With Angiotensin Converting Enzyme Inhibitory Activity Of Probiotic Screening

This project was one important part of"the key technology of oriented screening of probiotics and the development of products(2007AA10Z356)surpported by National High Technology Research and Development Program("863"Program)of China. By screening and appraising the probiotics which could inhibit angiotensin-convertion enzyme in vitro, the high-activity candidate strains were obtained. To insure their biological activity and the inhibition of ACE, isolation and purification of fermentation products and verification of bioactivities had been proceeded based on the test of bacterial morphology, physiology and biological research. The results were as follows:1. By comprehensive comparison of reported determination methods of ACE in vitro, it can be confirmed that the visible spectrophotometry method was accurate, convenient and stable. Six high-activity strains(DM84011, DM8319, DM8320, DM8308, DM84013, DM8317) were selected at last based on the verification of skimmed milk as fermental condition of probiotics and the investigation of its influential factors.2. The chromatography of SephadexG-50 for the candidate strains were carried out by using pH8.3 phosphate buffer as eluent, and colorimetric method of Coomassie brilliant blue coupled with SDS-PAGE had been taken to analyze the quality of the isolated ingredients. The results showed that: the isolated small peptide had a higher ACE inhibitory activity.3. The analysis of microbiology morphology, physiology and biological function for the candidate strains showed that the six candidate strains came from 6 different genera. DM84011 is Lactobacillus bulgaricus; DM8319 is Lactobacillus plantarum; DM8320 is Lactobacillus reuteri; DM84013,DM8308 are Bifidobacterium longum; DM8317 is Bacillus acidophilus; DM84023 is Streptococcus thermophilus respectively , in which DM84013 had better survival adaptabilities in vivo and higher ACE inhibitory activity than others.4. The DM84013 was proved to have better antioxidant capacity by the further evaluation on the antioxidant capacity of different isolates and extracts from the fermentation.Due to the differences of genera, physiological and metabolic characteristics in probiotics, ACE inhibitory activity and anti-oxidation activity were different. Further research and product development of the probiotics were focus on improving screening method in vitro and construction of model system. At the same time, the experimental results proved that further tests on the efficiency of organism were needed to enhance its capability.