In vitro inhibition of the growth of Helicobacter pylori by oil-macerated garlic constituents

Therapeutic potential of garlic, aged garlic extract and garlic‑derived compounds on pancreatic cancer (Review)

Garlic is a popular ingredient used in cuisines and traditional medicines worldwide. It contains numerous bioactive organosulfur-containing compounds, such as allicin, with reported potential for anticancer and antimicrobial therapy. The biological activity and potential use of garlic and its products have been extensively investigated. Aged garlic extract (AGE) is a product manufactured by aging garlic, and has been shown to have numerous health benefits. It has been previously revealed that several garlic-derived compounds, including AGE, have tumor-suppressive effects in various cancer models. Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers, and carries a dismal prognosis. Recently, numerous tumors, including PDAC, were shown to harbor intracellular bacteria, some of which are oral pathogens. Tumor-associated bacteria have been linked to cancer progression. Garlic may inhibit tumor development, in part, by targeting these bacteria. Although it requires further investigation, pharmacological and antibacterial effects of garlic and its products could offer significant therapeutic benefits for the prevention and treatment of PDAC. In the present review, the therapeutic potential of garlic on PDAC is summarized and discussed.

Association between Survival Duration of Older Patients with Advanced Unresectable Pancreatic Cancer and Appetite Loss: A Retrospective Cohort Study

This retrospective cohort study clarified associations between trajectories in palliative care and appetite loss among older patients with advanced unresectable pancreatic cancer and reviewed pancreatic cancer diagnosis among these populations in rural community hospitals. Patients aged >65 years and with pancreatic cancer in a rural community hospital were enrolled. The primary outcome was survival duration from the time of pancreatic cancer diagnosis. Participants were divided into those with and without appetite loss. Cumulative event-free survival rates were calculated using the Kaplan−Meier method, analyzed using the log-rank test, and stratified by factors with statistically significant between-group differences (serum albumin). The mean participant age was 84.14 (SD, 8.34) years; 31.4% were men. Significant between-group differences were noted in albumin concentration and survival duration. Kaplan−Meier curves showed a significant between-group difference in survival probability (p < 0.001). Survival duration significantly differed after stratification by albumin level (p < 0.001). Appetite loss may be a useful symptom for predicting mortality among older patients with unresectable pancreatic cancer, and hypoalbuminemia may accelerate deterioration in their conditions. Accordingly, subjective appetite loss observed by patients and families should be assessed to predict mortality, and it is advisable for physicians to promptly discuss relevant and advanced directives at appropriate timings.

Current studies and potential future research directions on biological effects and related mechanisms of allicin

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Construction of sulfur-containing compounds with anti-cancer stem cell activity using thioacrolein derived from garlic based on nature-inspired scaffolds

Sulfur-containing compounds, such as cyclic compounds with a vinyl sulfane structure, exhibit a wide range of biological activities including anticancer activity. Therefore, the development of efficient strategies to synthesize such compounds is a remarkable achievement. We have developed a unique approach for the rapid and modular preparation of nature-inspired cyclic and acyclic sulfur-containing compounds using thioacrolein, a naturally occurring chemically unstable intermediate. We constructed thiopyranone derivatives through the regioselective sequential double Diels-Alder reaction of thioacrolein produced by allicin, a major component in garlic, and two molecules of silyl enol ether as the diene partner. The cytotoxicity toward cancer stem cells of the thiopyranones was equal to or higher than that of (Z)-ajoene (positive control) derived from garlic, and the thiopyranones had higher chemical stability than (Z)-ajoene.

Antibacterial Properties of Organosulfur Compounds of Garlic (Allium sativum)

Garlic (Allium sativum), a popular food spice and flavoring agent, has also been used traditionally to treat various ailments especially bacterial infections for centuries in various cultures around the world. The principal phytochemicals that exhibit antibacterial activity are oil-soluble organosulfur compounds that include allicin, ajoenes, and allyl sulfides. The organosulfur compounds of garlic exhibit a range of antibacterial properties such as bactericidal, antibiofilm, antitoxin, and anti-quorum sensing activity against a wide range of bacteria including multi-drug resistant (MDR) strains. The reactive organosulfur compounds form disulfide bonds with free sulfhydryl groups of enzymes and compromise the integrity of the bacterial membrane. The World Health Organization (WHO) has recognized the development of antibiotic resistance as a global health concern and emphasizes antibiotic stewardship along with the urgent need to develop novel antibiotics. Multiple antibacterial effects of organosulfur compounds provide an excellent framework to develop them into novel antibiotics. The review provides a focused and comprehensive portrait of the status of garlic and its compounds as antibacterial agents. In addition, the emerging role of new technologies to harness the potential of garlic as a novel antibacterial agent is discussed.

Antimicrobial properties of hydrophobic compounds in garlic: Allicin, vinyldithiin, ajoene and diallyl polysulfides

Allium plants, such as garlic, onion and leek have long been known to be effective in the therapy of infectious diseases. In particular, garlic has a greater antimicrobial activity than other Allium plants as it contains several hydrophobic antimicrobial compounds, such as allicin, vinyldithiins, ajoenes and diallyl polysulfides. Allicin is a characteristic sulfur-containing compound found in raw garlic produced from alliin and exhibits antimicrobial activity against both Gram-positive and Gram-negative bacteria. In addition, allicin has been reported to inhibit the biofilm formation of bacteria, which is a major cause of bacterial resistance to the antibiotic treatment of infections, by regulating quorum sensing in microorganisms. Other hydrophobic compounds also have similar inhibitory effects on bacteria as allicin. These biological properties of garlic-derived hydrophobic compounds can be used to enhance the effects of existing drugs and may thus be used in the treatment of infections, such as by preventing drug resistance through the inhibition of biofilm formation. In this review, we summarize the effects of hydrophobic compounds of garlic on bacteria.

Helicobacter Pylori Eradication with Beta Carotene, Ascorbic Acid and Allicin

In this study, in vivo effectiveness of ascorbic acid (AA), beta carotene (BC) and allicin in HP eradication were evaluated. 210 patients who are HP positive in biopsy were involved in this study. The patients randomised to seven treatment groups (each group consisting of 30 patients). The first group was given standard eradication treatment (lansaprasol 30 mg bid, clarithromycin 500 mg bid, amoxicillin 1 g bid for 14 days). Second group received AA 1000 mg/day in addition to the standard treatment. Third group received only AA 1000 mg/day for 14 days. Fourth group was treated with standard regiment plus 120 mg/day BC. Fifth group was given only BC 120 mg/day for 14 days. Sixth group was given standard regiment and allicin 4200 μg/day. Seventh group received only Allicin 1200 μg/day for 14 days. The eradication was achieved in 20 (66.6 %) in group I, 15 (50 %) in group II, 3 (10 %) in group III, 15 (50 %) in group IV, 0 (0 %) in group V, 27 (90 %) in group VI and 7 (23.3 %) in group VII. Allicin seemed to be potentially effective agent for HP eradication but ascorbic acid, beta caroten was found to be ineffective.

Whole Transcriptome Sequencing Analysis of the Synergistic Antimicrobial Effect of Metal Oxide Nanoparticles and Ajoene on Campylobacter jejuni

Two metal oxide (i.e., Al₂O₃ and TiO₂) nanoparticles and ajoene, a garlic-derived organosulfur compound, were identified to be effective antimicrobials against Campylobacter jejuni, a leading cause of human gastrointestinal diseases worldwide. A significant synergistic antimicrobial effect was observed using ajoene and Al₂O₃/TiO₂ nanoparticles in a combined manner to cause at least 8 log₁₀ CFU/mL reduction of C. jejuni cells. Whole transcriptome sequencing (RNA-seq) and confocal micro-Raman spectroscopic analyses revealed the antimicrobial mechanism and identified the roles of ajoene and metal oxide nanoparticles in the synergistic treatment. Ajoene and metal oxide nanoparticles mediated a two-phase antimicrobial mechanism. Ajoene served as the inducing factor at the first phase that caused injury of cell membranes and increased the susceptibility of C. jejuni to stress. Metal oxide nanoparticles served as the active factor at the second phase that targeted sensitive cells and physically disrupted cell structure. This synergistic antimicrobial treatment demonstrates a potential to reduce the prevalence of C. jejuni and other pathogens on food contact surfaces and in the food chain.

Biotechnological aspects of plants metabolites in the treatment of ulcer: A new prospective

Ulcer is one of the most common diseases affecting throughout the world population. The allopathic treatment of ulcer adversely affects the health by causing harmful side effects. Currently, many herbal plants and secondary metabolites have been used for the ulcer treatment. In the present review, many herbal plants and their parts (root, rhizome, bark, leaves and fruits) have been listed in the table are currently being used for ulcer treatment. These metabolites are responsible for ulcer-neutralization or anti-inflammatory properties. In silico study, plant metabolites showed interaction between protodioscin (secondary metabolites of Asparagus racemosus) and interferon-γ (virulent factor of gastric ulcer) during molecular docking. All the residues of interferon-γ exhibited hydrophobic interactions with plant metabolites. These interactions helps in understanding the plant secondary metabolites vis a vis will open a new door in the research field of new drug discovery and designing for the ulcer treatment.

Antimicrobial activity of natural products against Helicobacter pylori: a review

Throughout the genetic and physiological evolution of microorganisms, the microbiological sciences have been expanding the introduction of new therapeutic trials against microbial diseases. Special attention has been paid to the bacterium Helicobacter pylori, which induces gastric infections capable of causing damage, ranging from acute and chronic gastritis to the development of gastric cancer and death. The use of compounds with natural origins has gained popularity in scientific research focused on drug innovation against H. pylori because of their broad flexibility and low toxicity. The aim of this study was to describe the use of natural products against H. pylori in order to clarify important parameters for related fields. The study demonstrated the vast therapeutic possibilities for compounds originating from natural sources and revealed the need for innovations from future investigations to expand the therapeutic arsenal in the fight against H. pylori infection.

Investigating the responses of Cronobacter sakazakii to garlic-drived organosulfur compounds: a systematic study of pathogenic-bacterium injury by use of high-throughput whole-transcriptome sequencing and confocal micro-raman spectroscopy

We present the results of a study using high-throughput whole-transcriptome sequencing (RNA-seq) and vibrational spectroscopy to characterize and fingerprint pathogenic-bacterium injury under conditions of unfavorable stress. Two garlic-derived organosulfur compounds were found to be highly effective antimicrobial compounds against Cronobacter sakazakii, a leading pathogen associated with invasive infection of infants and causing meningitis, necrotizing entercolitis, and bacteremia. RNA-seq shows changes in gene expression patterns and transcriptomic response, while confocal micro-Raman spectroscopy characterizes macromolecular changes in the bacterial cell resulting from this chemical stress. RNA-seq analyses showed that the bacterial response to ajoene differed from the response to diallyl sulfide. Specifically, ajoene caused downregulation of motility-related genes, while diallyl sulfide treatment caused an increased expression of cell wall synthesis genes. Confocal micro-Raman spectroscopy revealed that the two compounds appear to have the same phase I antimicrobial mechanism of binding to thiol-containing proteins/enzymes in bacterial cells generating a disulfide stretching band but different phase II antimicrobial mechanisms, showing alterations in the secondary structures of proteins in two different ways. Diallyl sulfide primarily altered the α-helix and β-sheet, as reflected in changes in amide I, while ajoene altered the structures containing phenylalanine and tyrosine. Bayesian probability analysis validated the ability of principal component analysis to differentiate treated and control C. sakazakii cells. Scanning electron microscopy confirmed cell injury, showing significant morphological variations in cells following treatments by these two compounds. Findings from this study aid in the development of effective intervention strategies to reduce the risk of C. sakazakii contamination in the food production environment and on food contact surfaces, reducing the risks to susceptible consumers.

Utilização do óleo de alho e da amoxilina, metronidazol e omeprazol no controle de Helicobacter spp. em cães

Avaliaram-se a eficácia do óleo de alho e da terapia tripla (amoxicilina, metronidazol e omeprazol) no tratamento de 21 cães infectados por Helicobacter spp., que apresentavam alterações histológicas nas biopsias endoscópicas da mucosa gástrica e reação positiva ao teste de urease. Os animais foram distribuídos, aleatoriamente, em três grupos de sete cães, os quais receberam os seguintes tratamentos: grupo 1 - cápsulas vazias; grupo 2 - 500mg de óleo de alho em cápsulas, diariamente, por um período de 30 dias; grupo 3 - amoxicilina, metronidazol e omeprazol, respectivamente, nas doses de 20mg/kg a cada 12 horas, 25mg/kg e 20mg/kg a cada 24 horas, durante 15 dias. Ao final dos tratamentos, os cães foram submetidos à endoscopia com realização de biopsias da mucosa gástrica. O tratamento com amoxicilina, metronidazol e omeprazol resultou em erradicação de Helicobacter spp. tanto na região fúndica quanto na pilórica. No grupo 2, houve redução da degeneração glandular na região fúndica em dois animais e em outros dois na pilórica. O tratamento com óleo de alho não foi eficaz em erradicar Helicobacter spp., apenas reduziu a sua colonização em quatro dos animais tratados.

Antibacterial activity of Tabebuia impetiginosa Martius ex DC (Taheebo) against Helicobacter pylori

The growth-inhibiting activity of Tabebuia impetiginosa Martius ex DC dried inner bark-derived constituents against Helicobacter pylori ATCC 43504 was examined using paper disc diffusion and minimum inhibitory concentration (MIC) bioassays. The activity of the isolated compounds was compared to that of the commercially available anti-Helicobacter pylori agents, amoxicillin, metronidazole, and tetracycline. The biologically active components of Tabebuia impetiginosa dried inner bark (taheebo) were characterized by spectroscopic analysis as 2-(hydroxymethyl)anthraquinone, anthraquinone-2-carboxylic acid, and 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone (lapachol). With the paper disc diffusion assay 2-(hydroxymethyl)anthraquinone exhibited strong activity against Helicobacter pylori ATCC 43504 at 0.01 mg/disc. Anthraquinone-2-carboxylic acid, lapachol and metronidazole were less effective, exhibiting moderate anti-Helicobacter pylori activity at 0.1 mg/disc. Amoxicillin and tetracycline were the most potent compounds tested, displaying very strong activity at 0.005 mg/disc. 2-(Hydroxymethyl)anthraquinone exhibited moderate activity at this dose. Tetracycline still had strong activity at 0.001 mg/disc while amoxicillin had little activity at this dose. In the MIC bioassay, 2-(hydroxymethyl)anthraquinone (2 microg/mL), anthraquinone-2-carboxylic acid (8 microg/mL), and lapachol (4 microg/mL) were more active than metronidazole (32 microg/mL) but less effective than amoxicillin (0.063 microg/mL) and tetracycline (0.5 microg/mL). The anti-Helicobacter pylori activity of seven 1,4-naphthoquinone derivatives (structurally related to lapachol), 1,4-naphthoquinone, 5,8-dihydroxy-1,4-naphthoquinone (naphthazarin), 2-methyl-1,4-naphthoquinone (menadione), 2-hydroxy-1,4-naphthoquinone (lawsone), 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin), 5-hydroxy-1,4-naphthoquinone (juglone), and 2,3-dichloro-1,4-naphthoquinone (dichlone) was also evaluated using the paper disc assay. Menadione and plumbagin were the most potent compounds tested with the later still exhibiting very strong activity at 0.001 mg/disc. Menadione, juglone and tetracycline had strong activity at this low dose while the latter two compounds and amoxicillin had very strong activity at 0.005 mg/disc. Lawsone was unusual in that it had very strong activity at 0.1 and 0.05 mg/disc but weak activity at doses of 0.01 mg/disc and lower. Naphthazalin, lapachol and dichlone had similar activities while metronidazole had the lowest activity of all compounds tested. These results may be an indication of at least one of the pharmacological actions of taheebo. The Tabebuia impetiginosa dried inner bark-derived materials, particularly 2-(hydroxymethyl)anthraquinone, merit further study as potential Helicobacter pylori eradicating agents or lead compounds.

Antimicrobial activities of Eugenol and Cinnamaldehyde against the human gastric pathogen Helicobacter pylori

BACKGROUND

Eradication of Helicobacter pylori is an important objective in overcoming gastric diseases. Many regimens are currently available but none of them could achieve 100% success in eradication. Eugenol and cinnamaldehyde that are commonly used in various food preparations are known to possess antimicrobial activity against a wide spectrum of bacteria.

AIM

The present study was performed to assess the in vitro effects of eugenol and cinnamaldehyde against indigenous and standard H. pylori strains, their minimum inhibitory concentrations (MICs) and time course lethal effects at various pH.

METHODS

A total of 31 strains (29 indigenous and one standard strain of H. pylori ATCC 26695, one strain of E. coli NCIM 2089) were screened. Agar dilution method was used for the determination of drug sensitivity patterns of isolates to the commonly used antibiotics and broth dilution method for the test compounds.

RESULTS

Eugenol and cinnamaldehyde inhibited the growth of all the 30 H. pylori strains tested, at a concentration of 2 mug/ml, in the 9th and 12th hours of incubation respectively. At acidic pH, increased activity was observed for both the compounds. Furthermore, the organism did not develop any resistance towards these compounds even after 10 passages grown at sub-inhibitory concentrations.

CONCLUSION

These results indicate that the two bioactive compounds we tested may prevent H. pylori growth in vitro, without acquiring any resistance.

Non-antibiotic therapies for Helicobacter pylori infection

Despite years of experience with Helicobacter pylori treatment, the ideal regimen for treating the infection has not been found. The most effective eradication treatment is the combination of a proton pump inhibitor with antibiotics, but 10-20% of the patients fail to obtain eradication of the infection. Antibiotic resistance is a major factor affecting the outcome of treatment. Non-antibiotic therapies, including phytomedicines, probiotics, and antioxidants, have been increasingly investigated as potential alternatives for the treatment of H. pylori. In this article, we review the non-antibiotic therapies for H. pylori infection.

Allium vegetables and stomach cancer risk in China

Although the incidence of stomach cancer has been declining, it remains the second leading cause of cancer death worldwide. Potential protective effects of allium vegetables against cancer have been reported by a few epidemiologic studies in Chinese populations, but the sample sizes of these studies were relatively small. We examined the associations between allium vegetable consumption and stomach cancer in a large population-based case-control study in Shanghai (750 cases and 750 age- and gender-matched controls) and Qingdao (201 cases and 201 age- and gender-matched controls). Epidemiological data were collected by a standard questionnaire, and odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression in SAS. After adjusting for matching variables, education, body mass index, pack-years of smoking, alcohol drinking, salt intake, and fruit and vegetable intake, inverse relationships with dose response pattern were observed between frequency of onion intake and stomach cancer in Qingdao (P for trend=0.02) and Shanghai (P for trend=0.04) populations. In Shanghai, negative dose-response relationships were observed between monthly intake of onions (P=0.03) or garlic stalks (P=0.04) and distal, but not cardia cancer. A negative association was also noted between intake of garlic stalks (often vs. never) and risk of stomach cancer in Qingdao (OR=0.30; 95% CI: 0.12-0.77). Our results confirm protective effects of allium vegetables (especially garlic and onions) against stomach cancer.

In vitro anti-Helicobacter pylori action of 30 Chinese herbal medicines used to treat ulcer diseases

Infection by Helicobacter pylori has been ascertained to be an important etiologic impetus leading usually to chronic active gastritis and gastric ulcer with growing incidences worldwide. Utilizing as the test pathogen a standard and five clinic strains of Helicobacter pylori, the antibacterial action was assessed in vitro with ethanol extracts of 30 Chinese herbal medicines which have been frequently prescribed since ancient times for treating gastritis-like disorders. Among the 30 tested materials, the ethanol extracts of Abrus cantoniensis (Fabaceae), Saussurea lappa (Asteraceae) and Eugenia caryophyllata (Myrtaceae) were strongly inhibitory to all test strains (MICs: approximately 40 microg/ml), and Hippophae rhamnoides (Elaeagnaceae), Fritillaria thunbergii (Liliaceae), Magnolia officinalis and Schisandra chinensis (Magnoliaceae), Corydalis yanhusuo (Papaveraceae), Citrus reticulata (Rutaceae), Bupleurum chinense and Ligusticum chuanxiong (Apiaceae) substantially active with MICs close to 60.0 microg/ml. As to antibacterial actions of the aqueous extracts of the same drugs, those derived from Cassia obtusifolia (Fabaceae), Fritillaria thunbergii and Eugenia caryophyllata were remarkably inhibitory against all the six Helicobacter pylori strains (MICs: approximately 60 microg/ml). The work compared almost quantitatively the magnitude of the anti-Helicobacter pylori actions of the 30 most prescribed gastritis-treating Chinese herbal drugs, and located as well some source plants where potent anti-Helicobacter pylori phytochemicals could be characterized.

Allyl-thiosulfinates, the bacteriostatic compounds of garlic against Helicobacter pylori

Allicin and allyl-methyl plus methyl-allyl thiosulfinate from acetonic garlic extracts (AGE) have been isolated by high-performance liquid chromatography. These compounds have shown inhibition of the in vitro growth of Helicobacter pylori (Hp), the bacterium responsible for serious gastric diseases such as ulcers and even gastric cancer. A chromatographic method was optimized and used to isolate these thiosulfinates. The method developed has allowed the isolation of natural thiosulfinates extracted from garlic by organic solvents and is an easy and cheap methodology that avoids complex synthesis and purification procedures. The capacity and effectiveness of isolated natural thiosulfinates have been tested, and this has enabled the identification of the main compounds responsible for the bacteriostatic activity shown by AGE origin of these kinds of organosulfur compounds along with ethanolic garlic extracts (EGE). Additionally, microbiological analyses have suggested that these compounds show a synergic effect on the inhibition of the in vitro growth of Hp. The results described here facilitate the process of obtaining garlic extracts with optimal bacteriostatic properties. The product is obtained in a way that avoids expensive purification methods and will allow the design of live tests with the aim of investigating the potential for the use of these garlic derivatives in the treatment of patients with Hp infections.

Thermal degradation of allicin in garlic extracts and its implication on the inhibition of the in-vitro growth of Helicobacter pylori

Allicin, the main active principle related to Allium sativum chemistry, is considered to be responsible for the bacteriostatic properties of garlic. The work described here has demonstrated the direct implication of the allicin present in solvent-free garlic extracts obtained with ethanol (ethanolic garlic extract, EGE) and acetone (acetonic garlic extract, AGE) in the inhibition of the in-vitro growth of Helicobacter pylori (Hp), the bacterium responsible for serious gastric diseases such as ulcers and even gastric cancer. The evolution of allicin concentration as a function of time and temperature has been the subject of a kinetic study. The reaction order, activation energy, and preexponential factor (in accordance with Arrhenius theory) have been determined for the decomposition process of allicin in these organic media. First-order decomposition, an activation energy of 97.4 kJ/mol, and an Arrhenius preexponential factor of 8.9 x 10(10) s(-1) have been determined for allicin in EGE. For allicin in AGE the kinetic order determined was 1.5, the activation energy 184.5 kJ/mol, and the preexponential factor 3.1 x 10(24) s(-1) (mg/L)(-0.5). The presence or absence of allicin in these garlic products was found to be crucial for the inhibition of the in-vitro growth of Hp, as demonstrated by microbiological analysis for AGE. A relationship has been identified between the effectiveness and durability of the anti-Hp properties shown by AGE and the allicin content of these products. The bacteriostatic properties were active for up to 10 months if the samples were maintained at 6 degrees C.

Efficacy of sulforaphane in eradicating Helicobacter pylori in human gastric xenografts implanted in nude mice

Sulforaphane, an isothiocyanate abundant in the form of its glucosinolate precursor in broccoli sprouts, has shown in vitro activity against Helicobacter pylori. We evaluated the effect of sulforaphane in vivo against this bacterium by using human gastric xenografts in nude mice. H. pylori was completely eradicated in 8 of the 11 sulforaphane-treated grafts. This result suggests that sulforaphane might be beneficial in the treatment of H. pylori-infected individuals.

Antimicrobial activity of essential oils against Helicobacter pylori

BACKGROUND

Helicobacter pylori is an important pathogen responsible for gastroduodenal diseases in humans. Although the eradication of H. pylori using antibiotics often improves gastroduodenal diseases, resistance to the antibiotics is emerging.

MATERIALS AND METHODS

The antimicrobial effect of essential oils and the development of resistance to the essential oils were evaluated in vitro and in vivo.

RESULTS

Thirteen essential oils used in this study completely inhibited the growth of H. pylori in vitro at a concentration of 0.1% (v/v). Cymbopogon citratus (lemongrass) and Lippia citriodora (lemon verbena) were bactericidal against H. pylori at 0.01% at pH 4.0 and 5.0. Resistance to lemongrass did not develop even after 10 sequential passages, whereas resistance to clarithromycin developed under the same conditions. In in vivo studies, the density of H. pylori in the stomach of mice treated with lemongrass was significantly reduced compared with untreated mice.

CONCLUSIONS

These results demonstrate that the essential oils are bactericidal against H. pylori without the development of acquired resistance, suggesting that essential oils may have potential as new and safe agents for inclusion in anti-H. pylori regimens.

A pilot study to determine the effectiveness of garlic oil capsules in the treatment of dyspeptic patients with Helicobacter pylori

BACKGROUND

Resistance of Helicobacter pylori to clarithromycin and metronidazole is now found worldwide. Steam-distilled garlic oil has in vitro activity against H. pylori and may be a useful alternative treatment strategy.

MATERIALS AND METHODS

In this pilot study dyspeptic patients with positive serology for H. pylori confirmed by 13C urea breath test (UBT), at 0 and 2 weeks, were enrolled. Treatment consisted of one 4 mg garlic oil capsule with a meal four times per day for 14 days. H. pylori eradication was defined as a negative UBT at both follow-up appointments. Suppression was defined as a 50% fall in 13C excess between baseline and follow-up 1.

RESULTS

Five patients completed the study. There was no evidence of either eradication or suppression of H. pylori or symptom improvement whilst taking garlic oil.

CONCLUSION

These negative results show that, within the gastric milieu, garlic oil at this dose does not inhibit H. pylori. A higher dose administered for a longer time-period may be effective. Antibiotics are usually combined with a proton-pump inhibitor or bismuth salt, as the only antibiotic with any in vivo activity against H. pylori in monotherapy is clarithromycin. A proton pump inhibitor raises gastric pH and, by increasing bacterial division, may increase the in vivo activity of garlic oil. This may be worth pursuing in a future trial.

Anti-Helicobacter pylori activity of Aristolochia paucinervis Pomel extracts

The anti-Helicobacter pylori effect of the extracts and the fractions obtained from Aristolochia paucinervis rhizome and leaves were studied against a reference strain of H. pylori by using the agar dilution method. Only the methanol extracts and the hexane fractions of either the rhizome or the leaves exhibited an inhibitory activity at a concentration of < or =128 microg/ml. The leaf hexane fraction APLH demonstrated a higher inhibitory activity (MIC: 4 microg/ml) than the rhizome hexane fraction APRH (MIC: 16 microg/ml), the leaf methanol extract APLM (MIC: 32 microg/ml) and the rhizome methanol extract APRM (MIC: 128 microg/ml). This inhibitory activity was confirmed for the active extracts and fractions against clinical isolates of H. pylori (n = 20) for which MIC50) and MIC90 were determined.

Astaxanthin-rich algal meal and vitamin C inhibit Helicobacter pylori infection in BALB/cA mice

Helicobacter pylori infection in humans is associated with chronic type B gastritis, peptic ulcer disease, and gastric carcinoma. A high intake of carotenoids and vitamin C has been proposed to prevent development of gastric malignancies. The aim of this study was to explore if the microalga Haematococcus pluvialis rich in the carotenoid astaxanthin and vitamin C can inhibit experimental H. pylori infection in a BALB/cA mouse model. Six-week-old BALB/cA mice were infected with the mouse-passaged H. pylori strain 119/95. At 2 weeks postinoculation mice were treated orally once daily for 10 days (i) with different doses of algal meal rich in astaxanthin (0.4, 2, and 4 g/kg of body weight, with the astaxanthin content at 10, 50, and 100 mg/kg, respectively), (ii) with a control meal (algal meal without astaxanthin, 4 g/kg), or (iii) with vitamin C (400 mg/kg). Five mice from each group were sacrificed 1 day after the cessation of treatment, and the other five animals were sacrificed 10 days after the cessation of treatment. Culture of H. pylori and determination of the inflammation score of the gastric mucosae were used to determine the outcome of the treatment. Mice treated with astaxanthin-rich algal meal or vitamin C showed significantly lower colonization levels and lower inflammation scores than those of untreated or control-meal-treated animals at 1 day and 10 days after the cessation of treatment. Lipid peroxidation was significantly decreased in mice treated with the astaxanthin-rich algal meal and vitamin C compared with that of animals not treated or treated with the control meal. Both astaxanthin-rich algal meal and vitamin C showed an inhibitory effect on H. pylori growth in vitro. In conclusion, antioxidants may be a new strategy for treating H. pylori infection in humans.

Activities of garlic oil, garlic powder, and their diallyl constituents against Helicobacter pylori

Chronic Helicobacter pylori disease is reduced with Allium vegetable intake. This study was designed to assess the in vivo anti-H. pylori potential of a variety of garlic substances. The garlic materials all showed substantial but widely differing anti-H. pylori effects against all strains and isolates tested. The MICs (range, 8 to 32 microg/ml) and minimum bactericidal concentrations (MBCs) (range, 16 to 32 microg/ml) of undiluted garlic oil (GO) were smaller than those of garlic powder (GP) (MIC range, 250 to 500 microg/ml; MBC range, 250 to 500 microg/ml) but greater than the MIC of allicin (4. 0 microg/ml) (Table 2) present in GP. Allicin (MIC, 6 microg/ml; MBC, 6 microg/ml) was more potent than diallyl disulfide (MIC range, 100 to 200 microg/ml; MBC range, 100 to 200 microg/ml), its corresponding sulfide, but of a strength similar to that of diallyl tetrasulfide (MIC range, 3 to 6 microg/ml; MBC range, 3 to 6 microg/ml). Antimicrobial activity of the diallyl sulfides increased with the number of sulfur atoms. Time course viability studies and microscopy showed dose-dependent anti-H. pylori effects with undiluted GO, GP, allicin, and diallyl trisulfide after a lag phase of ca. 1 to 2 h. Substantial in vitro anti-H. pylori effects of pure GO and GP and their diallyl sulfur components exist, suggesting their potential for in vivo clinical use against H. pylori infections.