益生菌降胆固醇机制初探

发布时间：2018-07-26 18:37

【摘要】：心脑血管疾病是一类危害人类健康且很难被攻克的慢性疾病。其致病因素众多,诸如遗传因素、不规律生活习惯、高热量食物的暴食等均会引起该类疾病的发生。至今,还未找到确实可行的治愈该疾病的有效方法,由此防重于治是控制该类疾病的有效方法。有证据表明,血液以及肝脏中胆固醇含量过高是诱发该类疾病的原因之一,如果可以维持血液中胆固醇水平且保持在合理的范围之内,则可减缓心脑血管疾病的发病趋势。经过多年的研究证实,某些益生菌可以降低血液及肝脏中的胆固醇含量。与传统药物治疗相比,具有降胆固醇功能的益生菌因其副作用小并且具有其他益生功效等特点,而被广泛关注。益生菌通过何种途径降低血液中胆固醇的含量一直是科研人员研究的重点,经过多年研究发现,益生菌降胆固醇机制存在四种假说,其中任何一种机制至今均未得到证实。由于某些益生菌的应用具有一定特殊性,其潜在的安全性问题也不容小觑。据文献报道,某些益生菌可能产生毒性物质而刺激机体产生不良反应以及菌体进入血液后可能引起菌血症等一些危害机体健康等风险:针对这些问题,供试菌株应在后续食品、药品开发前取得安全性评估才得以实施大规模生产。基于上述目的,本文利用皂化-比色法复筛具有降胆固醇能力的43株益生菌,其去除率为3.30%(±0.89)-85.93%(±0.38)之间,在这43株菌株中,肠球菌属与乳杆菌属所占比例较大,说明这两种菌种在降胆固醇方面具有很大潜力,可以进行深入研究。因此从中分别选取三株植物乳杆菌和三株屎肠球菌分别进行耐酸耐胆盐等益生能力以及胆盐水解酶活性检测。三株植物乳杆菌的耐酸能力较三株屎肠球菌菌株要强,而三株屎肠球菌的耐胆盐能力则强于三株植物乳杆菌菌株。在胆盐水解酶活性的检测中发现,植物乳杆菌S11菌株的酶活最低,基本检测不出,而植物乳杆菌QB3-1菌株的酶活则高达80%。在进一步研究胆固醇去除机制中发现,本文所得结果证明益生菌的去除机制存在菌株差异性,而且益生菌主要是通过多种机制的协同作用达到胆固醇去除目的,这也为后续进一步研究各种机制间的作用关系提供一定的理论基础。此外,还对这6株供试菌株初步实施安全性评价。6株菌株对10种抗生素的敏感程度不同,3株屎肠球菌均对万古霉素敏感,而QB3-2菌株是这6株菌株中对抗生素最为敏感的一株菌株。同时检测了3株屎肠球菌的溶血反应,试验结果表明,这三株菌株无溶血性,由此初步表明这6株供试菌株安全可靠。本文研究所得的各项研究成果为后续具有低胆固醇发酵食品的研发提供一定的理论基础。但是,要想将其应用到功能性发酵食品,还需进一步完善供试菌株的安全性评估。
[Abstract]:Cardio-cerebrovascular disease is a kind of chronic disease that endangers human health and is difficult to conquer. Many pathogenic factors, such as genetic factors, irregular living habits and high calorie food overeating, can lead to the occurrence of this disease. Up to now, no effective method has been found to cure the disease, so prevention and treatment is an effective way to control the disease. It has been shown that high cholesterol level in blood and liver is one of the causes of these diseases. If the cholesterol level in blood can be maintained within a reasonable range, it can slow down the development trend of cardiovascular and cerebrovascular diseases. Years of research have shown that certain probiotics lower cholesterol levels in the blood and liver. Compared with traditional drug therapy, probiotics with cholesterol lowering function have been widely concerned because of its small side effects and other probiotic effects. It has been the focus of researchers to study how probiotics reduce cholesterol content in blood. After many years of research, it has been found that there are four hypotheses on cholesterol lowering mechanism of probiotics, none of which has been proved. Because of the particularity of some probiotics, the potential safety problems should not be underestimated. According to literature reports, some probiotics may produce toxic substances that stimulate the body to produce adverse reactions, and bacteria entering the blood may cause bacteriaemia and other risks to the health of the body: in view of these problems, the strains to be tested should be in the follow-up food, Before the development of drugs, the safety assessment can be carried out in large scale production. For the above purpose, 43 strains of probiotics with cholesterol lowering ability were screened by saponification colorimetric method, the removal rate was between 3.30% (卤0.89) -85.93% (卤0.38). Among the 43 strains, Enterococcus and Lactobacillus accounted for a large proportion. These two strains have great potential in lowering cholesterol and can be studied in depth. Therefore, three strains of Lactobacillus plantarum and three strains of Enterococcus faecium were selected respectively to detect the probiotic ability of acid tolerance and bile salt tolerance and the activity of bile salt hydrolase. The acid tolerance of three strains of Lactobacillus plantarum was stronger than that of three strains of Enterococcus faecium, while the ability of three strains of Enterococcus faecium was stronger than that of three strains of Lactobacillus plantarum. In the detection of bile salt hydrolase activity it was found that Lactobacillus plantarum S11 strain had the lowest enzyme activity which could not be detected basically but the enzyme activity of Lactobacillus plantarum QB3-1 strain was as high as 80%. In the further study of cholesterol removal mechanism, we found that the removal mechanism of probiotics is different in strains, and the removal mechanism of probiotics is mainly through the synergistic action of various mechanisms to achieve the purpose of cholesterol removal. It also provides a theoretical basis for the further study of the interaction between various mechanisms. In addition, the safety evaluation of the 6 strains was carried out preliminarily. The sensitivity of 6 strains to 10 antibiotics was different. 3 strains of Enterococcus faecium were all sensitive to vancomycin, and 3 strains of Enterococcus faecium were sensitive to vancomycin. The QB3-2 strain was the most sensitive to antibiotics among the 6 strains. The hemolytic reaction of three strains of Enterococcus faecium was also detected. The results showed that the three strains had no hemolysis, which indicated that the 6 strains were safe and reliable. The research results of this paper provide a theoretical basis for the research and development of low cholesterol fermented foods. However, in order to be applied to functional fermented food, it is necessary to improve the safety assessment of the tested strains.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R371

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