Propolis: The future therapy against Helicobacter pylori-mediated gastrointestinal diseases

Machine Learning-Driven Classification of Urease Inhibitors Leveraging Physicochemical Properties as Effective Filter Criteria

Urease, a pivotal enzyme in nitrogen metabolism, plays a crucial role in various microorganisms, including the pathogenic Helicobacter pylori. Inhibiting urease activity offers a promising approach to combating infections and associated ailments, such as chronic kidney diseases and gastric cancer. However, identifying potent urease inhibitors remains challenging due to resistance issues that hinder traditional approaches. Recently, machine learning (ML)-based models have demonstrated the ability to predict the bioactivity of molecules rapidly and effectively. In this study, we present ML models designed to predict urease inhibitors by leveraging essential physicochemical properties. The methodological approach involved constructing a dataset of urease inhibitors through an extensive literature search. Subsequently, these inhibitors were characterized based on physicochemical properties calculations. An exploratory data analysis was then conducted to identify and analyze critical features. Ultimately, 252 classification models were trained, utilizing a combination of seven ML algorithms, three attribute selection methods, and six different strategies for categorizing inhibitory activity. The investigation unveiled discernible trends distinguishing urease inhibitors from non-inhibitors. This differentiation enabled the identification of essential features that are crucial for precise classification. Through a comprehensive comparison of ML algorithms, tree-based methods like random forest, decision tree, and XGBoost exhibited superior performance. Additionally, incorporating the "chemical family type" attribute significantly enhanced model accuracy. Strategies involving a gray-zone categorization demonstrated marked improvements in predictive precision. This research underscores the transformative potential of ML in predicting urease inhibitors. The meticulous methodology outlined herein offers actionable insights for developing robust predictive models within biochemical systems.

Phytochemical Profile and Antimicrobial Potential of Propolis Samples from Kazakhstan

In the current paper, we present the results of Kazakh propolis investigations. Due to limited data about propolis from this country, research was focused mainly on phytochemical analysis and evaluation of propolis antimicrobial activity. uHPLC-DAD (ultra-high-pressure-liquid chromatography coupled with diode array detection, UV/VIS) and uHPLC-MS/MS (ultra-high-pressure-liquid chromatography coupled with tandem mass spectrometry) were used to phytochemical characteristics while antimicrobial activity was evaluated in the serial dilution method (MIC, minimal inhibitory concentration, and MBC/MFC, minimal bactericidal/fungicidal concentration measurements). In the study, Kazakh propolis exhibited a strong presence of markers characteristic of poplar-type propolis—flavonoid aglycones (pinocembrin, galangin, pinobanksin and pinobanskin-3-O-acetate) and hydroxycinnamic acid monoesters (mainly caffeic acid phenethyl ester and different isomers of caffeic acid prenyl ester). The second plant precursor of Kazakh propolis was aspen–poplar with 2-acetyl-1,3-di-p-coumaroyl glycerol as the main marker. Regarding antimicrobial activity, Kazakh propolis revealed stronger activity against reference Gram-positive strains (MIC from 31.3 to above 4000 mg/L) and yeasts (MIC from 62.5 to 1000 mg/L) than against reference Gram-negative strains (MIC ≥ 4000 mg/L). Moreover, Kazakh propolis showed good anti-Helicobacter pylori activity (MIC and MBC were from 31.3 to 62.5 mg/L). All propolis samples were also tested for H. pylori urease inhibitory activity (IC50, half-maximal inhibitory concentration, ranged from 440.73 to 11,177.24 µg/mL). In summary Kazakh propolis are potent antimicrobial agents and may be considered as a medicament in the future.

A scoping review of African natural products against gastric ulcers and Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

African traditional medicine is one of the oldest and most diverse practices for treating ailments and numerous natural products have been recommended for gastric ulcer treatment. Helicobacter pylori is the main causative organism implicated in several diseases, most notably in causing inflammation and the onset of gastric ulcers. Current H. pylori treatment methods are losing efficacy as H. pylori rapidly gains resistance to antibiotics. Hence, a search into natural products and their historical traditional efficacy for the treatment of gastric ulcers is of interest.

AIM OF THE STUDY

This review aimed to summarise the African use of natural products, including medicinal plants noted in ethnobotanical reviews, used traditionally to treat gastric ulcers, and highlights the investigations into the anti-H. pylori activity of medicinal plants and bee products found in Africa.

METHODOLOGY

A systematic review was carried out to identify natural products, including those used traditionally in Africa to treat gastric ulcers, and to correlate this with scientific investigations into the anti-H. pylori activity of natural products used in Africa.

RESULTS

A total of 107 literature sources describing the traditional use of medicinal plants in gastric ulcer treatment were found, from which 360 medicinal plants were identified. Of the plants used traditionally for gastric ulcer treatment, 11% were investigated either in vitro or in vivo for anti-ulcer and anti-H. pylori activity. Of the 122 medicinal plants eliciting antimicrobial or anti-ulcer activity, Hibiscus sabdariffa L. calyx extract and Terminalia macroptera Guill. & Perr. root extract were found to have the most noteworthy antimicrobial activity, with minimum inhibitory concentrations (MICs) of 0.01 mg/mL and 0.03 mg/mL respectively. The essential oils of Piper longum L. and Pachira aquatica Aubl. displayed the most notable in vitro anti-H. pylori activity (MIC of 0.01 mg/mL and 0.02 mg/mL). Several in vivo studies found medicinal plant extracts effective in reducing the H. pylori load along the gastric mucosa. The South African honey variants, Pure Honey and Champagne Royal Train (common names given by supplier) were the most antimicrobially effective (MIC of 0.01-10.0%, 0.63-10.00% v/v) in inhibiting H. pylori when assessed in vitro.

CONCLUSION

These results highlight the potential of natural products to inhibit H. pylori growth and serve as a possible stepping-stone in understanding the management of ulcers. Furthermore, effective natural product treatment or prophylactic use for preventing H. pylori growth may provide a more affordable option for African populations.

Anti-Inflammatory Effect of Korean Propolis on Helicobacter pylori-Infected Gastric Mucosal Injury Mice Model

Propolis, a natural resinous substance obtained from a variety of buds and plants, has been reported to possess various biological functions. Several recent studies have demonstrated the inhibitory effects of propolis on the growth of Helicobacter pylori (H. pylori) in vitro; however, current research efforts on Korean propolis (KP) remain insufficient especially in vivo. Our study aims to investigate the anti-inflammatory effect and molecular mechanism of KP on mouse gastric mucosa during H. pylori infection. We examined an in vivo H. pylori-induced gastric mucosal injury mice model. We found that KP inhibited the growth of H. pylori and attenuated the expression of H. pylori virulence factors such as cytotoxin-associated gene A, encoding urease A subunit, surface antigen gene and neutrophil-activating protein A. Moreover, KP reduced both gross lesions and pathological scores in H. pylori-challenged mice. In addition, KP markedly restrained the production of pro-inflammatory cytokines and nitric oxide levels compared with an untreated H. pylori-infected group. In particular, we found that KP repressed the phosphorylation of IκBα and NF-κB p65 subunit, and subsequently suppressed their downstream target genes. Taken together, these findings demonstrate the beneficial effects of KP on inflammation through the inhibition of NF-κB signaling as well as inhibition of H. pylori growth in a mouse model infected with H. pylori. This suggests the potential application of KP as a natural supplement for patient’s suffering from gastric mucosal injury caused by H. pylori infection.

Exploring the potential of Cinnamomum zeylanicum oil against drug resistant Helicobacter pylori-producing cytotoxic genes

Thirty-one of sixty dyspeptic patients tested positive for Helicobacter pylori colonization in this study, as determined by histopathology and 16S rRNA. The cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA) genes were found in 67.7 and 93.5% of H. pylori patients, respectively. The cagA gene was found to be associated with 100% of patients with duodenal erosion and ulceration identified via endoscopy examination. In addition, 86.7% of patients with cancerous and precancerous lesions, glandular atrophy, and intestinal metaplasia identified via histopathology examination. The vacA s1m1 mutation was associated with more severe forms of gastric erosion and ulceration, as well as the presence of precancerous and cancerous lesions. Eighteen (64.3%) of the twenty-eight isolates were classified as multi-drug resistant (MDR) or pan-drug resistant (PDR) H. pylori. Due to a resurgence of interest in alternative therapies derived from plants as a result of H. pylori resistance to the majority of commonly used antibiotics, the inhibitory activity of five essential oils extracted from some commonly used medicinal plants was evaluated in vitro against drug-resistant H. pylori clinical isolates. Cinnamomum zeylanicum essential oil demonstrated the highest anti-H. pylori activity when compared to the other essential oils tested. Cinnamaldehyde was the most abundant compound in C. zeylanicum (65.91%). The toxicological evaluation established the safety of C. zeylanicum oil for human use. As a result, C. zeylanicum essential oil may represent a novel antibacterial agent capable of combating drug-resistant H. pylori carrying cytotoxin genes.

Revisiting Therapeutic Strategies for H. pylori Treatment in the Context of Antibiotic Resistance: Focus on Alternative and Complementary Therapies

The prevalence of Helicobacter pylori infection remains significant worldwide and it depends on many factors: gender, age, socio-economic status, geographic area, diet, and lifestyle. All successful infectious diseases treatments use antibiotic-susceptibility testing, but this strategy is not currently practical for H. pylori and the usual cure rates of H. pylori are lower than other bacterial infections. Actually, there is no treatment that ensures complete eradication of this pathogen. In the context of an alarming increase in resistance to antibiotics (especially to clarithromycin and metronidazole), alternative and complementary options and strategies are taken into consideration. As the success of antibacterial therapy depends not only on the susceptibility to given drugs, but also on the specific doses, formulations, use of adjuvants, treatment duration, and reinfection rates, this review discusses the current therapies for H. pylori treatment along with their advantages and limitations. As an alternative option, this work offers an extensively referenced approach on natural medicines against H. pylori, including the significance of nanotechnology in developing new strategies for treatment of H. pylori infection.

Epigallocatechin Gallate with Potent Anti-Helicobacter pylori Activity Binds Efficiently to Its Histone-like DNA Binding Protein

Helicobacter pylori (H. pylori)-a human gastric pathogen-forms a major risk factor for the development of various gastric pathologies such as chronic inflammatory gastritis, peptic ulcer, lymphomas of mucosa-associated lymphoid tissues, and gastric carcinoma. The complete eradication of infection is the primary objective of treating any H. pylori-associated gastric condition. However, declining eradication efficiencies, off-target effects, and patient noncompliance to prolong and broad-spectrum antibiotic treatments has spurred the clinical interest to search for alternative effective and safer therapeutic options. As natural compounds are safe and privileged with high levels of antibacterial-activity, previous studies have tested and reported a plethora of such compounds with potential in vitro/in vivo anti-H. pylori activity. However, the mode of action of majority of these natural compounds is unclear. The present study has been envisaged to compile the information of various such natural compounds and to evaluate their binding with histone-like DNA-binding proteins of H. pylori (referred here as Hup) using in silico molecular docking-based virtual screening experiments. Hup-being a major nucleoid-associated protein expressed by H. pylori-plays a strategic role in its survival and persistent colonization under hostile stress conditions. The ligand with highest binding energy with Hup-that is, epigallocatechin-(-)gallate (EGCG)-was rationally selected for further computational and experimental testing. The best docking poses of EGCG with Hup were first evaluated for their solution stability using long run molecular dynamics simulations and then using fluorescence and nuclear magnetic resonance titration experiments which demonstrated that the binding of EGCG with Hup is fairly strong (the resultant apparent dissociation constant (k _D) values were equal to 2.61 and 3.29 ± 0.42 μM, respectively).

Floating Drug Delivery Systems: An Emerging Trend for the Treatment of Peptic Ulcer

Floating drug delivery system (FDDS) is the main approach to prolonging the gastric residence time in the stomach in which the bilayer floating tablet has the main role. It is more suitable for the treatment of local infections such as peptic ulcer, gastritis, Zollinger-Ellision syndrome, indigestion, and other local infections related to the gastrointestinal tract and also used for systemic applications. FDDS provides protection for those drugs which are acid labile and have a short half-life. It also improves bioavailability, reduces drug waste, and enhances the residence time of drugs. Nowadays, various technologies are being used for the development of FDDS. Novel drug delivery systems incorporation into bilayer floating tablets have also broadened the role of FDDS. Polymers have the main role in the development of FDDS, which serve as carriers for the drug and determine the gastric retention time and drug protection. FDDS is also an easy, cheap, and more convenient method for dual drug delivery of drugs.

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

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

Multidrug resistance in Helicobacter pylori: current state and future directions

Introduction: Helicobacter pylori antibiotic resistance has increased worldwide and multidrug resistance (MDR), which seriously hampers eradication success of the frequent chronic infection, has often been reported. Areas covered: H. pylori MDR rates are discussed, mostly from recent articles published since 2015. Present approaches and future directions to counteract the MDR are outlined. Expert opinion: Alarming presence of triple, quadruple and, in some studies, quintuple and sextuple resistance was detected. Primary MDR rates ranged from <10% in most European countries to >40% in Peru. Post-treatment or overall MDR rates were >23-36% in about half of the studies. MDR prevalence has varied both among and within the countries. Factors linked to the MDR are national antibiotic consumption, antibiotic misuse, treatment failures and bacterial factors such as mutations, efflux pumps, and biofilms. Important directions to counteract the MDR increase can be optimization of present and new eradication regimens, wider use of bismuth-containing regimens, assessment of benefit of vonoprazan, new antibiotics such as newer fluoroquinolones and oxazolidinone analogues, adjuvants involving N-acetylcysteine and probiotics, anti-biofilm approaches using anti-biofilm peptides and rhamnolipid and development of vaccines and non-invasive tests for resistance detection. However, more efforts and studies are required. Strain susceptibility testing is increasingly important.