Analogs 2a Research Articles

Exploring 5-Nitro-N-phenyl-3-(phenylamino)-1H-indazole-1-carboxamide (5-NPIC) Derivatives as Anticancer Agents: Synthesis, Docking and Molecular Dynamics Insights

The synthesis and characterization of a series of 5-nitro-[Formula: see text]-phenyl-3-(phenylamino)-1[Formula: see text]-indazole-1-carboxamide 5-NPIC derivatives (5a– 5v) have been reported as anticancer agents in this study. These derivatives were synthesized by reacting 3-chloro-5-nitro-[Formula: see text]-phenyl-1[Formula: see text]-indazole-1-carboxamide (4) with a variety of aniline derivatives in isopropanol. FT-IR, 1H-NMR, 13C-NMR and mass spectral methods were employed to confirm the structures of analogues (5a– 5v). The anticancer activity evaluation of compounds 5a– 5v revealed that 3-((3-methoxyphenyl) amino)-5-nitro-[Formula: see text]-phenyl-1[Formula: see text]-indazole-1-carboxamide (5j) exhibited good efficacy. The stability of ligand–protein complexes was systematically evaluated using molecular dynamics simulations (MDS), which demonstrated a consistent and robust binding of the most potent compound within the binding sites of target proteins. The results confirmed the anticancer activity, which was further substantiated by comprehensive molecular docking analyses that revealed complex interactions involving hydrophobic contacts, electrostatic forces and hydrogen bonds. Our results would collectively provide invaluable insights into the intricate molecular structure and dynamics of receptor target sites, thereby establishing a solid foundation for the development of novel and potent anticancer agents with optimistic pharmaceutical implications in near future.

Curculigosides J–K and curcorchidihydrobenzofuran A, a dihydrobenzofuran with anti-proliferative properties from Curculigo orchioides

Phytochemical investigation of the rhizomes and the leaves of Curculigo orchioides led to the isolation of fourteen compounds. They consist of one undescribed dihydrobenzofuran, curcorchidihydrobenzofuran A (1), two undescribed benzyl benzoate glycosides, curculigoside J (2) and K (3), and eleven known compounds (4–14). The structures of the isolated compounds were elucidated by thorough analysis of spectroscopic (IR, NMR and ECD) and spectrometric (MS) data. Compound 1 displayed significant anti-proliferative activities against cervical cancer cells (HelaS3, IC50 = 3.6 µM) and breast cancer cells (MCF-7, IC50 = 13.9 µM) while showing moderate activities against lung cancer cells (A549, IC50 = 29.8 µM). Importantly, it was non-toxic to Vero cells. Compound 1 also inhibited the tyrosinase enzyme in a moderate manner (IC50 = 120.8 µM). Eventually, its permethylated synthetic analog 1a showed a significant suppression of lipopolysaccharide (LPS)-induced NO production in murine macrophage RAW 264.7 (IC50 = 23.4 µM).

Synthesis, characterization, and evaluation of pyrimidinone-linked thiazoles: DFT analysis, molecular docking, corrosion inhibition, and bioactivity studies

The paper describes the construction of a new series of pyrimidinone-linked thiazole derivatives through bromination of the initial Biginelli reaction product followed by the Hantzsch thiazole synthesis route. Various analytical techniques, including FT-IR, 1H NMR, 13C NMR, and LCMS analysis, were employed to confirm the formation of the products. The synthesized compounds were primarily evaluated for their antibacterial activity, with a specific focus on their IC50 values. Compound 4c demonstrated the most potent efficacy, displaying MIC and MBC values that varied from 0.23 to 0.71 mg/mL and 0.46–0.95 mg/mL, respectively. The anti-inflammatory potential was also observed in analogs 4a and 4c with marked activity in the 33.2–82.9 μM concentration range. Moreover, compounds 4a, and 4c demonstrated strong antioxidant effects, as reflected by their excellent IC50 values of 38.6–43.5 μM respectively. DFT investigation showed that B. cereus was more susceptible, and E. coli was more resistant, with chloro-substituted compounds exhibiting potential reactivity. Some molecules with chloro-substituents showed promising results in density functional theory when compared to other substituents. In addition, the molecules underwent a corrosion study and demonstrated a high level of inhibition efficiency (4c) in comparison to other molecules. Further in silico studies of the synthesized thiazoles confirmed the good interactions with the target.

Benzo-Crown-Ether Functionalized O-BODIPY Probes for Cations - A Selective Fluorescent Probe for Ba2.

Herein, we report the synthesis and sensing characteristics of 4,4'-methoxy-substituted BODIPY fluorescent probes (O-BODIPYs) 3, 4 and 5 equipped with differently sized benzo-crown ethers (cf. Scheme 1, 3 (benzo-15-crown-5), 4 (benzo-18-crown-6) and 5 (benzo-21-crown7)). O-BODIPYs 3, 4 and 5 exhibited in comparison to their known F-BODIPY analogues 3a, 4a and 5a (cf. Scheme 1) an improved solubility in aqueous medium and higher fluorescence quantum yields. Fluorometric study in aqueous solutions of 3, 4 and 5 in the presence of different cations show cation induced fluorescence enhancements (FE). Compared to the benzo-crown ether substituted F-BODIPY analogues 3a, 4a and 5a, we found for the free O-BODIPYs 3, 4 and 5 higher fluorescence quantum yields (φf) but lower cation induced FEs. We show that in aqueous medium the fluorescence quenching process (OFF switching), a photoinduced electron transfer, in O-BODIPYs 3, 4 and 5 is less effective and consequently sensitive and selective ON switching of the fluorescence by cations, too. Albeit these observations the novel benzo-21-crown-7 equipped fluorescent probe 5 exhibits a good fluorometric Ba2+ selectivity and Ba2+ sensitivity in conjunction to their aqueous solubility.

(E)-2-Benzylidenecyclanones: Part XIX. Reaction of (E)-2-(4'-X-Benzylidene)-1-tetralones with Cellular Thiols: Comparison of Thiol Reactivities of Open-Chain Chalcones and Their Six- and Seven-Membered Cyclic Analogs.

Non-enzyme-catalyzed thiol addition onto the α,β-unsaturated carbonyl system is associated with several biological effects. Kinetics and diastereoselectivity of non-enzyme catalyzed nucleophilic addition of reduced glutathione (GSH) and N-acetylcysteine (NAC) to the six-membered cyclic chalcone analogs 2a and 2b were investigated at different pH values (pH 3.2, 7.4 and 8.0). The selected compounds displayed in vitro cancer cell cytotoxicity (IC50) of different orders of magnitude. The chalcones intrinsically reacted with both thiols under all incubation conditions. The initial rates and compositions of the final mixtures depended both on the substitution and the pH. The stereochemical outcome of the reactions was evaluated using high-pressure liquid chromatography with UV detection (HPLC-UV). The structures of the formed thiol-conjugates and the retro-Michael products (Z)-2a and (Z)-2b were confirmed by high-pressure liquid chromatography-mass spectrometry (HPLC-MS). Frontier molecular orbitals and the Fukui function calculations were carried out to investigate their effects on the six-membered cyclic analogs. Data were compared with those obtained with the open-chain (1) and the seven-membered (3) analogs. The observed reactivities do not directly relate to the difference in in vitro cancer cell cytotoxicity of the compounds.

Destruxin E backbone modification effects on osteoclast Morphology: Synthesis and SAR study of N-Desmethyl and N-Methyl analogs

The design and synthesis of N-desmethyl and N-methyl destruxin E analogs have been demonstrated. The X-ray single crystal structure of destruxin E (1a) revealed a stable three-dimensional (3D) structure, including a s-cis amide bond at the MeVal–MeAla moiety and two intramolecular hydrogen bonds between NH(β-Ala) and OC(Ile) and between NH(Ile) and OC(β-Ala). N-Desmethyl analogs 2a (MeAla → Ala) and 2b (MeVal → Val) were synthesized through macrolactonization similar to our previously reported synthesis of 1a. Conversely, for the synthesis of N-methyl analogs 2c (Ile → MeIle) and 2d (β-Ala → Meβ-Ala), macrolactonization did not proceed; therefore, cyclization precursors 10c and 10d were designed to maintain the intramolecular hydrogen bonds described above during their cyclization. The macrolactamization proceeded despite the presence of a less reactive N-methylamino group at the N-terminus in both cases. Analog 2a, which exhibits multiple conformers in solutions, was inactive at 50 μM, whereas analog 2b, which exhibits a conformation similar to that of 1a in solutions, exhibited morphological changes against osteoclast-like multinuclear cells at 1.6 μM. The activity of the MeIle analog 2c, which cannot take the intramolecular hydrogen bond (Ile)NH•••OC(β-Ala) in 1a, was markedly diminished compared with that of 1a, and that of the Meβ-Ala analog 2d, which cannot take the intramolecular hydrogen bond (β-Ala)NH•••OC(Ile) in 1a, was further reduced to one-fourth of that of 2c. The overall results indicate that both the s-cis amide bond at the MeVal–MeAla moiety and two intramolecular hydrogen bonds (β-Ala)NH•••OC(Ile) and (Ile)NH•••OC(β-Ala) are important for constraining the conformation of the macrocyclic peptide backbone in destruxin E, thereby exhibiting its potent biological activity.

2‐(1‐Methyl‐1H‐indazol‐5‐yl)‐N‐arylisonicotinamide Analogs: Synthesis, Anticancer Screening, SAR and ADMET Studies

AbstractIn this current research framework, we detailed the synthesis of ten novel 2‐(1‐methyl‐1H‐indazol‐5‐yl)‐N‐arylisonicotinamide analogs (3a–j). The synthesis of these compounds (3a–j) involved a three‐step process, employing the Suzuki‐Miyaura coupling reaction, which successfully linked 1‐methyl‐1H‐indazole with isonicotinamide to satisfactory yields. The synthesized compounds were characterized using various spectroscopic techniques. To assess their potential, the anticancer activity of compounds (3a–j) was evaluated following the National Cancer Institute (NCI US) protocol against nine panels comprising different cancer cell lines, at a concentration of 10−5 M. Growth percentage (GP) and percentage growth inhibition (PGI) were calculated for each compound. Notably, the CNS cancer cell line SNB‐75 exhibited a remarkable PGI of 99.16 percent, indicating high sensitivity to the tested compound 3e. Additionally, ADMET prediction suggested that most of the synthesized compounds possess drug‐like properties, with low adverse effects and toxicity. These findings represent a significant advancement, offering potential avenues for further developments in the field of cancer research.

Synthesis of a novel fused thieno‐pyrimidine with tetrazole analogs

AbstractThis current investigation represents the new series of fused thieno‐pyrimidine with synthesized tetrazole analogs (6a–j). Intermediates thieno‐[2,3‐d]‐pyrimidine were prepared by utilizing the Gewald method, and tetrazole (5a–j) was synthesized by [3 + 2] cycloaddition of azide and appropriate nitrile. All the prepared novel molecules were characterized and confirmed by 1HNMR, 13CNMR, LC‐MS, and FT‐IR spectral analysis.

Synthesis and pharmacological characterization of conformationally restricted 2-amino-Adipic acid analogs and carboxycyclopropyl glycines as selective metabotropic glutamate 2 receptor agonists

The metabotropic glutamate (Glu) receptors (mGluRs) are G-protein coupled receptors, which play a central role in modulating excitatory neurotransmission in the central nervous system (CNS). Thus, the development of tool compounds thereto, continues to interest the scientific community. In this study, we report the design and synthesis of new conformationally restricted 2-aminoadipic acid (2AA) 2–4, and glutamic acid 5, 6 analogs, which share the cyclopropane ring as the restrictor. The analogs were characterized at rat mGlu1−8 in an IP-One functional assay. While the 2AA analogs 3a, 4a and CCG-I analog 5a were shown to be selective mGlu2 agonists with low micromolar potencies, CCG-II analog 5b was shown to be a potent full agonist at mGlu2 (EC50 = 82 nM) with ∼15-fold selectivity over mGlu3, >25-fold selectivity over group III, and >60-fold selectivity over group I subtypes. An in silico study was performed to address this significant change (>3500 fold) in potency upon introduction of this methyl group (L-CCG-II vs 5b).

1,3,4-oxadiazole derivatives: synthesis, characterization, antifungal activity, DNA binding investigations, TD-DFT calculations, and molecular modelling

1,3,4-Oxadiazole-based heterocyclic analogs (3a–3m) were synthesized via cyclization of Schiff bases with substituted aldehydes in the presence of bromine and acetic acid. The structural clarification of synthesized molecules was carried out with various spectroscopic techniques such as FT-IR,1H and 13C-NMR, UV–visible spectroscopy, and mass spectrometry. In-vitro antifungal activity was performed against C. albicans, C. glabrata and C. tropicalis and analogs 3g, 3i, and 3m showed potent MIC at 200 µg/ml and excellent ZOI measurements of 17–21 nm. The cell viability on Huh7 for lead molecules 3g, 3i, and 3m was found to be 99.5%, 92.3%, and 86.9% at 20, 10, and 20 μM, respectively. The antioxidant activity of molecules 3 g, 3i, and 3 m was estimated and exhibited great IC50 values of 0.104 ± 0.021, 0.145 ± 0.05, and 0.165 ± 0.018 μg/mL with DPPH and 0.107 ± 0.04, 0.191 ± 0.12, and 0.106 ± 0.08 with H2O2, respectively. The binding interaction mode for the lead molecules was also carried out with Ct-DNA using the absorption, emission, CV, CD, and Time resolve fluorescence techniques. The results showed good binding constant (Kb) values of 9.1 × 105, 9.94 × 105, and 9.32 × 105 M−1 for 3g, 3i, and 3m, respectively. TD-DFT study of compounds 3g, 3i, and 3m was done to find out HOMO/LUMO energy levels, surface study of the molecular electrostatic potential, Mulliken population analysis, and natural bond orbitals showing the linkages between the donors and acceptors.Molecular docking of three lead analogs with PDB ID: 1BNA and molecular modelling of compounds 3g, 3i, and 3m with C. albicans CYP51 protein (PDB ID: 5FSA) were carried out. Communicated by Ramaswamy H. Sarma

Isoxazole analogues of dibenzazepine as possible leads against ulcers and skin disease: In vitro and in silico exploration

Utilizing multi-target drugs shows great promise as an effective strategy against polygenic diseases characterized by intricate patho-mechanisms, such as ulcers, skin dermatitis, and cancers. The current research centers around the creation of hybrid compounds, connecting dibenzazepine and isoxazole, with the aim of exploring their potential as inhibitors for urease and tyrosinase enzymes. Analogs 6a, 6b, 6d, 6 h-6j, and 6 l demonstrated strong inhibitory potential against tyrosinase enzyme with IC50 values of 4.32 ± 0.31–12.36 ± 0.48. Whereas analogs 6a, 6c, 6e, 6f, 6h-6m, and 6r exhibited potent inhibitory activities against urease enzyme with IC50 values of 3.67 ± 0.91–15.60 ± 0.18 μM. Furthermore, compounds 6i, 6n, and 6r showed weak toxic effect in BJ-cell line, whereas the remaining compounds were found non-toxic to normal cell line. The mechanistic studies of potent inhibitors of both the enzymes showed competitive mode of inhibition. Molecular docking was employed to establish the relationship between structure and activity and to elucidate the interaction mechanism. This analysis revealed that the active analogs exhibited crucial interactions with the active site residues of urease and tyrosinase, thus corroborating our experimental results. Hence, the generated derivatives of dibenzazepine-linked isoxazoles present intriguing starting points for further investigations into their potential as inhibitors of urease and tyrosinase, with the potential for future modification and enhancement.

Cheminformatics-based discovery of new organoselenium compounds with potential for the treatment of cutaneous and visceral leishmaniasis

Leishmaniasis affects more than 12 million humans globally and a further 1 billion people are at risk in leishmaniasis endemic areas. The lack of a vaccine for leishmaniasis coupled with the limitations of existing anti-leishmanial therapies prompted this study. Cheminformatic techniques are widely used in screening large libraries of compounds, studying protein-ligand interactions, analysing pharmacokinetic properties, and designing new drug molecules with great speed, accuracy, and precision. This study was undertaken to evaluate the anti-leishmanial potential of some organoselenium compounds by quantitative structure-activity relationship (QSAR) modeling, molecular docking, pharmacokinetic analysis, and molecular dynamic (MD) simulation. The built QSAR model was validated (R2 train = 0.8646, R2 test = 0.8864, Q2 = 0.5773) and the predicted inhibitory activity (pIC50) values of the newly designed compounds were higher than that of the template (Compound 6). The new analogues (6a, 6b, and 6c) showed good binding interactions with the target protein (Pyridoxal kinase, PdxK) while also presenting excellent drug-likeness and pharmacokinetic profiles. The results of density functional theory, MD simulation, and molecular mechanics generalized Born surface area (MM/GBSA) analyses suggest the favourability and stability of protein-ligand interactions of the new analogues with PdxK, comparing favourably well with the reference drug (Pentamidine). Conclusively, the newly designed compounds could be synthesized and tested experimentally as potential anti-leishmanial drug molecules. Communicated by Ramaswamy H. Sarma

Enantioselective Synthesis, Computational Molecular Docking and In Vitro Anticoagulant Activity of Warfarin-based Derivatives

Abstract: Warfarin containing a 4-hydroxycoumarin moiety possesses excellent anticoagulant activity, with the (S) enantiomer being the eutomer. The present work is designed to synthesize warfarin based derivatives enantioselectivity to explore their anticoagulant potential. The substituted chalcones were reacted with 4-hydroxycoumarin in the presence of the chiral organocatalyst 9-amino-9-deoxyepiquinine to afford warfarin-based analogues 5a- 5k. The structures of synthesized compounds 5a-5k were confirmed by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) and electron ionization mass spectroscopy (EIMS) data. The enantiomeric excess (ee) has been found in the range of 16-99% as determined by chiral high-performance liquid chromatography (HPLC) analysis. The in vitro anticoagulant activity of the products 5a-5k was evaluated by plasma recalcification time (PRT) method, and it was found that most of the derivatives showed good anticoagulant activity, specifically compound 5b exhibited excellent results compared to that of warfarin. Compound 5b displayed an IC50 value of 249.88 μM, which is better than that of warfarin (IC50 408.70 μM). The molecular docking studies have been performed against vitamin K epoxide reductase with PDBID 3kp9. The synthesized compounds bind well in the active binding site of the target enzyme. The derivative 5b showed π-π stacking interactions with the amino acid phenylalanine (Phe 114). The antimicrobial activity of synthesized compounds has also been evaluated, and results showed moderate antimicrobial activity. Based on our results, it is proposed that derivative 5b may act as a lead compound to design more potent anticoagulant derivatives.

Leveraging the MMV Pathogen Box to Engineer an Antifungal Compound with Improved Efficacy and Selectivity against Candida auris.

Fungal infections pose a significant and increasing threat to human health, but the current arsenal of antifungal drugs is inadequate. We screened the Medicines for Malaria Venture (MMV) Pathogen Box for new antifungal agents against three of the most critical Candida species (Candida albicans, Candida auris, and Candida glabrata). Of the 14 identified hit compounds, most were active against C. albicans and C. auris. We selected the pyrazolo-pyrimidine MMV022478 for chemical modifications to build structure-activity relationships and study their antifungal properties. Two analogues, 7a and 8g, with distinct fluorine substitutions, greatly improved the efficacy against C. auris and inhibited fungal replication inside immune cells. Additionally, analogue 7a had improved selectivity toward fungal killing compared to mammalian cytotoxicity. Evolution experiments generating MMV022478-resistant isolates revealed a change in morphology from oblong to round cells. Most notably, the resistant isolates blocked the uptake of the fluorescent dye rhodamine 6G and showed reduced susceptibility toward fluconazole, indicative of structural changes in the yeast cell surface. In summary, our study identified a promising antifungal compound with activity against high-priority fungal pathogens. Additionally, we demonstrated how structure-activity relationship studies of known and publicly available compounds can expand the repertoire of molecules with antifungal efficacy and reduced cytotoxicity to drive the development of novel therapeutics.

Molecular modeling, synthesis, and in vitro acetylcholinesterase and butyrylcholinesterase inhibitory activities of novel benzimidazole-bearing thiadiazole derivatives

A new series of benzimidazole-based thiadiazole hybrids analogues (6a–p) as effective Alzheimer's inhibitors were synthesized and then evaluated for their inhibition profile against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes as compared to Donepezil as standard drug. All the synthesized benzimidazole-based thiadiazole analogues showed varied range of inhibitory potentials against targeted AChE & BuChE enzymes with IC50 values ranging from 1.32 ± 0.10 µM to 19.26 ± 0.60 µM (for AChE) and 1.94 ± 0.10 µM to 21.33 ± 0.70 µM (for BuChE) when compared to standard Donepezil (IC50 = 2.16 ± 0.050 µM for AChE) & 4.50 ± 0.10 µM for BuChE). As structure-activity relationship (SAR) studies revealed that the analogues 4d (bearing ortho‑hydroxy and para-NO2 on N-aryl ring along with ortho-NO2 substitution on another aryl ring) and 6k (that holds ortho‑hydroxy ¶-NO2 substitutions on N-aryl ring and 3,4-diCl moieties on another aryl ring) were emerged as the most potent analogues of AChE & BuChE enzymes having IC50 values of 1.32 ± 0.10 µM & 1.84 ± 0.20 µM (against AChE) and 1.94 ± 0.10 µM & 2.23 ± 0.20 µM (against BuChE) respectively. Furthermore, the active analogues were subjected to molecular docking studies in order to explore the binding interactions possess by potent analogues with the active sites of amino acids of targeted AChE & BuChE enzymes and result obtained shows that these active analogues furnished that several key interactions with targeted enzymes active sites. Additionally, all the synthesized analogues were elucidated structurally using variety of spectroscopic (1H NMR & 13C NMR) and spectrometric (HREI-MS) analysis.

Hybrid molecules of thiadiazole-based benzothioate and benzenesulfonothioate: synthesis, structural analysis, and evaluation as potential inhibitors of thymidine phosphorylase and β-glucuronidase through in vitro and in silico approaches

The thiadiazole-based benzothioate (3a-f) and benzenesulfonothioate (5a-f) hybrid derivatives were designed and synthesized in a single step reaction. All the synthesized compounds structures were confirmed through spectroscopic techniques including 1H NMR, 13C NMR and HRMS (ESI). Then, the synthesized compounds were subjected to in vitro thymidine phosphorylase and beta-glucuronidase inhibition profile. All the newly synthesized moieties (3a-f) & (5a-f) were found potent and showed moderately to good inhibition profile. Among benzothioate analogues (3a-f), the analogues 3d and 3c were identified to be active inhibitors of thymidine phosphorylase and beta-glucuronidase enzymes having IC50 values of 2.11 ± 0.31 μM & 3.28 ± 0.20 μM (against thymidine phosphorylase) and 2.50 ± 0.20 μM & 3.71 ± 0.10 μM (against beta-glucuronidase) respectively. However, among benzenesulfonothioate (5a-f) analogues, analogues 5a and 5d were found to be significantly active, even more than standard drugs with IC50 values of 2.23 ± 0.13 μM & 3.10 ± 0.17 μM (against thymidine phosphorylase) and 3.12 ± 0.20 μM & 5.60 ± 0.34 μM respectively. The results were compared to standard drugs such as D-saccharic acid with IC50 values of 10.10 ± 0.10 µM (for benzothioate series) & 8.50 ± 0.10 µM (for benzenesulfonothioate series) and 7-Deazaxanthine having IC50 values of 12.20 ± 0.10 µM (for benzothioate series) & 9.20 ± 0.30 µM (benzenesulfonothioate series) respectively. From structure-activity (SAR) analysis, it was confirmed that any variation found in inhibitory activities of both thymidine phosphorylase beta-glucuronidase enzymes was due to different substitution pattern of substituent(s) at variable position of aryl ring. Moreover, a good protein-ligand interaction (PLI) subjected to molecular docking study against shown by the most active analogues against corresponding target with key binding interactions with least binding energies. These findings reveal that thiadiazole-containing benzothioate (3a-f) and benzenesulfonothioate (5a-f) act as thymidine phosphorylase beta-glucuronidase inhibitors to develop novel therapeutics agents for the purpose of drug discovery.

Synthesis and Antibacterial Activity of Polyalthic Acid Analogs.

Polyalthic acid (PA) is a diterpene found in copaiba oil. As a continuation of our work with PA, we synthesized PA analogs and investigated their antibacterial effects on preformed biofilms of Staphylococcus epidermidis and determined the minimal inhibitory concentration (MIC) of the best analogs against planktonic bacterial cells. There was no difference in activity between the amides 2a and 2b and their corresponding amines 3a and 3b regarding their ability to eradicate biofilm. PA analogs 2a and 3a were able to significantly eradicate the preformed biofilm of S. epidermidis and were active against all the Gram-positive bacteria tested (Enterococcus faecalis, Enterococcus faecium, S. epidermidis, Staphylococcus aureus), with different MIC depending on the microorganism. Therefore, PA analogs 2a and 3a are of interest for further in vitro and in vivo testing to develop formulations for antibiotic drugs against Gram-positive bacteria.

Design, Synthesis, and Biological Evaluation of Novel Quinazolin-4(3H)-one-Based Histone Deacetylase 6 (HDAC6) Inhibitors for Anticancer Activity

A series of novel quinazoline-4-(3H)-one derivatives were designed and synthesized as histone deacetylase 6 (HDAC6) inhibitors based on novel quinazoline-4-(3H)-one as the cap group and benzhydroxamic acid as the linker and metal-binding group. A total of 19 novel quinazoline-4-(3H)-one analogues (5a–5s) were obtained. The structures of the target compounds were characterized using 1H-NMR, 13C-NMR, LC–MS, and elemental analyses. Characterized compounds were screened for inhibition against HDAC8 class I, HDAC4 class IIa, and HDAC6 class IIb. Among the compounds tested, 5b proved to be the most potent and selective inhibitor of HDAC6 with an IC50 value 150 nM. Some of these compounds showed potent antiproliferative activity in several tumor cell lines (HCT116, MCF7, and B16). Amongst all the compounds tested for their anticancer effect against cancer cell lines, 5c emerged to be most active against the MCF-7 line with an IC50 of 13.7 μM; it exhibited cell-cycle arrest in the G2 phase, as well as promoted apoptosis. Additionally, we noted a significant reduction in the colony-forming capability of cancer cells in the presence of 5c. At the intracellular level, selective inhibition of HDAC6 was enumerated by monitoring the acetylation of a-tubulin with a limited effect on acetyl-H3. Importantly, the obtained results suggested a potent effect of 5c at sub-micromolar concentrations as compared to the other molecules as HDAC6 inhibitors in vitro.

Drug Repurposing Approach in Developing New Furosemide Analogs as Antimicrobial Candidates and Anti-PBP: Design, Synthesis, and Molecular Docking

Multidrug-resistant microorganisms have become a global health problem, prompting research into new antimicrobials. Drug repurposing is a new technique in drug discovery used to improve drug development success. As a well-studied medication with a sulfonamide moiety, furosemide was chosen to study its antimicrobial effect on different microbial strains. In addition, a new family of furosemide analogs was investigated for their antimicrobial efficacy. According to the obtained results, the majority of the examined molecules exhibited potential antimicrobial activity. Compounds 3b and 4a had the best anti-MRSA results, with an MIC = 7.81 µg/mL. They also demonstrated potent anti-gram-negative activity against E. coli (MIC = 1.95 µg/mL and 3.91 µg/mL, respectively). A time-killing kinetics study against E. coli and MRSA showed bactericidal actions of 3b and 4a within 120–150 min. Moreover, an anti-PBP activity and an in vitro cytotoxicity evaluation were performed. Furosemide decreased the PBP2a levels in MRSA by 21.5% compared to the control. However, the furosemide analogs 3b and 4a demonstrated superior anti-PBP activity (55.9 and 57.1 % reduction in the expression of PBP2a, respectively). In addition, compound 4a was nearly nontoxic to normal WI-38 cells (IC50 = 248.60 μg /mL) indicating its high safety profile. Finally, the ability of furosemide and compounds 3b and 4a to bind to the target PBP2a enzyme has also been supported by molecular docking research.

Novel Glu-based pyrazolo[3,4-d]pyrimidine analogues: design, synthesis and biological evaluation as DHFR and TS dual inhibitors

A novel series of multifunctional pyrazolo[3,4-d]pyrimidine-based glutamate analogs (6a–l and 7a,b) have been designed and synthesized as antifolate anticancer agents. Among the tested compounds, 6i exhibited the most potent anti-proliferative activity towards NSCLC, CNS, Ovarian, Prostate, Colon, Melanoma, Breast, and Renal cancers with good to weak cytostatic activity and non-lethal actions. 6i demonstrated higher selectivity for cancer than normal cells. 6i could significantly increase the accumulation of S-phase cells during the cell cycle distribution of cancer cells with high potency in the induction of apoptosis. The results unveiled that 6i probably acts through dual inhibition of DHFR and TS enzymes (IC50 = 2.41 and 8.88 µM, correspondingly). Docking studies of 6i displayed that N1-p-bromophenyl and C3-Methyl groups participate in substantial hydrophobic interactions. The drug-likeness features inferred that 6i met the acceptance criteria of Pfizer. Taking together, 6i could be a promising prototype for further optimization as an effective anticancer drug.