Monotherapy with mastic does not eradicate Helicobacter pylori infection from mice.

OBJECTIVE To determine the ability of mastic monotherapy to eradicate Helicobacter pylori infection from mice. MATERIALS AND METHODS The susceptibility of H. pylori SS1 to mastic was assessed by broth dilution determination of the MIC and MBC. Mice were inoculated intragastrically with either a suspension of H. pylori SS1 (n = 70) or brain-heart infusion broth alone (n = 10). Mice were given antimicrobial chemotherapy 4 weeks after infection and were administered the mouse equivalent of either 2 g of mastic twice daily for 7 days or a triple therapy regimen containing the mouse equivalent of 400 mg of metronidazole, 250 mg of clarithromycin and 20 mg of omeprazole twice daily for 7 days. Mice were killed either immediately or 1 month after the completion of treatment, and their stomachs cultured for H. pylori. RESULTS The mastic MIC and MBC of H. pylori SS1 were 7.80 and 31.25 mg/L, respectively. The triple therapy regimen eradicated infection from 19 of 20 SS1-infected mice. Mastic failed to eradicate infection from any of the 18 SS1-infected mice (P < 0.001) and there was no signifi- cant reduction in gastric bacterial load in mice treated with this regimen. CONCLUSION Despite reported beneficial effects in ulcer patients and the good in vitro activity of mastic against H. pylori, this compound is unable to eradicate H. pylori infection from mice.