TDK conference 2019

Flavonoids display various beneficial effects in the human and animal body. Their anti-inflammatory, anti-cancer, anti-bacterial properties have been shown in several studies. The above-mentioned positive effects of these compounds are often attributed to their antioxidant properties which is in close correlation to the number and position of hydroxyl groups in the molecules. Besides hydroxyflavonoids, their methylated analogues have also significant antioxidant effect because these can modulate different protein kinase signalling pathways in the cells. Nevertheless, the information regarding their effects on intestinal epithelium is quite limited. The oxidative stress developed by intestinal infections and inflammation diseases caused by pathogen bacteria leads to serious economic and health problems in animal breeding. Alternative food and feed additives, such as quercetin and its methylated analogues, could be also effective to prevent the above-mentioned diseases.

In this study, the in vitro effect of quercetin, 3-O-methylquercetin and rhamnazin (3’,7-dimethylquercetin) has been investigated in order to evaluate whether these flavonoids could attenuate lipopolysaccharide (LPS) induced oxidative stress in IPEC-J2 non-transformed porcine intestinal epithelial cells. Moreover, effect of the flavonoids on the morphology of the enterocytes was examined.

The cells have been grown in 24-well cell culture plates until they formed a confluent monolayer. Oxidative stress has been induced by LPS from Salmonella Typhimurium (10 µg/ml). Quercetin, 3-O-methylquercetin and rhamnazin have been administered to the cells per se in different concentrations (25, 50 µM) and simultaneous treatment of cells with LPS and quercetin derivatives has been also performed. For the measurement of the extracellular H2O2 the luminescent ROS-Glo method has been used. Other cells have been cultured on Aclar film than treated with the flavonoids (25 µM) and prepared for electron microscopy (EM) examination. The EM pictures were evaluated with the ImageJ program.

The ROS-Glo measurements showed that quercetin and its derivatives significantly decreased the extracellular H2O2 level compared to the controls. The results of the EM measurements showed that flavonoid treatment decreased the number and size of vacuoles and increased the number of microvilli on the surface of the cells. In the future we would like to examine the cell morphology with EM after simultaneous treatment with LPS and the flavonoids.