Drugs That Changed Society: History and Current Status of the Early Antibiotics: Salvarsan, Sulfonamides, and β-Lactams

Dual Antibiotic Approach: Synthesis and Antibacterial Activity of Antibiotic-Antimicrobial Peptide Conjugates

In recent years, bacterial resistance to conventional antibiotics has become a major concern in the medical field. The global misuse of antibiotics in clinics, personal use, and agriculture has accelerated this resistance, making infections increasingly difficult to treat and rendering new antibiotics ineffective more quickly. Finding new antibiotics is challenging due to the complexity of bacterial mechanisms, high costs and low financial incentives for the development of new molecular scaffolds, and stringent regulatory requirements. Additionally, innovation has slowed, with many new antibiotics being modifications of existing drugs rather than entirely new classes. Antimicrobial peptides (AMPs) are a valid alternative to small-molecule antibiotics offering several advantages, including broad-spectrum activity and a lower likelihood of inducing resistance due to their multifaceted mechanisms of action. However, AMPs face challenges such as stability issues in physiological conditions, potential toxicity to human cells, high production costs, and difficulties in large-scale manufacturing. A reliable strategy to overcome the drawbacks associated with the use of small-molecule antibiotics and AMPs is combination therapy, namely the simultaneous co-administration of two or more antibiotics or the synthesis of covalently linked conjugates. This review aims to provide a comprehensive overview of the literature on the development of antibiotic-AMP conjugates, with a particular emphasis on critically analyzing the design and synthetic strategies employed in their creation. In addition to the synthesis, the review will also explore the reported antibacterial activity of these conjugates and, where available, examine any data concerning their cytotoxicity.

Removal of sulfonamide antibiotics by constructed wetland substrate with NaOH-modified corn straw biochar under different operating conditions

This study examined the elimination of sulfonamide antibiotics (SAs) by constructed wetland substrates with NaOH-modified corn straw biochar and assessed the impact of environmental conditions on the effectiveness of SAs removal. The study demonstrated that the constructed wetland substrate with NaOH-modified biochar significantly eliminated eight SAs, with a removal rate of over 94 %. During the removal process, the intermediates will undergo regeneration of the parent compounds under low DO concentrations. This was based on the linear stepwise regression analysis and Geodetector models. The results showed that SA types COD, NH4+-N, TN, and DO had a stronger influence. The dominant bacteria in the constructed wetland system were mainly affected by antibiotic concentration, DO, NH4+-N and NO3--N, which affected the removal of antibiotics. Overall, the constructed wetland substrate with NaOH-modified corn straw biochar can be effectively employed as an ecological method for eliminating SAs from the environment.

Biological puzzles solved by using Streptococcus pneumoniae: a historical review of the pneumococcal studies that have impacted medicine and shaped molecular bacteriology

The major human pathogen Streptococcus pneumoniae has been the subject of intensive clinical and basic scientific study for over 140 years. In multiple instances, these efforts have resulted in major breakthroughs in our understanding of basic biological principles as well as fundamental tenets of bacterial pathogenesis, immunology, vaccinology, and genetics. Discoveries made with S. pneumoniae have led to multiple major public health victories that have saved the lives of millions. Studies on S. pneumoniae continue today, where this bacterium is being used to dissect the impact of the host on disease processes, as a powerful cell biology model, and to better understand the consequence of human actions on commensal bacteria at the population level. Herein we review the major findings, i.e., puzzle pieces, made with S. pneumoniae and how, over the years, they have come together to shape our understanding of this bacterium's biology and the practice of medicine and modern molecular biology.

Expanding antibiotic, vaccine, and diagnostics development and access to tackle antimicrobial resistance

The increasing number of bacterial infections globally that do not respond to any available antibiotics indicates a need to invest in-and ensure access to-new antibiotics, vaccines, and diagnostics. The traditional model of drug development, which depends on substantial revenues to motivate investment, is no longer economically viable without push and pull incentives. Moreover, drugs developed through these mechanisms are unlikely to be affordable for all patients in need, particularly in low-income and middle-income countries. New, publicly funded models based on public-private partnerships could support investment in antibiotics and novel alternatives, and lower patients' out-of-pocket costs, making drugs more accessible. Cost reductions can be achieved with public goods, such as clinical trial networks and platform-based quality assurance, manufacturing, and product development support. Preserving antibiotic effectiveness relies on accurate and timely diagnosis; however scaling up diagnostics faces technological, economic, and behavioural challenges. New technologies appeared during the COVID-19 pandemic, but there is a need for a deeper understanding of market, physician, and consumer behaviour to improve the use of diagnostics in patient management. Ensuring sustainable access to antibiotics also requires infection prevention. Vaccines offer the potential to prevent infections from drug-resistant pathogens, but funding for vaccine development has been scarce in this context. The High-Level Meeting of the UN General Assembly in 2024 offers an opportunity to rethink how research and development can be reoriented to serve disease management, prevention, patient access, and antibiotic stewardship.

Exploration of Rhenium Bisquinoline Tricarbonyl Complexes for their Antibacterial Properties

Metal complexes have emerged as a promising source for novel classes of antibacterial agents to combat the rise of antimicrobial resistance around the world. In the exploration of the transition metal chemical space for novel metalloantibiotics, the rhenium tricarbonyl moiety has been identified as a promising scaffold. Here we have prepared eight novel rhenium bisquinoline tricarbonyl complexes and explored their antibacterial properties. Significant activity against both Gram-positive and Gram-negative bacteria was observed. However, all complexes also showed significant toxicity against human cells, putting into question the prospects of this specific rhenium compound class as metalloantibiotics. To better understand their biological effects, we conduct the first mode of action studies on rhenium bisquinoline complexes and show that they are able to form pores through bacterial membranes. Their straight-forward synthesis and tuneability suggests that further optimisation of this compound class could lead to compounds with enhanced bacterial specificity.

Navigating Antibacterial Frontiers: A Panoramic Exploration of Antibacterial Landscapes, Resistance Mechanisms, and Emerging Therapeutic Strategies

The development of effective antibacterial solutions has become paramount in maintaining global health in this era of increasing bacterial threats and rampant antibiotic resistance. Traditional antibiotics have played a significant role in combating bacterial infections throughout history. However, the emergence of novel resistant strains necessitates constant innovation in antibacterial research. We have analyzed the data on antibacterials from the CAS Content Collection, the largest human-curated collection of published scientific knowledge, which has proven valuable for quantitative analysis of global scientific knowledge. Our analysis focuses on mining the CAS Content Collection data for recent publications (since 2012). This article aims to explore the intricate landscape of antibacterial research while reviewing the advancement from traditional antibiotics to novel and emerging antibacterial strategies. By delving into the resistance mechanisms, this paper highlights the need to find alternate strategies to address the growing concern.

A microfluidic card-based electrochemical assay for the detection of sulfonamide resistance genes

Most electroanalytical detection schemes for DNA markers require considerable time and effort from expert personnel to thoroughly follow the analysis and obtain reliable outcomes. This work aims to present an electrochemical assay performed inside a small card-based platform powered by microfluidic manipulation, requiring minimal human intervention and consumables. The assay couples a sample/signal dual amplification and DNA-modified magnetic particles for the detection of DNA amplification products. Particularly, the sul1 and sul4 genes involved in the resistance against sulfonamide antibiotics were analyzed. As recognized by the World Health Organization, antimicrobial resistance threatens global public health by hampering medication efficacy against infections. Consequently, analytical methods for the determination of such genes in environmental and clinical matrices are imperative. Herein, the resistance genes were extracted from E. coli cells and amplified using an enzyme-assisted isothermal amplification at 37 °C. The amplification products were analyzed in an easily-produced, low-cost, card-based set-up implementing a microfluidic system, demanding limited manual work and small sample volumes. The target amplicon was thus captured and isolated using versatile DNA-modified magnetic beads injected into the microchannel and exposed to the various reagents in a continuously controlled microfluidic flow. After the optimization of the efficiency of each phase of the assay, the platform achieved limits of detections of 44.2 pmol L-1 for sul1 and 48.5 pmol L-1 for sul4, and was able to detect down to ≥500-fold diluted amplification products of sul1 extracted from E. coli living cells in around 1 h, thus enabling numerous end-point analyses with a single amplification reaction.

Origin of Antibiotics and Antibiotic Resistance, and Their Impacts on Drug Development: A Narrative Review

Antibiotics have revolutionized medicine, saving countless lives since their discovery in the early 20th century. However, the origin of antibiotics is now overshadowed by the alarming rise in antibiotic resistance. This global crisis stems from the relentless adaptability of microorganisms, driven by misuse and overuse of antibiotics. This article explores the origin of antibiotics and the subsequent emergence of antibiotic resistance. It delves into the mechanisms employed by bacteria to develop resistance, highlighting the dire consequences of drug resistance, including compromised patient care, increased mortality rates, and escalating healthcare costs. The article elucidates the latest strategies against drug-resistant microorganisms, encompassing innovative approaches such as phage therapy, CRISPR-Cas9 technology, and the exploration of natural compounds. Moreover, it examines the profound impact of antibiotic resistance on drug development, rendering the pursuit of new antibiotics economically challenging. The limitations and challenges in developing novel antibiotics are discussed, along with hurdles in the regulatory process that hinder progress in this critical field. Proposals for modifying the regulatory process to facilitate antibiotic development are presented. The withdrawal of major pharmaceutical firms from antibiotic research is examined, along with potential strategies to re-engage their interest. The article also outlines initiatives to overcome economic challenges and incentivize antibiotic development, emphasizing international collaborations and partnerships. Finally, the article sheds light on government-led initiatives against antibiotic resistance, with a specific focus on the Middle East. It discusses the proactive measures taken by governments in the region, such as Saudi Arabia and the United Arab Emirates, to combat this global threat. In the face of antibiotic resistance, a multifaceted approach is imperative. This article provides valuable insights into the complex landscape of antibiotic development, regulatory challenges, and collaborative efforts required to ensure a future where antibiotics remain effective tools in safeguarding public health.

Design, Synthesis, and Biological Evaluation of Novel Camphor-Based Hydrazide and Sulfonamide Derivatives as Laccase Inhibitors against Plant Pathogenic Fungi/Oomycetes

To discover novel natural product-based fungicidal agrochemicals, 41 novel camphanic acid hydrazide and camphor sulfonamide derivatives were designed, synthesized, and tested for their antifungal profile against four plant pathogenic fungi and three oomycetes. As a result, some derivatives presented pronounced inhibitory activities toward Botryosphaeria dothidea, Fusarium graminearum, Phytophthora capsici, and Phytophthora nicotianae. Especially, compound 4b demonstrated the most potent anti-B. dothidea activity (EC50 = 1.28 mg/L), much stronger than positive control chlorthalonil. The in vivo assay showed that 4b displayed significant protective and curative effects on apple fruits infected by B. dothidea. The primary antifungal mechanism study revealed that 4b could obviously enhance the cell membrane permeability, destroy the mycelial surface morphology and the cell ultrastructure, and reduce the ergosterol and exopolysaccharide contents of B. dothidea. Further, 4b showed potent laccase inhibitory activity in vitro with an IC50 value of 11.3 μM, superior to positive control cysteine. The molecular docking study revealed that 4b could dock well into the active site of laccase by forming multiple interactions with the key residues in the pocket. The acute oral toxicity test in rats presented that 4b had slight toxicity with an LD50 value of 849.1 mg/kg bw (95% confidence limit: 403.9-1785.3 mg/kg bw). This research identified that the camphanic acid hydrazide derivatives could be promising leads for the development of novel laccase-targeting fungicides.

Nanosilver: An Old Antibacterial Agent with Great Promise in the Fight against Antibiotic Resistance

Antibiotic resistance in bacteria is a major problem worldwide that costs 55 billion USD annually for extended hospitalization, resource utilization, and additional treatment expenditures in the United States. This review examines the roles and forms of silver (e.g., bulk Ag, silver salts (AgNO3), and colloidal Ag) from antiquity to the present, and its eventual incorporation as silver nanoparticles (AgNPs) in numerous antibacterial consumer products and biomedical applications. The AgNP fabrication methods, physicochemical properties, and antibacterial mechanisms in Gram-positive and Gram-negative bacterial models are covered. The emphasis is on the problematic ESKAPE pathogens and the antibiotic-resistant pathogens of the greatest human health concern according to the World Health Organization. This review delineates the differences between each bacterial model, the role of the physicochemical properties of AgNPs in the interaction with pathogens, and the subsequent damage of AgNPs and Ag+ released by AgNPs on structural cellular components. In closing, the processes of antibiotic resistance attainment and how novel AgNP-antibiotic conjugates may synergistically reduce the growth of antibiotic-resistant pathogens are presented in light of promising examples, where antibiotic efficacy alone is decreased.

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.

A Review of Antibiotics, Antibiotic Resistant Bacteria, and Resistance Genes in Aquaculture: Occurrence, Contamination, and Transmission

Antibiotics are commonly used to prevent and control diseases in aquaculture. However, long-term/overuse of antibiotics not only leaves residues but results in the development of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Antibiotics, ARB, and ARGs are widespread in aquaculture ecosystems. However, their impacts and interaction mechanisms in biotic and abiotic media remain to be clarified. In this paper, we summarized the detection methods, present status, and transfer mechanisms of antibiotics, ARB, and ARGs in water, sediment, and aquaculture organisms. Currently, the dominant methods of detecting antibiotics, ARB, and ARGs are UPLC-MS/MS, 16S rRNA sequencing, and metagenomics, respectively. Tetracyclines, macrolides, fluoroquinolones, and sulfonamides are most frequently detected in aquaculture. Generally, antibiotic concentrations and ARG abundance in sediment are much higher than those in water. Yet, no obvious patterns in the category of antibiotics or ARB are present in organisms or the environment. The key mechanisms of resistance to antibiotics in bacteria include reducing the cell membrane permeability, enhancing antibiotic efflux, and structural changes in antibiotic target proteins. Moreover, horizontal transfer is a major pathway for ARGs transfer, including conjugation, transformation, transduction, and vesiculation. Identifying, quantifying, and summarizing the interactions and transmission mechanisms of antibiotics, ARGs, and ARB would provide useful information for future disease diagnosis and scientific management in aquaculture.

Perspectives on Usage of Functional Nanomaterials in Antimicrobial Therapy for Antibiotic-Resistant Bacterial Infections

The clinical applications of nanotechnology are emerging as widely popular, particularly as a potential treatment approach for infectious diseases. Diseases associated with multiple drug-resistant organisms (MDROs) are a global concern of morbidity and mortality. The prevalence of infections caused by antibiotic-resistant bacterial strains has increased the urgency associated with researching and developing novel bactericidal medicines or unorthodox methods capable of combating antimicrobial resistance. Nanomaterial-based treatments are promising for treating severe bacterial infections because they bypass antibiotic resistance mechanisms. Nanomaterial-based approaches, especially those that do not rely on small-molecule antimicrobials, display potential since they can bypass drug-resistant bacteria systems. Nanoparticles (NPs) are small enough to pass through the cell membranes of pathogenic bacteria and interfere with essential molecular pathways. They can also target biofilms and eliminate infections that have proven difficult to treat. In this review, we described the antibacterial mechanisms of NPs against bacteria and the parameters involved in targeting established antibiotic resistance and biofilms. Finally, yet importantly, we talked about NPs and the various ways they can be utilized, including as delivery methods, intrinsic antimicrobials, or a mixture.

Impact of short chain fatty acids (SCFAs) on antimicrobial activity of new β-lactam/β-lactamase inhibitor combinations and on virulence of Escherichia coli isolates

In a healthy gut microbiota, short chain fatty acids (SCFAs) are produced. The antibacterial action of SCFAs against intestinal pathogens makes them useful for ensuring the safety of food and human health. In this study, we aimed to assess the in vitro inhibitory activity of SCFAs, and to report, for the first time, their impact on the activity of new β-lactam/β-lactamase inhibitor combinations. The minimum inhibitory concentrations of acetic, propionic, and butyric acids were determined against E. coli clinical isolates recovered from gastrointestinal infections. Cefoperazone/sulbactam, ceftazidime/avibactam and cefepime/enmetazobactam are new β-lactam/β-lactamase inhibitor combinations that were studied for their combined therapeutic effects. Also, the effects of pH and concentration of SCFAs were evaluated on in vitro bacterial growth and expression of genes encoding for motility, adhesion, invasion, and biofilm formation. SCFAs were tested at concentrations of 12 mM at pH 7.4 (ileum-conditions), in addition to 60 mM and 123 mM, at pH 6.5 (colon-conditions). The tested SCFAs showed the same MIC (3750 μg ml-1 ≃ 60 mM) against all isolates. Furthermore, the addition of SCFAs to the tested β-lactam/β-lactamase inhibitor combinations greatly restored the susceptibility of the isolates. SCFAs had significant effect on bacterial growth and virulence in a pH and concentration-dependent manner; low ileal concentration potentiated E. coli growth, while higher colonic concentration significantly suppressed growth and down-regulated the expression of virulence genes (fliC, ipaH, FimH, BssS). Therefore, the significant inhibitory effect of colonic SCFAs on β-lactam/β-lactamase inhibitor combinations might lead to the development of promising treatment strategies.

Novel Camphor Sulfonohydrazide and Sulfonamide Derivatives as Potential Succinate Dehydrogenase Inhibitors against Phytopathogenic Fungi/Oomycetes

To discover novel fungicidal agrochemicals for treating wheat scab, 39 novel camphor sulfonohydrazide/sulfonamide derivatives 4a-4t and 6a-6s were designed and synthesized. In the in vitro antifungal/antioomycete assay, compounds 4g, 4n, and 4o displayed significant inhibitory activities against Fusarium graminearum, Botryosphaeria dothidea, and Phytophthora capsici. Among them, 4n exhibited the best antifungal activity against F. graminearum with an EC₅₀ value of 0.41 mg/L, which was at the same level as that of pydiflumetofen. The in vivo experiment revealed that 4n presented excellent protective and curative efficacy toward F. graminearum. In the antifungal mechanism study, 4n could increase the cell membrane permeability and reduce the exopolysaccharide and ergosterol content of F. graminearum. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed that 4n could significantly damage the surface morphology and the cell ultrastructure of mycelia to interfere with the growth of F. graminearum. Furthermore, 4n exhibited potent succinate dehydrogenase (SDH) inhibitory activity in vitro with an IC₅₀ value of 3.94 μM, which was equipotent to pydiflumetofen (IC₅₀ = 4.07 μM). The molecular dynamics simulation and docking study suggested that compound 4n could well occupy the active site and form strong interactions with the key residues of SDH. The above-mentioned results demonstrated that the title camphor sulfonohydrazide/sulfonamide derivatives could be promising lead compounds for further succinate dehydrogenase inhibitor (SDHI) fungicide development.

The History of Infectious Diseases and Medicine

From ancient times to the present, mankind has experienced many infectious diseases, which have mutually affected the development of society and medicine. In this paper, we review various historical and current infectious diseases in a five-period scheme of medical history newly proposed in this paper: (1) Classical Western medicine pioneered by Hippocrates and Galen without the concept of infectious diseases (ancient times to 15th century); (2) traditional Western medicine expanded by the publication of printed medical books and organized medical education (16th to 18th century); (3) early modern medicine transformed by scientific research, including the discovery of pathogenic bacteria (19th century); (4) late modern medicine, suppressing bacterial infectious diseases by antibiotics and elucidating DNA structure as a basis of genetics and molecular biology (20th century, prior to the 1980s); and (5) exact medicine saving human life by in vivo visualization and scientifically verified measures (after the 1990s). The historical perspectives that these five periods provide help us to appreciate ongoing medical issues, such as the present COVID-19 pandemic in particular, and remind us of the tremendous development that medicine and medical treatment have undergone over the years.

Drugs That Changed Society: Microtubule-Targeting Agents Belonging to Taxanoids, Macrolides and Non-Ribosomal Peptides

During a screening performed by the National Cancer Institute in the 1960s, the terpenoid paclitaxel was discovered. Paclitaxel expanded the treatment options for breast, lung, prostate and ovarian cancer. Paclitaxel is only present in minute amounts in the bark of Taxia brevifolia. A sustainable supply was ensured with a culture developed from Taxus chinensis, or with semi-synthesis from other taxanes. Paclitaxel is marketed under the name Taxol. An intermediate from the semi-synthesis docetaxel is also used as a drug and marketed as Taxotere. O-Methylated docetaxel is used for treatment of some paclitaxel-resistant cancer forms as cabazitaxel. The solubility problems of paclitaxel have been overcome by formulation of a nanoparticle albumin-bound paclitaxel (NAB-paclitaxel, Abraxane). The mechanism of action is affinity towards microtubules, which prevents proliferation and consequently the drug would be expected primarily to be active towards cancer cells proliferating faster than benign cells. The activity against slowly growing tumors such as solid tumors suggests that other effects such as oncogenic signaling or cellular trafficking are involved. In addition to terpenoids, recently discovered microtubule-targeting polyketide macrolides and non-ribosomal peptides have been discovered and marketed as drugs. The revolutionary improvements for treatment of cancer diseases targeting microtubules have led to an intensive search for other compounds with the same target. Several polyketide macrolides, terpenoids and non-ribosomal peptides have been investigated and a few marketed.

Management of clinical infections of Escherichia coli by new β-lactam/β-lactamase inhibitor combinations

Background and Objectives

Escherichia coli (E. coli) is an important member of Enterobacteriaceae family involved in severe infections. The increased rate of resistance towards different classes of antibiotics limits their treatment options. The aim of this study was to assess the in vitro activity of classical and novel combinations of β-lactam/β-lactamase inhibitor against E. coli clinical isolates.

Materials and Methods

140 clinical isolates of E. coli were collected from clinical specimens from Gastrointestinal Surgery Center (GISC) in Egypt. Extended spectrum β-lactamase (ESBL) was detected by double disk synergy test. Furthermore, the minimum inhibitory concentrations (MICs) for five different combinations were determined using the broth microdilution method including: amoxicillin/clavulanate and ampicillin/sulbactam as an example for classical combinations and cefoperazone/sulbactam, ceftazidime/avibactam, and cefepime/enmetazobactam as an example for new combinations.

Results

The percentage of ESBL production among the tested isolates was 46.4%. Isolates were highly resistant to classical β-lactam/β-lactamase inhibitor combinations, where (40.7%) and (42.9%) of isolates were resistant to amoxicillin/clavulanate and ampicillin/sulbactam, respectively. While new β-lactam/β-lactamase inhibitor combinations had promising inhibitory action. The addition of novel β-lactamase inhibitors restored the susceptibility of isolates, where (94.3%) of isolates became susceptible to ceftazidime/avibactam combination, followed by cefoperazone/sulbactam (89.2%) and cefepime/enmetazobactam (85.7%). The synergistic effect seems to be effective where ceftazidime and avibactam were synergistic in 80% of isolates.

Conclusion

The antibacterial activity of some antimicrobial agents can be enhanced by the addition of new β-lactamase inhibitors. Further in vivo investigation is needed to confirm their therapeutic efficacy against local isolates.

Ligation Motifs in Zinc-Bound Sulfonamide Drugs Assayed by IR Ion Spectroscopy

The sulfonamide–zinc ion interaction, performing a key role in various biological contexts, is the focus of the present study, with the aim of elucidating ligation motifs in zinc complexes of sulfa drugs, namely sulfadiazine (SDZ) and sulfathiazole (STZ), in a perturbation-free environment. To this end, an approach is exploited based on mass spectrometry coupled with infrared multiple photon dissociation (IRMPD) spectroscopy backed by quantum chemical calculations. IR spectra of Zn(H2O+SDZ−H)+ and Zn(H2O+STZ−H)+ ions are consistent with a three-coordinate zinc complex, where ZnOH+ binds to the uncharged sulfonamide via N(heterocycle) and O(sulfonyl) donor atoms. Alternative prototropic isomers Zn(OH2)(SDZ−H)+ and Zn(OH2)(STZ−H)+ lie 63 and 26 kJ mol−1 higher in free energy, respectively, relative to the ground state Zn(OH)(SDZ)+ and Zn(OH)(STZ)+ species and do not contribute to any significant extent in the sampled population.

The Ascension of Targeted Covalent Inhibitors

Covalent drugs have made a major impact on human health but until recently were shunned by the pharmaceutical industry over concerns about the potential for toxicity. A resurgence has occurred driven by the clinical success of targeted covalent inhibitors (TCIs), with eight drugs approved over the past decade. The opportunity to create unique drugs by exploiting the covalent mechanism of action has enabled clinically decisive target product profiles to be achieved. TCIs have revolutionized the treatment paradigm for non-small-cell lung cancer and chronic lymphocytic leukemia. This Perspective will highlight the clinical and financial success of this class of drugs and provide early insight into toxicity, a key factor that had hindered progress in the field. Further innovation in the TCI approach, including expanding beyond cysteine-directed electrophiles, kinases, and cancer, highlights the broad opportunity to deliver a new generation of breakthrough therapies.

The importance of sulfur-containing motifs in drug design and discovery

INTRODUCTION

Sulfur-containing functional groups are privileged motifs that occur in various pharmacologically effective substances and several natural products. Various functionalities are found with a sulfur atom at diverse oxidation states, as illustrated by thioether, sulfoxide, sulfone, sulfonamide, sulfamate, and sulfamide functions. They are valuable scaffolds in the field of medicinal chemistry and are part of a large array of approved drugs and clinical candidates.

AREA COVERED

Herein, the authors review the current research on the development of organosulfur-based drug discovery. This article also covers details of their roles in the new lead compounds reported in the literature over the past five years 2017-2021.

EXPERT OPINION

Given its prominent role in medicinal chemistry and its importance in drug discovery, sulfur has attracted continuing interest and has been used in the design of various valuable compounds that demonstrate a variety of biological and pharmacological feature activities. Overall, sulfur's role in medicinal chemistry continues to grow. However, many sulfur functionalities remain underused in small-molecule drug discovery and deserve special attention in the armamentarium for treating diverse diseases. Research efforts are also still required for the development of a synthetic methodology for direct access to these functions and late-stage functionalization.