ANTIOXIDANT, ANTI-INFLAMMATORY AND GUT EPITHELIAL REGENERATIVE ACTIVITIES OF PREBIOTICS, PROBIOTICS AND BIOGENIC PROPOLIS


De Marco S., Piccioni M., Pagiotti R., Pietrella D.
University of Perugia, Italy

Introduction:
The most widely used probiotic strains in humans are Bifidobacteria and Lactobacilli, but other microorganisms, such as the yeast Saccharomyces boulardii, have been reported to have some beneficial effects. Probiotics can be administrated with specific prebiotics and biogenic compounds in a combination called synbiotic.
The aim of the present work was to assess the probiotic potentiality of Lactobacillus casei, Lactobacillus reuteri, Lactobacillus acidophilus, Lactococcus lactis and Saccharomyces boulardii and the effect of propolis extracts, as biogenic, in terms of antioxidant and anti-inflammatory activities. Successively, the effects of cell-free supernatants on regeneration of colon epithelial HT-29 cell line have been determined. Prebiotics inulin, fructo-oligosaccharide (FOS) and isomaltose were added to the cultures to observe if they could improve probiotic activities.

Methods:
Cell-free culture supernatants of probiotics incubated overnight in presence or absence of prebiotics were used in this study. Bee and bud poplar propolis samples were obtained by ethanol extraction.
The antioxidant activity of probiotic supernatants and propolis was measured by means of neutralizing the free DPPH radical and reducing ROS production by neutrophils activated with phorbol-12-myristate-13- acetate. The anti-inflammatory activity has been determined by testing the IL-8 secretion by intestinal cells (HT-29), IL-1β, TNF-α and IL-10 by peripheral blood mononuclear cells (PBMC) stimulated with LPS and/or probiotic supernatants or propolis extracts by immune assay ELISA.
Regeneration of HT-29 cells treated with cell-free supernatants was assessed by determining cell proliferation by bioluminescent detection of cellular ATP and by in vitro wound healing assay.

Results:
A dose-dependent DPPH radical scavenging activity of probiotic was observed for all strains with the exception of S. boulardii supernatant. Propolis showed a good anti-oxidant activity in cell-free and neutrophil-based assays.
Regarding anti-inflammatory activity, supernatants were able to down-regulate the basal production and the LPS-induced secretion of pro-inflammatory IL-8 in HT-29 cells in a dose dependent manner. Moreover, supernatants of L. acidophilus, L. lactis and L. reuteri were able to increase significantly the basal production of anti-inflammatory IL-10 in PBMC. Propolis extracts were able to inhibit the TNF-α and IL-1β secretion by human leukocytes stimulated with LPS. It is important to highlight that cell viability was not affected by LPS-stimulation and/or cell-free supernatants or propolis treatments.
All strains, except for L. reuteri, affect HT-29 cell proliferation: cell-free supernatants significantly increased the growth rate of cells after 48-h of incubation.
Furthermore, we observed that the addition of prebiotics did not promote probiotic effects in any activity tested.

Discussion:
Our results indicated that probiotic supernatants and propolis could effectively scavenge free radicals. Both propolis and probiotics have shown anti-inflammatory property. The modulation of pro- and anti-inflammatory cytokines expression is probably due to metabolites produced by probiotics during their growth. This activity suggests that a synbiotic combination of metabolites of cell-free supernatants and propolis could be used as adjuvant therapy in gut inflammatory diseases.

Keywords: Probiotics, Prebiotics, Propolis, Anti-inflammatory acitivity, Anti-oxidant activity, Regenerative activity

Citation:
De Marco S., Piccioni M., Pagiotti R., Pietrella D(2016). Antioxidant, anti-inflammatory and gut epithelial regenerative activities of prebiotics, probiotics and biogenic propolis. Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 90.). IPC2016

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