anti-Helicobacter Pylori Activity Research Articles

Anti-inflammatory and cytoprotective effects of selected Pakistani medicinal plants in Helicobacter pylori-infected gastric epithelial cells

Ethnopharmacological relevanceHelicobacter pylori infection is associated with gastritis, peptic ulcer, and gastric cancer. Due to its high global prevalence and uprising resistance to available antibiotics, efforts are now directed to identify alternative source to treat and prevent associated disorders. In the present study, effect of selected indigenous medicinal plants of Pakistan was evaluated on the secretion of interleukin-8 (IL-8) and generation of reactive oxygen species (ROS) in a bid to rationalize their medicinal use and to examine the anti-inflammatory and cytoprotective effects in gastric epithelial cells. Materials and methodsAGS cells and clinically isolated Helicobacter pylori strain (193C) were employed for co-culture experiments. Anti-Helicobacter pylori activity and cytotoxic effects of the selected plants were determined by serial dilution method and DNA fragmentation assay respectively. ELISA and flow cytometry were performed to evaluate the effect on IL-8 secretion and ROS generation in Helicobacter pylori-infected cells. ResultsAt 100μg/ml, extracts of Alpinia galangal, Cinnamomum cassia, Cinnamomum tamala, Mentha arvensis, Myrtus communis, Oligochaeta ramose, Polygonum bistorta, Rosa damascena, Ruta graveolens, Syzygium aromaticum, Tamarix dioica, and Terminalia chebula exhibited strong inhibitory activity against IL-8 secretion. Of these, four extracts of Cinnamomum cassia, Myrtus communis, Syzygium aromaticum, and Terminalia chebula markedly inhibited IL-8 secretion at both 50 and 100μg/ml. Cinnamomum cassia was further assessed at different concentrations against Helicobacter pylori and TNF-α stimulated IL-8 secretion, which displayed significant suppression of IL-8 in a concentration-dependent-manner. Among the plants examined against ROS generation, Achillea millefolium, Berberis aristata, Coriandrum sativum, Foeniculum vulgare, Matricaria chamomilla and Prunus domestica demonstrated significant suppression of ROS from Helicobacter pylori-infected cells (p<0.01). ConclusionResults of the study revealed anti-inflammatory and cytoprotective effects of selected medicinal plants which could partially validate the traditional use of these plants in GI disorders particularly associated with Helicobacter pylori. Furthermore, results obtained may lead to possible future candidates of chemoprevention against peptic ulcer or gastric cancer.

Anti-Helicobacter pylori and anti-internalization activities of Thai folk remedies used to treat gastric ailments

Invasion of gastric epithelium cells by Helicobacter pylori is associated with antibiotic resistance and persistence infection, which contribute to eradication failure in many circumstances. The aims of this study were to investigate the anti-H. pylori and anti-internalization activities of thirteen Thai plant extracts used for gastric ailments in traditional medicine including Curcuma longa (L.), Kaempferia parviflora Wall. Ex Baker, Abelmoschus esculentus (L.) Moench, Musa sapientum (L.), Aloe vera, Centella asiatica (L.), Allium sativum (L.), Zingiber officinale Roscoe, Alpinia galanga (L.) Swartz, Andrographis paniculata, Ocimum basilicum (L.), Ocimum sanctum (L.) and Cymbopogon citratus. The minimum inhibitory concentrations against 11 clinical isolates and 2 reference strains of H. pylori were examined using an agar dilution method. The level of internalization against HEp-2 cells by H. pylori was compared among 3 extracts of C. longa, K. parviflora and M. sapientumby a conventional gentamicin internalization assay. From thirteen methanolic extracts, the extracts of C. longa and K. parviflora exhibited significant anti- H. pylori activities at minimum inhibitory concentration (MIC) of 32 and 64 µg/ml, respectively. The extracts from C. longa andM. sapientum showed inhibitory effects on the internalization of H. pylori to HEp-2 cells at 3 h of treatment. However, the adverse effect of C. longa was found at 6 and 12 h by enhancing the internalization activities. Thus, appropriate use of medicinal plants may be valuable for curing and preventing H. pylori infection. Key words: Helicobacter pylori, medicinal plants, minimum inhibitory concentration (MIC), anti-internalization.

Anti-Helicobacter pylori activity and oxidative burst inhibition by the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin from Paepalanthus latipes

Helicobacter pylori is a bacterium recognized as the major cause of chronic gastritis and peptic ulcers. Infection by H. pylori induces inflammatory responses and pathological changes in the gastric microenvironment. The host Keywords: immune cells (especially neutrophils) release inflammatory mediators and large 5-methoxy-3,4-dehydroxanthomegnin amounts of reactive oxygen species (ROS), which are associated with an increased Helicobacter pyloririsk of developing gastric cancer. In this study, we evaluated the anti-H. pylori and oxidative burst antioxidantactivitiesofa1,4-naphthoquinone-5-methoxy-3,4-dehydroxanthomegnin. Paepalanthus latipes The antimicrobial activity was assessed using a spectrophotometric microdilution technique, and antioxidant activity was assessed by noting the effect of 5-methoxy3,4-dehydroxanthomegnin on the neutrophil oxidative burst using luminol-and lucigenin-amplified chemiluminescence. The results showed that 5-methoxy-3,4dehydroxanthomegnin is a potent anti-H. pylori compound (MIC 64 µg/mL and MBC 128 µg/mL) and a strong antioxidant. 5-Methoxy-3,4-dehydroxanthomegnin decreased luminol- and lucigenin-amplified chemiluminescence, with ED50 values of 1.58±0.09 µg/mL and 5.4±0.15 µg/mL, respectively, reflecting an inhibitory effect on the oxidative burst. These results indicate that 5-methoxy-3,4-dehydroxanthomegnin is a promising compound for the prevention and treatment of diseases caused by H. pylori infection, such as gastritis, peptic ulceration, and gastric cancer, because reactive oxygen intermediates are involved in the pathogenesis of gastric mucosal injury induced by H. pylori infections.

Anti-Helicobacter Pylori effect of fermented ginseng extracts with Lactobacillus plantarum MG 208

Water extract of ginseng was fermented using various lactic acid bacteria, and their anti-Helicobacter pylori activity was evaluated. The fermented ginseng extracts evidenced anti-H. pylori activity, including anti-bacterial, anti-adhesion, and urease inhibition effects. Among the four types of lactic acid bacteria, Lactobacillus plantarum MG 208 evidenced the most profound anti-H. pylori activity in fermented ginseng. Therefore, fermented ginseng extract containing L.plantarum MG 208 could prove useful as functional diet for the protection of the gastric environment against H. pylori.

Volatile compounds in the stem bark of Sclerocarya birrea (Anacardiaceae) possess antimicrobial activity against drug-resistant strains of Helicobacter pylori

The aim of this study was to isolate and identify phytochemicals with anti-Helicobacter pylori activity from the stem bark of Sclerocarya birrea. The plant crude extract was fractionated by silica gel column and thin layer chromatography techniques, initially with ethyl acetate (EA) and subsequently with a combination of ethyl acetate/methanol/water (EMW). Further fractionation and identification of the phytoconstituents was achieved by gas chromatography and mass spectrometry (GC/MS) analysis. The antimicrobial activity of the fractions and compounds was evaluated against five metronidazole- and clarithromycin-resistant strains of H. pylori as well as a reference strain ATCC 43526 using the microbroth dilution technique. Amoxicillin was included in the experiments as a positive control antibiotic. Of the 18 fractions collected, 16 demonstrated anti-H. pylori activity with 50% minimum inhibitory concentration (MIC50) values ranging from 310μg/mL to 2500μg/mL. Two of the fractions (EMW fraction 6 and EA fraction 1) revealed the presence of 5 and 24 compounds, respectively, representing 40.5% and 86.57% of the total composition. Most of the compounds were essential oils, with terpinen-4-ol being the most abundant agent (35.83%), followed by pyrrolidine (32.15%), aromadendrene (13.63%) and α-gurjunene (8.77%). MIC50 ranges for amoxicillin, terpinen-4-ol and pyrrolidine were 0.0003–0.06μg/mL, 0.004–0.06μg/mL and 0.005–6.3μg/mL, respectively. The inhibitory activities of terpinen-4-ol and pyrrolidine were similar to amoxicillin (P>0.05). Most of these compounds are being reported in this plant for the first time and may represent new sources of therapeutically useful compounds against H. pylori.

A toxicological investigation of a celery seed extract having anti-inflammatory activity

An extract of the seed from celery (Apium graviolens) (CSE), and fractions thereof, have been found to possess anti-inflammatory activity, gastro-protective activity, and anti-Helicobacter pylori activity. In view of the potential for employing these extracts for therapeutic use, toxicological investigations were undertaken with an alcoholic extract (A-CSE) which has previously been shown to have the above pharmacological activities. A 28-day toxicity study was performed in rats according to Good Laboratory Practice (GLP) conditions. Eighteen adult male and 18 adult female rats were randomly assigned to 3 treatment groups of 6 rats/sex/group and were dosed orally with A-CSE of 0, 150 or 5,000mg/kg per day. Daily observations of vital signs and body weights were recorded and ophthalmological investigations were performed. At autopsy, the principal organs were weighed and sections collected for histological analysis. Serum and urine samples were collected at termination for routine clinical chemistry. Under non-GLP conditions alpha-2-μ-globulin immunohistochemistry was performed on kidney tissues and hepatic cytochrome P450 protein was determined, as well as, the enzymatic activities of the principal isoforms. All animals survived treatments with no visible or behavioral signs of toxicity being observed during the study. There were no statistically significant differences in body weight gains, body weight gains per day or cumulative absolute body weight gains, for either sex, in any treatment groups when compared with controls. Slightly increased liver weight and liver to body and brain weight ratios were observed in female rats and in liver to body weight ratios in male rats given high dose A-CSE which was a test article effect, but the absence of any microscopic correlates for the liver weight increases suggests that these were not toxicologically significant. Treatment related macroscopic changes were not observed at necropsy and microscopic findings were limited to minimal increases in gastric eosinophils in several male and female rats in the 5,000mg/kg per day treatment groups. Minimal focal degeneration of renal tubules was observed sporadically in both sexes assigned to all treatment groups including control and was consistent with early spontaneous nephropathy of laboratory rats and thus was not considered to represent a pathologic change associated with the test article. Increased serum globulin and phosphorus levels were observed in male rats given 5,000mg/kg per day A-CSE and decreased serum triglycerides levels in female animals given 150 or 5,000mg/kg per day A-CSE. The increase in serum globulin and phosphorus in male animals was small in magnitude and not considered toxicologically significant. The mechanism for the decrease in serum triglycerides in female rats was not apparent. Changes in urinalysis parameters were limited to small decreases in urine pH in female animals in the 150 and 5,000mg/kg per day groups and were not deemed toxicologically significant. Alpha-2-μ-globulin immunohistochemistry was performed on kidney tissues from all animals and found to be within normal physiologic limits. Minor corneal mineralization occurred in some animals from all treatment groups. Cataracts were observed in one in the control and one in an animal that had 5,000mg/kg per day but since the cataracts occurred in the metabolically inactive region of the lens, these were not considered indicative of test article related lesions. There were no changes in total hepatic microsomal protein or in total cytochrome P450 protein. Although male rats appeared to have to higher levels of total microsomal protein than female rats, there appeared to be no treatment effect in either male or female animals. As regards the activity of the various isoforms tested (CYP2B1/2, CYP1A1/2, CYP3A1/2), with the large range of activities detected for each P450 isoform, no clear change in activity or protein were observed, however, these data were not statistically analyzed. These results suggest that there are no toxicologically significant sub-chronic effects of oral A-CSE in rats. The no adverse effect level for systemic toxicity would appear to be 5,000mg/kg per day.

In-vitro antimicrobial activity of Ageratum conyzoides (Linn) on clinical isolates of Helicobacter pylori

The present study evaluates the antimicrobial activity of fractionated extracts ofAgeratum conyzoides in a bid to isolate the active constituents of the plant with anti-Helicobacter pylori activity. Helicobacter pylori was isolated from the specimens following standard microbiology procedures and isolates subjected to pure fractions of plant extracts for antimicrobial assays. Extracts of A. conyzoides was fractionated by silica gel and thin layer chromatography to obtain pure fractions (17). Fractions 23 - 30 and 31 - 36 were so close and had crystals; it was assumed that they had the same active components, so they were combined and considered as one (Fractions 23 - 36). The disk diffusion method was used to determine the susceptibility of 15 strains of H. pylori to the fractions. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for the most active fraction was also determined by the broth dilution method. Results were analyzed by the Fisher’s exact test. All the fractions tested demonstrated antimicrobial activity with zone diameters of inhibition between 0 – 30 mm. However, two of the 17 fractions [23 - 36(100%Hex-Hex/EA20%) and 69 - 83(Hex/EA80%)] demonstrated very potent activities. The lowest MIC and MBC recorded were 0.002 and 0.016 mg/mL respectively. However the MIC of the fractions ranged from 0.016 - 0.500 mg/mL for fractions 23 - 36 and 0.002 - 0.500 mg/mL for fractions 69 - 83. The MBC of the fractions ranged from 0.063 - 0.500 mg/mL for fractions 23 - 36; 0.016 - 1.000 mg/mL for fractions 69 - 83. There was a statistically significant difference (P 0.05) in their activities both for the MIC and MBC. It is concluded that this plant may contain compounds with therapeutic activity, which may be found in fractions 23 - 36 (100%Hex-Hex/EA20%) and 69 - 83(Hex/EA80%). Key words: Antimicrobial activity, medicinal plant, minimum inhibitory concentration, minimum bactericidal concentration, Helicobacter pylori, antimicrobial resistance.

Anti-Helicobacter pylori activities of Eucalyptus grandis: Effects on susceptibility, urease activity and cell surface hydrophobicity

Helicobacter pylori is the primary etiologic agent of peptic ulcer, duodenal ulcer, chronic gastritis, gastric adenocarcinoma and related gastroduodenal disorders. Current triple therapy, including antibiotics and proton-pump inhibitors, has been successful; however, adverse events, non-patient compliance and consequent relapse of Helicobacter pylori infections are common. Crude methanol extracts of Eucalyptus grandis Hill ex. Maiden (Myrtaceae) stem bark were screened against a standard strain ATCC 43504 and ten clinical strains of H. pylori using the agar diffusion method on Mueller-Hinton agar supplemented with defibrinated horse blood and grown in a microaerophilic incubator. All the strains except UCH 97002 and UCH 98020 were inhibited by the extract to varying degrees. The minimum inhibitory concentration (MIC) against the susceptible strains tested ranged from 0.39 and 1.56 μg/mL. The urease activity of the three H. pylori strains tested decreased with increasing concentrations of the extract. The greatest inhibition of urease activity was observed in clinical strain UCH 97009. In addition, methanol extracts of the E. grandis enhanced cell aggregation of seven of the H. pylori strains leading to a decrease in the cell surface hydrophobicity. The salt aggregation test titer decreased from >3 to <1.5 for five of the strains and to <3 for two of the strains. Phytochemical screening of the plant revealed the presence of tannins, essential oils and saponins, while alkaloids were not detected. The anti-Helicobacter pylori activity observed in this study correlates well with the traditional use of this plant in Nigeria.

Anti-Helicobacter pylori activity in the garlic extract

Anti-Helicobacter pylori activity in the garlic extract

Cytotoxic and multidrug resistance reversal activity of a vegetable, 'Anastasia Red', a variety of sweet pepper.

The vegetable, Anastasia Red, Capsicum annuum L. var. angulosum Mill. (Solanaceae) was successively extracted with hexane, acetone, methanol and 70% methanol, and the extracts were further separated into a total of 21 fractions by silica gel or octadecylsilane (ODS) column chromatography. The biological activities of extracts and fractions were determined. These extracts showed relatively higher cytotoxic activity against two human oral tumor cell lines (HSC-2, HSG) than against normal human gingival fibroblasts (HGF), suggesting a tumor-specific cytotoxic activity. The cytotoxic activity of these extracts was enhanced by fractionation on silica gel [H2, A2, M1-M3] or ODS column chromatography [70M]. Several fractions [H2, H4, H5, A1, A2, A3, A5, A6, A7, M2] reversed the multidrug resistance (MDR) phenotype with L5178 mouse lymphoma T cells, more efficiently than (+/-)-verapamil. The extracts and fractions did not show any detectable anti-human immunodeficiency virus (HIV) or anti-Helicobacter pylori activity. Thus, this study suggests the effective and selective antitumor potential of 'Anastasia Red' of sweet pepper for further phytochemical and biological investigation.

Synthesis and anti-Helicobacter pylori activity of pyloricidin derivatives II. The combination of amino acid residues in the dipeptidic moiety and its effect on the anti-Helicobacter pylori activity.

The novel natural antibiotics pyloricidin A, B and C, consisting of a common (2S,3R,4R,5S)-5-amino-2,3,4,6-tetrahydroxyhexanoyl-beta-D-phenylalanine moiety and a terminal peptidic moiety (pyloricidin A: L-valine-L-valine-L-leucine; pyloricidin B: L-valine-L-leucine; pyloricidin C: L-leucine), exhibit potent and highly selective anti-Helicobacter pylori activity. In order to develop more potent compounds and to investigate structure activity relationships for the peptidic moiety with regard to the combination of amino acids, a series of derivatives with various dipeptidic moieties were prepared and evaluated for their anti-H. pylori activity. The combination of the two amino acids in the moiety was found to have a significant effect on the activity; the compound with Nva-Abu showed excellent anti-H. pylori activity with an MIC value of 0.013 microg/ml against H. pylori TN2. In addition, this compound was found to show 60% clearance of H. pylori from infected Mongolian gerbils upon repetitive oral administration (10 mg/kg, b. i. d. for 7 days).

YM-181741, a novel benz[a]anthraquinone antibiotic with anti-Helicobacter pylori activity from Streptomyces sp.

A novel benz[a]anthraquinone, YM-181741, was isolated from the culture broth of actinomycete strain Q57219. The strain was identified as Streptomyces sp. by morphological and chemotaxonomic characterization. YM-181741 was purified from the culture supernatant by serial column chromatography. The structure of YM-181741 was determined by spectroscopic analysis including one- and two-dimensional NMR experiments. YM-181741 showed selective anti-Helicobacterpylori activity with a MIC value of 0.2 microg/ml.

Bactericidal effect of a whey protein concentrate with anti-Helicobacter pylori activity.

To investigate the effect of whey protein concentrate (WPC) enriched in anti-Helicobacter pylori antibodies on growth of the organism in vitro. A WPC rich in H. pylori-specific antibodies was produced by immunizing lactating cows against H. pylori and processing pooled bulk milk samples into whey powder. The antibodies bound several proteins within the bacterial homogenate and were active at pH 5. In a complement-dependent reaction, the immune WPC was highly bactericidal against four H. pylori strains tested in vitro. WPC produced with milk from H. pylori-immunized cows contains antibodies that are active at the pH of the stomach, and bactericidal against H. pylori in vitro, via the classical complement pathway. This study has demonstrated the potential for use of WPC in the prevention/treatment of H. pylori infections.

Do mucosal defensive agents improve the cure rate when used with dual or triple therapy regimens for eradicating Helicobacter pylori infection?

Some of mucosal defensive agents have anti-Helicobacter pylori activities. However, their effectiveness in eradicating H. pylori infection has not been evaluated. To assess the additive effect of mucosal defensive agents in eradication regimens using statistical analysis. Pertinent studies were retrieved using the Medline and the Igaku-chuo-zasshi databases in Japan, reference and congress abstract lists. Studies in which regimens consisted of dual or triple therapy with mucosal defensive agents and without them, were selected from the retrieved studies. Eradication rates were extracted from studies according to intention-to-treat analysis. We evaluated the efficacies of mucosal defensive agents by pooled relative risk of eradication rates and its 95% confidence intervals (95% CI), which were calculated by Mantel-Haenszel method. Heterogeneity among the studies in treatment effect was evaluated by a chi2-test. In dual therapy regimens, mucosal defensive agents demonstrated significant additive effects (pooled relative risk 1.41; 95% CI: 1.24-1.61). In triple therapy regimens, these agents did not provide significant additive effect. The clinical usefulness of specific agents could not be established, when each agent was analysed independently. Mucosal defensive agents improve the cure rate when used with existing dual therapy regimens for eradicating H. pylori infection.

Discovery of a novel benzyloxyisoquinoline derivative with potent anti-Helicobacter pylori activity.

The synthesis and in vitro optimization of the anti-Helicobacter pylori activity of a novel series of benzyloxyisoquinoline derivatives discovered by a random screening process, are described. FR180102 (7f), having a 3-acetamido-2,6-dichlorobenzyl moiety, was found to have extremely potent activity against H. pylori and no effect against a series of common Gram-positive and Gram-negative bacteria.

Chemical structure of bismuth compounds determines their gastric ulcer healing efficacy and anti-Helicobacter pylori activity.

The recognition of the role of Helicobacter pylori in the pathogenesis of peptic ulcer disease has led to renewed interest in bismuth pharmacology since bismuth compounds have both anti-Helicobacter pylori and ulcer healing properties. The precise chemical structure of current bismuth compounds is not known. This has hindered the development of new and potentially more efficacious formulations. We have created two new compounds, 2-chloro-1,3-dithia-2-bismolane (CDTB) and 1,2-[bis(1,3-dithia-2-bismolane)thio]ethane (BTBT), with known structure. In a rat model of gastric ulceration, BTBT was comparable to, and CDTB was significantly less effective than colloidal bismuth subcitrate in healing cryoprobe-induced ulcers. However, both BTBT and CDTB inhibited H. pylori growth in vitro at concentrations <1/10 that of colloidal bismuth subcitrate. The effects on ulcer healing are not mediated by suppression of acid secretion, pepsin inhibition, or prostaglandin production. Since all treated animals received the same amount of elemental bismuth, it appears that the efficacy of bismuth compounds varies with compound structure and is not simply dependent on the delivery of bismuth ion. Because the structure of the novel compounds is known, our understanding of the relationship of bismuth compound structure and to biologic activity will increase. In the future it may be possible to design other novel bismuth compounds with more potent anti-H. pylori and ulcer healing effects.

Low cure rate of Helicobacter pylori infection with omeprazole and furazolidone dual therapy for one week.

Furazolidone is an inexpensive antibiotic that has considerable anti-Helicobacter pylori activity in vitro. Twenty-three patients with culture-proven H. pylori infection were treated for one week with a dual therapy containing omeprazole and furazolidone. Eradication succeeded in 10 of the first 20 evaluable patients (50%; 95% CI: 27.2-72.8%). This percentage was regarded as too low, and the study was terminated. Side-effects were mild. With the possible increase in resistance to metronidazole and clarithromycin world-wide, furazolidone may be useful alternative in the treatment of H. pylori infection. Dual therapy for one week, however, is not sufficient.

CJ-12,954 and its congeners, new anti-Helicobacter pylori compounds produced by Phanerochaete velutina: fermentation, isolation, structural elucidation and biological activities.

Seven new phthalide compounds with anti-Helicobacter pylori activities were isolated from the basidiomycete Phanerochaete velutina CL6387. The two most potent phthalide compounds, CJ-12,954 and CJ-13,014, have MICs of 5 ng/ml. The structure-activity relationship shows that the presence of a spiroketal part in addition to the phthalide part, greatly enhances the activity. The phthalide compounds appear to be specific for H. pylori, since they did not show antibacterial activities when tested against a panel of other microorganisms.

Effect of ranitidine bismuth citrate on postprandial plasma gastrin and pepsinogens.

Ranitidine bismuth citrate was compared with an equipotent dose of ranitidine, to determine whether the former, by an anti-Helicobacter pylori activity, would counteract the rise of gastrin resulting from ranitidine's gastric acid antisecretory activity. Twenty four men with duodenal ulcers were studied before and on the 8th day of dosing with either ranitidine bismuth citrate 800 mg twice daily or ranitidine 300 mg twice daily (double blind, randomised, parallel groups). Fasting and postprandial plasma gastrin and plasma pepsinogen I and II concentrations were measured, and a 13C-urea breath test was performed before and on the 8th day of dosing. The 13C-urea breath tests were positive in 21 patients before dosing and remained positive in nine of nine of the ranitidine dosed patients, whereas only two of 12 patients treated with ranitidine bismuth citrate remained positive. The expected rise in meal stimulated plasma gastrin with ranitidine was seen in the 12 patients who received ranitidine but, despite suppression of H pylori urease activity in 10 of 12 patients taking ranitidine bismuth citrate, there was no attenuation of the meal stimulated gastrin rise. There was no significant difference in the mean derived (4 hour) plasma pepsinogen I and II concentrations after dosing with ranitidine or ranitidine bismuth citrate.