Antibacterial effects of the urushiol component in the sap of the lacquer tree (Rhus verniciflua Stokes) on helicobacter pylori

Abstract

[한글]

[영문]Eradication regimens for Helicobacter pylori infection have side effect, compliance problem, relapse, and antibiotic resistance. Therefore, alternative anti-H. pylori and/or supportive antimicrobial agents with fewer complications are necessary for the treatment of H. pylori. Urushiol is a major component of the lacquor tree which has been used as a folk remedy for the relief of abdominal discomfort or dyspepsia. The aim of this study was evaluate the antibacterial effects of the urushiol on H. pylori. Two types of urushiol (mainly monomer urushiol and 2-4 polymer urushiol by mass spectrometer analysis) were used. In the in vitro study, we investigated the pH and concentration dependent antibacterial activity of the crude urushiol extract from the sap of the lacquer tree against 5 strains (NCTC 11637, 69, 219, 26695, and Sydney Strain 1) of H. pylori by the agar dilution method. In addition, the serial (before incubation, 3, 6, and 10 minutes after incubation) morphological effects of urushiol on H. pylori were examined by electron microscopy. In vivo animal study performed for the safety of the 2-4 polymer urushiol, the H. pylori eradiation rate of 2-4 polymer urushiol, the effects of urushiol on H. pylori-induced gastritis, and the expression of pro-inflammatory cytokines. All strains survived within a pH 6.0~9.0. The minimal inhibitory concentrations of the extract against strains ranged from 0.064 to 0.256 mg/mL. Urushiol caused mainly separation of the membrane, vacuolization, and lysis of H. pylori. Interestingly, these changes were observed within 10 minutes following incubation with the 1 × minimal inhibitory concentration of the 2-4 polymer urushiol. In the animal study, the 2-4 polymer urushiol (0.128 mg/mL/day for 7 days) feeding did not cause hypersensitivity reaction on mice. The H. pylori eradication rates were 33% in the urushiol monotherapy, 75% in the triple therapy (omeprazole + clarithromycin + metronidazole), and 100% in the combination of triple therapy with urushiol, respectively. H. pylori-induced gastritis was not changed by urushiol but reduced by eradication. Of the pro-inflammatory cytokines, only the expression of interleukin 1β in the gastric tissue was significantly increased by H. pylori infection and reduced by the urushiol and H. pylori eradication (p = 0.014). The results of this study suggest that the 2-4 polymer urushiol has an antibacterial effect against H. pylori infection and can be used safely below a concentration with 0.128 mg/mL/day for 7 days. Therefore, development of stable urushiol polymer without allergic reaction would be the next step to make it a new therapeutic agent on H. pylori eradication.