AUTHOR=Khalil Maha A. , Sonbol Fatma I. , Al-Madboly Lamiaa A. , Aboshady Tamer A. , Alqurashi Abeer S. , Ali Sameh S. 

TITLE=Exploring the Therapeutic Potentials of Exopolysaccharides Derived From Lactic Acid Bacteria and Bifidobacteria: Antioxidant, Antitumor, and Periodontal Regeneration

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.803688

DOI=10.3389/fmicb.2022.803688

ISSN=1664-302X

ABSTRACT=<p>The metabolites of lactic acid bacteria (LAB) and bifidobacteria (Bb) have recently received a lot of attention due to their ability to protect interactions in blood and tissues, as well as their biodegradability and biocompatibility in human tissue. Exopolysaccharides (EPS) derived from bacteria have a long history of use in therapeutic and other industrial applications with no adverse effects. In this regard, EPSs were isolated and characterized from LAB and Bb culture supernatants to determine their antioxidant, antitumor, and periodontal regeneration properties. The antioxidant capacity of the EPSs varied with concentration (0.625–20 mg/ml). The highest antioxidant activity was found in LAB: <italic>Streptococcus thermophiles</italic> DSM 24731-EPS<sub>1</sub>, <italic>Lactobacillus delbrueckii</italic> ssp. <italic>bulgaricus</italic> DSM 20081<sup>T</sup>-EPS<sub>5</sub>, <italic>Limosilactobacillus fermentum</italic> DSM 20049-EPS<sub>6</sub>, and Bb; <italic>Bifidobacterium longum</italic> ssp. <italic>longum</italic> DSM 200707-EPS<sub>10</sub>. Human breast cancer cells (MCF7), human colon cancer cells (CaCo2), human liver cancer cells (HepG2), and human embryonic kidney 293 (HEK 293) cells were used as controls to assess the antitumor properties of the selected EPSs. According to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, EPS<sub>5</sub> had the highest cytotoxicity against MCF7, CaCo2, and HepG2, with IC<sub>50</sub> values of 7.91, 10.69, and 9.12 mg/ml, respectively. Lactate dehydrogenase (LDH) activity was significantly higher in cell lines treated with EPS<sub>5</sub>-IC<sub>50</sub> values compared to other EPSs-IC<sub>50</sub> values (<italic>p</italic> &lt; 0.05). Real time (RT)-PCR results showed that EPS<sub>5</sub> treatment increased <italic>Bax</italic>, <italic>Caspase 8</italic>, <italic>Caspase 3</italic>, and <italic>p53</italic> gene expression. The expression of the <italic>BCL2</italic>, <italic>MCL1</italic>, and <italic>Vimentin</italic> genes, on the other hand, was reduced. The MTT test was used to examine the effect of EPS<sub>5</sub> on the viability of human periodontal ligament fibroblast cells (hPDLFCs), and it was discovered that EPS<sub>5</sub> increased hPDLFC viability. According to high-performance liquid chromatography (HPLC) analysis, galactose made up 12.5% of EPS<sub>5</sub>. The findings of this study pave the way for the use of EPS, which hold great promise for a variety of therapeutic purposes such as antioxidant, antitumor, and periodontal regeneration.</p>