Screening of lactic acid bacteria that have health promoting effect from Thai local fermented foods

Abstract

Aging has become one of the most important health considerations. Aging is caused by the generation of reactive oxygen species and the activity of free radicals which degenerate the cells in the human body. Aging is the prime factor for different types of diseases like cancer, cardiovascular problems, type II diabetics, hypertension, imbalance of important gut microbiota, and other diseases. Probiotics from fermented foods aid in health promoting functionalities as a function of antioxidant activity and promoting longevity which allows them to be a potential source of supplement. These factors open an interesting prospect of screening well known probiotics, especially lactic acid bacteria (LAB), which containing antioxidant activity from various Thai local fermented foods. This study aimed to screen targeted lactic acid bacteria (LAB) which is well known bacteria group, from 31 plant and animal based Thai local fermented foods in different regions (central, north, west, and north-east) by CaCO3 containing MRS agar and analyzed its probiotic properties and antioxidant activities. It was found that all 18 isolates considered as potential LAB as it had shown clear zone on CaCO3 containing MRS agar, and most isolates exhibited over 70% scavenging of DPPH in both supernatant and pellet except two isolates from plasom and kung jom having 49.12% for supernatant and 58.08% for pellet respectively. But only one isolate, called NYC8, from plant based fermented food showed significant potential probiotic properties, including hydrophobicity, acid-bile tolerance, and antimicrobial activity. Additionally, NYC8 isolate showed reducing ability equivalent to L-cysteine 195.91 µM along as well as lipid peroxidation inhibition capacity 44.34% for pellet and 4.34% for supernatant, and it was the one that had the one of the highest DPPH scavenging activities. After doing 16S rDNA sequencing, it was found that NYC8 isolate had 100% similarity with Lactiplantibacillus plantarum ATCC 14917T (ACGZ01000098) and Lactiplantibacillus argentoratensis 6365T (CP032751). This isolated strain might be further analyzed and developed as a potential longevity promoting supplement product.