Protective Effects of Humulus japonicus Extracts against Gastroesophageal Reflux Esophagitis in Rats

Abstract

The incidence of gastroesophageal reflux disease (GERD) is increasing in Asia. Considering that GERD is ahighly recurrent and chronic disease, there is an increasing demand for new therapeutic options. Humulus japonicus hasantioxidant and anti-inflammatory properties. In this study, the protective effects of H. japonicus extracts (HJE) wereevaluated in a surgically-induced reflux esophagitis rat model. Firstly, the esophageal mucosa was damaged in the controlgroup and lesions were developed. Administration of HJE markedly reduced the lesions in the esophageal mucosamacroscopically. The higher acidity and volume of gastric contents in the control group was decreased by the administrationof HJE. Malondialdehyde level, associated with lipid peroxidation due to oxidative stress, was reduced in the HJE-treatedgroup. The level of superoxide dismutase, an antioxidant enzyme, was increased in the HJE-treated group. The levels ofthe inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) were increased in the control group; however, HJEadministration significantly lowered these levels. This implied that reflux esophagitis is caused by the combined action ofoxidative stress and inflammatory response. HJE has shown protective effects against reflux esophagitis by its antioxidant,anti-inflammatory, and anti-secretory activities. These results suggested that HJE could have therapeutic effects in refluxesophagitis.