Amelioration of Ovalbumin-Induced Food Allergy in Mice by Targeted Rectal and Colonic Delivery of Cyanidin-3-O-Glucoside.

Targeted rectal and colonic delivery is an effective strategy to exploit the biological functions of polyphenols. This work investigated the anti-food allergy (FA) activity of cyanidin-3-O-glucoside (C3G) delivered by enteric sodium alginate in vivo. The results showed that through targeted rectal and colonic delivery, the C3G showed better results in ameliorating clinical allergic symptoms, diarrhea, and serological indicators including ovalbumin-specific IgE, histamine, and mast cell protease-1. The C3G was more efficient in enhancing the intestinal epithelial barrier by up-regulating the tight junction protein expression and promoting secretory IgA and β-defensin secretion. The improved bioactivity in regulating T helper (Th)1/Th2 immune balance in the intestinal mucosa was also observed. Compared with the intestinal microbiota structure of the model group, targeted rectal and colonic delivery of C3G was able to bring the abundance of Bacteroidota and Firmicutes close to the levels found in normal mice. Furthermore, there was an evident increase in beneficial bacteria in the intestinal flora, such as Lactobacillus and Odoribacter , and a decrease in pathogenic bacteria like Helicobacter and Turicibacter . Therefore, the anti-FA activity of C3G could be increased via targeted rectal and colonic delivery, while the mechanism might be attributed to the regulation of intestinal microecological homeostasis.