EFFECTS OF COLOR-FLESHED POTATOES ON DEXTRAN SULFATE SODIUM (DSS)-INDUCED COLITIS AND THE ROLE OF GUT MICROBIOTA
Open Access
- Author:
- Wang, Tianmin
- Graduate Program:
- Horticulture
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 11, 2019
- Committee Members:
- Lavanya Reddivari, Thesis Advisor/Co-Advisor
Surinder Chopra, Thesis Advisor/Co-Advisor
Mary J Kennett, Committee Member - Keywords:
- Anti-inflammatory
Color-fleshed Potato
DSS
Colitis
Anthocyanins
Intestinal Microbiota - Abstract:
- Inflammatory bowel diseases (IBD) are chronic inflammatory disorders in the gastrointestinal (GI) tract. Increasing attention has been given to IBD, including Crohn’s Disease (CD) and Ulcerative Colitis (UC), due to the large and growing number of people who are suffering from this disease all over the globe. Diet is one of the most important modulative factors of this disease, and dietary bioactive compounds, such as anthocyanins, exert health benefits in other chronic diseases, such as cardiovascular disease and cancer, due to the anti-inflammatory and anti-oxidant properties. Anthocyanins are a subgroup of polyphenols and widely exist in plants, contributing to the red, purple, and blue colors of flowers, fruits, and vegetables. In recent decades, new potato cultivars with a high content of anthocyanins, such as Purple Majesty (purple-flesh) and Mountain Rose (red-flesh) have been commercialized and considered as promising alternative sources of dietary anthocyanins since the large consumption of potato in the western diet. The intestinal microbiota is another modulator involved in the development of colitis, and there exists a two-way interaction between gut bacteria and dietary anthocyanins. However, how the interplay between intestinal microbiota and anthocyanins-containing food influences the inflammatory status in the lumen is unclear. Therefore, the goal of this project is to determine whether red- and purple-fleshed potatoes that contain anthocyanins have anti-inflammatory roles in protecting mice against DSS-induced colitis. In addition, we also aimed to investigate how gut microbiota and dietary compounds interaction contributes to the gut inflammation. To achieve our goals, in the first study, we investigated the anti-inflammatory potential of purple-fleshed potato cultivar, Purple Majesty. Mice (C57BL/6) were supplemented with 15% (P15) and 25% (P25) weight of purple-fleshed potato and control diet. After eight weeks of dietary treatment, dextran sulfate sodium (DSS) was introduced into drinking water to induce colitis. Colitis symptoms, such as colon shortening, elevated gut permeability, and splenomegaly, were reduced by both doses of purple-fleshed supplemented diets, which also resulted in suppression of excessive pro-inflammatory cytokines expression. There was a dose-dependent pattern observed in the anti-inflammatory property of purple-fleshed potato supplemented diets. The relative abundance of beneficial species, Akkermensia muciniphila, was increased, whereas specific pathogenic bacteria, pks+ E. coli, was suppressed in mice fed on P15 and P25 diets. The difference in the chemical structure of anthocyanins decides their color and antioxidative activities. Petunidin and malvidin contribute the purple color in the potato flesh, while pelargonidin is mainly found in red-fleshed potatoes. We next investigated whether the difference in anthocyanins in potatoes would influence the anti-inflammatory capacity, by comparing purple- and red-fleshed potato supplements in the DSS-induced colitis model. The results suggested that both red- and purple-fleshed potatoes supplemented diets displayed anti-inflammatory capacity in DSS-induced colitis and purple-fleshed potato was more effective compared to red-fleshed potatoes. In this study, we also investigated the role of intestinal microbiota involved in the protective effects of anthocyanins-containing potato on colitis by ablating gut microbiota. In the microbiota-ablated mice, a minimal protective effect of color-fleshed potato was observed, indicating the presence of intestinal microbiota is essential to fulfill the anti-inflammatory capacity of anthocyanins-rich potato in colitis. The combined results demonstrated that anthocyanins-containing potatoes exert the anti-inflammatory property on colitis in a dose-dependent pattern. Moreover, the intact intestinal microbiota plays an essential role in the protective effects of color-fleshed potatoes against colitis. Given these findings, anthocyanins-rich potatoes may have potential as ingredients for functional foods or nutraceuticals in current treatments of colitis in humans. Further studies are needed to analyze the bacterial metabolites of anthocyanins and investigate their effects on intestinal microbiota and colonic inflammation in colitis.