Protective effects of 18β-glycyrrhetinic acid on LPS-induced injury in intestinal epithelial cells

A Novel Biological Role of α-Mangostin via TAK1-NF-κB Pathway against Inflammatory

The oxysterone α-mangostin is isolated from mangosteen husks and is widely used in the treatment of abdominal pain, diarrhea, and dysentery. In this study, we established a lipopolysaccharide (LPS)-induced inflammatory model of rat intestinal epithelial cells (IEC-6 cells), at the same time we used differently concentration α-mangostin to detect its anti-inflammatory activity. We applied doses of α-mangostin (2.5, 5, and 10 μM) and detected apoptosis by flow cytometry, and the Griess reagent and the enzyme-linked immunosorbent assay (ELISA) method detected inflammatory factors such as nitric oxide (NO), prostaglandin (PG) E2, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. We also used quantitative real-time PCR (Q-PCR) to examine inflammatory factors and western blotting to examine the activation of transforming growth factor-activated kinase (TAK)-1-nuclear factor (NF)-κB signaling pathway-related proteins. Finally, we used laser confocal microscopy to detect the effect of the 10 μM α-mangostin on the nuclear import of NF-κB-p65. The results showed that α-mangostin treatment significantly reduced the apoptosis of LPS-stimulated IEC-6 cells, the production of inflammatory factors, the activation of TAK1-NF-κB signaling pathway-related proteins, and the entry of p65 into the nucleus. In conclusion, α-mangostin exerts its anti-inflammatory effects by inhibiting the activation of TAK1-NF-κB and it may be a potential choice for the treatment of inflammation diseases.

Influence of phytogenics on recovery of the barrier function of intestinal porcine epithelial cells after a calcium switch

Background

The gut barrier is essential for animal health as it prevents the passage of potentially harmful foreign substances. The epithelial tight junctions support the intestinal barrier and can be disrupted by stress caused, for example, by pathogens or dietary or environmental factors, predisposing the host to disease. In animal husbandry, phytogenics (plant‐derived feed additives) are used to support and maintain growth, feed efficiency and health. Therefore, several phytogenics were tested in vitro for their influence on the barrier function recovery of intestinal porcine epithelial cells (IPEC‐J2) after disruption, particularly on the abundance of tight junction proteins.

Results

IPEC‐J2 treated with 1,000 µg/ml liquorice root extract, 80 µg/ml plant powder mix, or 80 µg/ml angelica root powder showed significantly higher trans‐epithelial electric resistance (TEER) 24 hr after tight junction disruption via a calcium switch assay than the control. In contrast, cells treated with 1,000 µg/ml oak bark extract showed a significantly lower TEER after 6 hr but not at later time points. The increased TEER caused by the liquorice root extract correlated with an increase in the abundance of the tight junction protein claudin‐4.

Conclusions

This study suggests potential beneficial effects of liquorice and angelica root extracts on the gut barrier function when used as feed additives for livestock. Further studies, especially in vivo, are necessary to confirm these findings.