Alleviation of Ovalbumin-Allergic Reactions in Mice by Eucommia ulmoides Polysaccharides via Modulation of Intestinal Microbiota

Food allergy represents a prevalent immunological disorder, with current clinical management primarily emphasizing allergen avoidance and emergency pharmacological intervention. Eucommia ulmoides polysaccharides, the principal bioactive constituents of the traditional Chinese medicinal plant Eucommia ulmoides, have demonstrated anti-inflammatory and antioxidant properties: however, their specific effects on food allergies remain inadequately characterized. A total of thirty-six female BALB/c mice were randomly allocated into three groups (n = 12 per group): the control group (CON group, receiving saline treatment), the allergic model group (OVA group, subjected to ovalbumin sensitization), and the intervention group (OVA+PS group, undergoing OVA sensitization followed by Eucommia ulmoides polysaccharides administration via gavage). The anti-allergic efficacy of Eucommia ulmoides polysaccharides was comprehensively evaluated through clinical allergy symptom scoring, histological and pathological tissue analysis, real-time fluorescence quantitative PCR (qRT-PCR) for the assessment of key gene expression, and 16S rDNA sequencing. The findings indicated the following: (1) The allergy scores in the OVA+PS group were significantly lower than those in the OVA group (p &lt: 0.01). Following OVA stimulation, the rectal temperature of mice in the OVA group decreased sharply, whereas the temperature decline in the OVA+PS group was more gradual compared to the model group. (2) The liver, kidney, spleen, and intestinal tissues of mice in the OVA+PS group exhibited normal morphology, consistent with the CON group, which suggests that Eucommia ulmoides polysaccharides effectively mitigates the local inflammatory response induced by food allergy. (3) The expression of NICD in the spleen of mice in the OVA+PS group was significantly higher than in the OVA group (p &lt: 0.05), while the expression of the Hes1 gene was significantly elevated in the OVA group compared to both the CON and OVA+PS groups (p &lt: 0.05). In the OVA group, the expression level of Gata-3 was significantly elevated compared to both the CON group and the OVA+PS group (p &lt: 0.05). Similarly, the expression of STAT5 in the OVA group was markedly higher than in the other groups (p &lt: 0.05). (4) Eucommia ulmoides polysaccharides were found to modulate the intestinal microbiota composition in allergic mice, notably increasing the expression abundance of Enterobacter, Oscillibacter, and Butyricicoccus, while decreasing the expression abundance of Clostridium sensu stricto 1 and Turicibacter. (5) There was a correlation between alterations in the intestinal microbiota of mice and the expression of key genes. Specifically, the relative abundance of Blautia was negatively correlated with the expression of NICD and Gata-3 genes (p &lt: 0.05), and the relative abundance of the Lachnospiraceae_FCS020_group was negatively correlated with the expression of the Hes1 gene (p &lt: 0.05). In conclusion, Eucommia ulmoides polysaccharides demonstrate potential in alleviating allergic symptoms, providing a scientific foundation for the development of novel natural anti-allergic functional foods.