Antibacterial effect of plant extracts against Helicobacter pylori

Protective Effects of Cudrania tricuspidata Against Helicobacter pylori-Induced Inflammation in C57BL/6 Mice

Helicobacter pylori modulates the host inflammatory response, resulting in chronic gastritis, which contributes to gastric cancer pathogenesis. We verified the effect of Cudrania tricuspidata on H. pylori infection by inhibiting H. pylori-induced inflammatory activity. Five-week-old C57BL/6 mice (n = 8) were administered C. tricuspidata leaf extract (10 or 20 mg/kg per day) for 6 weeks. An invasive test (campylobacter-like organism [CLO]) and noninvasive tests (stool antigen test [SAT] and H. pylori antibody enzyme-linked immunosorbent assay) were performed to confirm the eradication of H. pylori. To evaluate the anti-inflammatory effect of C. tricuspidata, pro-inflammatory cytokines levels and inflammation scores were measured in mouse gastric tissue. C. tricuspidata significantly decreased the CLO score and H. pylori immunoglobulin G antibody optical density levels at both 10 and 20 mg/kg per day doses (P < .05). C. tricuspidata decreased the H. pylori antibody levels in a concentration-dependent manner, increased negative responses to SAT by up to 37.5%, and inhibited the pro-inflammatory cytokines interleukin (IL; IL-1β, IL-6, 1L-8, and tumor necrosis factor alpha). C. tricuspidata also relieved gastric erosions and ulcers and significantly reduced the inflammation score (P < .05). We measured rutin in C. tricuspidata extract as a standard for high-performance liquid chromatography. C. tricuspidata leaf extract showed anti-H. pylori activity through the inhibition of inflammation. Our findings suggest that C. tricuspidata leaf extract is potentially an effective functional food material against H. pylori.

Molecular Docking and Efficacy of Aloe vera Gel Based on Chitosan Nanoparticles against Helicobacter pylori and Its Antioxidant and Anti-Inflammatory Activities

The medicinal administration of Aloe vera gel has become promising in pharmaceutical and cosmetic applications particularly with the development of the nanotechnology concept. Nowadays, effective H. pylori treatment is a global problem; therefore, the development of natural products with nanopolymers such as chitosan nanoparticles (CSNPs) could represent a novel strategy for the treatment of gastric infection of H. pylori. HPLC analysis of A. vera gel indicated the presence of chlorogenic acid as the main constituent (1637.09 µg/mL) with other compounds pyrocatechol (1637.09 µg/mL), catechin (1552.92 µg/mL), naringenin (528.78 µg/mL), rutin (194.39 µg/mL), quercetin (295.25 µg/mL), and cinnamic acid (37.50 µg/mL). CSNPs and A. vera gel incorporated with CSNPs were examined via TEM, indicating mean sizes of 83.46 nm and 36.54 nm, respectively. FTIR spectra showed various and different functional groups in CSNPs, A. vera gel, and A. vera gel incorporated with CSNPs. Two strains of H. pylori were inhibited using A. vera gel with inhibition zones of 16 and 16.5 mm, while A. vera gel incorporated with CSNPs exhibited the highest inhibition zones of 28 and 30 nm with resistant and sensitive strains, respectively. The minimal inhibitory concentration (MIC) was 15.62 and 3.9 µg/mL, while the minimal bactericidal concentration (MBC) was 15.60 and 7.8 µg/mL with MBC/MIC 1 and 2 indexes using A. vera gel and A. vera gel incorporated with CSNPs, respectively, against the resistance strain. DPPH Scavenging (%) of the antioxidant activity exhibited an IC₅₀ of 138.82 μg/mL using A.vera gel extract, and 81.7 μg/mL when A.vera gel was incorporated with CSNPs. A.vera gel incorporated with CSNPs enhanced the hemolysis inhibition (%) compared to using A.vera gel alone. Molecular docking studies through the interaction of chlorogenic acid and pyrocatechol as the main components of A. vera gel and CSNPs with the crystal structure of the H. pylori (4HI0) protein supported the results of anti-H. pylori activity.

Three-Decade Failure to the Eradication of Refractory Helicobacter pylori Infection and Recent Efforts to Eradicate the Infection

BACKGROUND

Helicobacter pylori causes dangerous and deadly diseases such as gastric cancer and duodenal ulcers. Eradication and treatment of this bacterium are very important due to the deadly diseases caused by H. pylori and the high cost of treatment for countries.

METHODS

Thus, we present a complete list of the most important causes of failure in the treatment and eradication of H. pylori, and address new therapeutic methods that may be effective in controlling this bacterium in the future.

RESULTS

Many efforts have been made to control and eradicate this bacterium over the years, but no success has been achieved since its eradication is a complex process affected by the bacterial properties and host factors. Previous studies have shown that various factors are involved in the failure to eradicate H. pylori, such as new genotypes of the bacterium with higher pathogenicity, inappropriate patient cooperation, mutations, biofilm formation and dormant forms that cause antibiotic resistance, acidic stomach pH, high bacterial load, smoking, immunosuppressive features and intracellular occurrence of H. pylori. On the other hand, recent studies reported that the use of probiotics, nanoparticles, antimicrobial peptides, natural product and vaccines can be helpful in the treatment and eradication of H. pylori infections.

CONCLUSION

Eradication of H. pylori is crucial for the treatment of important diseases such as gastric cancer. Therefore, it seems that identifying the failure causes of treating this bacterium can be helpful in controlling the infections. Besides, further studies on new therapeutic strategies may help eradicate H. pylori in the future.

Co-delivery of hesperidin and clarithromycin in a nanostructured lipid carrier for the eradication of Helicobacter pylori in vitro

Effective and precise eradication of Helicobacter pylori (H. pylori) is the most promising approach to avoid H. pylori-related gastrointestinal disorders. The present study was conducted to demonstrate the efficacy of the co-delivery of hesperidin (Hesp) and clarithromycin (CLR) in nanostructured lipid carriers (NLCs) against H. pylori. We have produced a new delivery system by combining bioflavonoid Hesp and CLR NLCs to address the failure in single antibiotic therapies. Briefly, a blend of solid lipid, liquid lipid, and surfactant was used. Homogeneous NLCs with all the formulations showed a nano size and surface-negative charge and presented high in vitro stability and slow release of the drug even after 24 h. Bioimaging studies by scanning electron microscopy, transmission electron microscopy, and imaging flow cytometry indicated that NLCs interacted with the membrane by adhering to the outer cell membrane and disrupted the membrane that resulted in the leakage of cytoplasmic contents. The prepared NLCs provide sustained and controlled drug release that can be used to increase the rate of H. pylori eradication.

Insights into the Design of Inhibitors of the Urease Enzyme - A Major Target for the Treatment of Helicobacter pylori Infections

Expressed by a variety of plants, fungi and bacteria, the urease enzyme is directly associated with the virulence factor of many bacteria, including Helicobacter pylori, a gram-negative bacterium related to several gastrointestinal diseases and responsible for one of the most frequent bacterial infections throughout the world. The Helicobacter pylori Urease (HPU) is a nickel-dependent metalloenzyme expressed in response to the environmental stress caused by the acidic pH of the stomach. The enzyme promotes the increase of gastric pH through acid neutralization by the products of urea hydrolysis, then critically contributing to the colonization and pathogenesis of the microorganism. At the same time, standard treatments for Helicobacter pylori infections have limitations such as the increasing bacterial resistance to the antibiotics used in the clinical practice. As a strategy for the development of novel treatments, urease inhibitors have proved to be promising, with a wide range of chemical compounds, including natural, synthetic and semisynthetic products to be researched and potentially developed as new drugs. In this context, this review highlights the advances in the field of HPU inhibition, presenting and discussing the basis for the research of new molecules aiming at the identification of more efficient therapeutic entities.

Gastroprotective effect of phytoncide extract from Pinus koraiensis pinecone in Helicobacter pylori infection

For centuries, herbs have been used by traditional therapists around the world to treat gastrointestinal tract disorders, such as gastritis. We hypothesized that the anti-Helicobacter pylori properties of phytoncide, which is extracted from pinecone waste, would facilitate use as a natural gastroprotective product to treat gastrointestinal tract disorders. Thus, we investigated in vitro antibacterial efficacy against H. pylori by agar diffusion assay. To determine the gastroprotective properties of phytoncide, we conducted hematoxylin and eosin staining, performed assays for the detection of the cytotoxin gene, and evaluated pro-inflammatory cytokine expression in H. pylori-infected C57BL/6 mice. Phytoncide significantly inhibited the survival of H. pylori in the gastrointestinal system of C57BL/6 mice. Reduction of gastric severity in H. pylori-infected mice was associated with reductions in the expression levels of pro-inflammatory cytokines in the gastric mucosa, and of the cytotoxin CagA gene in phytoncide treated groups (P < 0.05 and P < 0.01). In conclusion, phytoncide significantly inhibited the growth of H. pylori in gastro tissue, possibly due to the abundant α-pinene present in the phytoncide as detected by HPLC analysis. Further studies are needed to validate our findings, but we suggest that phytoncide has the potential to be used as a natural ingredient in anti-H. pylori products.

Plants against Helicobacter pylori to combat resistance: An ethnopharmacological review

Worldwide, Helicobacter pylori (H. pylori) is regarded as the major etiological agent of peptic ulcer and gastric carcinoma. Claiming about 50 percent of the world population is infected with H. pylori while therapies for its eradication have failed because of many reasons including the acquired resistance against its antibiotics. Hence, the need to find new anti-H.pylori medications has become a hotspot with the urge of searching for alternative, more potent and safer inhibitors. In the recent drug technology scenario, medicinal plants are suggested as repositories for novel synthetic substances. Hitherto, is considered as ecofriendly, simple, more secure, easy, quick, and less toxic traditional treatment technique. This review is to highlight the anti-H. pylori medicinal plants, secondary metabolites and their mode of action with the aim of documenting such plants before they are effected by cultures and traditions that is expected as necessity.

Caenorhabditis elegans as an in vivo model to assess fucoidan bioactivity preventing Helicobacter pylori infection

Currently, Helicobacter pylori is the unique biological carcinogenic agent. The search for antimicrobial alternatives to antibiotics against this pathogen has been categorized as a priority due to the drastic failure associated with current applied antibiotic therapy. The present study assessed the bioactive antimicrobial capability of fucoidan ("Generally Recognized as Safe" approval - European Commission December 2017) from different species of Phaeophyceae algae (Fucus vesiculosus, Undaria pinnatifida, Macrocystis pyrifera) against H. pylori. All the studied fucoidans showed bacteriostatic and bactericidal effects at the studied concentrations [5-100] μg ml-1 and exposure times [0-7 days]. The most effective anti-H. pylori fucoidan was validated in Caenorhabditis elegans as an in vivo model. C. elegans feed was supplemented with Undaria pinnatifida [0-100] μg ml-1 fucoidan, resulting in a significant improvement in lifespan, lowered H. pylori concentration in the digestive tract, and increased egg-laying pattern. New research lines proposing this compound as an active agent in nutraceutical and preventive novel therapies should be opened.

Evaluation of Protective Impact of Algerian <I>Cuminum cyminum </I>L. and <I>Coriandrum sativum</I> L. Essential Oils on <I>Aspergillus flavus </I>Growth and Aflatoxin B<SUB>1</SUB> Production

BACKGROUND AND OBJECTIVE

Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. The aim of this investigation was to evaluate the inhibition of growth Aspergillus flavus E73 (A. flavus E73) and AFB1 production by Cuminum cyminum L. (C. cyminum L.) and Coriandrum sativum L. (C. sativum L.) essential oils (EOs) as well their antioxidant and phytotoxicity activities.

METHODOLOGY

The C. cyminum L. and C. sativum L. EOs were extracted by hydrodistillation. The chemical profile of EOs was identified by GC-MS, antifungal activity was assessed by poisoned food technique and in term Minimal Inhibitory Concentration (MIC) and minimal fungicidal concentration (MFC) and antiaflatoxin effect by broth medium. The antioxidant activity of EOs was determined by DPPH free radical scavenging assay, β-carotene bleaching test and total phenolic content by Folin-Ciocalteu. Phytotoxicity of C. cyminum L. and C. sativum L. EOs were determined for varieties of wheat. The results were analyzed by analysis of variance (one way ANOVA).

RESULTS

The GS/MS analysis showed that the major components of C. cyminum L. EO were cuminaldehyde (65.98%), o-cymene (18.40%) and C. sativum L. EO was mainly consisted of linalool (78.86%). The results showed that both the EOs could inhibit the growth of A. flavus E73 in the range of 24.27-84.90% for C. cyminum and 15.09-65.00% for C. sativum. During antiaflatoxin investigation, the oils exhibited noticeable inhibition on dry mycelium weight and synthesis of AFB1 by A. flavus E73. EOs of C. cyminum L. and C. sativum L. revealed complete inhibition of AFB1 at 1.25 and 1.5 mg mL-1, respectively. EOs exhibited inhibitory influence against some fungi. The IC50 values of C. cyminum L. and C. sativum L. EOs were 494.93 and 756.43 μg mL-1, respectively, while, β-carotene/linoleic acid bleaching was 47.68 and 29.29% , respectively. Total phenolic content of C. cyminum L. and C. sativum L. were 10.66 and 6.2 μg mg-1. Additionally, the EOs were non-phytotoxic on the two verities of wheat seeds.

CONCLUSION

The C. cyminum L. and C. sativum L EOs could be good alternative to protect foods.

Syzygium aromaticum L.: Traditional herbal medicine against cagA and vacA toxin genes-producing drug resistant Helicobacter pylori

The Pan-Drug Resistant (PDR), Helicobacter pylori remains an intractable challenge in public health worldwide and this pathogenicity is mainly due to the presence of a cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA). On the other hand, plant extracts such as Syzygium aromaticum contain a diverse array of secondary metabolites, which could be potentially used to combat H. pylori pathogens. To our knowledge, this is the first report on the biomedical potential of S. aromaticum extract against cytotoxin-associated genes producing PDR H. pylori. In this investigation, out of 45 gastric antral biopsy specimens of dyspeptic patients, 20 strains were confirmed as H. pylori. Eight (40%) out of 20 strains were PDR H. pylori while the rest of the strains were Multi-Drug Resistant (MDR) strains. Genotypic analyses of PDR H. pylori strains showed that cagA and vacA genes were found to be 75% and 87.5%, respectively and m2s2 was the most common subtype of vacA gene. S. aromaticum showed a significant higher anti-H. pylori activity compared to that of Cinnamomum zeylanicum and Thymus vulgaris. Eugenol was the major phenolic compound (28.14%) detected in the methanolic extract of S. aromaticum. Clearly, results of the toxicological assessment confirmed the safety of S. aromaticum for use. Hence, these results suggest that S. aromaticum could be a new useful natural antimicrobial agent that could potentially combat cytotoxin genes-producing drug-resistant H. pylori. Moreover, these findings provide a scientific basis for the development of antimicrobial agents from traditional herbal medicines for gastroprotection against gastric ulcer.

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Helicobacter pylori remains an intractable challenge in public health worldwide.

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CagA and VacA genes are H. pylori pathogenicity dependent.

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Eight strains of H. pylori were proven to pan-drug resistant.

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The cagA and vacA genes were found to be 75% and 87.5%, respectively.

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Syzygium aromaticum extract showed a significant higher anti-H. pylori activity.

Pistacia vera L. oleoresin and levofloxacin is a synergistic combination against resistant Helicobacter pylori strains

The increasing multidrug resistance in Helicobacter pylori, also correlated to its biofilm-forming ability, underlines the need to search novel strategies to improve the eradication rate. Natural compounds are proposed as antibiotic-resistant-breakers capable to restore the efficacy of conventional drugs. Aim of this work was to evaluate the capability of Pistacia vera L. oleoresin (ORS) to synergize with levofloxacin (LVX) against resistant H. pylori strains. The antimicrobial activity of P. vera L. ORS and LVX and their combinations was determined by MIC/MBC (in neutral and acidic environments) and checkerboard tests. The anti-biofilm effect was determined by biomass quantification. In vivo Galleria mellonella model was used to confirm in vitro data. Pistacia vera L. ORS and LVX MICs ranged respectively from 780 to 3120 mg/l and from 0.12 to 2.00 mg/l, at pH 7.0 and 5.5. MBCs were similar to MICs. Pistacia vera L. ORS was able to synergize with LVX, restoring its effectiveness in LVX resistant strains. Pistacia vera L. ORS, LVX and their synergistic combinations displayed significant biofilm reduction. Pistacia vera L. ORS and LVX, showed protective effect against H. pylori infection on G. mellonella (62% and 63% of survival, respectively). Pistacia vera L. ORS can be considered a promising potentiator to restore the effectiveness of LVX tackling the H. pylori antibiotic resistance phenomenon.

Herbal medicine as an auspicious therapeutic approach for the eradication of Helicobacter pylori infection: A concise review

Helicobacter pylori (H. pylori) causes gastric mucosa inflammation and gastric cancer mostly via several virulence factors. Induction of proinflammatory pathways plays a crucial role in chronic inflammation, gastric carcinoma, and H. pylori pathogenesis. Herbal medicines (HMs) are nontoxic, inexpensive, and mostly anti-inflammatory reminding meticulous emphasis on the elimination of H. pylori and gastric cancer. Several HM has exerted paramount anti-H. pylori traits. In addition, they exert anti-inflammatory effects through several cellular circuits such as inhibition of 5'-adenosine monophosphate-activated protein kinase, nuclear factor-κB, and activator protein-1 pathway activation leading to the inhibition of proinflammatory cytokines (interleukin 1α [IL-1α], IL-1β, IL-6, IL-8, IL-12, interferon γ, and tumor necrosis factor-α) expression. Furthermore, they inhibit nitrous oxide release and COX-2 and iNOS activity. The apoptosis induction in Th1 and Th17-polarized lymphocytes and M2-macrophagic polarization and STAT6 activation has also been exhibited. Thus, their exact consumable amount has not been revealed, and clinical trials are needed to achieve optimal concentration and their pharmacokinetics. In the aspect of bioavailability, solubility, absorption, and metabolism of herbal compounds, nanocarriers such as poly lactideco-glycolide-based loading and related formulations are helpful. Noticeably, combined therapies accompanied by probiotics can also be examined for better clearance of gastric mucosa. In addition, downregulation of inflammatory microRNAs (miRNAs) by HMs and upregulation of those anti-inflammatory miRNAs is proposed to protect the gastric mucosa. Thus there is anticipation that in near future HM-based formulations and proper delivery systems are possibly applicable against gastric cancer or other ailments because of H. pylori.

Antioxidant and antifungal activities of a new chemovar of cumin (Cuminum cyminum L.)

Chemical composition, antifungal and antioxidant properties of essential oil extracted from Cuminum cyminum from Iran was studied. GC-MS analysis revealed the presence of 18 components, with 3-caren-10-al and cuminal as the principal constituents. Hierarchical cluster analysis and antioxidant capacities showed that this essential oil made a single group at 64 unit distinct from other reported essential oils extracted from cumin in the literature and was with high antioxidant activity [150 µL exhibiting strong reducing power; 2200 (FRAP) μmol/L Fe⁺² during 15 min and ~ 89 DPPH % at 60 min]. The antifungal effects of the essential oil against three postharvest fungal pathogens, Botrytis cinerea, Aspergillus niger and Penicillim expansum revealed that at concentrations of ≥ 750 µL/L, the mycelial growth of the tested fungi were completely inhibited. Overall, the essential oil derived from this new cumin chemovar could be a promising candidate for its utilization as a natural preservative.

Phytochemicals in Helicobacter pylori Infections: What Are We Doing Now?

In this critical review, plant sources used as effective antibacterial agents against Helicobacter pylori infections are carefully described. The main intrinsic bioactive molecules, responsible for the observed effects are also underlined and their corresponding modes of action specifically highlighted. In addition to traditional uses as herbal remedies, in vitro and in vivo studies focusing on plant extracts and isolated bioactive compounds with anti-H. pylori activity are also critically discussed. Lastly, special attention was also given to plant extracts with urease inhibitory effects, with emphasis on involved modes of action.

Natural Products for the Prevention and Management of Helicobacter pylori Infection

Helicobacter pylori is the main pathogen that induces chronic gastritis, peptic ulcers, atrophic gastritis, and other gastric disorders, and it is classified as a group I carcinogen. To eradicate H. pylori infection, triple therapy consisting of two antibiotics and a proton pump inhibitor is the most widely recommended first-line therapeutic strategy. Antimicrobial resistance to antibiotics contained in triple therapy could lead to therapeutic regimen failures. Recent studies showed that many natural products, including fruits, vegetables, spices, and medicinal plants, possess inhibitory effects on H. pylori, indicating their potential to be alternatives to prevent and manage H. pylori infection. This review summarizes the effects of natural products on H. pylori infection and highlights the mechanisms of action.

Evaluation of pharmacodynamic properties and safety of Cinnamomum zeylanicum (Ceylon cinnamon) in healthy adults: a phase I clinical trial

Background

Cinnamon is considered as a treatment for many ailments in native medicine. Evidence suggests that Cinnamomum zeylanicum (CZ) has anti-microbial, anti-parasitic, anti-oxidant, blood glucose lowering properties and beneficial cardiovascular effects. The present study aims to evaluate Pharmacodynamic properties and safety of CZ in healthy adults using a Phase I Clinical Trial.

Methods

This phase I clinical trial was conducted at the Department of Pharmacology, Faculty of Medicine, University of Colombo, Sri Lanka. Thirty healthy adults were recruited for the study, conducted for a period of 3 months, with the dose of CZ (water extract) increased at monthly intervals (85 mg, 250 mg and 500 mg). Data collection was carried out at baseline and during each monthly follow up visit. Anthropometric, clinical and biochemical assessments were done at baseline and during follow up. Adverse effects and drug compliance was also evaluated.

Results

Twenty eight subjects completed the three months follow up. Mean age was 38.8 ± 10.4 years and 50% were males. There were no significant changes in the anthropometric parameters during the three months follow up. Both systolic and diastolic blood pressure reduced significant during the 1st month and this reduction was sustained throughout follow up. Full blood count, renal function tests, liver function tests, fasting blood glucose, HDL-c, VLDL-d and triglycerides remained within the normal range without any significant alteration during the 3 months. A significant reduction in the TC (p < 0.05) and LDL-c (p < 0.001) was noted at the end of the 3 months follow up period. There were no serious adverse effects (including hypersensitivity) noted. In two participants dyspepsia necessitated the discontinuation of study participation. Drug compliance was between 85 and 95% during the study period.

Conclusions

This is the first phase I clinical trial in health adults evaluating efficacy and safety of CZ. Our results demonstrate no significant side effects and toxicity of CZ, including hepatotoxicity and anti-coagulation properties. CZ demonstrated beneficial anti-hyperlipidaemic and blood pressure lowering effects among healthy adults. Further studies with larger samples and longer durations may be able to elucidate other side effects and better describe the pharmacodynamic properties.

Trial registration

SLCTR/2013/001 (Sri Lanka Clinical Trials Registry: http://www.slctr.lk/trials/106) (Date of Registration: 01/01/2013).

Influence of magnetopriming on germination, growth, physiology, oil and essential contents of cumin (Cuminum cyminum L.)

An environment friendly technique is desirable for enhancing of crop production. In this study, seeds of cumin (Cuminum cyminum L.) Yazd accession were treated with 0, 150 mT, 250 mT, 500 mT and 1 T magnetic field strengths for min and germination parameters were determined. All of the treatments improved germination parameters and seedling growth as compared with the control. However, 500 and 150 mT were the most effective treatments and thus selected for field studies. Seeds were exposed to 150 mT and 500 mT static magnetic field of strengths for 12 min, planted in the field during 2010-2012 in Isfahan, Iran. Static magnetic field treatment shortened the days to emergence, flowering and maturity, increased chlorophyll and reduced proline contents. Highest biological, seed and essential oil yield, oil content, and oil yield were recorded under 500 mT followed by 150 mT and control, respectively. The results suggested that the pretreatment of cumin seeds with static magnetic field can improve germination, growth and oil and essential contents of the cumin seed under the field.

Effectiveness of Citrus Fruits on Helicobacter pylori

It is known that Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer, and gastric carcinoma. Due to the increased side effects of the treatment regimens and the development of antimicrobial resistance, a number of natural compounds have been tested as potential alternatives. In this review, we will examine the current knowledge on the effect of Citrus fruits and their derivatives against H. pylori, highlighting the remaining outstanding questions on the development of novel therapeutic strategies.

In vitro activity of Aloe vera inner gel against microorganisms grown in planktonic and sessile phases

The failure of traditional antimicrobial treatments is becoming a worldwide problem. The use of Aloe vera is of particular interest for its role as curative agent and its efficacy in complementary therapies for a variety of illnesses. This study evaluated the antimicrobial activity of A. vera inner gel against a panel of microorganisms, Gram-positive and -negative bacteria, and Candida albicans. In addition to A. vera inner gel being used in the treatment of peptic ulcers, in dermatological treatments, and wound healing, it was also tested on the sessile phase of clinical Helicobacter pylori strains (including multi-drug-resistant strains) and on planktonic and sessile phase of Staphylococcus aureus/Pseudomonas aeruginosa clinical isolates from venous leg ulcers.A. vera inner gel expresses its prevalent activity against Gram-negative bacteria and C. albicans in respect to Gram-positive bacteria. The results of the A. vera antibiofilm activity showed a decrease of the produced biomass in a concentration-dependent-way, in each analyzed microorganism. The data obtained show that A. vera inner gel has both an antimicrobial and antibiofilm activity suggesting its potential use for the treatment of microbial infections, in particular for H. pylori gastric infection, especially in case of multi-drug-resistance, as well as for an effective wound dressing.

In vitro antimicrobial susceptibility of Helicobacter pylori to nine antibiotics currently used in Central Italy

OBJECTIVE

Helicobacter pylori expresses an increased resistance in respect to antimicrobials currently used in therapy. The aim of this study was to evaluate the antimicrobial profiles of H. pylori isolates to nine conventional antibiotics used in a Central Region (Abruzzo) of Italy.

MATERIALS AND METHODS

Biopsies were taken from antrum and fundus of 112 adult and 3 children with Urea Breath Test positive with dyspeptic symptoms and analyzed for H. pylori culture and antibacterial activity. Antimicrobial susceptibility tests were performed for clarithromycin, metronidazole, levofloxacin, moxifloxacin, ciprofloxacin, tetracycline, amoxicillin, ampicillin, and rifabutin by a modified agar dilution susceptibility test.

RESULTS

Bacterial culture was successful in 100 out of 115 patients. Helicobacter pylori strains were isolated from 98 antrum and 83 fundus samples. The rate of recovery of H. pylori strains was 90.50% (181/200). The percentages of resistance were as follows: clarithromycin 72.44% antrum, 72.28% fundus; metronidazole 34.69% antrum, 42.16% fundus; levofloxacin 42.85% antrum, 53.01% fundus; moxifloxacin 37.35% antrum, 46.57% fundus; ciprofloxacin 39.47% antrum, 44.28% fundus; tetracycline 2.63% antrum, 2.85% fundus; amoxicillin 1.02% antrum, 1.20% fundus; ampicillin 0% antrum and fundus and rifabutin 0% antrum, 1.20% fundus. A total of 35 subjects harbored multi-resistant strains.

CONCLUSIONS

This study underlines the high rate of resistance to clarithromycin, metronidazole and quinolones, which may reflect an overuse of them. Culture and susceptibility test, should be performed to prevent the emergence of multi-resistance and to assess an efficacious regimen.

In vitro effect of bergamot (Citrus bergamia) juice against cagA-positive and-negative clinical isolates of Helicobacter pylori

Background

Helicobacter pylori infection has been associated with chronic gastritis, peptic ulcer and gastric carcinoma as over half of the world's population is colonized with this gram-negative bacterium. Due to the increasing antibiotic resistance, its eradication rates fails in a great portion of patients. A number of studies showed that molecules largely distributed in commonly consumed fruits and vegetables may have antimicrobial activity. The aim of the present study was to investigate the effect of bergamot juice (BJ) against Helicobacter pylori in vitro. The potential therapeutic combination between BJ and the antibiotics amoxicillin (AMX), clarithromycin (CLA) and metronidazole (MTZ) has also been evaluated.

Methods

The minimum inhibitory concentration (MIC) of BJ, AMX, CLA and MTZ against 2 ATCC and 32 clinical isolates of H. pylori was assayed according to CLSI. The checkerboard method was used to determine the efficacy of the association BJ with the three reference antibiotics.

Killing curves were performed on the two cagA-positive ATCC strains of H. pylori (ATCC 43504 and ATCC 49503), on the clinical isolate cagA-positive HP6 strain of H. pylori and on the clinical isolate cagA-negative HP61 strain of H. pylori.

Results

BJ (2.5 %, v/v) inhibited the growth of 50 % of the H. pylori clinical isolates, whereas 5 % (v/v) inhibited 90 %. AMX was the most effective antibiotic against the reference strains and the clinical isolates, followed by CLA and MTZ. In the combination assays, synergism was observed between BJ and AMX and between BJ and MTZ against both the reference strains and the clinical isolates. Indifference was observed between BJ and CLA.

Conclusions

BJ was effective in vitro against H. pylori and the genotype status of the clinical strains may have an impact on its susceptibility. The synergistic combination of BJ and antibiotics could be used to prevent or treat resistance.

Medicinal plants in the treatment of Helicobacter pylori infections

CONTEXT

Helicobacter pylori is a small, spiral, Gram-negative bacillus that plays a role in the pathogenesis of a number of diseases ranging from asymptomatic gastritis to gastric cancer. Schedule compliance, antibiotic drug resistance, and side-effects of triple or quadruple therapy have led to research for novel candidates from plants.

OBJECTIVE

The purpose of this paper is to review the most potent medicinal plants of recently published literature with anti-H. pylori activity. For centuries, herbals have been used by traditional healers around the world to treat various gastrointestinal tract disorders such as dyspepsia, gastritis, and peptic ulcer disease. The mechanism of action by which these botanicals exert their therapeutic properties has not been completely and clearly elucidated. Anti-H. pylori properties may be one of the possible mechanisms by which gastroprotective herbs treat gastrointestinal tract disorders.

MATERIALS AND METHODS

Electronic databases such as PubMed, Google scholar, EBSCO, and local databases were explored for medicinal plants with anti-H. pylori properties between 1984 and 2013 using key words "medicinal plants" and "Helicobacter pylori" or "anti-Helicobacter pylori".

RESULTS

A total of 43 medicinal plant species belonging to 27 families including Amaryllidaceae, Anacardiaceae, Apiaceae, Apocynaceae, Asclepiadoideae, Asteraceae, Bignoniaceae, Clusiaceae, Chancapiedra, Combretaceae, Cyperaceae, Euphorbiaceae, Fabaceae, Geraniaceae, Lamiaceae, Lauraceae, Lythraceae, Menispermaceae, Myristicaceae, Myrtaceae, Oleaceae, Papaveraceae, Plumbaginaceae, Poaceae, Ranunculaceae, Rosaceae, and Theaceae were studied as herbs with potent anti-H. pylori effects.

CONCLUSION

Traditional folk medicinal use of some of these plants to treat gastric infections is substantiated by the antibacterial activity of their extracts against H. pylori.

Natural products and food components with anti-Helicobacter pylori activities

The bacterial pathogen Helicobacter pylori (H. pylori) colonizes in over half of the world’s population. H. pylori that establishes life-long infection in the stomach is definitely associated with gastro-duodenal diseases and a wide variety of non-gastrointestinal tract conditions such as immune thrombocytopenia. Triple therapy which consists of a proton pump inhibitor and combinations of two antibiotics (amoxicillin, clarithromycin or amoxicillin, metronidazol) is commonly used for H. pylori eradication. Recently, the occurrence of drug-resistant H. pylori and the adverse effect of antibiotics have severely weakened eradication therapy. Generally antibiotics induce the disturbance of human gastrointestinal microflora. Furthermore, there are inappropriate cases of triple therapy such as allergy to antibiotics, severe complications (liver and/or kidney dysfunction), the aged and people who reject the triple therapy. These prompt us to seek alterative agents instead of antibiotics and to develop more effective and safe therapy with these agents. The combination of these agents actually may result in lower a dose of antibiotics. There are many reports world-wide that non-antibiotic substances from natural products potentially have an anti-H. pylori agent. We briefly review the constituents derived from nature that fight against H. pylori in the literature with our studies.

Current knowledge on alleviating Helicobacter pylori infections through the use of some commonly known natural products: bench to bedside

Helicobacter pylori, a spiral-shaped Gram-negative bacterium, has been classified as a class I carcinogen by the World Health Organization and recognized as the causative agent for peptic ulcers, duodenal ulcer, gastritis, mucosa-associated lymphoid tissue lymphomas, and gastric cancer. Owing to their alarming rate of drug resistance, eradication of H. pylori remains a global challenge. Triple therapy consisting of a proton pump inhibitor, clarithromycin, and either amoxicillin or metronidazole, is generally the recommended standard for the treatment of H. pylori infection. Complementary and alternative medicines have a long history in the treatment of gastrointestinal ailments and various compounds has been tested for anti-H. pylori activity both in vitro and in vivo; however, their successful use in human clinical trials is sporadic. Hence, the aim of this review is to analyze the role of some well-known natural products that have been tested in clinical trials in preventing, altering, or treating H. pylori infections. Whereas some in vitro and in vivo studies in the literature have demonstrated the successful use of a few potential natural products for the treatment of H. pylori-related infections, others indicate a need to consider natural products, with or without triple therapy, as a useful alternative in treating H. pylori-related infections. Thus, the reported mechanisms include killing of H. pylori urease inhibition, induction of bacterial cell damage, and immunomodulatory effect on the host immune system. Furthermore, both in vitro and in vivo studies have demonstrated the successful use of some potential natural products for the treatment of H. pylori-related infections. Nevertheless, the routine prescription of potential complementary and alternative medicines continues to be restrained, and evidence on the safety and efficacy of the active compounds remains a subject of ongoing debate.

In vitro activity of Aloe vera inner gel against Helicobacter pylori strains

Aloe barbadensis Miller (Aloe vera) is a herbal remedy widely used for a variety of illnesses; A. vera leaf extracts have been promoted for detoxification, cure constipation, help flush out toxins and wastes from the body, promote digestion and are used in the treatment of peptic ulcer for cytoprotective action. The aim of this study was to evaluate the antibacterial activity of A. vera inner gel against both susceptible and resistant Helicobacter pylori strains isolated in Abruzzo region, Italy. The inner gel of leaves of a 5-year-old plant of A. vera was extracted, homogenized and tested from 800 to 1.56 mg ml(-1) against 14 clinical strains and one reference strain of H. pylori using the broth microdilution methodology. Furthermore, the sample of A. vera was investigated for the chemical fingerprint of anthraquinones. The inhibitory concentrations of A. vera inner gel were similar to the bactericidal ones, with values ranging from 6.25 to 800 mg ml(-1) . Fifty per cent of the detected strains, independently of their susceptibility profile, were inhibited in their growth at 100 mg ml(-1) . Aloe vera inner gel expresses antibacterial properties against H. pylori and, therefore, in combination with antibiotics, could represent a novel strategy for the treatment of the infection of H. pylori, especially in cases of multiresistance.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study demonstrates that the Aloe vera inner gel expresses antibacterial properties against both susceptible and resistant Helicobacter pylori strains. These findings may impact on the antimicrobial resistance phenomenon of H. pylori, proposing the A. vera inner gel as a novel effective natural agent for combination with antibiotics for the treatment of H. pylori gastric infection.

Helicobacter pylori infection: A brief overview on alternative natural treatments to conventional therapy

Helicobacter pylori is a human gastric pathogen considered as the etiologic agent of several gastric disorders, that may range from chronic gastritis to more severe outcomes, including gastric cancer. The current therapeutic scheme relies on the combination of several pharmacological substances, namely antibiotics and proton pump inhibitors. However, the cure rates obtained have been declining over the years, mostly due to bacterial resistance to antibiotics. In this context, the use of non-antibiotic substances is of the utmost importance regarding H. pylori eradication. In this review, we present different classes of compounds obtained from natural sources that have shown to present anti-H. pylori potential; we briefly highlight their possible use in the context of developing new therapeutic approaches.

Antibacterial activities of almond skins on cagA-positive and-negative clinical isolates of Helicobacter pylori

BACKGROUND

Helicobacter pylori is known to be a gastric pathogen of humans. Eradication regimens for H. pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, the need for alternative therapies for H. pylori infections is of special interest. We have previously shown that polyphenols from almond skins are active against a range of food-borne pathogens. The aim of this study was to evaluate the antibacterial effects of natural almond skins before and after simulated human digestion and the pure flavonoid compounds epicatechin, naringenin and protocatechuic acid against H. pylori.

RESULTS

H. pylori strains were isolated from gastric biopsy samples following standard microbiology procedures. Also, cagA and vacA genes were identified using PCR. Susceptibility studies on 34 strains of H. pylori, including two reference strains (ATCC 43504, ATCC 49503), were performed by the standard agar dilution method.

CONCLUSIONS

Polyphenols from almond skins were effective in vitro against H. pylori, irrespective of genotype status and could therefore be used in combination with antibiotics as a novel strategy for antibiotic resistance.

Anti-Helicobacter pylori potential of artemisinin and its derivatives

The antimalarial drug artemisinin from Artemisia annua demonstrated remarkably strong activity against Helicobacter pylori, the pathogen responsible for peptic ulcer diseases. In an effort to develop a novel antimicrobial chemotherapeutic agent containing such a sesquiterpene lactone endoperoxide, a series of analogues (2 natural and 15 semisynthetic molecules), including eight newly synthesized compounds, were investigated against clinical and standard strains of H. pylori. The antimicrobial spectrum against 10 H. pylori strains and a few other bacterial and fungal strains indicated specificity against the ulcer causing organism. Of five promising molecules, a newly synthesized ether derivative β-artecyclopropylmether was found to be the most potent compound, which exhibited MIC range, MIC(90), and minimum bactericidal concentration range values of 0.25 to 1.0 μg/ml, 1.0 μg/ml, and 1 to 16 μg/ml, respectively, against both resistant and sensitive strains of H. pylori. The molecule demonstrated strong bactericidal kinetics with extensive morphological degeneration, retained functional efficacy at stomach acidic pH unlike clarithromycin, did not elicit drug resistance unlike metronidazole, and imparted sensitivity to resistant strains. It is not cytotoxic and exhibits in vivo potentiality to reduce the H. pylori burden in a chronic infection model. Thus, β-artecyclopropylmether could be a lead candidate for anti-H. pylori therapeutics. Since the recurrence of gastroduodenal ulcers is believed to be mainly due to antibiotic resistance of the commensal organism H. pylori, development of a candidate drug from this finding is warranted.

Antibacterial effects of the urushiol component in the sap of the lacquer tree (Rhus verniciflua Stokes) on Helicobacter pylori

BACKGROUND

Urushiol is a major component of the lacquer tree which has been used as a folk remedy for the relief of abdominal discomfort in Korea. The aim of this study was to evaluate the antibacterial effects of the urushiol on Helicobacter pylori.

MATERIALS AND METHODS

Monomer and 2-4 polymer urushiol were used. In the in vitro study, pH- and concentration-dependent antibacterial activity of the urushiol against H. pylori were investigated. In addition, the serial morphological effects of urushiol on H. pylori were examined by electron microscopy. In vivo animal study was performed for the safety, eradication rate, and the effect on gastritis of urushiol. The expression of pro-inflammatory cytokines was checked.

RESULTS

  All strains survived within a pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged 0.064-0.256 mg/mL. Urushiol caused separation of the membrane and lysis of H. pylori within 10 minutes. Urushiol (0.128 mg/mL × 7 days) did not cause complications on mice. The eradication rates were 33% in the urushiol monotherapy, 75% in the triple therapy (omeprazole + clarithromycin + metronidazole), and 100% in the urushiol + triple therapy, respectively. H. pylori-induced gastritis was not changed by urushiol but reduced by eradication. Only the expression of interleukin-1β in the gastric tissue was significantly increased by H. pylori infection and reduced by the urushiol and H. pylori eradication (p = .014).

CONCLUSIONS

The urushiol has an antibacterial effect against H. pylori infection and can be used safely for H. pylori eradication in a mouse model.

Essential oils and fatty acids composition of Tunisian and Indian cumin (Cuminum cyminum L.) seeds: a comparative study

BACKGROUND

Cumin (Cuminum cyminum L.) seeds of two geographic origins, Tunisia (TCS) and India (ICS), were studied regarding their fatty acid and essential oil composition.

RESULTS

Oil yields were 17.77 and 15.40% for TCS and ICS respectively. Petroselinic acid (C18:1n-12) was the major fatty acid in both varieties, with a higher proportion being found in TCS (55.90% of total fatty acids (TFA)) than in ICS (41.42% TFA). Moreover, the most predominant fatty acids were palmitic, petroselenic and linoleic acids, accounting for more than 91% TFA in both varieties. The unsaturated fatty acid content was high: 70.95% TFA in TCS and 62.17% TFA in ICS. Essential oil yields differed significantly (P < 0.05) between the two varieties: 1.21 and 1.62% for ICS and TCS respectively. A total of 40 compounds were identified, 34 of which were present in both essential oils. The two varieties displayed different chemotypes: γ-terpinene/1-phenyl-1,2-ethanediol for TCS and cuminaldheyde/γ-terpinene for ICS.

CONCLUSION

The study revealed that the biochemical composition of cumin seeds is origin-dependent and that cumin seeds are rich in an unusual fatty acid, petroselinic acid. Besides, cumin essential oil is a rich source of many compounds, including cuminaldehyde and γ-terpinene. The overall results suggest the exploitation of cumin seeds as a low-cost renewable source for industrial processing in the fields of cosmetics, perfumes and pharmaceuticals.

Cuminum cyminum and Carum carvi: An update

Cuminum cyminum and Carum carvi are the sources of cumin and caraway seeds respectively, which have been used since antiquity for the treatment of various indications in traditional healing systems in wide geographical areas. Cumin and caraway seeds are rich sources of essential oils and have been actively researched for their chemical composition and biological activities. In recent times (especially during the last 3 years) considerable progress has been made regarding validation of their acclaimed medicinal attributes by extensive experimental studies. In this attempt many novel bioactivities have been revealed. This review highlights the significance of cumin and caraway as potential source of diverse natural products and their medicinal applications.

In vitro and in vivo effects of apple peel polyphenols against Helicobacter pylori

The inhibitory effects of a standarized apple peel polyphenol-rich extract (APPE) against Helicobacter pylori infection and vacuolating bacterial toxin (VacA) induced vacuolation were investigated. Apple peel polyphenols significantly prevented vacuolation in HeLa cells with an IC(50) value of 390 microg of gallic acid equivalents (GAE)/mL. APPE also displayed an in vitro antiadhesive effect against H. pylori. A significant inhibition was observed with a 20-60% reduction of H. pylori attachment at concentrations between 0.250 and 5 mg of GAE/mL. In a short-term infection model (C57BL6/J mice), two levels of APPE doses (150 and 300 mg/kg/day) showed an inhibitory effect on H. pylori attachment. Orally administered apple peel polyphenols also showed an anti-inflammatory effect on H. pylori-associated gastritis, lowering malondialdehyde levels and gastritis scores.

Anti-Helicobacter pylori activity of plant extracts traditionally used for the treatment of gastrointestinal disorders

The antibacterial activity of plant extracts obtained from Bixa orellana L., Chamomilla recutita L., Ilex paraguariensis A. St.-Hil., Malva sylvestris L., Plantago major L. and Rheum rhaponticum L. has been evaluated against two reference strains and eleven clinical isolates of Helicobacter pylori. All the plant species chosen are used in popular Brazilian cuisine and folk medicine in the treatment of gastrointestinal disorders. Initial screening was made by the disk diffusion test and then minimum inhibitory concentration was determined by the agar dilution method. The results presented in this work demonstrated that among the plant preparations analyzed, B. orellana L., C. recutita L., I. paraguariensis A. St.-Hil. and M. sylvestris L. were capable of inhibiting the in vitro growth of H. pylori.

Anti-secretory, anti-inflammatory and anti-Helicobacter pylori activities of several fractions isolated from Piper carpunya Ruiz & Pav

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Piper carpunya Ruiz & Pav. (syn Piper lenticellosum C.D.C.) (Piperaceae), are widely used in folk medicine in tropical and subtropical countries of South America as an anti-inflammatory, anti-ulcer, anti-diarrheal and anti-parasitical remedy as well as an ailment for skin irritations.

AIMS OF THE STUDY

To study the anti-inflammatory, anti-secretory and anti-Helicobacter pylori activities of different fractions isolated from an ethanolic extract of the leaves of Piper carpunya, in order to provide evidence for the use of this plant as an anti-ulcer remedy. Moreover, to isolate the main compounds of the extract and relate their biological activity to the experimental results obtained with the fractions.

MATERIALS AND METHODS

Sixteen fractions were obtained from the ethanolic extract (F I-XVI) and 16 pure compounds were isolated and identified from these fractions. We studied the effects of the fractions (0.1-400microg/mL) on the release of myeloperoxidase (MPO) enzyme from rat peritoneal leukocytes, on rabbit gastric microsomal H(+), K(+)-ATPase activity and anti-Helicobacter pylori anti-microbial activity using the microdilution method (MM). The main compounds contained in the fractions were isolated and identified by (1)H- and (13)C NMR spectra analysis and comparison with the literature data.

RESULTS

Eight fractions showed inhibition of MPO enzyme (F I-IV, X, XII, XIV and XV). The highest inhibition was observed with F XIV (50microg/mL, 60.9%, p<0.001). F X and XII were the most active ones, inhibiting the gastric H(+), K(+)-ATPase activity with IC(50) values equal to 22.3microg/mL and 28.1microg/mL, respectively. All fractions, except F XV, presented detectable anti-Helicobacter pylori activity, with a diameter of inhibition zones ranging from 11mm up to 50mm. The best anti-Helicobacter pylori activity was obtained with F III and V. Both fractions killed Helicobacter pylori with lowest concentration values, about 6.25mug/mL. Sixteen pure compounds were isolated, five of them are flavonoids that possess strong anti-oxidant and free radical scavenging activity, e.g. vitexin, isovitexin, and rhamnopyranosylvitexin. Terpenoids like sitosterol, stigmasterol and phytol, which have shown gastroprotective activity, and dihydrochalcones, like asebogenin, with anti-bacterial activity, were also isolated. Furthermore, the rare neolignan 1, that is a DNA polymerase beta lyase inhibitor, and (6S, 9S)-roseoside, that shows strong anti-bacterial activity, were isolated, for the first time, from the genus Piper.

CONCLUSIONS

We suggest that the flavonoids isolated from F I and II (vitexin, isovitexin, rhamnopyranosylvitexin and isoembigenin) contribute to the anti-MPO activity, as well as to their anti-Helicobacter pylori activity. These flavonoids may also be responsible for the important inhibition of H(+), K(+)-ATPase activity. Also the phytosterols and phytol obtained from F XIV and XV could be involved in these gastroprotective activities. These results encourage us to continue phytochemical studies on these fractions in order to obtain full scientific validation for this species.

In vitro antibacterial and morphological effects of the urushiol component of the sap of the Korean lacquer tree (Rhus vernicifera Stokes) on Helicobacter pylori

Eradication regimens for Helicobacter pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, alternative anti-H. pylori or supportive antimicrobial agents with fewer disadvantages are necessary for the treatment of H. pylori. We investigated the pH-(5.0, 6.0, 7.0, 8.0, 9.0, and 10.0) and concentration (0.032, 0.064, 0.128, 0.256, 0.514, and 1.024 mg/mL)-dependent antibacterial activity of crude urushiol extract from the sap of the Korean lacquer tree (Rhus vernicifera Stokes) against 3 strains (NCTC11637, 69, and 219) of H. pylori by the agar dilution method. In addition, the serial (before incubation, 3, 6, and 10 min after incubation) morphological effects of urushiol on H. pylori were examined by electron microscopy. All strains survived only within pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged from 0.064 mg/mL to 0.256 mg/mL. Urushiol caused mainly separation of the membrane, vacuolization, and lysis of H. pylori. Interestingly, these changes were observed within 10 min following incubation with the 1xminimal inhibitory concentrations of urushiol. The results of this work suggest that urushiol has potential as a rapid therapeutic against H. pylori infection by disrupting the bacterial cell membrane.

Antimicrobial activity of two propolis samples against human Campylobacter jejuni

The aim of this study was to analyze the antimicrobial activity of two ethanolic extracts of propolis (EEPs) and selected flavonoids against 16 Campylobacter jejuni clinical isolates and several Gram-positive and Gram-negative human pathogens. The antimicrobial activity of EEPs and flavonoids was evaluated by the agar well diffusion method. The EEPs inhibited the growth of C. jejuni, Enterobacter faecalis, and Staphylococcus aureus. The most active flavonoid was galangin, with the highest percentage of sensitivity among C. jejuni strains (68.8%); lower percentages of sensitivity were observed for quercetin (50%). The minimal inhibitory concentrations (MICs) of EEPs and flavonoids for C. jejuni isolates were determined by the agar dilution method. EEPs showed MIC values of 0.3125-0.156 mg/mL for all C. jejuni strains; galangin and quercetin gave MICs ranging from 0.250 to 0.125 mg/mL. Thus propolis preparations could be used as support to traditional therapy for Campylobacter infection, especially when the antibiotic agents show no activity against this microorganism.

Antibacterial activity of grape extracts on cagA-positive and -negative Helicobacter pylori clinical isolates

There is considerable interest in alternative/adjuvant approaches for the eradication of Helicobacter pylori using biologically active compounds, especially antioxidants from plants. In the present work, we tested the antioxidant and antimicrobial activities of hydro-alcoholic extracts from Colorino, Sangiovese and Cabernet Sauvignon grape cultivars against H. pylori G21 (cagA-negative, cagA-) and 10K, (cagApositive, cagA+) clinical isolates. We determined the minimum bactericidal concentration (MBC) by incubating strain suspensions in Brucella broth with fetal bovine serum and samples at different concentrations in a final volume of 100 microl in a microaerobic atmosphere. After incubation, subcultures were carried out on Brucella agar plates which were incubated for 3-5 days in a microaerobic environment. The lowest concentration in broth, where the subculture on agar showed complete absence of growth, was considered the MBC.The Colorino extract showed the highest antibacterial activity against G21 strain (MBC=1.35 mg/ml), while Sangiovese and Carbernet MBCs were 4.0 mg/ml ca. H. pylori 10K was only susceptible to Colorino after 48 hours (MBC = 3.57 mg/ml). Resveratrol exhibited the highest antibacterial activity. interestingly, the most pathogenic strain (10K) was less susceptible to both the grape extracts and the isolated compounds. These results suggest that the administration of grape extracts and wine constituents, in addition to antibiotics, might be useful in the treatment of H. pylori infection. Should the reduced susceptibility of 10K strain be extended to all the cagA+ H. pylori isolates, which are endowed with cancer promoter activity, this observation may help explain why the organisms expressing CagA are more closely associated with atrophic gastritis and gastric carcinoma development.