Helicobacter pylori is a well-known pathogen that is responsible for gastric disorders. Overcoming of the antibiotic-resistance is a main barrier to treat H. pylori infection. In our search for anti-H. pylori compounds from natural resources, bioactivity-guided isolation on the ethyl acetate fraction of Fraxinus mandshurica bark that had shown anti-H. pylori activity gave twelve compounds (1 - 12) of six coumarins, three phenylethanoids, two secoiridoids, and a lignan using silica gel column chromatography, Sephadex-LH 20, and recrystallization.The chemical structures were identified by spectroscopic data analysis, including 1D, 2D NMR, and mass spectrometry. Among them, compounds 2, 10, and 11 showed moderate growth inhibitory activity against three strains ofH. pylori, compared with positive controls of quercetin and metronidazole. Compounds 5, 6, 8, and 12 exhibited the inhibitory activity against strains 26695 or 43504. This is the first report on the anti-H. pylori activity of this plant and the isolated compounds.

Anti-Helicobacter pylori activity guided fractionation led to the isolation of five anthraquinones, two stilbenes and one naphthoquinone from the EtOAc fraction of Polygonum cuspidatum, using silica gel column chromatography, Sephadex-LH20, MPLC and recrystallization. The chemical structures were identified to be physcion (1), emodin (2), anthraglycoside B (3), trans-resveratrol (4), anthraglycoside A (5), polydatin (6), 2-methoxy-6-acetyl-7-methyljuglone (7) and citreorosein (8) by UV, ¹H-NMR, ¹³C-NMR and mass spectrometry. Anti-Helicobacter pylori activity including MIC values of each compound was evaluated. All of the isolates exhibited anti-H. pylori activity of which MIC values were lower than that of a positive control, quercetin. Compounds 2 and 7 showed potent growth inhibitory activity. Especially, a naphthoquinone, compound 7 displayed most potent antibacterial activity with MIC₅₀ value of 0.30 µM and MIC₉₀ value of 0.39 µM. Although anti-H. pylori activity of this plant was previously reported, this is the first report on that of compounds isolated from this species. From these findings, P. cuspidatum roots or its isolates may be useful for H. pylori infection and further study is needed to elucidate mechanism of action.
Anthraquinones ; Chromatography ; Emodin ; Fallopia japonica* ; Mass Spectrometry ; Plants ; Polygonum* ; Quercetin ; Silica Gel ; Stilbenes

Rumex acetosa is a folk medicine for gastritis and gastric ulcers. In our previous study, the ethanol extract of R. acetosa inhibited gastric ulcers and protected gastric tissue in mice induced with HCl/ethanol from gastric ulcers. Moreover, we isolated six anthraquinone compounds from this plant and evaluated their antiHelicobacter pylori activity. Therefore, this study was conducted to identify further the related antioxidant and anti-inflammatory activities and the bioactive constituents. Five fractions of n-hexane, methylene chloride, ethyl acetate, n-butanol, and aqueous fractions were obtained from the total ethanolic extract from whole parts of R. acetosa that had exhibited antioxidant and anti-inflammatory activities. The ethyl acetate fraction contained the highest total phenol and flavonoid contents among the five fractions and exhibited the most potent antioxidant effect on 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Among the six compounds, emodin showed the most potent antioxidant activity. Next, we induced inflammation in the LPS-induced RAW 264.7 cell line. The methylene chloride fraction showed the strongest reducing nitric oxide production activity among the fractions. In addition, the methylene chloride fraction suppressed the phosphorylation of ERK and JNK, and the expression of cyclooxygenase-2 in a dose-dependent manner. These physiological activities of the fraction and the compounds could be involved in the anti-gastric ulcer activity of R. acetosa