Quercetin ameliorates celiac-related intestinal inflammation caused by wheat gluten through modulating oxidative stress, Th1/Th2/Treg balance, and intestinal microflora structure†

Celiac disease is a chronic inflammatory autoimmune disease of the small bowel, and about 1% of the world's population is afflicted with celiac disease. To date, the most efficient treatment option is that the patient is required to strictly follow a gluten-free diet for their entire life, but it's difficult to adhere to and can lead to new nutritional imbalances, making it urgent to find novel nutritional interventions. Our aim was to explore the effects of nutritional intervention with quercetin on the celiac toxic effects of wheat gluten. This study systematically assessed the regulatory roles of quercetin on intestinal oxidative damage, immune response, inflammatory damage, and intestinal microflora dysbiosis in celiac disease by utilizing the established celiac in vitro and in vivo models induced by gluten. We discovered that quercetin could play a crucial role in intervening in celiac pathogenesis, not only owing to its antioxidant properties, but also because it modulates immune cell function and the intestinal microflora structure, particularly the regulation of Th1/Th2/Treg immune cell subpopulations and their functions, inhibition of the abundance of celiac disease marker flora such as Clostridium_celatum and Bacteroides_acidifaciens, and upregulation of the abundance of beneficial flora such as Butyricoccus_pullicaecorum and Bifidobacterium_longum, which ultimately worked together to ameliorate the celiac-related intestinal inflammation triggered by gluten. This study might provide new insights into the regulation of gut immunity and intestinal microflora homeostasis, as well as the potential application of quercetin in celiac disease.