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

Methods of Isolation of Active Substances from Garlic (Allium sativum L.) and Its Impact on the Composition and Biological Properties of Garlic Extracts

Garlic (Allium sativum L.) is widely used in the human diet and in scientific research due to its biological properties. Various factors, e.g., temperature, pressure, extraction method, type of solvent, size, and territorial origin of garlic, affect the amount and type of bioactive compounds obtained from garlic extracts. In turn, the content of bioactive compounds correlates with the biological activity of the extracts. Therefore, the aim of this review was to summarize the current state of knowledge of the methods and effectiveness of isolation of active substances from garlic and their impact on the garlic extract composition and, consequently, biological properties. According to the literature, extracts obtained using water as a solvent are mainly responsible for antimicrobial properties, which is related to, inter alia, the high content of allicin. The use of alcohols, such as methanol or ethanol, is associated with the outstanding antioxidant power of extracts resulting from the presence of phenolic compounds. In turn, due to the presence of diallyl disulfide and disulfide trisulfide, garlic oil has anticancer potential. Acetone is the most effective organic solvent; however, it is not suitable for immediate consumption.

Solvent Mixture Optimization in the Extraction of Bioactive Compounds and Antioxidant Activities from Garlic (Allium sativum L.)

Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water–acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.

Current Advances and Outlook in Gastric Cancer Chemoresistance: A Review

BACKGROUND

Surgical resection of the lesion is the standard primary treatment of gastric cancer. Unfortunately, most patients are already in the advanced stage of the disease when they are diagnosed with gastric cancer. Alternative therapies, such as radiation therapy and chemotherapy, can achieve only very limited benefits. The emergence of cancer drug resistance has always been the major obstacle to the cure of tumors. The main goal of modern cancer pharmacology is to determine the underlying mechanism of anticancer drugs.

OBJECTIVE

Here, we mainly review the latest research results related to the mechanism of chemotherapy resistance in gastric cancer, the application of natural products in overcoming the chemotherapy resistance of gastric cancer, and the new strategies currently being developed to treat tumors based on immunotherapy and gene therapy.

CONCLUSION

The emergence of cancer drug resistance is the main obstacle in achieving alleviation and final cure for gastric cancer. Mixed therapies are considered to be a possible way to overcome chemoresistance. Natural products are the main resource for discovering new drugs specific for treating chemoresistance, and further research is needed to clarify the mechanism of natural product activity in patients. .

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.

Allium sativum derived carbon dots as a potential theranostic agent to combat the COVID-19 crisis

Coronavirus disease 2019 (COVID-19) is one of the worst pandemics to have hit the humanity. The manifestations are quite varied, ranging from severe lung infections to being asymptomatic. Hence, there is an urgent need to champion new tools to accelerate the end of this pandemic. Compromised immunity is a primary feature of COVID-19. Allium sativum (AS) is an effective dietary supplement known for its immune-modulatory, antibacterial, anti-inflammatory, anticancer, antifungal, and anti-viral properties. In this paper, it is hypothesized that carbon dots (CDs) derived from AS (AS-CDs) may possess the potential to downregulate the expression of pro-inflammatory cytokines and revert the immunological aberrations to normal in case of COVID-19. CDs have already been explored in the world of nanobiomedicine as a promising theranostic candidates for bioimaging and drug/gene delivery. The antifibrotic and antioxidant effects of AS are elaborated, as demonstrated in several studies. It is found that the most active constituent of AS, allicin has a highly potent antioxidant and reactive oxygen species (ROS) scavenging effect. The antibacterial, antifungal, and anti-viral effects along with their capability of negating inflammatory effects and cytokine storm are discussed. The synthesis of theranostic CDs from AS may provide a novel weapon in the therapeutic armamentarium for the management of COVID-19 infection and, at the same time, could act as a diagnostic agent for COVID-19.

Helicobacter pylori: Perturbation and restoration of gut microbiome

Alternate remedies with natural products provides unlimited opportunities for new drug development. These can be either as pure compounds or as standardized set of compounds. The phytochemicals and secondary metabolites are in great demand for screening bioactive compounds and plays an important role towards drug development. Natural products have many advantages over to synthetic chemical drugs. Helicobacter pylori (H. pylori) a Gram-negative bacteria has been classified as Class I carcinogen by World Health Organization in 1994. Current treatment regimens for H. pylori is ‘triple therapy’ administrated for two weeks which includes a combination of two antibiotics like Amoxicillin and Clarithromycin and a proton pump inhibitor (PPI) like Lansoprazole, and for ‘quadruple therapy’ in addition to antibiotics and a PPI, Bismuth is used. Antibiotic resistance can be named as the main factor for failure of treatment of H. pylori infection. The need of the hour is to develop a herbal remedy that could combat the growth of H. pylori. Probiotics can also be used as ‘feasible’ tool for H. pylori infection management. Present review is an attempt to briefly discuss about the pathogenicity, genetic predisposition, perturbation of gut microbiota due to antibiotic treatment and restoration of healthy gut microbiota with phytochemicals and probiotics.

Structures of Cyclic Organosulfur Compounds From Garlic (Allium sativum L.) Leaves

Five new cyclic organosulfur compounds, foliogarlic disulfanes A₁ (1), A₂ (2), and A₃ (3) and foliogarlic trisulfane A₁ (4) and A₂ (5), were isolated from the leaves of Allium sativum (garlic). The chemical structures of these compounds were elucidated on the basis of physicochemical evidence including Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS). Compounds 1-5 were obtained as complex compounds with disulfane or trisulfane and tetrahydro-2H-difuro[3,2-b:2',3'-c]furan-5(5aH)-one. In addition, the hypothetical biosynthetic pathways of these compounds were suggested.

Cost Effective Use of a Thiosulfinate-Enriched Allium sativum Extract in Combination with Chemotherapy in Colon Cancer

In this work, we sought to investigate the effects of a thiosulfinate-enriched garlic extract, co-administered with 5-fluorouracil (5-FU) or oxaliplatin chemotherapy, on the viability of colon cancer cells (Caco-2 and HT-29). We also addressed the economic feasibility of a new combined treatment of this thiosulfinate-enriched garlic extract, with oxaliplatin that could reduce the dosage and costs of a monotherapy. The thiosulfinate-enriched garlic extract not only enhanced the impact of 5-FU and oxaliplatin (500 µM) in decreasing Caco-2 and HT-29 viability, but also showed a higher effect than standard 5-FU and oxaliplatin chemotherapy as anti-cancer agents. These results provided evidences for the combination of lyophilized garlic extract and 5-FU or oxaliplatin as a novel chemotherapy regimen in colon cancer cells that may also reduce the clinical therapy costs.

Allicin as add-on therapy for Helicobacter pylori infection: A systematic review and meta-analysis

BACKGROUND

Allicin (2-propene-1-sulfinothioic acid S-2-propenyl ester, diallyl thiosulfinate) extracted from garlic, has proven activity against Helicobacter pylori (H. Pylori) infection. In recent years, clinical trials have explored its utility as an add-on therapy with variable outcomes reported.

AIM

To perform a systemic review of allicin as an add-on treatment for H. Pylori infection and assess its efficacy in randomized controlled trials (RCTs).

METHODS

Electronic databases including MEDLINE, EMBASE, the Web of Science, the Cochrane Database, the China National Knowledge Infrastructure Database, Chinese VIP Information Databases, Chinese Medical Databases, and the Wan-Fang Database were searched for keywords including "allicin", "Helicobacter pylori", "randomized clinical trials", and their synonyms. A meta-analysis was performed using the fixed-effects model for low heterogeneity and the random-effects model for high heterogeneity with sensitivity analysis. Bias was evaluated using Egger's tests. Trial sequential analysis (TSA) was used to evaluate information size and treatment benefits. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the level of quality, and studies were classed as "high quality", "moderate quality", "low quality", and "very low quality".

RESULTS

A total of eight RCTs consisting of 867 participants (435 from the allicin group and 432 from the control group) were included. Eradication rate in the allicin group (93.33%, 406/435) was significantly higher than that of the control group (83.56%, 361/432) [I 2 = 0%, odds ratio (OR) = 2.75, 95% confidence interval (CI): 1.74-4.35, P < 0.001]. The healing rate of ulcers following H. pylori therapy in the allicin group (86.17%, 349/405) was significantly higher than that of the control group (75.87%, 305/402) [I 2 = 0%, OR = 2.05, 95%CI: 1.39-3.03, P < 0.001]. The total remission rate of peptic ulcers across all allicin groups was 97.16%, which was significantly higher than that of controls [96.05% (389/405) vs 86.55% (360/402), I 2 = 0, OR = 3.04, 95%CI: 1.51-6.12, P = 0.015]. No significant differences in side effects were observed. TSA suggested that the trials were of sufficient standard to draw reliable conclusions. The quality of outcomes including eradication rates and side effects was graded as "very low" due to downgrades for "risk of bias" and "indirectness". Other outcomes such as ulcer healing rates and total ulcer remission rates were graded as "low" due to downgrades for "risk of bias".

CONCLUSION

Allicin as an add-on therapy improves H. pylori eradication, healing of ulcers, and remission of symptoms. These results are suggested to be treated with caution due to limited quality.

Allium vegetable consumption and health: An umbrella review of meta-analyses of multiple health outcomes

Previously, our meta-analysis and other studies have suggested that allium vegetable consumption is beneficial for health, but no umbrella review has been conducted to assess the evidence of the various health benefits of allium vegetable consumption. Therefore, we conducted this umbrella review on this topic. This umbrella review included a total of 16 meta-analyses with 50 unique outcomes. The most beneficial cancer-related outcome was shown for gastric cancer (risk ratio 0.78; 95% confidence interval [CI] 0.67-0.91). In addition, only 8 weeks of garlic consumption significantly decreased serum total cholesterol (weighted mean differences -17.20 mg/dl; 95% CI -23.10 to -11.30), and patients with dyslipidemia who consumed garlic experienced more benefits than the whole population. Diabetic patients with longer durations of garlic intake experienced more benefits in terms of fasting blood glucose (FBG), HbA1c, and serum fructosamine than healthy participants, and garlic intake was associated with blood pressure reduction in hypertensive patients but not in normotensive participants. Limited side effects of garlic, such as garlic odor and gastrointestinal complaints, were reported among the included meta-analyses. Our results suggested that allium vegetables might be beneficial for cancer prevention. In particular, garlic was comparatively safe and is recommended as a long-term dietary component for patients with dyslipidemia, diabetes, and hypertension.

Peptic Ulcer Disease: A Brief Review of Conventional Therapy and Herbal Treatment Options

Peptic ulcer is a chronic disease affecting up to 10% of the world's population. The formation of peptic ulcers depends on the presence of gastric juice pH and the decrease in mucosal defenses. Non-steroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori (H. pylori) infection are the two major factors disrupting the mucosal resistance to injury. Conventional treatments of peptic ulcers, such as proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists, have demonstrated adverse effects, relapses, and various drug interactions. On the other hand, medicinal plants and their chemical compounds are useful in the prevention and treatment of numerous diseases. Hence, this review presents common medicinal plants that may be used for the treatment or prevention of peptic ulcers.

Dithiosulfinates and Sulfoxides with Antifungal Activity from Bulbs of Allium sativum L. var. Voghiera

A bioassay guided phytochemical analysis of the bulbs of Allium sativum L. var. Voghiera, typical of Voghiera, Ferrara (Italy), allowed the isolation of six new sulfur compounds with dithiosulfinates and sulfoxides functionalities. Structure elucidation of the isolated compounds was carried out by spectroscopic analyses, including NMR spectroscopy and MS spectrometry. Compounds showed significant antimicrobial activity towards two fungal species, the air-borne pathogen Botrytis cinerea and the beneficial fungus Trichoderma harzianum.

Synthesis and in vitro biological evaluation of thiosulfinate derivatives for the treatment of human multidrug-resistant breast cancer

Organosulfur compounds derived from Allium vegetables have long been recognized for various therapeutic effects, including anticancer activity. Allicin, one of the main biologically active components of garlic, shows promise as an anticancer agent; however, instability makes it unsuitable for clinical application. The aim of this study was to investigate the effect of stabilized allicin derivatives on human breast cancer cells in vitro. In this study, a total of 22 stabilized thiosulfinate derivatives were synthesized and screened for their in vitro antiproliferative activities against drug-sensitive (MCF-7) and multidrug-resistant (MCF-7/Dx) human adenocarcinoma breast cancer cells. Assays for cell death, apoptosis, cell cycle progression and mitochondrial bioenergetic function were performed. Seven compounds (4b, 7b, 8b, 13b, 14b, 15b and 18b) showed greater antiproliferative activity against MCF-7/Dx cells than allicin. These compounds were also selective towards multidrug-resistant (MDR) cells, a consequence attributed to collateral sensitivity. Among them, 13b exhibited the greatest anticancer activity in both MCF-7/Dx and MCF-7 cells, with IC₅₀ values of 18.54±0.24 and 46.50±1.98 μmol/L, respectively. 13b altered cellular morphology and arrested the cell cycle at the G₂/M phase. Additionally, 13b dose-dependently induced apoptosis, and inhibited cellular mitochondrial respiration in cells at rest and under stress. MDR presents a significant obstacle to the successful treatment of cancer clinically. These results demonstrate that thiosulfinate derivatives have potential as novel anticancer agents and may offer new therapeutic strategies for the treatment of chemoresistant cancers.

Can Diet Modulate Helicobacter pylori-associated Gastric Pathogenesis? An Evidence-Based Analysis

Helicobacter pylori is involved in the pathogenesis of gastritis, peptic ulcer, and gastric cancer. The infection is prevalent in more than half of the world's population. Although the infection may lead to detrimental consequences, still the majority of the infected individuals only develop mild gastritis. Several factors are behind this paradoxical outcome including virulence of the infecting H. pylori strains, genetic background of the host, and factors related to lifestyle such as dietary habits. Among these, lifestyle including dietary factors was not in the limelight, until recently, as one of the important factors that could modulate H. pylori-linked gastric diseases. This review is directed to gather and elucidate the role of dietary components in augmenting or attenuating pathological processes initiated by H. pylori. Available evidence strongly supports the notion that the diet may play a critical role in defining the final outcome of H. pylori infection particularly if certain dietary components are taken on a regular basis for a long time. Despite a recent surge in research related to the role of dietary ingredients, further studies involving large-scale clinical trials are required to gain a better understanding of the precise role played by the dietary ingredients in H. pylori-associated pathogenesis.

Yap1p, the central regulator of the S. cerevisiae oxidative stress response, is activated by allicin, a natural oxidant and defence substance of garlic

Allicin is a thiol-reactive sulfur-containing natural product from garlic with a broad range of antimicrobial effects against prokaryotes and eukaryotes. Previous work showed that the S. cerevisiae OSI1 gene is highly induced by allicin and other thiol-reactive compounds, and in silico analysis revealed multiple Yap1p binding motifs in the OSI1 promoter sequence. An OSI1-promoter::luciferase reporter construct expressed in Wt and Δyap1 cells showed absolute Yap1p-dependence for allicin-induced OSI1-expression.

A GFP

Yap1p fusion protein accumulated in the nucleus within 10min of allicin treatment and a Δyap1 mutant was highly sensitive to allicin. Yap1p regulates glutathione (GSH) metabolism genes, and Δgsh1, Δgsh2 and Δglr1 mutants showed increased sensitivity to allicin. Allicin activated the OSI1-promoter::luciferase reporter construct in Δgpx3 and Δybp1 cells, indicating that allicin activates Yap1p directly rather than via H₂O₂ production. A systematic series of C-to-A Yap1p exchange mutants showed that the C-term C598 and C620 residues were necessary for allicin activation. These data suggest that Yap1p is an important transcriptional regulator for the resistance of yeast cells to allicin, and that activation occurs by direct modification of C-term cysteines as shown for other electrophiles.

Phytochemicals for human disease: An update on plant-derived compounds antibacterial activity

In recent years, many studies have shown that phytochemicals exert their antibacterial activity through different mechanisms of action, such as damage to the bacterial membrane and suppression of virulence factors, including inhibition of the activity of enzymes and toxins, and bacterial biofilm formation. In this review, we summarise data from the available literature regarding the antibacterial effects of the main phytochemicals belonging to different chemical classes, alkaloids, sulfur-containing phytochemicals, terpenoids, and polyphenols. Some phytochemicals, besides having direct antimicrobial activity, showed an in vitro synergistic effect when tested in combination with conventional antibiotics, modifying antibiotic resistance. Review of the literature showed that phytochemicals represent a possible source of effective, cheap and safe antimicrobial agents, though much work must still be carried out, especially in in vivo conditions to ensure the selection of effective antimicrobial substances with low side and adverse effects.

Dietary, non-microbial intervention to prevent Helicobacter pylori-associated gastric diseases

Since the discovery of Helicobacter pylori (H. pylori) infection as the major cause of gastroduodenal disorders including acute and chronic gastritis, gastroduodenal ulcer, chronic atrophic gastritis, and gastric cancer almost three decades ago, the possibility of preventing these clinical diseases through eradicating H. pylori has been the focus of active research, but soon debate in the scientific community, though eradication opens the feasibility of cancer prevention and the removal of bacteria significantly prevents development or recurrence of peptic ulcer diseases and some clinical diseases, was proposed due to uncertainty in either achievement of complete eradication or inefficacy in cancer prevention with eradication alone. Still its linkage to gastric cancer is incontestable. Since the multiple combination of bacterial factors, environmental insults, and the host immune response that drives the initiation and progression of mucosal atrophy, metaplasia, and dysplasia toward gastric cancer is intervened, simple eradication deemed the feasibility of cancer prevention. Therefore, our group open strong hypothesis that non-microbial, dietary approach might be the alternate, for which several interventions of nutritional components can highlight rejuvenation of chronic atrophic gastritis as well as amelioration of H. pylori-associated procarcinogenic inflammation. In this review article, the experience and outcome regarding nutritional application to rejuvenate gastric atrophy will be introduced, using Korean red ginseng, garlic extracts, cancer preventive Korea kimchi, n-3 polyunsaturated fatty acids (PUFA), special form of licorice, and probiotics. The detailed influence of dietary intervention and bacterial eradication therapy on disease progression and reversibility of premalignant lesions are discussed.

S-allyl cysteine alleviates nonsteroidal anti-inflammatory drug-induced gastric mucosal damages by increasing cyclooxygenase-2 inhibition, heme oxygenase-1 induction, and histone deacetylation inhibition

BACKGROUND AND AIM

Nonsteroidal anti-inflammatory drugs (NSAIDs), the most highly prescribed drugs in the world for the treatment of pain, inflammation, and fever, are associated with gastric mucosal damages including ulcer directly or indirectly. This study was aimed to document the preventive effects of an organosulfur constituent of garlic, S-allyl cysteine (SAC), against NSAIDs-induced gastric damages, as well the elucidation of its pharmacological actions, such as anti-inflammatory, anti-oxidative, and cytoprotective actions.

METHODS

Different doses of SAC were administrated intragastrically before the indomethacin administration. After killing, in addition to gross and pathological evaluations of ulcer, the expressions of inflammatory mediators, including cyclooxygenase-2, prostaglandin E2 , IL-1β, tumor necrosis factor-α, IL-6, and anti-oxidant capacity, were analyzed by Western blot analysis or ELISA, respectively. Transferase deoxytidyl uridine end labeling assay, periodic acid and Schiff staining, F4/80 staining, and CD31 staining were compared among doses of SAC. Detailed documentation of in vitro biological actions of SAC, including NF-κB, histone deacetylator inhibition, phase 2 enzyme, and MAPKs, was performed.

RESULTS

SAC was very effective in preventing indomethacin-induced gastric damages in a low dose through significant decreases in macrophage infiltration as well as restorative action. Indomethacin-induced expressions of inflammatory mediators were all significantly attenuated with SAC in accordance with histone deacetylator inhibition. In addition, SAC significantly increased the total anti-oxidant concentration and mucus secretion, and allows for a significant induction of HO-1. However, these preventive effects of SAC were dependent on dosage of SAC; higher dose above 10 μM paradoxically aggravated NSAID-induced inflammation.

CONCLUSION

Synthetic SAC can be promising therapeutics agent to provide potent anti-inflammatory, anti-oxidative, and mucosa protective effects against NSAID-induced damages.

Comparitive study on volatile aroma compounds of two different garlic types (Kastamonu and Chinese) using gas chromatography mass spectrometry (HS-GC/MS) technique

BACKROUND

The medicinal use of garlic is much older than its usage as a food. The medical importance of garlic comes forward for its sulfur-containing components. In this study, it was aimed to compare Kastamonu garlic type with Chinese garlic type based on their aroma profiles.

MATERIALS AND METHODS

Fresh Kastamonu garlic samples harvested from Kastamonu region of Turkey and Chinese garlic samples obtained from Turkish market were used as plant material. Volatile aroma compounds were determined using Headspace Gas Chromatography Mass Spectrometry (HS-GC/MS).

RESULTS

Sixteen and twenty aroma components were identified in Kastamonu and Chinese garlic types, respectively. Kastamonu garlic type was found to be richer than Chinese garlic types in terms of sulfur-containing compounds. Diallyl disulphide, which is one of these components, was detected at level of 41.87% and 34.95% in the Kastamonu and Chinese garlic types, respectively. Also di-2-propenyl trisulfide was found only in Kastamonu garlic types. Disulfide, methyl 2-propenyl was determined at similar levels in both garlic types.

CONCLUSION

The majority of garlic grown in Kastamonu region of Turkey is assessed by medical companies.

CONCLUSION

The results of the current study showed that Kastamonu garlic type has important medical properties. Therefore, this garlic can also be used in the medical field, as well as the consumption as food.

Nontraditional therapies to treat Helicobacter pylori infection

The Gram-negative pathogen Helicobacter pylori is increasingly more resistant to the three major antibiotics (metronidazole, clarithromycin and amoxicillin) that are most commonly used to treat infection. As a result, there is an increased rate of treatment failure; this translates into an overall higher cost of treatment due to the need for increased length of treatment and/or the requirement for combination or sequential therapy. Given the rise in antibiotic resistance, the complicated treatment regime, and issues related to patient compliance that stem from the duration and complexity of treatment, there is clearly a pressing need for the development of novel therapeutic strategies to combat H. pylori infection. As such, researchers are actively investigating the utility of antimicrobial peptides, small molecule inhibitors and naturopathic therapies. Herein we review and discuss each of these novel approaches as a means to target this important gastric pathogen.

Exploring alternative treatments for Helicobacter pylori infection

Helicobacter pylori (H. pylori) is a successful pathogen that can persist in the stomach of an infected person for their entire life. It provokes chronic gastric inflammation that leads to the development of serious gastric diseases such as peptic ulcers, gastric cancer and Mucosa associated lymphoid tissue lymphoma. It is known that these ailments can be avoided if the infection by the bacteria can be prevented or eradicated. Currently, numerous antibiotic-based therapies are available. However, these therapies have several inherent problems, including the appearance of resistance to the antibiotics used and associated adverse effects, the risk of re-infection and the high cost of antibiotic therapy. The delay in developing a vaccine to prevent or eradicate the infection has furthered research into new therapeutic approaches. This review summarises the most relevant recent studies on vaccine development and new treatments using natural resources such as plants, probiotics and nutraceuticals. In addition, novel alternatives based on microorganisms, peptides, polysaccharides, and intragastric violet light irradiation are presented. Alternative therapies have not been effective in eradicating the bacteria but have been shown to maintain low bacterial levels. Nevertheless, some of them are useful in preventing the adverse effects of antibiotics, modulating the immune response, gastroprotection, and the general promotion of health. Therefore, those agents can be used as adjuvants of allopathic anti-H. pylori eradication therapy.

Transformation of synthetic allicin: the influence of ultrasound, microwaves, different solvents and temperatures, and the products isolation

The transformation of the synthesized allicin, using conventional method, the influence of ultrasound and microwaves, in different organic solvents (acetonitrile, acetone, methanol, and chloroform), at various temperatures (room temperature, 45 °C, and 55 °C) was investigated. Allicin degradation kinetic was monitored by HPLC. Allicin transformation under the effect of microwaves is faster than transformations performed under the influence of ultrasound or by conventional method. Increase of the temperature accelerates allicin transformation. Pharmacologically active compounds of (E)-ajoene, (Z)-ajoene, 3-vinyl-4H-1,2-dithiin, 2-vinyl-4H-1,3-dithiin, and diallyl disulfide were isolated from the mixture of transformation products of allicin under the influence of microwaves in methanol at 55 °C, which is according to kinetic parameters (highest values of the order of reaction and the lowest activation energy) the optimal method.

Garlic in health and disease

The present article reviews the historical and popular uses of garlic, its antioxidant, haematological, antimicrobial, hepatoprotective and antineoplastic properties and its potential toxicity (from sulfoxide). Garlic has been suggested to affect several cardiovascular risk factors. It has also been shown that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. Since garlic and its constituents can suppress carcinogen formation, bioactivation and tumour proliferation, it is imperative that biomarkers be established to identify which individuals might benefit most. Garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis. Garlic has also been found to have synergistic effects against Helicobacter pylori with a proton pump inhibitor. The active compound allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages. Freshly prepared garlic homogenate protects against isoniazid+rifampicin-induced liver injury in experimental animal models. Several mechanisms are likely to account for this protection.

The antibacterial mode of action of allitridi for its potential use as a therapeutic agent against Helicobacter pylori infection

Eradication of Helicobacter pylori with traditional therapy often fails in clinical treatment. As a result, a novel efficacious therapeutic agent is strongly needed. Allitridi, a proprietary garlic derivative, has been successfully used to treat both systemic fungal and bacterial infections in China. Our previous study has shown a dose-dependent inhibitory effect of allitridi on H. pylori growth. However, the antibacterial mode of action of allitridi is still unclear. Proteomic analysis was used to study the global protein alterations induced by allitridi. A total of 21 protein spots were identified to be differentially expressed. Our results indicated that the bacteriostatic mechanism of allitridi in H. pylori can be attributed to its multitarget inhibitory effects in energy metabolism and biosynthesis including amino acid biosynthesis, protein synthesis, mRNA synthesis and fatty acid biosynthesis. Allitridi can also disturb the expression of antioxidant proteins and decrease the production of virulence factors. Western blot analysis showed that allitridi at subinhibitory concentrations can potently suppress the production of CagA and VacA. Our investigations on the antibacterial mode of action of allitridi provide an insight into the potential use of allitridi as a therapeutic agent against H. pylori infection.

Phytoceuticals: mighty but ignored weapons against Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection causes peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas, for which the pathogenesis of chronic gastric inflammation prevails and provides the pathogenic basis. Since the role of H. pylori infection is promoting carcinogenesis rather than acting as a direct carcinogen, as several publications show, eradication alone cannot be the right answer for preventing H. pylori-associated gastric cancer. Therefore, a non-antimicrobial approach has been suggested to attain microbe-associated cancer prevention through controlling H. pylori-related chronic inflammatory processes and mediators responsible for carcinogenesis. Phytoceutical is a term for plant products that are active on biological systems. Phytoceuticals such as Korean red ginseng, green tea, red wine, flavonoids, broccoli sprouts, garlic, probiotics and flavonoids are known to inhibit H. pylori colonization, decrease gastric inflammation by inhibiting cytokine and chemokine release, and repress precancerous changes by inhibiting nuclear factor-kappa B DNA binding, inducing profuse levels of apoptosis and inhibiting mutagenesis. Even though further unsolved issues are awaited before phytoceuticals are accepted as a standard treatment for H. pylori infection, phytoceuticals can be a mighty weapon for either suppressing or modulating the disease-associated footprints of H. pylori infection.

Fungitoxicity of lyophilized and spray-dried garlic extracts

Among the compounds discussed for anti-microbial and anti-fungal use allicin (allylthiosulfinate, diallyl disulfide-S-monoxide), an active ingredient of garlic, has attracted considerable attention. The objective of this study is to determine the antifungal activity of a local garlic ecotype (Voghiera) extracts against different pathogens. Primary screening was carried out by the agar plates technique using ethanol garlic extract at four final concentrations against the following organisms: Alternaria alternata, Aspergillus spp., Colletotrichum acutatum, Didymella bryoniae, Fusarium culmorum, Fusarium avenaceum, Fusarium gramineareum, Gliocladium roseum 47, Pythium splendens, Rhizoctonia solani, Sclerotium rolfsii, Stemphylium vesicarium, Trichoderma longibranchiatum, and Botrytis cinerea. Secondary screening was carried out using a lyophilized and a spray-dried preparation at different concentrations against the organisms selected for the high inhibition garlic effect in the primary screening and compared with the commercial fungicides mancozeb and iprodione. The best results were observed for the spray-dried garlic compound that showed a good fungicidal activity at the concentration of 1.5 g/10 mL while lyophilized garlic at the same concentration exhibited less inhibition activity against the four fungi analyzed in the second screening.

The analysis of onion and garlic

Onion (Allium cepa L.) and garlic (Allium sativum L.), among the oldest cultivated plants, are used both as a food and for medicinal applications. In fact, these common food plants are a rich source of several phytonutrients recognized as important elements of the Mediterranean diet, but are also used in the treatment and prevention of a number of diseases, including cancer, coronary heart disease, obesity, hypercholesterolemia, diabetes type 2, hypertension, cataract and disturbances of the gastrointestinal tract (e.g. colic pain, flatulent colic and dyspepsia). These activities are related to the thiosulfinates, volatile sulfur compounds, which are also responsible for the pungent of these vegetables. Besides these low-molecular weight compounds, onion and garlic are characterized by more polar compounds of phenolic and steroidal origin, often glycosilated, showing interesting pharmacological properties. These latter compounds, compared to the more studied thiosulfinates, present the advantages to be not pungent and more stable to cooking. Recently, there has been an increasing scientific attention on such compounds. In this paper, the literature about the major volatile and non-volatile phytoconstituents of onion and garlic has been reviewed. Particular attention was given to the different methodology developed to perform chemical analysis, including separation and structural elucidation.

Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori

AIM

To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H. pylori).

METHODS

Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H. pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H. pylori to stomach sections.

RESULTS

Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H. pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H. pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric, borage and parsley were able to inhibit the adhesion of H. pylori strains to the stomach sections.

CONCLUSION

Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H. pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H. pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.

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.

Bioactive S-alk(en)yl cysteine sulfoxide metabolites in the genus Allium: the chemistry of potential therapeutic agents

S-Alk(en)yl cysteine sulfoxides are odourless, non-protein sulfur amino acids typically found in members of the family Alliaceae and are the precursors to the lachrymatory and flavour compounds found in the agronomically important genus Allium. Traditionally, Allium species, particularly the onion (Allium cepa) and garlic (A. sativum), have been used for centuries in European, Asian and American folk medicines for the treatment of numerous human pathologies, however it is only recently that any significant progress has been made in determining their mechanisms of action. Indeed, our understanding of the role of Allium species in human health undoubtedly comes from the combination of several academic disciplines including botany, biochemistry and nutrition. During tissue damage, S-alk(en)yl cysteine sulfoxides are converted to their respective thiosulfinates or propanethial-S-oxide by the action of the enzyme alliinase (EC 4.4.1.4). Depending on the Allium species, and under differing conditions, thiosulfinates can decompose to form additional sulfur constituents including diallyl, methyl allyl, and diethyl mono-, di-, tri-, tetra-, penta-, and hexasulfides, the vinyldithiins and (E)- and (Z)-ajoene. Recent reports have shown onion and garlic extracts, along with several principal sulfur constituents, can induce phase II detoxification enzymes like glutathione-S-transferases (EC 2.5.1.18) and quinone reductase (QR) NAD(P)H: (quinine acceptor) oxidoreductase (EC 1.6.99.2) in mammalian tissues, as well as also influencing cell cycle arrest and apoptosis in numerous in vitro cancer cell models. Moreover, studies are also beginning to highlight a role of Allium-derived sulfur compounds in cardiovascular protection. In this review, we discuss the chemical diversity of S-alk(en)yl cysteine sulfoxide metabolites in the context of their biochemical and pharmacological mechanisms.