NOS2 and irritable bowel syndrome: Similarly, luteolin also ameliorates irinotecan-induced inflammation and oxidative stress in Caco-2 cells by upregulating PPARγ, HO-1, and SOD and downregulating IL-1β and iNOS; however, its protective effect is lost when PPARγ is downregulated, except for IL-1β, indicating luteolin’s PPARγ-dependent mechanism in IBD (205).