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

为了探讨饮食中摄入大豆肽可能有益于老年人口腔健康的假设，我们研究了大豆多肽对口腔致病微生物生长的影响。大豆多肽“Hinute-R”(平均链长3-4)对牙周炎病原菌伴生放线杆菌的生长有抑制作用。对白色念珠菌和光滑念珠菌的早期生长也有抑制作用，可引起机会性口腔感染。通过凝胶过滤层析，从Hinute-R中分离得到两个组分。与Hinant-R和分子量约2000道尔顿的组分II相比，组分I显示出约10,000道尔顿的分子量，在抑制光滑线虫的生长方面非常有效。从大豆蛋白消化液中提取的抗氧化肽LLPHH的浓度为2.5和12.5 mg/ml时，光肩星毛藻的生长分别下降了23%和42%。大豆多肽对人细胞无明显毒性。这些结果支持了大豆多肽对于抵抗力较差的老年受试者的潜力。在项目的第二部分，我们展示了吸引法对于不能轻易进食或吐痰的老年受试者唾液蛋白质谱的信息是有用的。作为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的关系。在被调查的成分中，P物质，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。这一信息可能对使用大豆多肽进行进一步的临床试验有用。

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.