Herbal Formula-3 ameliorates OVA-induced food allergy in mice may via modulating the gut microbiota.

Formula-3 is a Chinese herbal medicine formula that was shown to inhibit food allergy in rats by stabilizing mast cells. But whether Formula-3 ameliorates food allergy through modulating the composition of intestinal microbiota remains to be explored. Here, we aimed to determine whether gut microbiota mediate the anti-food allergic effects of Formula-3. Mouse model of food allergy (FA) was induced by intragastrically administered with ovalbumin and cholera toxin for two weeks, then these mice were orally administrated daily with 1 ml PBS (0.1 mmol/L) or 1 ml Formula-3 (100 mg/m1) for four weeks. The number and abundance of gut mircrobiota were measured with 16S rRNA gene sequencing. We found administration of Formula-3 significantly alleviated FA by decreasing the serum levels of specific IgE, and Th2 cytokine IL-4, IL-5, and IL-13. The dominant characteristics of gut microbiota in mice with FA was the increase in Firmicutes and decrease in Bacteroidetes, and the emergence of Deferribacteres. Formula-3 treatment partially reversed the gut bacterial dysbiosis via increasing Bacteroidetes and decreasing Firmicutes. Moreover, Formula-3 decreased the bacteria from Prevotella, Moryella and Clostridium, and increased Rikenella. Functional analysis indicated modules involved in phosphotransferase system and lipopolysaccharide biosynthesis were enriched in FA mice, while Formula-3 treatment enriched pathways of multiple transport system. Our study reveals that Formula-3 may ameliorate food allergy through modulating the bacterial dysbiosis.