White rose (Rosa hybrida) petals were extracted with ethanol (EtOH) or butanol (BuOH), and tested for
their antimicrobial activities against two species of Gram-positive bacteria, six species of Gram-negative
bacteria, and two species of fungi. On in vitro antimicrobial assays, Helicobacter pylori and Propionibacterium
acnes were highly susceptible to white rose petal extract (WRPE)-EtOH and WRPE-BuOH,
leading to minimal inhibitory concentrations of 100 and 10 mg/mL for H. pylori and 400 and 40 mg/mL
for P. acnes, respectively. In in vivo experiments, C57BL/6 mice were infected with H. pylori by intragastric
inoculation (1 108 CFU/mouse) 3 times, and orally treated twice a day for 14 days with WRPE-EtOH and
WRPE-BuOH. On a CLO kit assay, 200 mg/kg of WRPE-EtOH fully eliminated the bacteria from the gastric
mucosa, and the effect of 100 mg/kg of ethanol fraction was similar to pantoprazole (30 mg/kg), displaying
75% elimination. WRPE-BuOH was more effective, exhibiting 75% elimination at 20 mg/kg. The
CLO test results were confirmed by bacterial identification. WRPE-EtOH and WRPE-BuOH inhibited the
growth of various bacteria and fungi, and in particular, they effectively killed H. pylori and eliminated the
bacteria from the mouse stomach. The results indicate that WRPE-EtOH and WRPE-BuOH could be good
candidates for the elimination of H. pylori.