Activities of muscadine grape skin and quercetin against Helicobacter pylori infection in mice

Chaenomelin, a New Phenolic Glycoside, and Anti-Helicobacter pylori Phenolic Compounds from the Leaves of Salix chaenomeloides

Salix chaenomeloides Kimura, commonly known as pussy willow, is a deciduous shrub and tree belonging to the Salicaceae family. The genus Salix spp. has been known as a healing herb for the treatment of fever, inflammation, and pain relief. The current study aimed to investigate the potential bioactive natural products from S. chaenomeloides leaves and evaluate their antibacterial activity against Helicobacter pylori. A phytochemical investigation of the ethanol (EtOH) extract of S. chaenomeloides leaves led to the isolation of 13 phenolic compounds (1-13) from the ethyl acetate (EtOAc) fraction, which showed antibacterial activity against H. pylori strain 51. The chemical structure of a new phenolic glycoside, chaenomelin (1), was established by a detailed analysis of 1D and 2D (1H-1H correlation spectroscopy (COSY), heteronuclear single-quantum coherence (HSQC), and heteronuclear multiple-bond correlation (HMBC)) nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectroscopy (HR-ESIMS), and chemical reactions. The other known compounds were identified as 5-O-trans-p-coumaroyl quinic acid methyl ester (2), tremulacin (3), citrusin C (4), benzyl 3-O-β-d-glucopyranosyl-7-hydroxybenzoate (5), tremuloidin (6), 1-[O-β-d-glucopyranosyl(1→2)-β-d-glucopyranosyl]oxy-2-phenol (7), arbutin cinnamate (8), tremulacinol (9), catechol (10), 4-hydroxybenzaldehyde (11), kaempferol 3-rutinoside (12), and narcissin (13), based on the comparison of their NMR spectra with the reported data and liquid chromatography/mass spectrometry (LC/MS) analysis. The isolated compounds were evaluated for antibacterial activity against H. pylori strain 51. Among the isolates, 1-[O-β-d-glucopyranosyl(1→2)-β-d-glucopyranosyl]oxy-2-phenol (7) and arbutin cinnamate (8) exhibited antibacterial activity against H. pylori strain 51, with inhibitions of 31.4% and 33.9%, respectively, at a final concentration of 100 μM. These results were comparable to that of quercetin (38.4% inhibition), which served as a positive control. Generally, these findings highlight the potential of the active compounds 7 and 8 as antibacterial agents against H. pylori.

Natural foods resources and dietary ingredients for the amelioration of Helicobacter pylori infection

Helicobacter pylori (H. pylori) is a gastric-persistent pathogen that can cause peptic ulcer disease, gastric cancer, and mucosal-associated lymphoid tissue lymphoma. This pathogen is commonly treated with antibiotic-based triple or quadruple therapy. However, antibiotic therapy could result in the bacterial resistance, imbalance of gut microbiota, and damage to the liver and kidneys, etc. Therefore, there is an urgent need for alternative therapeutic strategies. Interestingly, natural food resources, like vegetables, fruits, spices, and edible herbs, have potent inhibitory effects on H. pylori. In this review, we systematically summarized these foods with supporting evidence from both animal and clinical studies. The results have indicated that natural foods may possess temporary inhibition effect on H. pylori rather than durable eradication, and may help to reduce H. pylori colonization, enhance the effect of antibiotics and modulate the host's immune response.

Anti-Helicobacter pylori Activity of Six Major Compounds Isolated from Rumex acetosa

Gastric problems are often caused by the well-known Helicobacter pylori (H. pylori) bacterium. One of the biggest obstacles to the treatment of H. pylori infections is increasing the antibiotic resistance. During our search for naturally derived anti-H. pylori compounds, six major compounds were isolated from the methylene chloride (CH2Cl2) and ethyl acetate (EtOAc) fractions of Rumex acetosa that showed anti-H. pylori activity. Three anthraquinones and three anthraquinone glucosides were identified as the major chemical constituents of the CH2Cl2 and EtOAc fractions, respectively. The chemical structures were identified to be emodin (1), chrysophanol (2), physcion (3), emodin-8-O-β-d-glucoside (4), chrysophanol-8-O-β-d-glucoside (5), and physcion-8-O-β-d-glucoside (6) by UV, 1H NMR, 13C NMR, and mass spectrometry. Anti-H. pylori activity, including the minimum inhibitory concentration (MIC) value of each compound, was evaluated against two H. pylori strains. All isolates exhibited anti-H. pylori activity with different potencies, with an MIC value ranging between 3.13 and 25 μM. However, some variations were found between the two strains. While compound 5 displayed the most potent antibacterial activity with an MIC50 value of 8.60 μM and an MIC90 value of 15.7 μM against H. pylori strain 51, compound 1 exhibited the most potent inhibitory activity against H. pylori strain 43504. The two compounds also showed moderate urease inhibitory activity, with compound 1 demonstrating activity higher than that of compound 5. Furthermore, a molecular docking study revealed the high binding ability of compounds 1 and 5 to the active site of H. pylori urease. The present study suggests that the six anthraquinones isolated from R. acetosa with the whole parts of this plant may be natural candidates for the treatment of H. pylori infection. Further studies are required to determine the exact mechanism of action and to evaluate safety issues in the human body.

Preparation of Corn Peptides with Anti-Adhesive Activity and Its Functionality to Alleviate Gastric Injury Induced by Helicobacter pylori Infection In Vivo

More than 50% of the world population is infected with Helicobacter pylori (H. pylori), which is classified as group I carcinogen by the WHO. H. pylori surface adhesins specifically recognize gastric mucosal epithelial cells' (GES-1 cells) receptor to complete the adhesion. Blocking the adhesion with an anti-adhesion compound is an effective way to prevent H. pylori infection. The present study found that corn protein hydrolysate, hydrolyzed by Neutral, effectively alleviated gastric injury induced by H. pylori infection through anti-adhesive and anti-inflammatory effects in vitro and in vivo. The hydrolysate inhibited H. pylori adhesion to GES-1 cells significantly, and its anti-adhesive activity was 50.44 ± 0.27% at 4 mg/mL, which indicated that the hydrolysate possessed a similar structure to the GES-1 cells' receptor, and exhibited anti-adhesive activity in binding to H. pylori. In vivo, compared with the H. pylori infection model group, the medium and high dose of the hydrolysate (400-600 mg/kg·bw) significantly decreased (p < 0.05) the amount of H. pylori colonization, pro-inflammatory cytokines (IL-6, IL-1β, TNF-α and MPO), chemokines (KC and MCP-1) as well as key metabolites of NF-κB signaling pathway levels (TLR4, MyD88 and NF-κB), and it increased antioxidant enzyme contents (SOD and GSH-Px) and the mitigation of H. pylori-induced pathological changes in the gastric mucosa. Taken together, these results indicated that the hydrolysate intervention can prevent H. pylori-induced gastric injury by anti-adhesive activity and inhibiting the NF-κB signaling pathway's induction of inflammation. Hence, the corn protein hydrolysate might act as a potential anti-adhesive agent to prevent H. pylori infection.

Phytochemicals as Antimicrobials: Prospecting Himalayan Medicinal Plants as Source of Alternate Medicine to Combat Antimicrobial Resistance

Among all available antimicrobials, antibiotics hold a prime position in the treatment of infectious diseases. However, the emergence of antimicrobial resistance (AMR) has posed a serious threat to the effectiveness of antibiotics, resulting in increased morbidity, mortality, and escalation in healthcare costs causing a global health crisis. The overuse and misuse of antibiotics in global healthcare setups have accelerated the development and spread of AMR, leading to the emergence of multidrug-resistant (MDR) pathogens, which further limits treatment options. This creates a critical need to explore alternative approaches to combat bacterial infections. Phytochemicals have gained attention as a potential source of alternative medicine to address the challenge of AMR. Phytochemicals are structurally and functionally diverse and have multitarget antimicrobial effects, disrupting essential cellular activities. Given the promising results of plant-based antimicrobials, coupled with the slow discovery of novel antibiotics, it has become highly imperative to explore the vast repository of phytocompounds to overcome the looming catastrophe of AMR. This review summarizes the emergence of AMR towards existing antibiotics and potent phytochemicals having antimicrobial activities, along with a comprehensive overview of 123 Himalayan medicinal plants reported to possess antimicrobial phytocompounds, thus compiling the existing information that will help researchers in the exploration of phytochemicals to combat AMR.

Network Pharmacology and Molecular Docking Analysis on Pharmacological Mechanisms of Astragalus membranaceus in the Treatment of Gastric Ulcer

BACKGROUND

Astragalus membranaceus (AM, family: Leguminosae) exerts significant therapeutic effect on gastric ulcer (GU); however, there are scarce studies on its molecular mechanism against GU. This study aims to explore the key ingredients, key targets, and potential mechanisms of AM in the treatment of GU by utilizing network pharmacology and molecular docking.

METHODS

Several public databases were used to predict the targets of AM and GU, respectively, and the drug and disease targets were intersected to obtain the common targets. Next, the key ingredients and key targets were identified by constructing ingredient-target network and protein-protein-interaction (PPI) network. Gene Ontology biological processes (GOBP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were carried out on the common targets in order to ascertain the biological processes and signaling pathways involved. Finally, molecular docking was conducted to verify the binding affinity between the key ingredients and key targets.

RESULTS

A total of 552 predicted targets were obtained from 23 screened active ingredients, of which 203 targets were the common targets with GU. Quercetin, kaempferol, and isorhamnetin were identified as the key ingredients by constructing ingredient-target network, and TP53, AKT1, VEGFA, IL6, TNF, CASP3, and EGFR were selected as the key targets by constructing PPI network. GOBP and KEGG pathway enrichment analysis suggested that the therapeutic effect of AM on GU involved multiple biological processes and signaling pathways related to inflammation, oxidative stress, apoptosis, cell proliferation, and angiogenesis. Molecular docking validation demonstrated that all key ingredients had good binding affinity with the key targets.

CONCLUSION

This study revealed the key ingredients, key targets, and potential mechanisms of AM against GU, and these data may provide some crucial references for subsequent research and development of drugs for treating GU.

Chromosome-level genome sequence assembly and genome-wide association study of Muscadinia rotundifolia reveal the genetics of 12 berry-related traits

Vitis has two subgenera: Euvitis, which includes commercially important Vitis vinifera and interspecific hybrid cultivars, and Muscadinia. Of note, the market for Muscadinia grapes remains small, and only Muscadinia rotundifolia is cultivated as a commercial crop. To establish a basis for the study of Muscadinia species, we generated chromosome-level whole-genome sequences of Muscadinia rotundifolia cv. Noble. A total of 393.8 Mb of sequences were assembled from 20 haploid chromosomes, and 26 394 coding genes were identified from the sequences. Comparative analysis with the genome sequence of V. vinifera revealed a smaller size of the M. rotundifolia genome but highly conserved gene synteny. A genome-wide association study of 12 Muscadinia berry-related traits was performed among 356 individuals from breeding populations of M. rotundifolia. For the transferability of markers between Euvitis and Muscadinia, we used 2000 core genome rhAmpSeq markers developed to allow marker transferability across Euvitis species. A total of 1599 (80%) rhAmpSeq markers returned data in Muscadinia. From the GWAS analyses, we identified a total of 52 quantitative trait nucleotides (QTNs) associated with the 12 berry-related traits. The transferable markers enabled the direct comparison of the QTNs with previously reported results. The whole-genome sequences along with the GWAS results provide a new basis for the extensive study of Muscadinia species.

Promising Natural Products in New Drug Design, Development, and Therapy for Skin Disorders: An Overview of Scientific Evidence and Understanding Their Mechanism of Action

The skin is the largest organ in the human body, composed of the epidermis and the dermis. It provides protection and acts as a barrier against external menaces like allergens, chemicals, systemic toxicity, and infectious organisms. Skin disorders like cancer, dermatitis, psoriasis, wounds, skin aging, acne, and skin infection occur frequently and can impact human life. According to a growing body of evidence, several studies have reported that natural products have the potential for treating skin disorders. Building on this information, this review provides brief information about the action of the most important in vitro and in vivo research on the use of ten selected natural products in inflammatory, neoplastic, and infectious skin disorders and their mechanisms that have been reported to date. The related studies and articles were searched from several databases, including PubMed, Google, Google Scholar, and ScienceDirect. Ten natural products that have been reported widely on skin disorders were reviewed in this study, with most showing anti-inflammatory, antioxidant, anti-microbial, and anti-cancer effects as the main therapeutic actions. Overall, most of the natural products reported in this review can reduce and suppress inflammatory markers, like tumor necrosis factor-alpha (TNF-α), scavenge reactive oxygen species (ROS), induce cancer cell death through apoptosis, and prevent bacteria, fungal, and virus infections indicating their potentials. This review also highlighted the challenges and opportunities of natural products in transdermal/topical delivery systems and their safety considerations for skin disorders. Our findings indicated that natural products might be a low-cost, well-tolerated, and safe treatment for skin diseases. However, a larger number of clinical trials are required to validate these findings. Natural products in combination with modern drugs, as well as the development of novel delivery mechanisms, represent a very promising area for future drug discovery of these natural leads against skin disorders.

Fighting the Antibiotic Crisis: Flavonoids as Promising Antibacterial Drugs Against Helicobacter pylori Infection

Over half of the world’s population is estimated to be infected with Helicobacter pylori. Chronic infection with this microbial class I carcinogen is considered the most important risk factor for developing gastric cancer. The increasing antimicrobial resistance to first-line antibiotics mainly causes the failure of current eradication therapies, inducing refractory infections. The alarming increase in multidrug resistance in H. pylori isolates worldwide is already beginning to limit the efficacy of existing treatments. Consequently, the World Health Organization (WHO) has included H. pylori in its list of “priority pathogens” for which new antibiotics are urgently needed. Novel strategies must be followed to fight this antibiotic crisis, including properly exploiting the proven therapeutic potential of medicinal plants and plant-derived phytochemicals. In this mini-review, we overview the impressive properties of naturally occurring flavonoids as effective antimicrobial agents against H. pylori, which support the use of these plant-derived bioactive compounds as promising drug candidates for inclusion in novel and personalized combinatory therapies against H. pylori infection.

Fermented-Rhus verniciflua extract ameliorate Helicobacter pylori eradication rate and gastritis

An antibacterial effect of fermented-Rhus verniciflua extract (FRVE), an urushiol-free extract fermented by Fomitella fraxinea, on Helicobacter pylori was evaluated in mice. Minimal inhibitory concentration of FRVE against H. pylori eradication was checked with serial dilution method in vitro. H. pylori infection-induced mice were utilized to determine the effect of oral administration of FRVE with/without standard triple therapy (STT: metronidazole, omeprazole, and clarithromycin) on H. pylori colonization and gastric inflammation. H. pylori was clearly eradicated by FRVE at a concentration of ≥2 mg/ml in vitro. In animal study, FRVE at a concentration of ≥6 mg/ml significantly reduced colonized H. pylori grading (0.2 vs. 2.2, p < .01) and improved gastric inflammation (0.4 vs. 1.6, p < .01) compared to control. STT with FRVE (3 mg/ml) exerted synergistic effect on both H. pylori colonization grade (STT, 0.6 ± 0.9; FRVE, 1.4 ± 0.5; STT + FRVE, 0.8 ± 0.4) and gastric inflammation (STT, 0.4 ± 0.5; FRVE, 1.4 ± 0.5; STT + FRVE,1.0 ± 0.1) compared with single therapy (p < .01). H. pylori eradication rate of FRVE (6 mg/ml) was higher than that of STT (60% vs. 20%). FRVE has potential antibacterial activity against H. pylori infection and can be used as an additional therapy on STT.

A Review of the Role of Flavonoids in Peptic Ulcer (2010-2020)

Peptic ulcers are characterized by erosions on the mucosa of the gastrointestinal tract that may reach the muscle layer. Their etiology is multifactorial and occurs when the balance between offensive and protective factors of the mucosa is disturbed. Peptic ulcers represent a global health problem, affecting millions of people worldwide and showing high rates of recurrence. Helicobacter pylori infection and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most important predisposing factors for the development of peptic ulcers. Therefore, new approaches to complementary treatments are needed to prevent the development of ulcers and their recurrence. Natural products such as medicinal plants and their isolated compounds have been widely used in experimental models of peptic ulcers. Flavonoids are among the molecules of greatest interest in biological assays due to their anti-inflammatory and antioxidant properties. The present study is a literature review of flavonoids that have been reported to show peptic ulcer activity in experimental models. Studies published from January 2010 to January 2020 were selected from reference databases. This review refers to a collection of flavonoids with antiulcer activity in vivo and in vitro models.

Procyanidin-Rich Extract from Grape Seeds as a Putative Tool against Helicobacter pylori

Strains of Helicobacter pylori (H. pylori) resistant to various antibiotics have increased in recent years. In this context, the search for new therapeutic approaches is crucial. The aim of the present study was to demonstrate the antibacterial activity of a procyanidin-rich extract obtained from food-grade winery grape seeds against 14 H. pylori strains and elucidate its phenolic composition. Ten strains (71.4%) showed resistance to at least some of the tested antibiotics, while four isolates (28.6%) were susceptible to all antibiotics. Resistance to more than one class of antibiotics was observed in six strains (42.9%). The extract was able to inhibit the growth of all H. pylori strains in a range of a minimum inhibitory concentration (MIC) from 0.015 mg/mL to 0.125 mg/mL, confirming also the existence of a strain-dependent effect. The phenolic composition determined by reverse phase high pressure liquid chromatography, photodiode array, and mass spectrometry detection (RP-HPLC-PAD-MS) analysis revealed the presence of 43 individual compounds and allowed the quantification of 41 of them, including seven procyanidin tetramers, seven procyanidin pentamers, and six galloylated procyanidin dimers, trimers, and tetramers. The extract was composed mainly by catechin and procyanidin oligomers with a total amount of 5801 mg/100 g, which represent 92% of the total individual phenolic content. Among them, the most abundant were catechins (2047 mg/100 g), followed by procyanidin dimers (1550 mg/100 g), trimers (1176 mg/100 g), tetramers (436 mg/100 g), and pentamers (296 mg/100 g) that represent 35, 27, 20, 8, and 5%, respectively of the total flavanol constituents. The composition profile information may help to improve the production process of useful antibacterial extracts against H. pylori.

Preclinical Evaluation of the Antimicrobial-Immunomodulatory Dual Action of Xenohormetic Molecules against Haemophilus influenzae Respiratory Infection

Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammation and impaired airway immunity, providing an opportunistic platform for nontypeable Haemophilus influenzae (NTHi) infection. In this context, therapies targeting not only overactive inflammation without significant adverse effects, but also infection are of interest. Increasing evidence suggests that polyphenols, plant secondary metabolites with anti-inflammatory and antimicrobial properties, may be protective. Here, a Cistus salviifolius plant extract containing quercetin, myricetin, and punicalagin was shown to reduce NTHi viability. Analysis of these polyphenols revealed that quercetin has a bactericidal effect on NTHi, does not display synergies, and that bacteria do not seem to develop resistance. Moreover, quercetin lowered NTHi airway epithelial invasion through a mechanism likely involving inhibition of Akt phosphorylation, and reduced the expression of bacterially-induced proinflammatory markers il-8, cxcl-1, il-6, pde4b, and tnfα. We further tested quercetin’s effect on NTHi murine pulmonary infection, showing a moderate reduction in bacterial counts and significantly reduced expression of proinflammatory genes, compared to untreated mice. Quercetin administration during NTHi infection on a zebrafish septicemia infection model system showed a bacterial clearing effect without signs of host toxicity. In conclusion, this study highlights the therapeutic potential of the xenohormetic molecule quercetin against NTHi infection.

Review of the health effects of berries and their phytochemicals on the digestive and immune systems

Berries are generally considered beneficial to health. This health-promoting potential has mainly been ascribed to berries' phytochemical and vitamin content, and little attention has been paid to the potential benefits of berries for the digestive tract, despite this being the first point of contact. In vivo studies that described the health effects of berries on individual parts of the digestive tract (ie, the mouth, esophagus, stomach, small and large intestine, microbiome, and immune system) were reviewed. Immune effects were included because a large part of the immune system is located in the intestine. Beneficial health effects were mainly observed for whole berry extracts, not individual berry components. These effects ranged from support of the immune system and beneficial microbiota to reduction in the number and size of premalignant and malignant lesions. These results demonstrate the potency of berries and suggest berries can serve as a strong adjuvant to established treatments or therapies for a variety of gastrointestinal and immune-related illnesses.

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.

Lactoferrin Adsorbed onto Biomimetic Hydroxyapatite Nanocrystals Controlling - In Vivo - the Helicobacter pylori Infection

Background

The resistance of Helicobacter pylori to the antibiotic therapy poses the problem to discover new therapeutic approaches. Recently it has been stated that antibacterial, immunomodulatory, and antioxidant properties of lactoferrin are increased when this protein is surface-linked to biomimetic hydroxyapatite nanocrystals.

Objective

Based on these knowledge, the aim of the study was to investigate the efficacy of lactoferrin delivered by biomimetic hydroxyapatite nanoparticles with cell free supernatant from probiotic Lactobacillus paracasei as an alternative therapy against Helicobacter pylori infection.

Methods

Antibacterial and antinflammatory properties, humoral antibody induction, histopathological analysis and absence of side effects were evaluated in both in vitro and in vivo studies.

Results

The tests carried out have been demonstrated better performance of lactoferrin delivered by biomimetic hydroxyapatite nanoparticles combined with cell free supernatant from probiotic Lactobacillus paracasei compared to both lactoferrin and probiotic alone or pooled.

Conclusion

These findings indicate the effectiveness and safety of our proposed therapy as alternative treatment for Helicobacter pylori infection.

Synergy and Mode of Action of Ceftazidime plus Quercetin or Luteolin on Streptococcus pyogenes

Streptococcus pyogenes causes streptococcal toxic shock syndrome. The recommended therapy has been often failure through the interfering of beta-lactamase-producing bacteria (BLPB). The present study was to investigate antibacterial activity, synergy, and modes of action of luteolin and quercetin using alone and plus ceftazidime against S. pyogenes. The MICs of ceftazidime, luteolin, and quercetin against all S. pyogenes were 0.50, 128, and 128 µg mL⁻¹, respectively. A synergistic effect was exhibited on luteolin and quercetin plus ceftazidime against these strains at fractional inhibitory concentration indices 0.37 and 0.27, respectively, and was confirmed by the viable count. These combinations increased cytoplasmic membrane (CM) permeability, caused irregular cell shape, peptidoglycan, and CM damage, and decreased nucleic acid but increased proteins in bacterial cells. Enzyme assay demonstrated that these flavonoids had an inhibitory activity against β-lactamase. In summary, this study provides evidence that the inhibitory mode of action of luteolin and quercetin may be mediated via three mechanisms: (1) inhibiting of peptidoglycan synthesis, (2) increasing CM permeability, and (3) decreasing nucleic acid but increasing the protein contents of bacterial cells. So, luteolin and quercetin propose the high potential to develop adjunct to ceftazidime for the treatment of coexistence of the BLPB and S. pyogenes infections.

Role of dietary polyphenols in the management of peptic ulcer

Peptic ulcer disease is a multifactorial and complex disease involving gastric and duodenal ulcers. Despite medical advances, the management of peptic ulcer and its complications remains a challenge, with high morbidity and death rates for the disease. An accumulating body of evidence suggests that, among a broad reach of natural molecules, dietary polyphenols with multiple biological mechanisms of action play a pivotal part in the management of gastric and duodenal ulcers. The current review confirmed that dietary polyphenols possess protective and therapeutic potential in peptic ulcer mediated by: improving cytoprotection, re-epithelialization, neovascularization, and angiogenesis; up-regulating tissue growth factors and prostaglandins; down-regulating anti-angiogenic factors; enhancing endothelial nitric oxide synthase-derived NO; suppressing oxidative mucosal damage; amplifying antioxidant performance, antacid, and anti-secretory activity; increasing endogenous mucosal defensive agents; and blocking Helicobacter pylori colonization associated gastric morphological changes and gastroduodenal inflammation and ulceration. In addition, anti-inflammatory activity due to down-regulation of proinflammatory cytokines and cellular and intercellular adhesion agents, suppressing leukocyte-endothelium interaction, inhibiting nuclear signaling pathways of inflammatory process, and modulating intracellular transduction and transcription pathways have key roles in the anti-ulcer action of dietary polyphenols. In conclusion, administration of a significant amount of dietary polyphenols in the human diet or as part of dietary supplementation along with conventional treatment can result in perfect security and treatment of peptic ulcer. Further well-designed preclinical and clinical tests are recommended in order to recognize higher levels of evidence for the confirmation of bioefficacy and safety of dietary polyphenols in the management of peptic ulcer.

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.

Activities of muscadine grape skin and polyphenolic constituents against Helicobacter pylori

AIMS

To identify active phenolic constituents in muscadine grape skin (MGS) extracts and determine interactions among compounds while further exploring their anti-Helicobacter pylori potential in vitro.

METHODS AND RESULTS

The inhibitory effects of quercetin and resveratrol, active polyphenols identified in MGS extracts, against H. pylori were investigated. Quercetin and resveratrol significantly (P < 0.05) reduced H. pylori counts regardless of pH with minimal bactericidal concentrations of 256 and 128 μg ml(-1), respectively. MGS extracts displayed the highest efficacy, suggesting additional unidentified compounds not determined in this study. Time-course viability experiments showed a dose-dependent anti-H. pylori response to quercetin and resveratrol. Interestingly, neither quercetin nor resveratrol affected H. pylori outer membrane (OM) integrity as determined by 1-N-phenylnaphthylamine (NPN) uptake assays. However, treatment with MGS extract did increase NPN uptake, indicating OM destabilization possibly by additional unknown components. Furthermore, quercetin was found to enter H. pylori as measured by HPLC supporting intracellular drug accumulation.

CONCLUSIONS

Quercetin and resveratrol possess strong anti-H. pylori activity in vitro and are independent of pH. Our results also suggest that these compounds do not affect H. pylori OM integrity as previously hypothesized and that the primary antimicrobial activity of quercetin may be linked to interactions with intracellular components.

SIGNIFICANCE AND IMPACT OF THE STUDY

The anti-H. pylori effects of quercetin and resveratrol suggest that these compounds may be useful in the dietary prevention and/or treatment of H. pylori infection.

Anticomplement and Antimicrobial Activities of Flavonoids from Entada phaseoloides

Seventeen flavonoids isolated from the extracts of the stem of Entada phaseoloides were investigated for their anticomplement (both classic and alternative pathways) and antimicrobial activities against Gram-positive bacteria (MRSA, MSSA, Standard Enterococcus and Bacillus subtilis), Gram-negative bacteria ( Escherichia coli, Pseudomonas aeuroginosa) and the yeast-like pathogenic fungus Candida albicans. The anticomplement studies revealed a dose-dependent activity among isolated quercetin, luteolin, apigenin, galangin, 5,2′,5′-trihydroxy-3,7,4′-trimethoxyflavone-2′-O-β-D-glucoside (+)-3,3′,5′,5,7-pentahydroflavanone, (+)-dihydrokaempferol, (-)-epicatechin, (+)-catechin, naringenin, and 5,7,3′,5′-tetrahydroxyflavanone, and the antimicrobial results indicated that quercetin, 5,7,4′-trihydroxy-3′-methoxyflavonol and galangin produced the inhibitory activities against MRSA, MSSA, and Standard Enterococcus, while luteolin and rhamnocitrin displayed inhibition against only MRSA and MSSA. To the best of our knowledge, this is the first report that describes the anticomplement and antimicrobial activities of the stem of E. phaseoloides.