Maize flavonoid rich diet ameliorates experimental colitis - role of gut microbiota
Open Access
- Author:
- Wu, Binning
- Graduate Program:
- Plant Biology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 16, 2020
- Committee Members:
- Surinder Chopra, Dissertation Advisor/Co-Advisor
Surinder Chopra, Committee Chair/Co-Chair
Richard P Marini, Committee Member
Cristina Rosa, Committee Member
Mary J Kennett, Outside Member
Lavanya Reddivari, Special Member
Teh-Hui Kao, Program Head/Chair - Keywords:
- flavonoids
anthocyanins
phlobaphenes
near-isogenic lines
gut microbiota
inflammatory bowel disease - Abstract:
- Inflammatory bowel diseases (IBDs), characterized by gut bacterial dysbiosis, impaired epithelial barrier function, and intestinal inflammation, await effective prophylactic and therapeutic strategy without undesirable side effects. Emerging evidence has associated the consumption of plant-based diets with reduced risk of IBD, partially due to the intake of phytochemicals that offer great health benefits. The naturally occurring flavonoids are being extensively studied for their anti-inflammatory properties and are considered promising therapeutic agents against IBD. However, given their structural variation and the complexity of food matrix that closely interact with flavonoids, studies using whole-food or isolated flavonoids cannot identify with certainty any specific class of compounds providing in their original forms that promote health. To precisely assess the health-promoting properties of two flavonoid classes, anthocyanins and phlobaphenes, we developed four maize near-isogenic lines (NILs) that differ only in pericarp color1 (p1), red1 (r1), and colorless1 (c1) constitution: line ‘A’ lacked both anthocyanins and phlobaphenes, line ‘B’ contained phlobaphenes, line ‘C’ contained anthocyanins, and line ‘D’ contained both anthocyanins and phlobaphenes. Animal experiments using NIL-supplemented diets as feeding materials showed that matrix-bound phlobaphenes could protect against carboxymethylcellulose (CMC)-induced adiposity and low-grade colonic inflammation via intestinal mucus restoration. Further more, matrix-bound anthocyanins and phlobaphenes were capable of modulating the gut microbiota and restoring intestinal barrier function to alleviate experimental colitis. In the microbiota-ablated mice model, we found that the prophylactic efficacy, including the barrier function-restoring properties of anthocyanins and phlobaphenes were significantly weakened. Nevertheless, the intestinal barrier function restoration of anthocyanins and phlobaphenes was partially retrieved in the germ-free mice model. Collectively, these results indicated that the protective effects conferred by anthocyanins and phlobaphenes were partially dependent on the gut microbiota. In summary, our findings shed light on the mechanisms by which anthocyanins and phlobaphenes directly act on the epithelium for barrier function restoration, or indirectly contribute to barrier enhancement via gut microbiota modulation. Our study also provides a rationale to breed for crops with elevated flavonoid content for increased nutritional value and improved dietary benefits.