AUTHOR=Srikham Kantapich , Daengprok Wichittra , Niamsup Piyanuch , Thirabunyanon Mongkol 

TITLE=Characterization of Streptococcus salivarius as New Probiotics Derived From Human Breast Milk and Their Potential on Proliferative Inhibition of Liver and Breast Cancer Cells and Antioxidant Activity

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.797445

DOI=10.3389/fmicb.2021.797445

ISSN=1664-302X

ABSTRACT=Breast milk is well known as the abundant source of beneficial bacteria. The aim in this study was to investigate the anticancer and antioxidant efficacies of the new potential probiotics isolated from human breast milk. Three strains of lactic acid bacteria (LAB) have shown their potential probiotic criteria including antimicrobial activity, non-hemolysis and survival in acid and bile salt conditions.  These strains showed high abilities on cell surface hydrophobicity, auto-aggregation, and co-aggregation. The genera identification by 16S rRNA sequence and comparison revealed that they were Streptococcus salivarius BP8, S. salivarius BP156 and S. salivarius BP160. The inhibition of liver cancer cells (HepG2) and breast cancer cells (MCF-7) proliferation by these probiotic strains using MTT assay have 44.83–59.65% and 29.85–37.16%, respectively. The probiotic action mode was inducted via apoptotic mechanisms since they stimulate the liver and breast cancer cell death through DNA fragmentation and positive morphological changed by AO/PI staining.  The antioxidant activity of these probiotics in the form of intact cells, cell free supernatant (CFS) and heat-killed cells was evaluated by DPPH assay, resulting in the scavenging activity rates of 16.93–25.43%, 15.47–28.03% and 13.67–23.0%, respectively. These results indicated that these probiotic strains of S. salivarius BP8 and S. salivarius BP160 could be applied as functional foods or new alternative bioprophylactic for treating liver and breast cancers.