Investigation of the effects of some natural compounds on the formation of biofilm on intestinal cells

Planktonic and biofilm forms of microorganisms; it consists of a potential threat in areas such as food, health, agriculture and industry. Biofilm formation occurs changing from planktonic forms of microorganisms to biofilm forms. In recent years, problems related to biofilm formation gradually have been increasing. Biofilm-related infections caused by opportunistic pathogens frequently occur, especially in immunocompromised individuals. In this thesis, antibacterial and antibiofilm effects of gallic acid, resveratrol and curcumin against P. aeruginosa, S. aureus, E. faecalis and E. coli bacteria were investigated. The antiproliferative effects of these compounds in Caco-2 human colon cancer and THP-1 human monocyte cell lines were also investigated. As a result of these studies, natural compounds used decreased the proliferation of bacteria and cell lines depending on the concentration. Particularly in the Caco-2 cell, the IC50 concentration of gallic acid was determined to be 50 µM E. coli LPS was used to compose inflammation in the in vitro co-culture model since E. coli is the predominant species of normal intestinal flora. THP-1 monocyte cells were constituted inflammation by having stimulated with E. coli LPS. In in vitro co-culture model by having use THP-1 and Caco-2 cells, immunological effects of 50 µM gallic acid in terms of pro/anti-inflammatory cytokines were evaluated and inhibition of TNF-α and IL-1ß levels was observed. At the same time, the effects of gallic acid in ulcerative colitis model studied in rats as in vivo were investigated and it was observed that gallic acid plays an important role in reducing the formation of pathogenesis. Gallic acid is an important natural compound with antimicrobial, antimicrobial activity, showing anti-inflammatory effect in the in vitro co-culture model and in vivo ulcerative colitis model.