Mina Tabak

Cinnamon extracts’ inhibitory effect on Helicobacter pylori

Ethanol and methylene chloride extracts of cinnamon were compared for their effect on Helicobacter pylori growth and urease activity. Methylene chloride extract was found to inhibit growth of H. pylori, while ethanol extract counteracted its urease activity. Cinnamon extract (from methylene chloride) inhibited H. pylori at concentration range of common antibiotics. Complete inhibition in vitro was achieved by 50 microg/ml in solid medium (egg yolk emulsion agar) and by 15 microg/ml in liquid medium (supplemented brain heart infusion broth). The cinnamon extracts were more inhibitory on free urease than on whole cell urease.

Controlled trial of the effect of cinnamon extract on Helicobacter pylori.

Background. Helicobacter pylori has been associated with the pathogenesis of antral gastritis, duodenal ulcer, and gastric lymphoma. Eradication of H. pylori has been shown to reverse or prevent relapse of these diseases. Antimicrobials employed in the eradication of H. pylori are not without adverse effects. Newer treatment modalities, therefore, are required. In vitro studies have shown the effectiveness of cinnamon extract against H. pylori and its urease. In this pilot study, we tested the activity of an alcoholic extract of cinnamon in a group of patients infected with H. pylori.

Quinolone Resistance of Salmonella enterica Serovar Virchow Isolates from Humans and Poultry in Israel: Evidence for Clonal Expansion

ABSTRACT Salmonella enterica serovar Virchow is highly prevalent in humans and farm animals in Israel. In addition to high rates of resistance to multiple antibiotics, this serovar exhibits a high incidence of resistance to nalidixic acid. More than 90% of Salmonella serovar Virchow isolates of human and poultry origin obtained from 1997 to 2004 were resistant to nalidixic acid (MIC ≥ 128 μg/ml), with reduced susceptibility to ciprofloxacin (MIC between 0.125 and 0.250 μg/ml). Most isolates belonged to two predominant, closely related pulsed-field gel electrophoresis image types. Investigation of the mechanisms of quinolone resistance revealed that this pathogen probably emerged from a parental clone that overproduced the AcrAB efflux pump and had a single point mutation in gyrA leading to the Asp87Tyr substitution. The close resemblance between human and poultry isolates points to poultry as a likely source of Salmonella serovar Virchow in the food chain.

Diverse effects of ascorbic acid and palmitoyl ascorbate on Helicobacter pylori survival and growth

Among many antioxidants used in the food, pharmaceutical and cosmetic industries, ascorbic acid (AA) is one of the most important. AA has been suggested to decrease the risk of gastric disease (gastritis, duodenal ulcer, and carcinoma) by direct action on Helicobacter pylori. However, there are limited studies on the possible role of AA and its derivatives such as palmitoyl ascorbate (PA) on the growth and survival of H. pylori. In the present study it was demonstrated in vitro that AA in the concentration range 10-20 mg x ml(-1) (50-100 mM) inhibited H. pylori growth in liquid medium under microaerophilic conditions. In contrast, under aerobic conditions AA in the concentration range 2-20 mg x ml(-1) (10-100 mM) significantly increased the survival of H. pylori presumably eliminating the toxic effect of reactive oxygen species on bacterial cells. The hydrophobic derivative of AA, PA (a food antioxidant), demonstrated a strong antibacterial effect, under both aerobic and microaerophilic conditions in the concentration range 0.04-0.4 mg x ml(-1) (0.1-1.0 mM). This effect was also tested on other bacterial strains: Escherichia coli, Proteus vulgaris, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Clostridium sporogenes and Campylobacter jejuni. Among these bacterial strains, PA showed a similar inhibitory effect on B. cereus and B. subtilis as observed with H. pylori. The results suggest that PA may be considered an important AA derivative in eradication of H. pylori in vitro and in vivo and to decrease the risk for gastric diseases.

Effect of ranitidine on the urea breath test: a controlled trial.

Because Helicobacter pylori is an acid-sensitive organism, an elevation of the gastric pH by H2 inhibitors might improve the intragastric conditions for the development of this organism. We tested this hypothesis in a prospective and controlled trial including 43 patients positive for H. pylori using the rapid urease test. Twenty-six patients received 150 mg ranitidine twice daily and 17 patients received no treatment. The 14C-urea breath test was performed in both groups at the beginning of the study and 2 weeks later. Radioactive 14C in exhaled carbon dioxide was significantly increased (p = 0.045) in the patients treated with ranitidine, compared with the patients in the control group. Administration of this drug to patients infected with H. pylori is associated with an increase in the bacterial load after 2 weeks of treatment. This phenomenon might be attributed to increased bacterial growth due to the H2 blocker.

Inhibition of bacterial urease by autoxidation of furan C-18 fatty acid methyl ester products

Autoxidation products of synthetic methyl 9,12-epoxy-octadeca-9,11-dienoate (MEFA) were investigated by gas chromatography-mass spectrometry analysis and tested for bacterial urease inhibition. A suspension of oxidized MEFA in 10% Tween 80 was an effective inhibitor for bacterial urease extract fromHelicobacter pylori (I50=1.3 mM) and for commercial urease fromBacillus pasteurii (I50=0.06 mM). The urease inhibitory effect was cancelled by adding cysteine to the reaction mixture. The total content of biologically active oxidized products in the mixture was found to be 6.2%. Dioxo-ene derivatives of MEFA on the thin-layer chromatography plate surface were converted into more stable compounds, whose formation in the mixture reduced inhibition ofB. pasteurii to about 2% of the former level. The mechanism of urease inhibition is supposed to involve the interaction of the thiol groups of the enzyme’s active center with the inhibitor molecules.

Antioxidant Properties of Honey Produced by Bees Fed with Medical Plant Extracts

Honey is known to exert beneficial effect on many pathological conditions. The full gamut of its biological activity has yet to be elucidated. In this study five type of honey (regular commercial honey, Chinese honey and three other honeys, namely, Laryngomel, Bronchomel, and Dermomel) were studied for their antioxidant effect. Unlike regular honey, three last honey species were a product of bees which have been fed on a mixture of several medico-herbal water extracts with regular honey. All the assessed honeys demonstrated prevention of β-carotene degradation in linoleic acid emulsion and obviation of Superoxide radical generation by xanthine/xanthine oxidase system. Laryngomel and Bronchomel were particularly effective in reactive oxygen species scavenging at a concentration range 7–50 μg/ml. The relationship between the antioxidant properties of honey and its physiological activity is discussed.