects with poor resistance to infections.In the second part of the project, we showed that the suction method is useful to obtain information regarding the salivary protein profiles in aged subjects who cannot eat or spit saliva easily. As preliminary studies for our clinical trials, we investigated the relationship between salivary components and oral conditions in the elderly requiring care. Among components investigated, the substance P, an endogenous substance causing cough reflex and involved in swallowing function, was positively correlatedwith the number of teeth present. This information may be useful for further clinical trials using the soybean peptides.