
Abdelrahman S MayhoubAl-Azhar University · College of Pharmacy
Abdelrahman S Mayhoub
PhD
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79
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Introduction
Additional affiliations
May 2012 - present
September 2008 - April 2012
August 2004 - August 2008
Publications
Publications (79)
The coexistence of Gram‐negative organisms, such as Acinetobacter baumannii and methicillin‐resistant Staphylococcus aureus (MRSA) in diabetic foot ulcers poses significant therapeutic challenges and increases the rate of treatment failure. By studying the structure‐activity relationships of small alkynylphenyl‐aminoguanidine molecules, we identifi...
The discovery of novel antibacterial agents holds promise in mitigating the escalating threat of antimicrobial resistance (AMR). Guided by the structure-activity relationships (SAR) of our lead compound 1 against MRSA, we developed novel anti-MRSA compounds with a repositioned lipophilic tail from para to meta position. This strategic modification...
The structure–activity relationship of a new tert-butylphenylthiazole series, with a pyrimidine linker, was investigated. We wished to expand knowledge of this novel class of antibiotics by generating 21 new derivatives bearing ≥2 heteroatoms in their side chains. Their activity was examined against isolates of methicillin-resistant Staphylococcus...
The combination of antibacterial and antiviral agents is becoming a very important aspect of dealing with resistant bacterial and viral infections. The N ‐phenylthiazole scaffold was found to possess significant anti‐MRSA, antifungal, and anti‐COVID‐19 activities as previously published; hence, a slight refinement was proposed to attach various alk...
Antimicrobial resistance has become a concern as a worldwide threat. A novel scaffold of phenylthiazoles was recently evaluated against multidrug-resistant Staphylococci to control the emergence and spread of antimicrobial resistance, showing good results. Several structural modifications are needed based on the structure-activity relationships (SA...
With the continuous and alarming threat of exhausting the current antimicrobial arsenals, efforts are urgently needed to develop new effective ones. In this study, the antibacterial efficacy of a set of structurally related acetylenic-diphenylurea derivatives carrying the aminoguanidine moiety was tested against a panel of multidrug-resistant Gram-...
Antimicrobial resistance is an aggravating global issue therefore it has been under extensive research in an attempt to reduce the number of antibiotics that are constantly reported as obsolete jeopardizing the lives of millions worldwide. Thiazoles possess a reputation as one of the most diverse biologically active nuclei, and phenylthiazoles are...
Exploring the structure–activity relationships (S.A.R.) of a new set of phenylpyrazoles unveiled a potential anti‐enterococcus lead compound 12. The benzofuran moiety linked to the phenylpyrazole 12 was 32 times better than vancomycin against Enterococcus faecalis ATCC 51299. Besides, compound 12 is expected to have an excellent oral bioavailabilit...
The thiazole scaffold is an essential structural foundation in a plethora of pharmaceutical products having an extensive array of biological activities. Consequently, its synthesis has been extensively discussed in the literature. In this mini review, we have summarized the recent advances of thiazole synthesis covering articles published between 2...
A set of structurally related diphenylurea derivatives bearing aminoguanidine moiety were synthesized, and their antibacterial activity was assessed against a panel of multi-drug resistant Gram-positive clinical isolates. Two compounds 6 and 24 were identified with better bacteriological profile than the lead compound I. The multi-step resistance d...
To minimize the intrinsic toxicity of the antibacterial agent hydrazinyloxadiazole 1, the hydrazine moiety was replaced with ethylenediamine (compound 7). This replacement generated a potent antifungal agent with no antibacterial activity. Notably, use of a 1,2-diaminocyclohexane moiety, as a conformationally-restricted isostere for ethylenediamine...
Exploring the structure-activity-relationship (SAR) at the cationic part of arylthiazole antibiotics revealed hydrazine as an active moiety. The main objective of the study is to overcome the inherited-toxicity associated with the free-hydrazine. A series of hydrocarbon bridges was inserted in between, to separate the two amino groups. Hence, the a...
The rise of extensive and multidrug-resistant strains of Neisseria gonorrhoeae has occurred in parallel with the increasing demand for new drugs. However, the current methods of drug discovery are burdened with rigorous assessments and requires more time than can be spared until gonococcal infections become hard to control. To address this urgency,...
The increasing emergence of antibiotic-resistant bacterial pathogens calls for additional urgency in the development of new antibacterial candidates. N-Phenyl-2-aminothiazoles are promising candidates that possess potent anti-MRSA activity and could potentially replenish the MRSA antibiotic pipeline. The initial screen of a series of compounds in t...
The limited number of antifungals and the rising frequency of azole-resistant Candida species are growing challenges to human medicine. Drug repurposing signifies an appealing approach to enhance the activity of current antifungal drugs. Here, we evaluated the ability of Pharmakon 1600 drug library to sensitize an azole-resistant Candida albicans t...
Azole antifungals are vital therapeutic options for treating invasive mycotic infections. However, the emergence of azole-resistant isolates combined with limited therapeutic options presents a growing challenge in medical mycology. To address this issue, we utilized microdilution checkerboard assays to evaluate nine stilbene compounds for their ab...
Clostridium difficile is a leading cause of morbidity and mortality particularly in hospital settings. In addition, treatment is very challenging due to the scarcity of effective therapeutic options. Thus, there remains an unmet need to identify new therapeutic agents capable of treating C. difficile infections. In the current study, we screened tw...
Studying the structure-activity relationships (SAR) of oxadiazolylthiazole antibiotics unexpectedly led us to identify ethylenediamine- and propylenediamine-analogs as potential antimycotic novel lead structures. Replacement of the ethylenediamine moiety for the lead compound 7 with cis-diaminocyclohexyl group (compound 18) significantly enhanced t...
Candida species are a leading source of healthcare infections globally. The limited number of antifungal drugs combined with the isolation of Candida species, namely C. albicans and C. auris, exhibiting resistance to current antifungals necessitates the development of new therapeutics. The present study tested 85 synthetic phenylthiazole small mole...
The U.S. Centers for Disease Control and Prevention (CDC) lists Neisseria gonorrhoeae as one of the most urgent antibiotic-resistant threats in the United States. This is due to the emergence of clinical isolates that have developed resistance to nearly every antibiotic used to treat gonorrhea and highlights the critical need to find new therapeuti...
Bacterial resistance to antibiotics is presently one of the most pressing healthcare challenges and necessitates discovering new antibacterials with unique chemical scaffolds. However, determining the optimal balance between structural requirements for pharmacological action and pharmacokinetic properties of novel antibacterial compounds is a signi...
Compounds with high lipophilic properties are often associated with bad physicochemical properties, triggering many off-targets, and less likely to pass clinical trials. Two metabolically stable phenylthiazole antibiotic scaffolds having notable high lipophilic characters, one with alkoxy side chain and the other one with alkynyl moiety, were deriv...
The discovery of 3rd and 4th generations of currently existing classes of antibiotics has not hindered bacterial resistance, which is escalating at an alarming global level. This review follows WHO recommendations through implementing new criteria for newly discovered antibiotics. These recommendations focus on abandoning old scaffolds and hitting...
Antibiotic resistance remains a pressing medical challenge for which novel antibacterial agents are urgently needed. The phenylthiazole scaffold represents a promising platform to develop novel antibacterial agents for drug-resistant infections. However, enhancing the physicochemical profile of this class of compounds remains a challenging endeavor...
The narrow antibacterial spectrum of phenylthiazole antibiotics was expanded by replacing the central thiazole with a pyrazole ring while maintaining its other pharmacophoric features. The most promising derivative, compound 23, was more potent than vancomycin against MDR-Gram-positive clinical isolates, including vancomycin- and linezolid-resistan...
A novel series of phenylthiazoles bearing cyclic amines at the phenyl-4 position was prepared with the objective of decreasing lipophilicity and improving the overall physicochemical properties and pharmacokinetic profile of the compounds. Briefly, the piperidine ring (compounds 10 and 12) provided the best ring size in terms of antibacterial activ...
The limited number of systemic antifungals and the emergence of azole-resistant Candida species constitute a growing challenge to human medicine. Combinatorial drug therapy represents an appealing approach to enhance the activity of, or restore the susceptibility to current antifungals. Here, we evaluated the fluconazole chemosensitization activity...
The structure-activity and structure-kinetic relationships of a new tert-butylphenylthiazole series with oxadiazole linkers were conducted with the objective of obtaining a new orally available antibacterial compounds. Twenty-two new compounds were prepared, purified and identified. Their activity against methicillin-resistant Staphylococcus aureus...
Chloramphenicol nitroreductase (CNR), a drug-modifying enzyme from Haemophilus influenzae, has been shown to be responsible for the conversion of the nitro group into an amine in the antibiotic chloramphenicol (CAM). Since CAM structurally bears a 4-nitrobenzene moiety, we explored the substrate promiscuity of CNR by investigating its nitroreductio...
Thirty-two new naphthylthiazole derivatives were synthesized with the aim of exploring their antimicrobial effect on multidrug-resistant Gram-positive bacteria. Compounds 25 and 32, with ethylenediamine and methylguanidine side chains, represent the most promising derivatives, as their antibacterial spectrum includes activity against multidrug-resi...
With the continued rise of antibiotic resistance and reduced susceptibility to almost all front-line antibiotics, multidrug-resistant Gram-positive bacterial infections represent an incessant threat to healthcare providers. This study presents a new series of phenylthiazole compounds where two active moieties were combined into one scaffold. The an...
A common cause of resistance to kanamycin (KAN) in tuberculosis is overexpression of the enhanced intracellular survival (Eis) protein. Eis is an acetyltransferase that multiacetylates KAN and other aminoglycosides, rendering them unable to bind the bacterial ribosome. By high-throughput screening, a series of substituted 1,2,4-triazino[5,6b]indole...
A new series of phenylthiazoles with t-butyl lipophilic component was synthesized and their antibacterial activity against a panel of multidrug-resistant bacterial pathogens was evaluated. Five compounds demonstrated promising antibacterial activity against methicillin-resistant staphylococcal strains and several vancomycin-resistant staphylococcal...
Invasive candidiasis presents an emerging global public health challenge due to the emergence of resistance to the frontline treatment options, such as fluconazole. Hence, the identification of other compounds capable of pairing with fluconazole and averting azole-resistance would potentially prolong the clinical utility of this important group. In...
The promising activity of phenylthiazoles against multidrug-resistant bacterial pathogens, in particular MRSA, has been hampered by their limited systemic applicability, due to their rapid metabolism by hepatic microsomal enzymes, resulting in short half-lives. Here, we investigated a series of phenylthiazoles with alkynyl side-chains that were syn...
Bacterial resistance to antibiotics remains an imposing global public health challenge. Of the most serious pathogens, methicillin-resistant Staphylococcus aureus (MRSA) is problematic given strains have emerged that exhibit resistance to several antibiotic classes including β-lactams and agents of last resort such as vancomycin. New antibacterial...
The emergence of antibiotic-resistant bacterial species, such as vancomycin-resistant enterococci (VRE), necessitates the development of new antimicrobials. Here, we investigate the spectrum of antibacterial activity of three phenylthiazole-substituted aminoguanidines. These compounds possess potent activity against VRE, inhibiting growth of clinic...
A new class of diphenylurea was identified as a novel antibacterial scaffold with an antibacterial spectrum that includes highly resistant staphylococcal isolates, namely methicillin-and vancomycin-resistant Staphylococcus aureus (MRSA & VRSA). Starting with a lead compound 3 that carries an aminoguanidine functionality from one side and a n-butyl...
Bacterial resistance to conventional antibiotics is an increasingly serious threat to public health worldwide that requires immediate exploration and the development of novel antimicrobial compounds. Drug repurposing is an inexpensive and untapped source of new antimicrobial leads, and it holds many attractive features warranting further attention...
Antibacterial resistance is a pressing global health challenge that necessitates the development of new therapeutic agents. Phenylthiazole antibacterial agents have been extensively studied, by our group, as a potential novel class of antibiotics to circumvent the scourge of antibacterial resistance. Previously, the phenylthiazole lead compound 1 w...
A series of second-generation analogues for 2-(1-(2-(4-butylphenyl)-4-methylthiazol-5-yl)ethylidene)aminoguanidine (1) have been synthesized and tested against methicillin-resistant Staphylococcus aureus (MRSA). The compounds were designed with the objective of improving pharmacokinetic properties. This main aim has been accomplished by replacing t...
The usefulness of non-steroidal anti-inflammatory drugs (NSAIDs) is hampered by their gastrointestinal side effects. Non-selective cyclooxygenases inhibitors interfere with both COX-1 and COX-2 isozymes. Since COX-1 mediates cytoprotection of gastric mucosa, its inhibition leads to the undesirable side effects. On the other hand, COX-2 is undetecta...
Staphylococcus pseudintermedius is a commensal organism of companion animals that is a significant source of opportunistic infections in dogs. With the emergence of clinical isolates of S. pseudintermedius (chiefly methicillin-resistant S. pseudintermedius (MRSP)) exhibiting increased resistance to nearly all antibiotic classes, new antimicrobials...
Type 2 diabetes mellitus is a vast growing progressive disease that almost affects one person among every twelve globally. Regardless the availability of wide variety of oral hypoglycemics, only one third of patients achieves proper glycemic control. With the advantage of the low risk of hypoglycemia, DPP-IV attracted the attention of medicinal che...
The aim of this part of the project was to design and synthesize new phenylthaizoles with longer duration of action, enhanced bactericidal activity, improved toxicity profile and lowered induction of bacterial resistance.
Methicillin-resistant Staphylococcus aureus (MRSA) infections are a leading cause of death among all fatalities caused by antibiotic-resistant bacteria. With the rise of increasing resistance to current antibiotics, new antimicrobials and treatment strategies are urgently needed. Thiazole compounds have been shown to possess potent antimicrobial ac...
Methicillin- and vancomycin-resistant Staphylococcus aureus (MRSA & VRSA) infections are growing global health concerns. Structure-activity-relationships of phenylthiazoles as a new antimicrobial class have been addressed. We present 10 thiazole derivatives that exhibit strong activity against 18 clinical strains of MRSA and VRSA with acceptable PK...
The number of people suffering from Alzheimer's disease (AD) is expected to increase dramatically in the coming decades. Currently, acetylcholinesterase inhibitors (AChEis) provide some relief of cognitive symptoms, while newer approaches, such as amyloid-β (Aβ)-targeted metal chelation, offer potential hope for slowing and/or reversing disease pro...
The number of people suffering from Alzheimer's disease (AD) is expected to increase dramatically in the coming years, placing a huge burden on society. Current treatments for AD leave much to be desired, and numerous research efforts around the globe are focused on developing improved therapeutics. In addition, current diagnostic tools for AD rely...
Objectives:
The enhanced intracellular survival (Eis) protein from Mycobacterium tuberculosis (Eis_Mtb), a regio-versatile N-acetyltransferase active towards many aminoglycosides (AGs), confers resistance to kanamycin A in some cases of extensively drug-resistant tuberculosis (XDR-TB). We assessed the activity of Eis_Mtb and of its homologue from...
The Mycobacterium tuberculosis enhanced intracellular survival (Eis_Mtb) protein is a clinically important aminoglycoside (AG) multi-acetylating enzyme. Eis homologues are found in a variety of mycobacterial and non-mycobacterial species. Variation of the residues lining the AG-binding pocket and positions of the loops bearing these residues in the...
Hepatitis C virus (HCV), like many other flaviviruses, is widely distributed worldwide with estimated chronically infected victims between 170 and 200 million. HCV inherent error-prone RNA-dependent RNA polymerase (RdRp) is an attractive target for medicinal chemists because of the conservative nature of NS5B nucleotide-binding site. In addition, t...
Introduction:
Pyrazolines are well-known and important nitrogen-containing five-membered ring heterocyclic compounds. Various methods have been worked out for their synthesis. Several pyrazoline derivatives have been found to possess diverse biological properties, which has stimulated research activity in this field.
Areas covered:
The present r...
Chemoprevention is an approach to decrease cancer morbidity and mortality through inhibition of carcinogenesis and prevention of disease progression. Although the trans stilbene derivative resveratrol has chemopreventive properties, its action is compromised by weak non-specific effects on many biological targets. Replacement of the stilbene ethyle...
Aryl thioamides undergo a very rapid condensation in the presence of methyl bromocyanoacetate to provide quantitative yields of 3,5-diaryl-1,2,4-thiadiazoles with easy work-up and a high degree of product purity. The method can be scaled up with no loss in efficiency.
To improve the treatment of breast cancer, there has been a need for alternative aromatase inhibitors (AIs) that bring about adequate aromatase inhibition, while limiting side effects. Since two tamoxifen metabolites have been documented as AIs, we tested a wide range of tamoxifen metabolites on aromatase in order to better understand structural in...
A series of third-generation analogues of methyl 4-(dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxylate (1), which had the most potent antiviral activity among the first- and second-generation compounds, have been synthesized and tested against yellow fever virus using a cell-based assay. The compounds were designed with the objectives of impro...
The versatile hitherto unreported 3-[(E)-3-(dimethylamino)acryloyl]-1,5-diphenyl-1H-pyrazole-4-carbonitrile (3) was prepared via the reaction of 3-acetyl-1,5-diphenyl-1H-pyrazole-4-carbonitrile (1) with dimethylformamid-dimethylacetal (DMF-DMA). The latter product and 3-((E)-3-morpholin-4-yl-acryloyl)-1,5-diphenyl-1H-pyrazole-4-carbonitrile (4) und...
Several 4-cyano-1,5-diphenylpyrazoles attached to different heterocyclic ring systems at position 3 were synthesized starting from ethyl 4-cyano-1,5-diphenyl-1H-pyrazole-3-carboxylate 1. The newly synthesized compounds were tested in vivo for their anti-estrogenic effects and evaluated in vitro for their cytotoxic properties against estrogen-depend...