Dihydrofolate Reductase Research Articles

Modeling of new potential inhibitors of dihydrofolate reductase based on 1,3,4-thiadiazole amidoalkyl derivatives

Derivatives of 1,3,4-thiadiazole are very important for medical chemistry and pharmacy as potential drug substances. In this work, we carried out molecular docking studies of amidoalkyl derivatives of 1,3,4-thiadiazole: N-(2,2,2-trichloro-1-((5-aryl-1,3,4-thiadiazol-2-yl)amino)ethyl)carboxamides and N-(2,2,2-trichloro-1-((5-(arylamino)-1,3,4-thiadiazol-2-yl)amino)ethyl)carboxamides with dihydrofolate reductase (DHFR). The AutoDock Vina program based on the PyRx 0.8 platform was used for docking. Before docking, the enzyme structure (PDB ID: 1DLS) was prepared using the Chimera 1.14 program, and the structures of potential inhibitors and reference preparations were optimized by the PM3 method in the ArgusLab 4.0.1 program. According to the results of molecular docking, the analyzed compounds effectively interact with the active site of DHFR. It is shown that the introduction of an NH group between the 1,3,4-thiadiazole and aromatic rings leads to stronger binding of ligands to DHFR. Based on the results of molecular docking, the following hit compounds were selected: 4-methyl-N-(2,2,2-trichloro-1-((5-(phenylamino)-1,3,4-thiadiazol-2-yl)amino)ethyl)benzamide and 4-methyl-N-(2,2,2-trichloro-1-((5-(p-tolylamino)-1,3,4-thiadiazol-2-yl)amino)ethyl)benzamide, which are superior to the reference compounds according to the strength of the formed complex.

Plasmodium falciparum Genetic Diversity and Resistance Genotype Profile in Infected Placental Samples Collected After Delivery in Ouagadougou.

Intermittent preventive treatment with sulfadoxine-pyrimethamine is widely used for the prevention of malaria in pregnant women in Africa. Known resistance cases of sulfadoxine-pyrimethamine during pregnancy need to be follow up to support IPTp implementation in Burkina Faso. However, data on the development and spread of resistance to this molecule are lacking. This study aimed to investigating the genetic diversity of P. falciparum and the mutation prevalence in the dhfr and dhps genes infected from postpartum infected placentas. This was a prospective and cross-sectional study conducted between April 2019 and March 2020 in four health districts of Ouagadougou capital city. From the placentas collected after delivery, P. falciparum detection and mps1 and msp2 polymorphism analysis were performed by nested PCR. The resistance profile was checked after analyzing the mutation point on dhfr and dhps genes. PCR-positive samples were estimated at 96% for msp1 and 98% for msp2. The polymorphism analysis showed that the RO33 and 3D7 allelic families were the most widespread with 62.5% and 91.83%, respectively. Multiple infections by msp1 and msp2 were frequent with 12.50% and 92.92%, respectively. The prevalence of individual dhfr mutation point, 51I, 108A, and 59R, was 1.96, 15.68, and 7.84, respectively, and the dhps mutation point, 437G, was 3.92. There is no detected mutation at the point 164L and 540E. The triple (51I+108A+59R) in dhfr and quadruple (51I+108A+59R+ 437G) mutation were not found. The results showed that Plasmodium falciparum has a high genetic diversity of msp1 and msp2. This suggests that dhfr and dhps mutant genotypes are potential early warning factors in the increase in the sulfadoxine-pyrimethamine resistance.

Comparative Genomic Analysis Reveals the Emergence of ST-231 and ST-395 Klebsiella pneumoniae Strains Associated with the High Transmissibility of blaKPC Plasmids.

Conjugative transposons in Gram-negative bacteria have a significant role in the dissemination of antibiotic-resistance-conferring genes between bacteria. This study aims to genomically characterize plasmids and conjugative transposons carrying integrons in clinical isolates of Klebsiella pneumoniae. The genetic composition of conjugative transposons and phenotypic assessment of 50 multidrug-resistant K. pneumoniae isolates from a tertiary-care hospital (SQUH), Muscat, Oman, were investigated. Horizontal transferability was investigated by filter mating conjugation experiments. Whole-genome sequencing (WGS) was performed to determine the sequence type (ST), acquired resistome, and plasmidome of integron-carrying strains. Class 1 integrons were detected in 96% of isolates and, among integron-positive isolates, 18 stains contained variable regions. Horizontal transferability by conjugation confirmed the successful transfer of integrons between cells and WGS confirmed their presence in conjugative plasmids. Dihydrofolate reductase (dfrA14) was the most prevalent (34.8%) gene cassette in class 1 integrons. MLST analysis detected predominantly ST-231 and ST-395. BlaOXA-232 and blaCTX-M-15 were the most frequently detected carbapenemases and beta-lactamases in the sequenced isolates. This study highlighted the high transmissibility of MDR-conferring conjugative plasmids in clinical isolates of K. pneumoniae. Therefore, the wise use of antibiotics and the adherence to effective infection control measures are necessary to limit the further dissemination of multidrug-resistant bacteria.

B-149 Next-generation Sequencing Via Targeted Metagenomics for Broad Antimicrobial Resistance Surveillance

Abstract Background Antimicrobial-resistant infections secondary to the overuse of antibiotics are a major public health threat. The standard of care for identifying resistance is antimicrobial susceptibility testing, the phenotypic characterization of minimum inhibitory concentrations (mic) for antibiotics in the presence of bacterial growth, but these methods are labor intensive, have long turnaround times, and face challenges with non-cultivable bacteria. Molecular methods for antimicrobial resistance (AMR) ascertainment are high-throughput, robust, and sensitive and have gained interest as a genotypic complement to traditional phenotypic methods. Since the COVID-19 pandemic, next-generation sequencing has emerged as the leading technology for tracking and surveillance of infectious diseases and antimicrobial resistance, emphasizing the need for flexible sequencing panels that are easily interchangeable and capable of detecting pathogens and AMR genes. Methods In a collaboration between Illumina, a national retail pharmacy, and Aegis Sciences Corporation, residual, self-collected nasal swab samples (n = 4390) submitted for COVID-19 testing from patients across the U.S. were sequenced using the Respiratory Pathogen ID/AMR Panel (RPIP, Illumina – For Research Use Only), a target capture-based next-generation sequencing panel targeting 282 respiratory pathogens and 2097 relevant AMR markers. Sequencing data was analyzed using the Explify RPIP Analysis app (BaseSpace, Illumina) and paired with self-reported patient data submitted via an online questionnaire. Data including pathogens and anti-microbial resistance (AMR) genes detected, age, race, gender, residing state of the patient, collection month, self-reported symptoms, and health risks were collated, imported into Microsoft PowerBI software, and used to create interactive visuals for a surveillance dashboard. Results In this cohort of sequenced specimens, 85.1% (n = 3576) had one or more viral, bacterial, or fungal pathogens present, 41% (n = 1816) had one or more AMR genes present, and 38.4% (n = 1685) had one or more pathogens and AMR genes co-detected. Twenty-six different AMR genes were identified with the most prevalent being Erm 23S ribosomal RNA methyltransferase (65.5%; n = 1115). Erm was identified in samples from all 50 US states and was co-detected with staphylococcus aureus (18.2%; n = 216) and streptococcus pneumoniae (4.9%; n = 57), among others. Following Erm in prevalence, this cohort of samples harbored genes for trimethoprim resistant dihydrofolate reductase (dfr = 27.9%), tetracycline-resistant ribosomal protection protein (tet = 21.0%), and macrolide phosphotransferase (MPH = 14.2%). The data also revealed AMR gene-pathogen co-detections listed as CDC serious threats, such as the mecA gene responsible for methicillin resistance in staphylococcal species. The mecA gene was co-detected in 5.3% (n = 28) of staphylococcus aureus positive samples in this cohort. Finally, although not classified as a serious threat, neuraminidase inhibitor resistance, associated with less susceptibility to anti-virals, was found in 12% (n = 15) of all influenza A (H3N2) infected samples (n = 112). Conclusions Completion of these studies demonstrated that next-generation sequencing using targeted metagenomics with RPIP is a cost effective, high-throughput option for large-scale surveillance of AMR genes in potential respiratory infections.

Revelation of potential drug targets of luteolin in Plasmodium falciparum through multi-target molecular dynamics simulation studies

In-silico techniques offer a fast, accurate, reliable, and economical approach to studying the molecular interactions between compounds and proteins. In this study, our main aim is to use in-silico techniques as a rational approach for the prediction of the molecular drug targets for luteolin against Plasmodium falciparum. Multi-target molecular docking, 100 nanoseconds (ns) molecular dynamics (MD) simulations, and Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) binding free energy calculations were carried out for luteolin against dihydrofolate reductase thymidylate synthase (PfDHFR-TS), dihydroorotate dehydrogenase (PfDHODH), and falcipain-2. The native ligands of each protein were used as a reference to evaluate the performance of luteolin. Luteolin outperformed the native ligands of all proteins at molecular docking and MD simulations studies. However, in the MM-GBSA calculations, luteolin outperformed the native ligand of only PfDHFR-TS but not PfDHODH and falcipain-2. Among the studied proteins, the in-silico approach predicted PfDHFR-TS as the most favorable drug target for luteolin. Communicated by Ramaswamy H. Sarma

Biofabrication of Acer palmatum-Mediated Multifunctional CuO Nanoparticles for Dye Removal, Antibacterial-Antifungal Activity, and Molecular Docking.

Copper oxide nanoparticles (CuONPs) are used in many fields from electronics to medicine due to their multifunctionality, and therefore, their production with environmentally friendly methods is a current issue. In this study, biofabricated CuONPs were obtained by using the leaf extract of Acer palmatum plant originating from the Far East to enlighten the characteristics of the novel nanoparticles differentiating from those existing in the literature. Multifunctional nature of the CuONPs was evaluated by the antibacterial, antifungal, and decolorative applications and also by performing molecular docking analysis. The fabricated CuONPs were characterized using ultraviolet-visible spectroscopy (UV-vis), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and dynamic light scattering (DLS). The absorbance seen at 270 nm in the SPR band obtained by UV-vis spectroscopy proved the presence of CuONPs, while the 602, 560, and 540 cm-1 vibrations obtained in the FT-IR spectroscopy indicated the same result. SEM images proved that the nanoparticles were in spherical form with sizes ranging from 140 to 225 nm. The result of DLS analysis showed that the average particle size was 229 nm in diameter, and CuONPs had monodisperse systems (polydispersity index, 0.184). The dye removal potency of CuONPs was also investigated by using remazol brilliant blue R (RBBR) and napthol blue black (NBB). Decolorizations (74 and 86%) of RBBR and NBB were obtained in 90 min at 50 °C, respectively. The strong antibacterial properties of the synthesized CuONPs were observed on both Gram (-) and Gram (+) bacterial strains by disk diffusion and optical analyses, and their antifungal activity was close to that of Amphotericin B, which was applied as a positive control. Molecular docking analysis was performed with Escherichia coli dihydrofolate reductase and Staphylococcus aureus DNA Gyrase B to analyze the antibacterial mechanisms of CuONP and observed that they exhibit good interactions with their targets with binding energies of -12.562 and -8.797 kcal/mol, respectively. Our findings suggested that CuONPs are crucial in the mechanisms of folate metabolism and DNA replication associated with bacterial proliferation. This work will provide significant guidance for the biofabrication of CuONPs and their medical and industrial applications.

Synthesis and dihydrofolate reductase inhibitory activity of 2-amino-6-(arylaminomethyl) thieno[2,3-d]pyrimidin-4(3H)-ones

Synthesis and dihydrofolate reductase inhibitory activity of 2-amino-6-(arylaminomethyl) thieno[2,3-d]pyrimidin-4(3H)-ones

Dual-Target Mycobacterium tuberculosis Inhibition: Insights into the Molecular Mechanism of Antifolate Drugs.

The escalating prevalence of drug-resistant strains of Mycobacterium tuberculosis has posed a significant challenge to global efforts in combating tuberculosis. To address this issue, innovative therapeutic strategies are required that target essential biochemical pathways while minimizing the potential for resistance development. The concept of dual targeting has gained prominence in drug discovery against resistance bacteria. Dual targeting recognizes the complexity of cellular processes and disrupts more than one vital pathway, simultaneously. By inhibiting more than one essential process required for bacterial growth and survival, the chances of developing resistance are substantially reduced. A previously reported study investigated the dual-targeting potential of a series of novel compounds against the folate pathway in Mycobacterium tuberculosis. Expanding on this study, we investigated the predictive pharmacokinetic profiling and the structural mechanism of inhibition of UCP1172, UCP1175, and UCP1063 on key enzymes, dihydrofolate reductase (DHFR) and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate reductase (RV2671), involved in the folate pathway. Our findings indicate that the compounds demonstrate lipophilic physiochemical properties that promote gastrointestinal absorption, and may also inhibit the drug-metabolizing enzyme, cytochrome P450 3A4, thus enhancing their biological half-life. Furthermore, key catalytic residues (Serine, Threonine, and Aspartate), conserved in both enzymes, were found to participate in vital molecular interactions with UCP1172, which demonstrated the most favorable free binding energies to both DHFR and RV2671 (-41.63 kcal/mol, -48.04 kcal/mol, respectively). The presence of characteristic loop shifts, which are similar in both enzymes, also indicates a common inhibitory mechanism by UCP1172. This elucidation advances the understanding of UCP1172's dual inhibition mechanism against Mycobacterium tuberculosis.

Exploration and Biological Evaluation of 1,3-Diamino-7H-pyrrol[3,2-f]quinazoline Derivatives as Dihydrofolate Reductase Inhibitors.

Dihydrofolate reductase (DHFR), a core enzyme of folate metabolism, plays a crucial role in the biosynthesis of purines and thymidylate for cell proliferation and growth in both prokaryotic and eukaryotic cells. However, the development of new DHFR inhibitors is challenging due to the limited number of scaffolds available for drug development. Hence, we designed and synthesized a new class of DHFR inhibitors with a 1,3-diamino-7H-pyrrol[3,2-f]quinazoline derivative (PQD) structure bearing condensed rings. Compound 6r exhibited therapeutic effects on mouse models of systemic infection and thigh infection caused by methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300. Moreover, methyl-modified PQD compound 8a showed a strong efficacy in a murine model of breast cancer, which was better than the effects of taxol. The findings showcased in this study highlight the promising capabilities of novel DHFR inhibitors in addressing bacterial infections as well as breast cancer.

In vitro biological activities of novel Ni(II)-2-chloroquinoline derivative complex: Synthesis, characterization and computational studies

Quinoline derivative nickel complexes have received considerable attention in biomedical research. Herein, novel nickel(II) complex [Ni(II)(HL)2].2H2O was synthesized from newly synthesised ligand 2-((2-hydroxyethyl)amino)quinoline-3-carbaldehyde (H2L) through bidentate fashion of metal–ligand interaction. The complex was characterized using spectroscopic and physicochemical methods. The formation constant (KNi(II) = 2.36 × 107) of the complex was calculated spectroscopically and thermodynamic parameters (ΔG, ΔH and ΔS) were determined from it. In vitro antibacterial activity analysis of the newly synthesized complex exhibited mean inhibition zones ranging from medium to high (16.55 ± 1.03 mm, 16.69 ± 0.63 and 20.94 ± 2.01 mm) at 600 μg/mL against E. coli, S. aureus and P. aeruginosa, respectively. The complex also showed enhanced antioxidant activities compared with the corresponding free ligand. The energy band gap (1.183 eV) was calculated from the HOMO and LUMO of the most stable structure of the synthesized complex. The DFT calculated results and molecular docking analysis results showed good agreement with the experimental results. The complex showed pronounced biological activities than the free ligand. The in silico binding modes of the complex against E. Coli DNA Gyrase and S. aureus Dihydrofolate reductase (PDB: 2w9h) were found to be in excellent agreement with the in vitro biological studies.

Limited Polymorphism in the Dihydrofolate Reductase (dhfr) and dihydropteroate synthase genes (dhps) of Plasmodium knowlesi isolate from Thailand

BackgroundThe 2022 malaria WHO reported around 4000 P. knowlesi infections in the South-East Asia region. In the same period, 72 positive cases were reported by the Department of Disease Control in Thailand, suggesting a persistent infection. Little is known about dihydrofolate reductase (pkdhfr) and dihydropteroate synthase (pkdhps), putative antimalarial resistance markers for P. knowlesi. The relevant amplification and sequencing protocol are presently unavailable. In this study, we developed a protocol for amplifying and evaluating pkdhps mutations. The haplotype pattern of pkdhfr–pkdhps in Thai isolates was analyzed, and the effects of these pkdhps mutations were predicted by using a computer program. MethodsPkdhps were amplified and sequenced from 28 P. knowlesi samples collected in 2008 and 2020 from nine provinces across Thailand. Combining pkdhfr sequencing data from previous work with pkdhps data to analyze polymorphisms of pkdhfr and pkdhps haplotype. Protein modeling and molecular docking were constructed using two inhibitors, sulfadoxine and sulfamethoxazole, and further details were obtained through analyses of protein–ligand interactions by using the Genetic Optimisation for Ligand Docking program. A phylogenetic tree cluster analysis was reconstructed to compare the P. knowlesi Malaysia isolates. ResultsFive nonsynonymous mutations in the pkdhps were detected outside the equivalence of the binding pocket sites to sulfadoxine and sulfamethoxazole, which are at N391S, E421G, I425R, A449S, and N517S. Based on the modeling and molecular docking analyses, the N391S and N517S mutations located close to the enzyme-binding pocket demonstrated a different docking score and protein–ligand interaction in loop 2 of the enzyme. These findings indicated that it was less likely to induce drug resistance. Of the four haplotypes of pkdhfr–pkdhps, the most common one is the R34L pkdhfr mutation and the pkdhps quadruple mutation (GRSS) at E421G, I425R, A449S, and N517S, which were observed in P. knowlesi in southern Thailand (53.57%). Based on the results of neighbor-joining analysis for pkdhfr and pkdhps, the samples isolated from eastern Thailand displayed a close relationship with Cambodia isolates, while southern Thailand isolates showed a long branch separated from the Malaysian isolates. ConclusionsA new PCR protocol amplification and evaluation of dihydropteroate synthase mutations in Knowlesi (pkdhps) has been developed. The most prevalent pkdhfr-pkdhps haplotypes (53.57%) in southern Thailand are R34L pkdhfr mutation and pkdhps quadruple mutation. Further investigation requires additional phenotypic data from clinical isolates, transgenic lines expressing mutant alleles, or recombinant proteins.

Dihydrofolate reductase activity controls neurogenic transitions in the developing neocortex.

One-carbon/folate (1C) metabolism supplies methyl groups required for DNA and histone methylation, and is involved in the maintenance of self-renewal in stem cells. Dihydrofolate reductase (DHFR), a key enzyme in 1C metabolism, is highly expressed in human and mouse neural progenitors at the early stages of neocortical development. Here, we have investigated the role of DHFR in the developing neocortex and report that reducing its activity in human neural organoids and mouse embryonic neocortex accelerates indirect neurogenesis, thereby affecting neuronal composition of the neocortex. Furthermore, we show that decreasing DHFR activity in neural progenitors leads to a reduction in one-carbon/folate metabolites and correlates with modifications of H3K4me3 levels. Our findings reveal an unanticipated role for DHFR in controlling specific steps of neocortex development and indicate that variations in 1C metabolic cues impact cell fate transitions.

Chemico-pharmacological and computational studies of Ophiorrhiza fasciculata D. Don and Psychotria silhetensis Hook. f. focusing cytotoxic, thrombolytic, anti-inflammatory, antioxidant, and antibacterial properties

The current study sought to examine the pharmacological potentials of crude methanolic extracts of Ophiorrhiza fasciculata and Psychotria silhetensis, as well as their various solvent fractionates, with a focus on cytotoxic, thrombolytic, membrane stabilizing, antioxidant, and antibacterial activities via in vitro and in silico approaches. The extensive chromatographic and spectroscopic analyses confirmed and characterized two compounds as (±)-licarin B (1) and stigmasterol (2) from O. fasciculata and P. silhetensis, respectively. Petroleum ether soluble fraction of O. fasciculata and the aqueous soluble fraction of P. silhetensis showed the lowest 50% lethal concentrations (1.41 and 1.94 μg/mL, respectively) in brine shrimp bioassay. Likewise, petroleum ether soluble fraction of O. fasciculata and aqueous soluble fraction of P. silhetensis showed the highest thrombolytic activity with 46.66% and 50.10% lyses of the clot, respectively. The methanol and dichloromethane soluble fractions of O. fasciculata reduced erythrocyte hemolysis by 64.03% and 37.08%, respectively, under hypotonic and heat-induced conditions, compared to 81.97% and 42.12% for standard acetylsalicylic acid. In antioxidant activity test, aqueous soluble fraction O. fasciculata (IC50 = 7.22 μg/mL) revealed promising antioxidant potentialities in comparison to standard butylated hydroxytoluene (IC50 = 21.20 μg/mL). In antibacterial screening, chloroform, and dichloromethane soluble fractions of P. silhetensis showed a mild antibacterial activity compared with the standard drug ciprofloxacin. Additionally, the molecular docking study corroborated the current in vitro findings, and the isolated two constituents had higher binding affinities toward epidermal growth factor receptor, tissue plasminogen activator, vFLIP-IKK gamma stapled peptide dimer, glutathione reductase, and dihydrofolate reductase enzyme than their corresponding standard drugs. In addition, the both isolated compounds exerted favorable pharmacokinetics (absorption, distribution, metabolism, excretion) and toxicological profiles with drug-like qualities in computational-based ADMET and drug likeliness analyses. The current research suggests that both plants have potential as a natural treatment for treating thrombosis, inflammation, and oxidative stress. However, more thorough research is required to thoroughly screen for phytochemicals and pinpoint the precise mechanisms of action of the bioactive metabolites derived from these plants against a broad range of molecular targets.

Phytochemical Profiling and Pharmacological Evaluation of Leaf Extracts of Ruellia tuberosa L.: An In Vitro and In Silico Approach.

The present study was designed to appraise the photoprotective, antioxidant, and antibacterial bioactivities of Ruellia tuberosa leaves extracts (RtPE, RtChl, RtEA, RtAc, RtMe, and RtHMe). The results showed that, RtHMe extracts of R. tuberosa was rich in total phenolic content, i. e., 1.60 mgGAE/g dry extract, while highest total flavonoid content was found in RtAc extract, i. e., 0.40 mgQE/g. RtMe showed effective antioxidant activity (%RSA: 58.16) at the concentration of 120 μL. RtMe, RtEA and RtHMe exhibited effective in vitro antibacterial activity against Gram-negative bacteria (E. coli). In silico docking studies revealed that paucifloside (-11.743 kcal/mol), indole-3-carboxaldehyde (-7.519 kcal/mol), nuomioside (-7.275 kcal/mol), isocassifolioside (-6.992 kcal/mol) showed best docking score against PDB ID 2EX8 [penicillin binding protein 4 (dacB) from Escherichia coli, complexed with penicillin-G], PDB ID 6CQA (E. coli dihydrofolate reductase protein complexed with inhibitor AMPQD), PDB ID 2Y2I [Penicillin-binding protein 1B in complex with an alkyl boronate (ZA3)] and PDB ID 2OLV (from S. aureus), respectively. Docked phytochemicals also showed good drug likeness properties.

Quinoline Hydrazone Derivatives as New Antibacterials Against Multidrug Resistant Strains.

To develop novel antimicrobial agents a series of 2(4)-hydrazone derivatives of quinoline were designed, synthesized and tested. QSAR models of the antibacterial activity of quinoline derivatives were developed by the OCHEM web platform using different machine learning methods. A virtual set of quinoline derivatives was verified with a previously published classification model of anti-E. coli activity and screened using the regression model of anti-S. aureus activity. Selected and synthesized 2(4)-hydrazone derivatives of quinoline exhibited antibacterial activity against the standard and antibiotic-resistant S. aureus and E. coli strains in the range from 15 to 30 mm by the diameter of growth inhibition zones. Molecular docking showed the complex formation of the studied compounds into the catalytic domain of dihydrofolate reductase with an estimated binding affinity from -8.4 to -9.4 kcal/mol.

BCp12/PLA combination: A novel antibacterial agent targeting Mur family, DNA gyrase and DHFR

The combination of natural antimicrobial peptide BCp12/phenyllatic acid (BCp12/PLA) presents a more efficient antibacterial effect, but its antibacterial mechanism remains unclear. This study studied the synergistic antibacterial mechanism of BCp12 and PLA against S. aureus. The results demonstrated that the BCp12/PLA combination presented a synergistic antibacterial effect against S. aureus, with a fractional inhibitory concentration of 0.05. Furthermore, flow cytometry and scanning electron microscope analysis revealed that BCp12 and PLA synergistically promoted cell membrane disruption compared with the group treated only with one compound, inducing structural cell damage and cytoplasmic leakage. In addition, fluorescence spectroscopy analysis suggested that BCp12 and PLA synergistically influenced genomic DNA. BCp12 and PLA targeted enzymes related to peptidoglycan and DNA synthesis and interacted by hydrogen bonding and hydrophobic interactions with mur enzymes (murC, murD, murE, murF, and murG), dihydrofolate reductase, and DNA gyrase. Additionally, the combined treatment successfully inhibited microbial reproduction in the storage of pasteurized milk, indicating that the combination of BCp12 and PLA can be used as a new preservative strategy in food systems. Overall, this study could provide potential strategies for preventing and controlling foodborne pathogens.

Rescue therapy in methotrexate toxicity: case report

Methotrexate (MTX) is widely used for the treatment of psoriasis. It has an antiproliferative action by inhibiting dihydrofolate reductase enzyme, therefore interferes with folic acid synthesis. MTX toxicity is rarely reported and the most common cause of it is accidental overdosage by the patient. This is a case report of a 51-year-old male, a known case of psoriasis, who presented with multiple erythematous tender plaques associated with burning sensation. He self-medicated with tablet MTX 5 mg daily for 10 days when the lesions got exacerbated and was found to be leucopenic. On skin biopsy, diagnosis of psoriasis with MTX induced epidermal necrolysis was established. Patient was treated with filgrastim 300 μg which was given subcutaneously 1 day apart. On follow up, lesions subsided and repeat counts were within normal limits. Patients should be explained about the selected treatment regime and discouraged from self-medicating.

INTERACTION OF PTERIDOPHYTIC BIOACTIVE COMPOUNDS WITH FUNGAL DIHYDROFOLATE REDUCTASE ENZYME AS INHIBITOR

Objective: Fungal infections which are relatively common mainly invades the body of an immunosuppressed patients and people undergoing therapy. These pathogens act through different pathways like the Dihydrofolate reductase (DHFR) has a role in the folate synthetic pathway which is responsible for DNA synthesis. Since the early ages herbal remedies were used and have been tested for treating these fungal infections. Previous studies have revealed the use of bioactive molecules of pteridophytes to demonstrate antifungal activity. Material and Method: In the present study different pteridophytes were selected from available library which showed the presence of bioactive phytoconstituents. In-silico studies on DHFR target (PDB ID: 6DRS and PDB ID: 3QLW) was carried out using PyRx program (India) to determine the affinity of bioactive molecules against the fungal strain. Result and Discussion: Molecular docking was performed with 11 bioactive molecules showing activity against the selected target proteins. So, we can conclude that the selected bioactive molecules are active against fungal strain and can be further investigated for both in-vivo and in-vitro studies.

A novel antifolate suppresses growth of FPGS-deficient cells and overcomes methotrexate resistance.

Cancer cells make extensive use of the folate cycle to sustain increased anabolic metabolism. Multiple chemotherapeutic drugs interfere with the folate cycle, including methotrexate and 5-fluorouracil that are commonly applied for the treatment of leukemia and colorectal cancer (CRC), respectively. Despite high success rates, therapy-induced resistance causes relapse at later disease stages. Depletion of folylpolyglutamate synthetase (FPGS), which normally promotes intracellular accumulation and activity of natural folates and methotrexate, is linked to methotrexate and 5-fluorouracil resistance and its association with relapse illustrates the need for improved intervention strategies. Here, we describe a novel antifolate (C1) that, like methotrexate, potently inhibits dihydrofolate reductase and downstream one-carbon metabolism. Contrary to methotrexate, C1 displays optimal efficacy in FPGS-deficient contexts, due to decreased competition with intracellular folates for interaction with dihydrofolate reductase. We show that FPGS-deficient patient-derived CRC organoids display enhanced sensitivity to C1, whereas FPGS-high CRC organoids are more sensitive to methotrexate. Our results argue that polyglutamylation-independent antifolates can be applied to exert selective pressure on FPGS-deficient cells during chemotherapy, using a vulnerability created by polyglutamylation deficiency.

The Role of Flavanones as Scaffolds for the Development of New Treatments against Malaria and African and American Trypanosomiases.

Parasitic infections are diseases transmitted by parasites usually found in contaminated food, water, or insect bites. Generally classified as neglected tropical diseases, malaria and trypanosomiases are some of the most prominent parasitic diseases that cause significant loss of life annually. In 2020, an estimated 241 million malaria cases were reported, with 627,000 deaths worldwide. An estimated 6 to 7 million people are infected with Trypanosoma cruzi worldwide, whereas an estimated 1000 global cases of African human trypanosomiasis were reported in 2020. Flavanones are a group of compounds that belong to the flavonoid family and are chemically obtained by direct cyclization of chalcones. Recent pharmacological studies have demonstrated the effectiveness of plant flavanones in inhibiting the growth of the parasites responsible for malaria and trypanosomiases. The present work aims to summarize up-to-date and comprehensive literature information on plant flavanones with antimalarial and antitrypanosomal activities. The mechanisms of action of the antiparasitic flavanones are also discussed. A literature search was performed for naturally occurring flavanones and antimalarial and antitrypanosomal activities by referencing textbooks and scientific databases (SciFinder, Wiley, American Chemical Society, Science Direct, National Library of Medicine, Scientific Electronic Library Online, Web of Science, etc.) from their inception until April 2022. Based on in vitro experiments, more than sixty flavanones were reported to exhibit antimalarial, anti-T. cruzi, and anti-T. brucei activities. Previous studies demonstrated that these compounds bind to PGP-like transporters of P. falciparum to reverse the parasite's resistance. Other reports pinpointed the direct effect of these compounds on the mitochondria of the malaria parasite. Moreover, flavanones have shown strong docking to several validated T. cruzi and T. brucei protein targets, including adenosine kinase, pteridine reductase 1, dihydrofolate reductase, and trypanothione reductase, among others. Flavanones, isolated and characterized from diverse plant parts, were reported to exhibit moderate to high activity against P. falciparum, T. cruzi, and T. brucei in in vitro studies. These potentially active flavanones can be used as scaffolds for the development of new antiparasitic agents. However, more studies on the cytotoxicity, pharmacokinetics, and mechanisms of action of potent flavanones should be performed.