Epicatechin protects mice against OVA-induced asthma through inhibiting airway inflammation and modulating gut microbiota

Allergic asthma is a chronic airway inflammatory reaction that seriously affects people's quality of life and even endangers their lives. The aim of this study was to explore the role of epicatechin (EC) on asthma and its potential mechanism. A mice model of allergic asthma was established by intraperitoneal injection of ovalbumin (OVA) with aluminum hydrogen solution, and nebulized inhalation of OVA to stimulate. EC (10, 20, 40 mg/kg) was administered 30 min before nebulization for three consecutive days. The results showed that EC attenuated OVA-induced lung injury, inflammatory cell infiltration, IgE, and inflammatory cytokine production. EC also inhibited OVA-induced NF-κB activation and increased Nrf2 and HO-1 expression. 16S rRNA sequencing analysis demonstrated that at genus level, EC significantly increased the abundance of Lachnospiraceae_NK4A136_group, Ligilactobacillus, Alloprevotella. Meanwhile, EC inhibited the abundance of Clostridia UCG-014, Helicobacter, Paramuribaculum, and Escherichia-Shigella. In conclusion, EC can effectively alleviate the symptoms of asthma in mice, which may through regulating the composition of gut microbiota and inhibiting inflammatory response.