Antioxidant activity and short-chain fatty acid production of lactic acid bacteria isolated from Korean individuals and fermented foods.

Compounds of the cell walls of heat-killed lactic acid bacteria show immunomodulatory properties which boost immunological systems, and are used ad postbiotics (paraprobiotics). In this study, we used 17 different heat-killed isolates as postbiotics and evaluated their anti-inflammatory potential on the expression of proinflammatory mediators and cellular signaling pathways of murine macrophage, RAW 264.7 cells. Bifidobacterium bifidum MG731 showed the high 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity (90.6%), followed by Bifidobacterium lactis MG741 (59.6%). The Bi. lactis MG741 showed the high ABTS free radical scavenging activity (99.5%), followed by Lactobacillus plantarum MG989 (98.9%), Lactobacillus salivarius MG242 (97.1%), and Bi. bifidum MG731 (96.1%). In addition, Bi. bifidum MG731 showed the lowest nitric oxide production (4.28 µM), followed by B. lactis MG741 (10.80 µM), L. salivarius MG242 (14.60 µM), and L. plantarum MG989 (19.60 µM). The selected strains showed a decreased nitric oxide production via downregulation of inducible nitric oxide synthase and cyclooxygenase 2, which were upregulated via LPS-stimulated RAW 264.7 macrophages. Short-chain fatty acids (SCFA) including acetic, propionic, and butyric acid were produced by four strains. The Bi. bifidum MG731 showed total SCFAs production (4998.6 µg/g), Bi. lactis MG741 (2613.9 µg/g), L. salivarius MG242 (1456.1 µg/g), and L. plantarum MG989 (630.2 µg/g). These results indicated that the various selected strains may possess an anti-inflammatory potential and provide a molecular basis for the development of functional probiotics.

Heat-Killed Lactic Acid Bacteria Inhibit Nitric Oxide Production via Inducible Nitric Oxide Synthase and Cyclooxygenase-2 in RAW 264.7 Cells.

Heat-killed lactic acid bacteria perform immunomodulatory functions and are advantageous as probiotics, considering their long product shelf-life, easy storage, and convenient transportation. In this study, we aimed to develop appropriate heat treatments for industrial preparation of probiotics with antioxidant activity. Among 75 heat-killed strains, Lactococcus lactis MG5125 revealed the highest nitric oxide inhibition (86.2%), followed by Lactobacillus acidophilus MG4559 (86.0%), Lactobacillus plantarum MG5270 (85.7%), Lactobacillus fermentum MG4510 (85.3%), L. plantarum MG5239 (83.9%), L. plantarum MG5289 (83.2%), and L. plantarum MG5203 (81.8%). Moreover, the heat-killed selected strains markedly inhibited lipopolysaccharide-induced nitric oxide synthase and cyclooxygenase-2 expression. The use of heat-killed bacteria with intact bio-functionality can elongate the shelf-life and simplify the food processing steps of probiotic foods, given their high stability. The antioxidant and immune-modulatory activities of the heat-killed strains selected in this study indicate a strong potential for their utilization probiotic products manufacturing.

Inhibition of Nitric Oxide Production, Oxidative Stress Prevention, and Probiotic Activity of Lactic Acid Bacteria Isolated from the Human Vagina and Fermented Food.

In this study, lactic acid bacteria (LAB) with antioxidative and probiotic activities were isolated from the vaginas of Korean women and from fermented food. Among 34 isolated LAB strains, four strains (MG4221, MG4231, MG4261, and MG4270) exhibited inhibitory activity against nitric oxide production. The MG4221 and MG4270 strains were identified as Lactobacillus plantarum, and MG4231 and MG4261 were identified as Lactobacillus fermentum. These strains were able to tolerate pepsin and pancreatin, which is required for probiotic potential. The antioxidant effects of culture filtrates obtained from selected strains included 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity. Most of the culture filtrates had effective DPPH scavenging activity.In conclusion, the selected strains have significant activities and are potentially applicable to the development of functional foods. These strains might also contribute to the prevention and control of several diseases associated with oxidative stress, when used as functional probiotics.

In vitro probiotic properties of vaginal Lactobacillus fermentum MG901 and Lactobacillus plantarum MG989 against Candida albicans.

Candida albicans is the most important Candida species causing vulvovaginal candidiasis (VVC). We investigated the potential of the probiotic strains Lactobacillus fermentum MG901 and L. plantarum MG989 towards control of C. albiacns. Cell viability tests following co-culturing with lactobacilli revealed that C. albicans cells lost metabolic activity and were eventually killed. Further studies revealed that MG901 and MG989 had high surface hydrophobicity that enhanced its adhesion ability to epithelial cell. The MG901 and MG989 showed coaggregation with E. coli and C. albicans to affect their adhesion and colonization. The adhesion of MG901 and MG989 to HT-29 cell and its inhibition of E. coli and C. albicans adherence to these cells were demonstrated. These incidences provided evidence of the possible colonization of MG901 and MG989 that would prevent binding and growth of E. coli and C. albicans onto intestinal epithelial cells. Following daily administration of 108 CFU of viable MG901 and MG989 orally, the animals' feces were examined for bacterial excretion. The potential probiotic MG901 and MG989 were found to persist for up to 6 days in the feces of mice. In conclusion, L. fermentum MG901 and L. plantarum MG989 have the potential to inhibit the yeast growth, which could possibly have played an important role in helping to clear VVC in vivo.

In Vitro Probiotic Properties of Lactobacillus salivarius MG242 Isolated from Human Vagina.

Vulvovaginal candidiasis (VVC) is a very common infection worldwide that is mainly caused by Candida albicans. In a previous study, we showed that Lactobacillus salivarius MG242 has anti-Gardnerella vaginalis activity. In this study, we investigated the potential of using L. salivarius MG242 for biocontrol of C. albicans. In line with the results from a spot overlay assay, MG242 inhibited the growth of C. albicans by 99.99 ± 0.01% in co-culture, suggesting that L. salivarius MG242 has the potential to be developed into a probiotic formula to treat or prevent VVC. Accelerated storage tests using dehydrated live cell powder at 50, 60, and 70 °C were performed, and the results showed that immobilization with 10% skim milk effectively increased the thermal resistance of entrapped microorganisms, resulting in sevenfold longer shelf-life than the control (in PBS). Lower storage temperatures also increased the shelf-life up to 8.31 months.

Inhibitory effects of fermented extract of Ophiopogon japonicas on thrombin-induced vascular smooth muscle cells.

Ophiopogon japonicus is known to have various pharmacological effects. The present study investigated the effects of an extract of fermented Ophiopogon japonicas (FEOJ) on thrombin­treated vascular smooth muscle cells (VSMCs). FEOJ treatment inhibited the proliferation of VSMCs treated with thrombin as indicated by an MTT assay. These inhibitory effects were associated with decreased phosphorylation of AKT, reduced expression of cyclin D1 and increased expression of p27KIP1 in thrombin­induced VSMCs. In addition, FEOJ treatment suppressed the thrombin­stimulated migration of VSMCs as demonstrated by a wound­healing migration assay. Furthermore, zymographic analyses demonstrated that treatment of FEOJ with VSMCs suppressed the thrombin­induced expression of matrix metalloproteinase (MMP)­2, which was attributed to the reduction of nuclear factor (NF)­κB binding activity. Collectively, these results demonstrated that FEOJ induced p27KIP1 expression, reduced cyclin D1 expression and AKT phosphorylation, and inhibited MMP­2 expression mediated by downregulation of NF­κB binding activity in thrombin­treated VSMCs, which led to growth inhibition and repression of migration. These results supported the use of FEOJ for the prevention of vascular diseases and provided novel insight into the underlying mechanism of action.

Anti-inflammatory actions of probiotics through activating suppressor of cytokine signaling (SOCS) expression and signaling in Helicobacter pylori infection: a novel mechanism.

BACKGROUND AND AIMS: In spite of the International Agency for Research on Cancer's definition that Helicobacter pylori is the definite carcinogen of gastric cancer, the simple eradication of the bug is not enough to prevent resultant gastric cancer, and increasing microbial resistance further limits the eradication application. Therefore, probiotics, non-pathogenic microbial feed that can affect the host in a beneficial manner, could be an alternate way to enhance anti-inflammation against H. pylori. However, the mechanism of their anti-inflammatory actions is still unclear. In the current study, we hypothesized that suppressor of cytokine signaling (SOCS) signaling could be a feasible anti-inflammatory mechanism of probiotics against H. pylori infection. RESULTS: H. pylori infection or their lipopolysaccharide stimulation led to significant increased expressions of inflammatory mediators including tumor necrosis factor-alpha, interleukin-8, inducible nitric oxide synthase and cyclooxygenase-2 in AGS cells and pretreatment of Lactobacillus plantarum, Lactobacillus rhamnosis and Lactobacillus acidophilus significantly attenuated the expressions of these inflammatory mediators in accordance with the blocking action of nuclear factor-kappaB nuclear translocation. Probiotic administration increased expression of SOCS-2 and SOCS-3 and exerted the active SOCS signaling featured with earlier and higher expressions of SOCS-2 and SOCS-3. In contrast to weak inactivation of mitogen-activated protein kinases including p-38 and extracellular signal-regulated kinase 1/2, probiotic-induced SOCS expressions were mediated through either significant phosphorylation of signal transducers and activation of transcription (STAT)-1 and STAT-3 or simultaneous inhibition of Janus kinase (JAK)2 phosphorylation, which is known to signal SOCS-2/SOCS-3 negatively. CONCLUSION: Anti-inflammatory signals of SOCS through STAT-1/STAT-3 activation and JAK2 inactivation might be a key anti-inflammatory mechanism of probiotics, setting probiotics as a non-microbial strategy to H. pylori infection.