Phenol glycosides with in vitro anti-Helicobacter pylori activity from Hypericum erectum Thunb

To evaluate the anti-Helicobacter pylori activity of Hypericum erectum methanol extracts in order to provide the primary evidence for their use in clinical practice. An ethyl acetate fraction of H. erectum suspension-cell cultures inhibited the growth of H. pylori in vitro, with a MIC50 range of 38.7-63.2 μg/mL, comparable to metronidazole (MIC50  = 43.2 μg/mL). To further investigate the involved active compounds of the H. erectum extracts, four phenol glycosides were isolated for the current study: quercetin-3'-O-β-D-galactopyranoside, quercetin-3'-O-(2''-acetyl)-β-D-glucopyranoside, 4,6-dihydroxy-2-methoxyphenyl-1-O-β-D-glucopyranoside and 4-hydroxy-2,6-dimethoxyphenyl-1-O-α-L-rhamnopyranosyl(1-6)-β-D-glucopyranoside. The MIC50 values of 4,6-dihydroxy-2-methoxyphenyl-1-O-β-D-glucopyranoside and 4-hydroxy-2,6-dimethoxyphenyl-1-O-α-L-rhamnopyranosyl(1-6)-β-D-glucopyranoside from ATCC43504 strains were 7.3 and 27.3 μg/mL, respectively. The other two phenol glycosides did not show anti-H. pylori activity. The results of this work suggest that H. erectum has some therapeutic potential against H. pylori infection, which could be explored for patients with gastroduodenal disorders.