A proton-pump inhibitor expedition: the case histories of omeprazole and esomeprazole

The role of the methoxy group in approved drugs

The methoxy substituent is prevalent in natural products and, consequently, is present in many natural product-derived drugs. It has also been installed in modern drug molecules with no remnant of natural product features because medicinal chemists have been taking advantage of the benefits that this small functional group can bestow on ligand-target binding, physicochemical properties, and ADME parameters. Herein, over 230 methoxy-containing small-molecule drugs, as well as several fluoromethoxy-containing drugs, are presented from the vantage point of the methoxy group. Biochemical mechanisms of action, medicinal chemistry SAR studies, and numerous X-ray cocrystal structures are analyzed to identify the precise role of the methoxy group for many of the drugs and drug classes. Although the methoxy substituent can be considered as the hybridization of a hydroxy and a methyl group, the combination of these functionalities often results in unique effects that can amount to more than the sum of the individual parts.

Argel's stemmoside C as a novel natural remedy for mice with alcohol-induced gastric ulcer based on its molecular mechanistic pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Solenostemma argel is widely distributed in Africa & Asia with traditional usage in alleviating abdominal colic, aches, & cramps. This plant is rich in phytochemicals, which must be explored for its pharmacological effects.

PURPOSE

Peptic Ulcer Disease (PUD) is the digestion of the digestive tube. PUD not only interferes with food digestion & nutrient absorption, damages one of the largest defensive barriers against pathogenic micro-organisms, but also impedes drug absorption & bioavailability, rendering the oral route, the most convenient way, ineffective. Omeprazole, one of the indispensable cost-effective proton-pump inhibitors (PPIs) extensively prescribed to control PUD, is showing growing apprehensions toward multiple drug interactions & side effects. Hence, finding a natural alternative with Omeprazole-like activity & limited side effects is a medical concern.

STUDY DESIGN

Therefore, we present Stemmoside C as a new gastroprotective phytochemical agent isolated from Solenostemma argel to be tested in upgrading doses against ethanol-induced gastric ulcers in mice compared to negative, positive, & reference Omeprazole groups.

METHODS

We carried out in-depth pharmacological & histopathological studies to determine the possible mechanistic pathway.

RESULTS

Our results showed that Stemmoside C protected the stomach against ethanol-induced gastric ulcers parallel to Omeprazole. Furthermore, the mechanistic studies revealed that Stemmoside C produced its effect using an orchestrated array of different mechanisms. Stemmoside C stimulates stomach defense by increasing COX-2, PGE-2, NO, & TFF-1 healing factors, IL-10 anti-inflammatory cytokine, & Nrf-2 & HO-1 anti-oxidant pathways. It also suppresses stomach ulceration by inhibiting leucocyte recruitment, especially neutrophils, leading to subsequent inhibition of NF-κBp65, TNF-α, IL-1β, & iNOS pro-inflammatory cytokines & JAK-1/STAT-3 inflammation-induced carcinogenicity cascade in addition to MMP-9 responsible for tissue degradation.

CONCLUSION

These findings cast light on Stemmoside C's clinical application against gastric ulcer progression, recurrence, & tumorigenicity & concurrently with chemotherapy.

Managing gastrointestinal manifestations in systemic sclerosis, a mechanistic approach

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disease with heterogeneous presentation. Gastrointestinal (GI) complications of SSc are characterized by esophageal reflux, abnormal motility, and microbiome dysbiosis, which impact patient quality of life and mortality. Preventative therapeutics are lacking, with management primarily aimed at symptomatic control.

AREAS COVERED

A broad literature review was conducted through electronic databases and references from key articles. We summarize the physiology of gastric acid production and GI motility to provide context for existing therapies, detail the current understanding of SSc-GI disease, and review GI medications studied in SSc. Finally, we explore new therapeutic options. We propose a management strategy that integrates data on drug efficacy with knowledge of disease pathophysiology, aiming to optimize future therapeutic targets.

EXPERT OPINION

SSc-GI complications remain a challenge for patients, clinicians, and investigators alike. Management presently focuses on treating symptoms and minimizing mucosal damage. Little evidence exists to suggest immunosuppressive therapy halts progression of GI involvement or reverses damage, leaving many unanswered questions about the optimal clinical approach. Further research focused on identifying patients at risk for GI progression, and the underlying mechanism(s) that drive disease will provide opportunities to prevent long-term damage, and significantly improve patient quality of life.

ICH S1 prospective evaluation study and weight of evidence assessments: commentary from industry representatives

Industry representatives on the ICH S1B(R1) Expert Working Group (EWG) worked closely with colleagues from the Drug Regulatory Authorities to develop an addendum to the ICH S1B guideline on carcinogenicity studies that allows for a weight-of-evidence (WoE) carcinogenicity assessment in some cases, rather than conducting a 2-year rat carcinogenicity study. A subgroup of the EWG composed of regulators have published in this issue a detailed analysis of the Prospective Evaluation Study (PES) conducted under the auspices of the ICH S1B(R1) EWG. Based on the experience gained through the Prospective Evaluation Study (PES) process, industry members of the EWG have prepared the following commentary to aid sponsors in assessing the standard WoE factors, considering how novel investigative approaches may be used to support a WoE assessment, and preparing appropriate documentation of the WoE assessment for presentation to regulatory authorities. The commentary also reviews some of the implementation challenges sponsors must consider in developing a carcinogenicity assessment strategy. Finally, case examples drawn from previously marketed products are provided as a supplement to this commentary to provide additional examples of how WoE criteria may be applied. The information and opinions expressed in this commentary are aimed at increasing the quality of WoE assessments to ensure the successful implementation of this approach.

Protective effects of an alcoholic extract of Kaempferia galanga L. rhizome on ethanol-induced gastric ulcer in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Kaempferia galanga L., a medicinal and edible Plant, was widely distributed in many Asian and African counties. It has been traditionally used to treat gastroenteritis, hypertension, rheumatism and asthma. However, there is a lack of modern pharmacology studies regarding its anti-gastric ulcer activity.

AIM OF THE STUDY

The objective of this study is to investigate the protective effects of an extract from K. galanga L. rhizome (Kge) and its active components kaempferol and luteolin on ethanol-induced gastric ulcer.

MATERIALS AND METHODS

The kge was prepared by ultrasonic-assisted extraction, and the contents of kaempferol and luteolin were determined by HPLC. The mice were randomly divided into seven groups: blank control (0.5 % CMC-Na; 0.1 mL/10 g), untreatment (0.5 % CMC-Na; 0.1 mL/10 g), Kge (100, 200 and 400 mg/kg), kaempferol (100 mg/kg) and luteolin (100 mg/kg) groups. The mice were treated intragastrically once daily for 7 days. At 1 h post the last administration, the mice in all groups except the blank control group were intragastrically administrated with anhydrous alcohol (0.1 mL/10 g) once to induce gastric ulcer. Then, fasting was continued for 1 h, followed by sample collection for evaluation by enzyme-linked immunosorbent assay and real-time reverse transcription polymerase chain reaction assay.

RESULTS

The contents of kaempferol and luteolin in Kge were determined as 3713 μg/g and 2510 μg/g, respectively. Alcohol induced severely damages with edema, inflammatory cell infiltration and bleeding, and the ulcer index was 17.63 %. After pre-treatment with Kge (100, 200 and 400 mg/kg), kaempferol and luteolin, the pathological lesions were obviously alleviated and ulcer indices were reduced to 13.42 %, 11.65 %, 6.54 %, 3.58 % and 3.85 %, respectively. In untreated group, the contents of Ca2+, myeloperoxidase, malondialdehyde, NO, cyclic adenosine monophosphate and histamine were significantly increased, while the contents of hexosamine, superoxide dismutase, glutathione peroxidase, and prostaglandin E2 were significantly decreased; the transcriptional levels of IL-1α, IL-1β, IL-6, calcitonin gene related peptide, substance P, M3 muscarinic acetylcholine receptor, histamine H2 receptor, cholecystokinin 2 receptor and H+/K+ ATPase were significantly increased when compared with the blank control group. After pre-treatment, all of these changes were alleviated, even returned to normal levels. Kge exhibited anti-gastric ulcer activity and the high dose of Kge (400 mg/kg) exhibited comparable activity to that of kaempferol and luteolin.

CONCLUSION

The study showed that K. galanga L., kaempferol, and luteolin have protective effects against ethanol-induced gastric ulcers. This is achieved by regulating the mucosal barrier, oxidative stress, and gastric regulatory mediators, as well as inhibiting the TRPV1 signaling pathway and gastric acid secretion, ultimately reducing the gastric ulcer index.

Engineering of methionine sulfoxide reductase A with simultaneously improved stability and activity for kinetic resolution of chiral sulfoxides

Methionine sulfoxide reductase A (MsrA) has emerged as promising biocatalysts in the enantioselective kinetic resolution of racemic (rac) sulfoxides. In this study, we engineered robust MsrA variants through directed evolution, demonstrating substantial improvements of thermostability. Mechanism analysis reveals that the enhanced thermostability results from the strengthening of intracellular interactions and increase in molecular compactness. Moreover, these variants demonstrated concurrent improvements in catalytic activities, and notably, these enhancements in stability and activity collectively contributed to a significant improvement in enzyme substrate tolerance. We achieved kinetic resolution on a series of rac-sulfoxides with high enantioselectivity under initial substrate concentrations reaching up to 93.0 g/L, representing a great improvement in the aspect of the substrate concentration for biocatalytic preparation of chiral sulfoxide. Hence, the simultaneously improved thermostability, activity and substrate tolerance of MsrA represent an excellent biocatalyst for the green synthesis of optically pure sulfoxides.

Pantoprazole and Vonoprazan Performed Well in Preventing Peptic Ulcer Recurrence in Low-Dose Aspirin Users

BACKGROUND

Low-dose aspirin (LDA) administration is associated with an elevated risk of recurring peptic ulcer (PU) and gastrointestinal (GI) hemorrhage.

AIMS

This systematic review and Bayesian network meta-analysis aimed to comprehensively assess the effectiveness of diverse medications in preventing the recurrence of PU and GI hemorrhage in patients with a history of PU receiving long-term LDA therapy.

METHODS

This systematic review and network meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and was registered on PROSPERO (CRD42023406550). We searched relevant studies in main databases from inception to March 2023. All statistical analyses were performed using R (version 4.1.3), with the "Gemtc" (version 1.0-1) package. The pooled risk ratio (RR), corresponding 95% credible interval (95% CrI), and the surface under the cumulative ranking curve (SUCRA) were calculated.

RESULTS

11 Randomized clinical trials (RCTs) were included. The analysis underscored pantoprazole was the most efficacious for reducing the risk of PU recurrence (RR [95% CrI] = 0.02 [0, 0.28]; SUCRA: 90.76%), followed by vonoprazan (RR [95% CrI] = 0.03 [0, 0.19]; SUCRA: 86.47%), comparing with the placebo group. Pantoprazole also performed well in preventing GI hemorrhage (RR [95% CrI] = 0.01[0, 0.42]; SUCRA: 87.12%) compared with Teprenone.

CONCLUSIONS

For patients with a history of PU receiving LDA, pantoprazole and vonoprazan might be the optimal choices to prevent PU recurrence and GI hemorrhage.

Simultaneous Determination of Enantiomeric Purity and Organic Impurities of Dexketoprofen Using Reversed-Phase Liquid Chromatography-Enhancing Enantioselectivity through Hysteretic Behavior and Temperature-Dependent Enantiomer Elution Order Reversal on Polysaccharide Chiral Stationary Phases

A reversed-phase high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of the potential impurities of dexketoprofen, including the distomer R-ketoprofen. After screening the separation capability of four polysaccharide columns (Lux Amylose-1, Lux Amylose-2, Lux Cellulose-1 and Lux Cellulose-2) in polar organic and in reversed-phase modes, appropriate enantioseparation was observed only on the Lux Amylose-2 column in an acidified acetonitrile/water mixture. A detailed investigation of the mobile phase composition and temperature for enantio- and chemoselectivity showed many unexpected observations. It was observed that both the resolution and the enantiomer elution order can be fine-tuned by varying the temperature and mobile phase composition. Moreover, hysteresis of the retention times and enantioselectivity was also observed in reversed-phase mode using methanol/water mixtures on amylose-type columns. This could indicate that the three-dimensional structure of the amylose column can change by transitioning from a polar organic to a reversed-phase mode, which affects the enantioseparation process. Temperature-dependent enantiomer elution order and rare enthalpic/entropic controlled enantioseparation in the operative temperature range were also observed in reversed-phase mode. To find the best methodological conditions for the determination of dexketoprofen impurities, a full factorial optimization design was performed. Using the optimized parameters (Lux Amylose-2 column with water/acetonitrile/acetic acid 50/50/0.1 (v/v/v) at a 1 mL/min flow rate at 20 °C), baseline separations were achieved between all compounds within 15 min. Our newly developed HPLC method was validated according to the current guidelines, and its application was tested on commercially available pharmaceutical formulations. According to the authors' knowledge, this is the first study to report hysteretic behavior on polysaccharide columns in reversed-phase mode.

Chirality of New Drug Approvals (2013-2022): Trends and Perspectives

Many drugs are chiral with their chirality determining their biological interactions, safety, and efficacy. Since the 1980s, there has been a regulatory preference to bring single enantiomer to market. This perspective discusses trends related to chirality that have developed in the past decade (2013-2022) of new drug approvals. The EMA has not approved a racemate since 2016, while the average for the FDA is one per year from 2013 to 2022. These 10 include drugs which have been previously marketed elsewhere for several decades, analogues of pre-existing drugs, or drugs where the undefined stereocenter does not play a role in therapeutic activity. Two chiral switches were identified which were both combined with drug repurposing. This combination strategy has the potential to produce therapeutically valuable drugs in a faster time frame. Two class III atropisomers displaying axial chirality were approved between 2013 and 2022, one as a racemate and one as a single enantiomer.

Chinese herb pollen derived micromotors as active oral drug delivery system for gastric ulcer treatment

Considerable efforts have been devoted to treating gastric ulcers. Attempts in this field tend to develop drug delivery systems with prolonged gastric retention time. Herein, we develop novel Chinese herb pollen-derived micromotors as active oral drug delivery system for treating gastric ulcer. Such Chinese herb pollen-derived micromotors are simply produced by asymmetrically sputtering Mg layer onto one side of pollen grains. When exposed to gastric juice, the Mg layer can react with the hydrogen ions, resulting in intensive generation of hydrogen bubbles to propel the micromotors. Benefiting from the autonomous motion and unique spiny structure, our micromotors can move actively in the stomach and adhere to the surrounding tissues. Besides, their special architecture endows the micromotors with salient capacity of drug loading and releasing. Based on these features, we have demonstrated that our Chinese herb pollen-derived micromotors could effective deliver berberine hydrochloride and show desirable curative effect on the gastric ulcer model of mice. Therefore, these Chinese herb pollen-derived micromotors are anticipated to serve as promising oral drug delivery carriers for clinical applications.

Evaluating protein cross-linking as a therapeutic strategy to stabilize SOD1 variants in a mouse model of familial ALS

Mutations in the gene encoding Cu-Zn superoxide dismutase 1 (SOD1) cause a subset of familial amyotrophic lateral sclerosis (fALS) cases. A shared effect of these mutations is that SOD1, which is normally a stable dimer, dissociates into toxic monomers that seed toxic aggregates. Considerable research effort has been devoted to developing compounds that stabilize the dimer of fALS SOD1 variants, but unfortunately, this has not yet resulted in a treatment. We hypothesized that cyclic thiosulfinate cross-linkers, which selectively target a rare, 2 cysteine-containing motif, can stabilize fALS-causing SOD1 variants in vivo. We created a library of chemically diverse cyclic thiosulfinates and determined structure-cross-linking-activity relationships. A pre-lead compound, "S-XL6," was selected based upon its cross-linking rate and drug-like properties. Co-crystallographic structure clearly establishes the binding of S-XL6 at Cys 111 bridging the monomers and stabilizing the SOD1 dimer. Biophysical studies reveal that the degree of stabilization afforded by S-XL6 (up to 24°C) is unprecedented for fALS, and to our knowledge, for any protein target of any kinetic stabilizer. Gene silencing and protein degrading therapeutic approaches require careful dose titration to balance the benefit of diminished fALS SOD1 expression with the toxic loss-of-enzymatic function. We show that S-XL6 does not share this liability because it rescues the activity of fALS SOD1 variants. No pharmacological agent has been proven to bind to SOD1 in vivo. Here, using a fALS mouse model, we demonstrate oral bioavailability; rapid engagement of SOD1G93A by S-XL6 that increases SOD1G93A's in vivo half-life; and that S-XL6 crosses the blood-brain barrier. S-XL6 demonstrated a degree of selectivity by avoiding off-target binding to plasma proteins. Taken together, our results indicate that cyclic thiosulfinate-mediated SOD1 stabilization should receive further attention as a potential therapeutic approach for fALS.

The Importance of Tracking "Missing" Metabolites: How and Why?

Technologies currently employed to find and identify drug metabolites in complex biological matrices generally yield results that offer a comprehensive picture of the drug metabolite profile. However, drug metabolites can be missed or are captured only late in the drug development process. This could be due to a variety of factors, such as metabolism that results in partial loss of the molecule, covalent bonding to macromolecules, the drug being metabolized in specific human tissues, or poor ionization in a mass spectrometer. These scenarios often draw a great deal of attention from chemistry, safety assessment, and pharmacology. This review will summarize scenarios of missing metabolites, why they are missing, and associated uncovering strategies from deeper investigations. Uncovering previously missed metabolites can have ramifications in drug development with toxicological and pharmacological consequences, and knowledge of these can help in the design of new drugs.

Evidence of Reliable Gastro-Resistance of Novel Enteric Ready-to-Fill Capsules Simplifying Pharmaceutical Manufacturing

Developing delayed-release formulations for acid-sensitive actives can be a costly and time-consuming process. However, ready-to-fill functional capsules, such as EUDRACAP® can significantly mitigate these challenges. The in vitro performance of EUDRACAP® enteric was evaluated in two typical delayed-release scenarios: for diclofenac (a drug that can cause irritation to gastric mucosa), and for omeprazole (a drug susceptible to degradation due to the acidity of gastric fluid). The prototypes were tested in HCl 0.1N according to the USP <711> for at least 2 h and compared to commercial products. The results showed that the performance of EUDRACAP® was below LOD and in compliance with the requirements for drug release in acidic media (NMT 10%). Additionally, the impurities were evaluated after the acidic stress. The low total percentage of impurities of 0.44% for diclofenac (NMT 1.50%) and 0.22% for omeprazole (NMT 2.00%) indicates a very good protection by EUDRACAP®. A comprehensive comparative analysis of the in vitro performance clearly showed the acid protection capability of EUDRACAP® enteric capsules making them a serious alternative to existing enteric dosage forms alternatives. EUDRACAP® is an accessible solution both in large-scale industrial and smaller pharmacy settings. Offering increased accessibility, affordability, and convenience to manufacturers and consumers alike and leading to improved healthcare outcomes.

History of key regulatory peptide systems and perspectives for future research

Throughout the 20th Century, regulatory peptide discovery advanced from the identification of gut hormones to the extraction and characterization of hypothalamic hypophysiotropic factors, and to the isolation and cloning of multiple brain neuropeptides. These discoveries were followed by the discovery of G-protein-coupled and other membrane receptors for these peptides. Subsequently, the systems physiology associated with some of these multiple regulatory peptides and receptors has been comprehensively elucidated and has led to improved therapeutics and diagnostics and their approval by the US Food and Drug Administration. In light of this wealth of information and further potential, it is truly a time of renaissance for regulatory peptides. In this perspective, we review what we have learned from the pioneers in exemplified fields of gut peptides, such as cholecystokinin, enterochromaffin-like-cell peptides, and glucagon, from the trailblazing studies on the key stress hormone, corticotropin-releasing factor, as well as from more recently characterized relaxin-family peptides and receptors. The historical viewpoints are based on our understanding of these topics in light of the earliest phases of research and on subsequent studies and the evolution of knowledge, aiming to sharpen our vision of the current state-of-the-art and those studies that should be prioritized in the future.

Neuroendocrine mechanism of gastric acid secretion: Historical perspectives and recent developments in physiology and pharmacology

The physiology of gastric acid secretion is one of the earliest subjects in medical literature and has been continuously studied since 1833. Starting with the notion that neural stimulation alone drives acid secretion, progress in understanding the physiology and pathophysiology of this process has led to the development of therapeutic strategies for patients with acid-related diseases. For instance, understanding the physiology of parietal cells led to the developments of histamine 2 receptor blockers, proton pump inhibitors (PPIs), and recently, potassium-competitive acid blockers. Furthermore, understanding the physiology and pathophysiology of gastrin has led to the development of gastrin/CCK2 receptor (CCK2 R) antagonists. The need for refinement of existing drugs in patients have led to second and third generation drugs with better efficacy at blocking acid secretion. Further understanding of the mechanism of acid secretion by gene targeting in mice has enabled us to dissect the unique role for each regulator to leverage and justify the development of new targeted therapeutics for acid-related disorders. Further research on the mechanism of stimulation of gastric acid secretion and the physiological significances of gastric acidity in gut microbiome is needed in the future.

Guidelines on optimizing the use of proton pump inhibitors: PPI stewardship

Proton pump inhibitors (PPIs) have been available for over three decades and are among the most commonly prescribed medications. They are effective in treating a variety of gastric acid-related disorders. They are freely available and based on current evidence, use of PPIs for inappropriate indications and duration appears to be common. Over the years, concerns have been raised on the safety of PPIs as they have been associated with several adverse effects. Hence, there is a need for PPI stewardship to promote the use of PPIs for appropriate indication and duration. With this objective, the Indian Society of Gastroenterology has formulated guidelines on the rational use of PPIs. The guidelines were developed using a modified Delphi process. This paper presents these guidelines in detail, including the statements, review of literature, level of evidence and recommendations. This would help the clinicians in optimizing the use of PPIs in their practice and promote PPI stewardship.

Is Target-Based Drug Discovery Efficient? Discovery and "Off-Target" Mechanisms of All Drugs

Target-based drug discovery is the dominant paradigm of drug discovery; however, a comprehensive evaluation of its real-world efficiency is lacking. Here, a manual systematic review of about 32000 articles and patents dating back to 150 years ago demonstrates its apparent inefficiency. Analyzing the origins of all approved drugs reveals that, despite several decades of dominance, only 9.4% of small-molecule drugs have been discovered through "target-based" assays. Moreover, the therapeutic effects of even this minimal share cannot be solely attributed and reduced to their purported targets, as they depend on numerous off-target mechanisms unconsciously incorporated by phenotypic observations. The data suggest that reductionist target-based drug discovery may be a cause of the productivity crisis in drug discovery. An evidence-based approach to enhance efficiency seems to be prioritizing, in selecting and optimizing molecules, higher-level phenotypic observations that are closer to the sought-after therapeutic effects using tools like artificial intelligence and machine learning.

Discovery and Mechanism Study of SARS-CoV-2 3C-like Protease Inhibitors with a New Reactive Group

3CLpro is an attractive target for the treatment of COVID-19. Using the scaffold hopping strategy, we identified a potent inhibitor of 3CLpro (3a) that contains a thiocyanate moiety as a novel warhead that can form a covalent bond with Cys145 of the protein. Tandem mass spectrometry (MS/MS) and X-ray crystallography confirmed the mechanism of covalent formation between 3a and the protein in its catalytic pocket. Moreover, several analogues of compound 3a were designed and synthesized. Among them, compound 3h shows the best inhibition of 3CLpro with an IC50 of 0.322 μM and a kinact/Ki value of 1669.34 M-1 s-1, and it exhibits good target selectivity for 3CLpro against host proteases. Compound 3c inhibits SARS-CoV-2 in Vero E6 cells (EC50 = 2.499 μM) with low cytotoxicity (CC50 > 200 μM). These studies provide ideas and insights to explore and develop new 3CLpro inhibitors in the future.

Sequence-based drug design as a concept in computational drug design

Drug development based on target proteins has been a successful approach in recent decades. However, the conventional structure-based drug design (SBDD) pipeline is a complex, human-engineered process with multiple independently optimized steps. Here, we propose a sequence-to-drug concept for computational drug design based on protein sequence information by end-to-end differentiable learning. We validate this concept in three stages. First, we design TransformerCPI2.0 as a core tool for the concept, which demonstrates generalization ability across proteins and compounds. Second, we interpret the binding knowledge that TransformerCPI2.0 learned. Finally, we use TransformerCPI2.0 to discover new hits for challenging drug targets, and identify new target for an existing drug based on an inverse application of the concept. Overall, this proof-of-concept study shows that the sequence-to-drug concept adds a perspective on drug design. It can serve as an alternative method to SBDD, particularly for proteins that do not yet have high-quality 3D structures available.

Increased mortality in patients with hematologic malignancies treated with proton pump inhibitors: a nationwide cohort study

Proton Pump inhibitors (PPIs) are frequently prescribed to cancer patients to prevent gastric mucosal damage. Post-diagnostic PPI use in patients with solid tumors may be associated with increased cancer mortality. However, the hazardous impact of PPIs in patients with hematologic malignancies remains unknown. This association was investigated in a large, retrospective cohort study using data from the Danish nationwide health registries. The outcomes were cancer-specific or non-cancer deaths. We identified 15,320 patients with hematologic malignancies and of these 1811 were identified as post-diagnostic PPI users. PPI users had significantly increased HRs for cancer-specific mortality (HR 1.31; 95% CI, 1.18-1.44) and 1-year cancer-specific mortality (HR 1.50, 95% CI 1.29-1.74) as compared to nonusers. The association between PPI use and increased cancer-specific mortality in Danish patients with hematologic malignancies supports the raised concerns regarding the frequent use of PPIs in cancer patients.

Expanding the Use of Peroxygenase from Oat Flour in Organic Synthesis: Enantioselective Oxidation of Sulfides

Biocatalyzed oxidations are an important target in sustainable synthesis since chemical oxidations often require harsh conditions and metal-based catalysts. A raw peroxygenase-containing enzymatic preparation from oat flour was tested as a biocatalyst for the enantioselective oxidation of sulfides to sulfoxides and the variations of some reaction parameters were evaluated. Under optimal conditions, thioanisole was fully converted into the corresponding (R)-sulfoxide with high optical purity (80% ee) and the same stereopreference was maintained in the oxidation of some other sulfides. Changes in the substituent on the sulfur atom affected the selectivity of the enzyme and the best results were obtained with phenyl methoxymethyl sulfide, which gave the corresponding sulfoxide in 92% ee as exclusive product. The over-oxidation of sulfides to sulfones was instead detected in all the other cases and preferential oxidation of the (S)-enantiomer of the sulfoxide intermediate was observed, albeit with low selectivity. Carrying out the oxidation of thioanisole up to the 29% formation of sulfone led to enhancement of the sulfoxide optical purity (89% ee). The activity in sulfoxidation reactions, in addition to that reported in the epoxidation of different substrates, makes this plant peroxygenase a promising and useful tool in organic synthesis.

Bletilla striata Polysaccharide Nanoparticles Improved the Therapeutic Efficacy of Omeprazole on the Rat Gastric Ulcer Induced by Ethanol

Gastric ulcers are a common clinical presentation affecting anyone, regardless of their age or gender. Nanoparticles (NPs) containing Bletilla striata polysaccharide (BSP) and omeprazole (OME) were investigated in the study for their therapeutic effect on gastric ulcers. Ethanol-induced gastric ulcers in rats (240 ± 30 g) were established. Our OME-BSP NPs were more stable than free OME in the acidic environment and can increase the absorption of OME in rat stomach, which was confirmed by in situ gastric absorption and distribution experiments. The extended blood circulation of OME-BSP NPs was also observed in rats with gastric ulcer. More importantly, OME-BSP NPs not only decreased the area of gastric ulcer and inhibited gastric acid secretion but also reversed gastric tissue damage and cell apoptosis, as revealed by HE and TUNEL staining. Subsequent SOD, MDA, PGE₂, IL-6, and TNF-α tests further verified the superiority of OME-BSP NPs against rat gastric ulcer, which properly originated from superior antioxidant and anti-inflammatory effects. As a result, our OME-BSP NPs' drug delivery system improved the stability and absorption of OME in the rat stomach and achieved targeted treatment of gastric ulcers.

Pharmacokinetics and Pharmacodynamics of Esomezol DR, a New Dual Delayed-Release Formulation of Esomeprazole 20 Mg or 40 Mg, in Healthy Subjects

Background

Esomeprazole, a proton pump inhibitor (PPI), is widely used to treat acid-related disorders, but it has short plasma half-life which can cause insufficient gastric acid suppression, such as nocturnal acid breakthrough. A new dual delayed-release (DR) formulation of esomeprazole (Esomezol DR), was developed to extend the duration of gastric acid suppression.

Purpose

This study aimed to evaluate the pharmacokinetics (PKs) and pharmacodynamics (PDs) of esomeprazole for the DR formulation compared to a conventional enteric-coated (EC) formulation (Nexium) in healthy male subjects.

Methods

Two randomized, open-label, multiple-dose, two-way crossover studies with esomeprazole 20 mg and 40 mg were conducted. Subjects received the DR formulation or the EC formulation once daily for 7 days in each period with a 7-day washout. Serial blood samples were collected up to 24 hours after the 1st dose, and 24-hour intragastric pH was continuously monitored before the 1st dose as baseline and after the 1st and the 7th dose.

Results

In 20 mg and 40 mg dose groups, 38 and 44 subjects completed the study, respectively. The DR formulation exhibited the dual-release pattern of esomeprazole, resulting in more sustained plasma concentration-time profiles compared to the EC formulation. The systemic exposure of esomeprazole for the DR formulation was comparable to that for the EC formulation, showing the similar area under the plasma concentration-time curve. The 24-hour gastric acid suppression was also similar between the two formulations, while the inhibition during night-time (22:00-06:00) showed a better tendency in the DR formulation.

Conclusion

The sustained exposure of esomeprazole in the DR formulation led to well-maintained and higher acid inhibition compared to the EC formulation, especially during the night-time. These results suggest that the DR formulation can be an alternative formulation to the conventional EC formulation, expecting the potential of relieving nocturnal acid-related symptoms.

Estimates of Chronic Kidney Diseases Associated with Proton-Pump Inhibitors Using a Retrospective Hospital-Based Cohort in Thailand

PURPOSE

Potential adverse outcomes of Proton pump inhibitors (PPIs) have increasingly been reported. The potential risks to PPIs include hypomagnesemia and chronic kidney disease (CKD). Unlike a real-world electronic medical record (RW-EMR) with active-comparator design, claim databases and special population cohort with non-user design, using in previous studies, resulted in a wide range of strength of association with indication bias. This study aimed to measure the total effect of association between PPIs use and CKD incidence using Thai RW-EMR.

PATIENTS AND METHODS

A retrospective hospital-based cohort was applied into this study. Electronic medical records and administrative data of out- and inpatient were retrieved from October 1st, 2010 to September 30th, 2017. On-treatment with grace period as well as propensity score matching was used in data analysis. Cox proportional hazard models were applied to evaluate the PPIs-CKD association.

RESULTS

Of all 63,595 participants, a total of 59,477 new PPIs and 4118 Histamine 2-receptor antagonist (H2RA) users were eligible for follow-up. As compared with H2RA, the PPI users were non-elderly and more likely being female. The association of PPIs with CKD was statistically significant (adjusted hazard ratio [HR] = 3.753, 95% CI = 2.385-5.905). The HR were not statistically different by concomitant use PPIs with NSAIDs and by medication possession ratio levels.

CONCLUSION

The association between PPIs and CKD incidence was statistically significant in this hospital-based cohort. However, self-treatment with over-the-counter PPIs, as well as, smoking, drinking alcohol and body mass index could not be fully retrieved, affecting the estimation of treatment effect.

Advances in covalent drug discovery

Covalent drugs have been used to treat diseases for more than a century, but tools that facilitate the rational design of covalent drugs have emerged more recently. The purposeful addition of reactive functional groups to existing ligands can enable potent and selective inhibition of target proteins, as demonstrated by the covalent epidermal growth factor receptor (EGFR) and Bruton's tyrosine kinase (BTK) inhibitors used to treat various cancers. Moreover, the identification of covalent ligands through 'electrophile-first' approaches has also led to the discovery of covalent drugs, such as covalent inhibitors for KRAS(G12C) and SARS-CoV-2 main protease. In particular, the discovery of KRAS(G12C) inhibitors validates the use of covalent screening technologies, which have become more powerful and widespread over the past decade. Chemoproteomics platforms have emerged to complement covalent ligand screening and assist in ligand discovery, selectivity profiling and target identification. This Review showcases covalent drug discovery milestones with emphasis on the lessons learned from these programmes and how an evolving toolbox of covalent drug discovery techniques facilitates success in this field.

An Evidence-Based Retrospective Study for the Management of Acid Peptic Disease With Omeprazole, a Proton Pump Inhibitor, in Indian Patients With Type 2 Diabetes Mellitus (PRIDE-1)

Background In this study, we aimed to assess the effectiveness of omeprazole therapy in the management of acid peptic disease (APD) among type 2 diabetes mellitus (T2DM) patients. Methodology In this multicenter retrospective study, electronic medical records (EMRs) of T2DM patients with APD who were prescribed omeprazole between March 2018 and April 2021 at multiple Indian healthcare settings were reviewed. The resolution of APD symptoms was assessed at visit five (120 days after the index visit) and compared to visit one (index visit). Safety was established in terms of reported adverse events during the study period. Results Overall, 174 patients were included. The majority of patients (63.8%) were males with a mean age of 48.6 ± 11.03 years. After receiving omeprazole therapy, a significant number of patients reported improvement in symptoms such as abdominal pain (98.2%), epigastric burning (74.2%), altered bowel movements (62.1%), and nausea (80.5%) (p < 0.001 for each). Complete resolution was observed in all patients who complained about flatulence (100.0%) and loss of appetite (100.0%) (p < 0.001 for each). The drug was found to be well tolerated. Conclusions Omeprazole therapy was well tolerated and highly effective in resolving APD symptoms among T2DM patients receiving fixed oral hypoglycemic agents.

Evidence for Metabolic Activation of Omeprazole In Vitro and In Vivo

Omeprazole (OPZ) is a proton pump inhibitor commonly used for the treatment of gastric acid hypersecretion. Studies have revealed that use of OPZ can induce hepatotoxicity, but the mechanisms by which it induces liver injury are unclear. This study aimed to identify reactive metabolites of OPZ, determine the pathways of the metabolic activation, and define the correlation of the bioactivation with OPZ cytotoxicity. Quinone imine-derived glutathione (GSH), N-acetylcysteine (NAC), and cysteine (Cys) conjugates were detected in OPZ-fortified rat and human liver microsomal incubations captured with GSH, NAC, or Cys. The same GSH conjugates were detected in bile of rats and cultured liver primary cells after exposure to OPZ. Similarly, the same NAC conjugates were detected in urine of OPZ-treated rats. The resulting quinone imine was found to react with Cys residues of hepatic protein. CYP3A4 dominated the metabolic activation of OPZ. Exposure to OPZ resulted in decreased cell survival in cultured primary hepatocytes. Pretreatment with ketoconazole attenuated the susceptibility of hepatocytes to the cytotoxicity of OPZ.

Chalcogen bond-guided conformational isomerization enables catalytic dynamic kinetic resolution of sulfoxides

Conformational isomerization can be guided by weak interactions such as chalcogen bonding (ChB) interactions. Here we report a catalytic strategy for asymmetric access to chiral sulfoxides by employing conformational isomerization and chalcogen bonding interactions. The reaction involves a sulfoxide bearing two aldehyde moieties as the substrate that, according to structural analysis and DFT calculations, exists as a racemic mixture due to the presence of an intramolecular chalcogen bond. This chalcogen bond formed between aldehyde (oxygen atom) and sulfoxide (sulfur atom), induces a conformational locking effect, thus making the symmetric sulfoxide as a racemate. In the presence of N–heterocyclic carbene (NHC) as catalyst, the aldehyde moiety activated by the chalcogen bond selectively reacts with an alcohol to afford the corresponding chiral sulfoxide products with excellent optical purities. This reaction involves a dynamic kinetic resolution (DKR) process enabled by conformational locking and facile isomerization by chalcogen bonding interactions.

Conformational isomerization of organic molecules can be guided by noncovalent interactions. Here, the authors report the synthesis of chiral sulfoxides catalyzed by N-heterocyclic carbenes; intramolecular chalcogen bonding interactions are key for conformational locking.

Visible Light-Driven Reductive Azaarylation of Coumarin-3-carboxylic Acids

In the manuscript, reductive and decarboxylative azaarylation of coumarin-3-carboxylic acids is described. It utilizes the photocatalytic activation of (cyano)azaarenes in the presence of fac-Ir(ppy)₃ as a photocatalyst. The methodology is versatile and provides access to biologically relevant 4-substituted-chroman-2-ones. Visible light, photoredox catalyst, base, anhydrous solvent, and inert atmosphere constitute key parameters for the success of the described strategy. The developed methodology involves a wide range of coumarin-3-carboxylic acids as well as (cyano)azaarenes.

Thioetherification of Aryl Halides with Thioacetates

A palladium-catalyzed cross-coupling of thioacetates and aryl halides is described herein. Using a catalyst screening kit, ^tBuBrettPhos Pd G3 was found to be a unique catalyst for this reaction, affording the desired thioarene products in high yields under mild reaction conditions. The thioacetate starting materials are readily available, allowing for quick access to these more lab friendly reagents. Reactions described herein range from the late-stage coupling of complex thioacetates to the first report of a mild set of conditions for thiomethylation of aryl halides.

A review on lactoferrin as a proton pump inhibitor

Lactoferrin (Lf) is a versatile natural milk-derived protein that exhibits multiple interesting biological activities. Since it is safe for human administration and currently manufactured using low cost and well-established large-scale processes, the Lf scientific community has been devoted at dissecting its mechanisms of action towards its more rational and efficient use for various applications. Emerging literature has identified proton pumping ATPases as molecular targets of Lf in different cellular models linked to distinct activities of this natural protein. Information on this subject has not been systematically analysed before, hence herein we review the current state of art on the effect of Lf on proton pumping ATPases. Though structurally different, we propose that Lf holds a proton pump inhibitor (PPI)-like activity based on the functional resemblance with the classical inhibitors of the stomach H⁺/K⁺-ATPase. The downstream events and outcomes of the PPI-like activity of Lf, as well as its impact for the development of improved Lf applications are also discussed.

Omeprazole prevents stress induced gastric ulcer by direct inhibition of MMP-2/TIMP-3 interactions

The healing of damaged tissues in gastric tract starts with the extracellular matrix (ECM) remodeling by the action of matrix metalloproteinases (MMPs). Particularly, MMP-2 (gelatinase-A) maintains ECM structure and function by degrading type IV collagen, the major component of basement membranes and by clearing denatured collagen. The proteolytic activities of MMPs are critically balanced by endogenous tissue inhibitors of metalloproteinases (TIMPs) and disruption of this balance results in several diseases. The well-known drug omeprazole is a proton pump inhibitor used for curing gastric ulcer. However, the action of omeprazole in ECM remodeling on gastroprotection has never been explored. Herein, using rat model of gastric ulcer, we report that restraint cold stress caused increase apoptosis to surface epithelia of gastric tissues along with TIMP-3 upregulation and inhibition of MMP-2 activity thereon. In contrast, omeprazole treatment suppressed TIMP-3 while increasing MMP-2 activity and thereby, restoring MMP-2/TIMP-3 balance. Additionally, nanomolar binding constant (K_d = 318 nM) of omeprazole with purified MMP-2 indicates a direct effect of omeprazole in restoring MMP-2 activity. Further in silico simulations revealed a plausible mechanism of action of omeprazole for TIMP-3 deactivation. Altogether, omeprazole restores MMP-2 activity and reduces apoptosis while preventing acute stress-induced gastric ulcer that occurs via suppression of nuclear factor kappa B (NF-κB) activity and peroxisome proliferator-activated receptor gamma activity (PPAR-γ). This represents an unprecedented correlation between physical docking of drug molecule to a protease and the severity of organ injury and provides a novel therapeutic approach to prevent stress induced tissue damage.

Lansoprazole-induced osteoporosis via the IP3R- and SOCE-mediated calcium signaling pathways

Background

Many clinical studies have shown a correlation between proton pump inhibitors (PPIs) and osteoporosis or fractures. The purpose of this study was to establish a murine model of chronic oral PPI administration to verify whether PPIs caused bone metabolic impairment and investigate the relevant molecular mechanism underlying the effects of PPIs on MC3T3-E1 murine osteoblasts.

Methods

A lansoprazole-induced bone loss model was used to investigate the damaging effects of PPIs. In vivo, immunohistochemistry, Hematoxylin–Eosin (HE) staining, micro-CT analysis, and blood biochemical analyses were used to evaluate the effect of lansoprazole on bone injury in mice. In vitro, the effects of lansoprazole and related signaling pathways in MC3T3-E1 cells were investigated by CCK-8 assays, EdU assays, flow cytometry, laser confocal microscopy, patch clamping, reverse transcription-quantitative polymerase chain reaction and Western blotting.

Results

After 6 months of lansoprazole gavage in ICR mice, the micro-CT results showed that compared with that in the vehicle group, the bone mineral density (BMD) in the high-dose group was significantly decreased (P < 0.05), and the bone microarchitecture gradually degraded. Biochemical analysis of bone serum showed that blood calcium and phosphorus were both decreased (P < 0.01). We found that long-term administration of lansoprazole impaired skeletal function in mice. In vitro, we found that lansoprazole (LPZ) could cause calcium overload in MC3T3-E1 cells leading to apoptosis, and 2-APB, an inhibitor of IP3R calcium release channel and SOCE pathway, effectively blocked increase in calcium caused by LPZ, thus protecting cell viability.

Conclusions

Longterm administration of LPZ induced osteoporotic symptoms in mice, and LPZ triggered calcium increases in osteoblasts in a concentration-dependent manner. Intracellular calcium ([Ca²⁺]_i) persisted at a high concentration, thereby causing endoplasmic reticulum stress (ERS) and inducing osteoblast apoptosis.

Chiral Switch: Between Therapeutical Benefit and Marketing Strategy

Chirality of pharmaceutical substances is an important aspect in drug research because it determines how enantiomers will interact with chiral biological targets. Enantiomers of a chiral drug can have different pharmacokinetic and pharmacological profiles; consequently, using a single pure enantiomer instead of a racemate can enhance the effectiveness and/or safety of the treatment. The tendencies of modern pharmaceutical industry regarding the current market of chiral drugs are divided between the chiral switch of previously used racemates and the development of new enantiopure drugs. The term chiral switch refers to the replacement on the market of a previously approved racemate with its single enantiomer version. The potential advantages of chiral switch can be related to a higher therapeutic index due to better potency, selectivity and fewer adverse effects, faster onset of action and exposure of the patient to lower drug dosages. However, chiral switch is also a strategy that permits manufacturers to keep market exclusivity for chiral pharmaceuticals that have lost their patent protection, even if the pure enantiomers have not demonstrated higher effectiveness or safety profile compared with the racemates.

Fucoidan from Sargassum hemiphyllum inhibits infection and inflammation of Helicobacter pylori

Having infected by Helicobacter pylori, the infection often leads to gastritis, gastric ulcer, or even gastric cancer. The disease is typically treated with antibiotics as they used to effectively inhibit or kill H. pylori, thus reducing the incidence of gastric adenoma and cancer to significant extent. H. pylori, however, has developed drug resistance to many clinically used antibiotics over the years, highlighting the crisis of antibiotic failure during the H. pylori treatment. We report here that the fucoidan from Sargassum hemiphyllum can significantly reduce the infection of H. pylori without developing to drug resistance. Fucoidan appears to be a strong anti-inflammation agent as manifested by the RAW264.7 cell model examination. Fucoidan can prohibit H. pylori adhesion to host cells, thereby reducing the infection rate by 60%, especially in post treatment in the AGS cell model assay. Mechanistically, fucoidan intervenes the adhesion of BabA and AlpA of H. pylori significantly lowering the total count of H. pylori and the level of IL-6 and TNF-α in vivo. These results all converge on the same fact that fucoidan is an effective agent in a position to protect the stomach from the H. pylori infection by reducing both the total count and induced inflammation.

Chemical Approaches for Studying the Biology and Pharmacology of Membrane Transporters: The Histidine/Large Amino Acid Transporter SLC7A5 as a Benchmark

The localization of membrane transporters at the forefront of natural barriers makes these proteins very interesting due to their involvement in the absorption and distribution of nutrients and xenobiotics, including drugs. Over the years, structure/function relationship studies have been performed employing several strategies, including chemical modification of exposed amino acid residues. These approaches are very meaningful when applied to membrane transporters, given that these proteins are characterized by both hydrophobic and hydrophilic domains with a different degree of accessibility to employed chemicals. Besides basic features, the chemical targeting approaches can disclose information useful for pharmacological applications as well. An eminent example of this picture is the histidine/large amino acid transporter SLC7A5, known as LAT1 (Large Amino Acid Transporter 1). This protein is crucial in cell life because it is responsible for mediating the absorption and distribution of essential amino acids in peculiar body districts, such as the blood brain barrier and placenta. Furthermore, LAT1 can recognize a large variety of molecules of pharmacological interest and is also considered a hot target for drugs due to its over-expression in virtually all human cancers. Therefore, it is not surprising that the chemical targeting approach, coupled with bioinformatics, site-directed mutagenesis and transport assays, proved fundamental in describing features of LAT1 such as the substrate binding site, regulatory domains and interactions with drugs that will be discussed in this review. The results on LAT1 can be considered to have general applicability to other transporters linked with human diseases.

Formulation strategies to improve the efficacy of intestinal permeation enhancers. Adv Drug Deliv Rev 2021;177:113925. [PMID: 34418495 DOI: 10.1016/j.addr.2021.113925]

The use of chemical permeation enhancers (PEs) is the most widely tested approach to improve oral absorption of low permeability active agents, as represented by peptides. Several hundred PEs increase intestinal permeability in preclinical bioassays, yet few have progressed to clinical testing and, of those, only incremental increases in oral bioavailability (BA) have been observed. Still, average BA values of ~1% were sufficient for two recent FDA approvals of semaglutide and octreotide oral formulations. PEs are typically screened in static in vitro and ex-vivo models where co-presentation of active agent and PE in high concentrations allows the PE to alter barrier integrity with sufficient contact time to promote flux across the intestinal epithelium. The capacity to maintain high concentrations of co-presented agents at the epithelium is not reached by standard oral dosage forms in the upper GI tract in vivo due to dilution, interference from luminal components, fast intestinal transit, and possible absorption of the PE per se. The PE-based formulations that have been assessed in clinical trials in either immediate-release or enteric-coated solid dosage forms produce low and variable oral BA due to these uncontrollable physiological factors. For PEs to appreciably increase intestinal permeability from oral dosage forms in vivo, strategies must facilitate co-presentation of PE and active agent at the epithelium for a sustained period at the required concentrations. Focusing on peptides as examples of a macromolecule class, we review physiological impediments to optimal luminal presentation, discuss the efficacy of current PE-based oral dosage forms, and suggest strategies that might be used to improve them.

Sulfoxide Reductases and Applications in Biocatalytic Preparation of Chiral Sulfoxides: A Mini-Review

Chiral sulfoxides are valuable organosulfur compounds that have been widely used in medicinal and organic synthesis. Biocatalytic approaches for preparing chiral sulfoxides were developed in the past few years, mainly through asymmetric oxidation of prochiral sulfides. Recently, the application of sulfoxide reductase to prepare chiral sulfoxides through kinetic resolution has emerged as a new method, exhibiting extraordinary catalytic properties. This article reviews the chemical and biological functions of these sulfoxide reductases and highlights their applications in chiral sulfoxide preparation.

Macromolecular Nanotherapeutics and Antibiotic Adjuvants to Tackle Bacterial and Fungal Infections

The escalating rise in the population of multidrug-resistant (MDR) pathogens coupled with their biofilm forming ability has struck the global health as nightmare. Alongwith the threat of aforementioned menace, the sluggish development of new antibiotics and the continuous deterioration of the antibiotic pipeline has stimulated the scientific community toward the search of smart and innovative alternatives. In near future, membrane targeting antimicrobial polymers, inspired from antimicrobial peptides, can stand out significantly to combat against the MDR superbugs. Many of these amphiphilic polymers can form nanoaggregates through self-assembly with superior and selective antimicrobial efficacy. Additionally, these macromolecular nanoaggregrates can be utilized to engineer smart antibiotic-delivery system for on-demand drug-release, exploiting the infection site's micoenvironment. This strategy substantially increases the local concentration of antibiotics and reduces the associated off-target toxicity. Furthermore, amphiphilc macromolecules can be utilized to rejuvinate obsolete antibiotics to tackle the drug-resistant infections. This review article highlights the recent developments in macromolecular architecture to design numerous nanostructures with broad-spectrum antimicrobial activity, their application in fabricating smart drug delivery systems and their efficacy as antibiotic adjuvants to circumvent antimicrobial resistance. Finally, the current challenges and future prospects are briefly discussed for further exploration and their practical application in clinical settings.

Doubly Decarboxylative Synthesis of 4-(Pyridylmethyl)chroman-2-ones and 2-(Pyridylmethyl)chroman-4-ones under Mild Reaction Conditions

The doubly decarboxylative Michael-type addition of pyridylacetic acid to chromone-3-carboxylic acids or coumarin-3-carboxylic acids has been developed. This protocol has been realized under Brønsted base catalysis, providing biologically interesting 4-(pyridylmethyl)chroman-2-ones and 2-(pyridylmethyl)chroman-4-ones in good or very good yields. The decarboxylative reaction pathway has been confirmed by mechanistic studies. Moreover, attempts to develop an enantioselective variant of the cascade are also described.

Synthesis and evaluation of novel 2,4-diaminopyrimidines bearing a sulfoxide moiety as anaplastic lymphoma kinase (ALK) inhibition agents

Anaplastic lymphoma kinase (ALK) targeted therapies have demonstrated remarkable efficacy in ALK-positive lung adenocarcinomas. Here we synthesized and evaluated sixteen new 2,4-diaminopyrimidines bearing a sulfoxide moiety as anaplastic lymphoma kinase (ALK) inhibitors. The optimal compound 9e exhibited excellent antiproliferative activity against non-small cell lung cancer NCI-H2228 cells, which is better than that of Brigatinib and similar to Ceritinib. Mechanism study revealed that the optimal compound 9e decreased the mitochondrial membrane potential and arrested NCI-H2228 cells in the G0/G1 phase, finally resulting in cellular apoptosis. It is interesting that 9e could effectively inhibit the migration of NCI-H2228 cells and may be a promising leading compound for chemotherapy of metastatic cancer.

Comparative evaluation of the concentration-dependent effect of proton-pump inhibitor in association with calcium hydroxide and chlorhexidine on Enterococcus faecalis: An in vitro study

Background

Enterococcus faecalis is the most persistent organism in the root canal which resists most of the intracanal medicaments. There is always a constant attempt to eliminate this endodontic pathogen from the root canal system.

Aim

The aim of this study was to evaluate the efficacy of the association of different concentrations of proton-pump inhibitor (PPI) (Lansoprazole) with calcium hydroxide (CH) and chlorhexidine (CHX) against E. faecalis using a broth dilution method.

Materials and Methods

E. faecalis was inoculated into brain-heart infusion broth at 37°C for 5 h. The master broth was then treated with CH (Group 1); CH + 2% CHX (Group 2); CH + PPI 6.25 μg/ml (Group 3A); CH + PPI 25 μg/ml (Group 3B); 2% CHX + PPI 6.25 μg/ml (Group 4A); 2% CHX + PPI 25 μg/ml (Group 4B); CH + 2% CHX + PPI 6.25 μg/ml (Group 5A), and CH + 2% CHX + PPI 25 μg/ml (Group 5B). The groups were spectrophotometrically analyzed at 630 nm at 24 h to determine the group with the least optical density.

Statistical Analysis

Comparison between the groups was done by the one-way analysis of variance and Kruskal-Wallis test for multiple comparisons.

Results

The mean percentage inhibition of E. faecalis by Group 5A (CH + 2% CHX + PPI 6.25 μg/ml) was the highest compared to other groups. The lowest mean value was observed in Group 3A (CH + PPI 6.25 μg/ml) indicating least efficiency.

Conclusion

There was a concentration-dependent effect of PPI on CH and CHX against E. faecalis. The maximum efficacy was found when the lower concentration of PPI was associated with CH/CHX mixture.

Cytotoxic and antimicrobial potential of benzimidazole derivatives

New benzimidazole derivatives were synthesized and their structures were characterized by spectroscopic and microanalysis techniques. The cytotoxic properties of ten benzimidazole derivatives, five of which were synthesized in our previous studies, were determined against the lung cancer cell line, A549, and the healthy lung epithelial cell line, BEAS-2B. Among the ten compounds tested, based on the 72-h incubation results, compound 12 was the most cytotoxic against the A549 cell line, whereas against the BEAS-2B cell line, it was as cytotoxic as cisplatin. The IC₅₀ values of compound 12 were 3.98 and 2.94 µg/ml for A549 and BEAS-2B cells, respectively. The cisplatin values were 6.75 and 2.75 µg/ml for A549 and BEAS-2B cells, respectively. Compounds 10, 8, 7, and 13 showed toxic effects against A549 cells, but were less toxic against BEAS-2B cells than cisplatin. The antimicrobial activity of these compounds against pathogenic bacteria and yeasts was also evaluated based on their minimum inhibitory concentration (MIC) values. The compounds, except 12 and 13, generally showed higher antimicrobial activity against yeasts, compared with bacteria. Compound 12 showed better activity against Pseudomonas aeruginosa and Staphylococcus aureus than against Escherichia coli. Compounds 7, 8, and 11 were the most effective ones against the microorganisms, and yeasts were highly sensitive to these compounds with MIC values of 25-100 µg/ml.

Interface-Mediated Mechanism of Action-The Root of the Cytoprotective Effect of Immediate-Release Omeprazole

Omeprazole is usually administered under an enteric coating. However, there is a Food and Drug Administration-approved strategy that enables its release in the stomach. When locally absorbed, omeprazole shows a higher efficacy and a cytoprotective effect, whose mechanism was still unknown. Therefore, we aimed to assess the effect of the absorption route on the gastric mucosa. 2D and 3D models of dipalmitoylphosphatidylcholine (DPPC) at different pH values (5.0 and 7.4) were used to mimic different absorption conditions. Several experimental techniques, namely, fluorescence studies, X-ray scattering methodologies, and Langmuir monolayers coupled with microscopy, X-ray diffraction, and infrared spectroscopy techniques, were combined with molecular dynamics simulations. The results showed that electrostatic and hydrophobic interactions between omeprazole and DPPC rearranged the conformational state of DPPC. Omeprazole intercalates among DPPC molecules, promoting domain formation with untilted phospholipids. Hence, the local release of omeprazole enables its action as a phospholipid-like drug, which can reinforce and protect the gastric mucosa.