Antiadhesion and anti-inflammation effects of noni (Morinda citrifolia) fruit extracts on AGS cells during Helicobacter pylori infection

Helicobacter pylori is a human gastric pathogen that adheres to host cells and injects cytotoxin-associated gene A (CagA) to induce interleukin-8 (IL-8), inducible nitric oxide (iNOS), and cyclooxygenase 2 (COX-2). Noni (Morinda citrifolia) is found to possess antibacteria, anti-inflammation, and antioxidation activities, but its effect on H. pylori infection is still unknown. Ethanol and ethyl acetate extracts of noni fruit were used in this study. The inhibitory effect on CagA and H. pylori-induced IL-8, iNOS, and COX-2 were determined. The coculture medium was collected for measuring neutrophil chemotaxis. Both extracts of noni fruit showed weak inhibition on H. pylori. Both ethanol and ethyl acetate extracts provided antiadhesion of H. pylori to AGS cells and down-regulation on the CagA, IL-8, COX-2, and iNOS expressions. Results also indicated both extracts relieved neutrophil chemotaxis. Noni fruit extracts down-regulated inflammatory responses during H. pylori infection, and the phenolic compounds play key role in antiadhesion.