New antibacterial and 5-lipoxygenase activities of synthetic benzyl phenyl ketones: Biological and docking studies

Substituted aryl piperazine ligands as new dual 5-hLOX/COX-2 inhibitors. Synthesis, biological and computational studies

Two series of cyano (1a-l) and amino (2a-l) aryl piperazines were synthesized and evaluated for their inhibitory activity against 5-lipoxygenase (5-hLOX) and cyclooxygenase-2 (COX-2). The newly designed derivatives feature diphenyl methyl (a-d), phenyl (e-h), or methoxyphenyl (i-l) groups, respectively, and demonstrated significant inhibition of 5-hLOX. Noteworthy were compounds 1b, 1 g, 1 k, 2f, and 2 g, exhibiting IC50 values ranging from 2.2 to 3.3 μM. The most potent inhibitors (1b, 1 g, 1 k, 2c, and 2f) were characterized by a competitive inhibition mechanism, with Ki values ranging between 1.77 μM and 9.50 μM. Additionally, compounds 2a, 2b, 2 g, and 2 h displayed promising dual inhibition of 5-hLOX and COX-2, with IC50 values below 15 μM. Cytotoxicity assessments against HEK293 cells revealed that the cyano derivatives (1a-l) were non-cytotoxic (CC50 > 200 μM), whereas the amino derivatives (2a-l) exhibited moderate cytotoxicity (CC50 < 50 μM). Notably, the most active derivatives against both targets were non-cytotoxic at their respective inhibitory concentrations. Computational studies, including docking and molecular dynamics simulations, indicated that compound 1 g demonstrated greater stability within the catalytic site of 5-hLOX compared to compound 2f, correlating with the higher affinity observed in kinetic assays. Furthermore, quantitative structure-activity relationship (QSAR) analyses revealed strong correlations between theoretical and experimental IC50 values (97 % for 1a-l and 93 % for 2a-l). These findings, combined with absorption, distribution, metabolism, and excretion (ADME) predictions, suggest that these derivatives are promising candidates as dual inhibitors of 5-hLOX and COX-2.

Development of Ferrocenyl and Ruthenocenyl Zileuton Analogs with Enhanced Bioactivity toward Human 5-Lipoxygenase: Innovation in Drugs for Inflammatory Diseases

Zileuton is the only FDA-approved 5-lipoxygenase (5-LOX) inhibitor for asthma treatment, but it produces hepatotoxicity associated with the benzothiophene fragment. Using the concept of organometallic derivatization pioneered by Jaouen and Brocard, we synthesized five new organometallic Zileuton derivatives, maintaining the urea fragment and incorporating ferrocenyl and ruthenocenyl moiety (3a-e). Their biological activity was evaluated against 5-LOX, 15-LOX, COX-1, and COX-2 enzymes. The ferrocenyl and ruthenocenyl N-hydroxyurea complexes coined Ferroleuton (3a) and Ruthenoleuton (3e) showed the highest selective inhibitory activity against 5-LOX, with IC50 values of 0.21 ± 0.12 and 3.49 ± 1.11 μM, respectively. Notably, 3a exhibited superior activity compared to Zileuton (IC50 0.67 ± 0.09 μM), demonstrating the key role of N-hydroxyurea and ferrocenyl fragments in the inhibitory process. Worthy of note, both compounds displayed low cytotoxicity in lung fibroblast healthy cells line (MRC-5) (CC50 of 116.40 and >200 μM, respectively). Enzyme kinetic studies indicated competitive and mixed types of inhibition for 3a and 3e, respectively. Additionally, they demonstrated superior antioxidant capacity compared to Zileuton (DPPH, ABTS, and FRAP assays). Electrochemical and molecular dynamics (MD) studies suggest a chelating-redox deactivation mechanism for 5-LOX. These findings position Ferroleuton (3a) and Ruthenoleuton (3e) as promising candidates for inflammatory disease treatment.

2,4-Quinolinedione alkaloids: occurrence and biological activities

Natural products are an important source of chemical scaffolds that have diverse biological activities. They can be used directly or as starting templates for the development of innovative pharmaceutical agents. Among natural products, quinoline alkaloids are one of the most extensively studied groups. 2,4-Quinolinedione (2,4-QD) alkaloids, which are found in a variety of natural sources, possess valuable biological properties. This review examines the natural occurrence and bioactivities of 2,4-QD alkaloids, which have not been studied in as much depth in previous research.

Evaluating the inhibitory activity of ferrocenyl Schiff bases derivatives on 5-lipoxygenase: Computational and biological studies

In the search for new 5-LOX inhibitors, two ferrocenyl Schiff base complexes functionalized with catechol ((ƞ5-(E)-C5H4-NCH-3,4-benzodiol)Fe(ƞ5-C5H5) (3a)) and vanillin ((ƞ5-(E)-C5H4-NCH-3-methoxy-4-phenol)Fe(ƞ5-C5H5) (3b)) were obtained. Complexes 3a and 3b were biologically evaluated as 5-LOX inhibitors showed potent inhibition compared to their organic analogs (2a and 2b) and known commercial inhibitors, with IC50 = 0.17 ± 0.05 μM for (3a) and 0.73 ± 0.06 μM for (3b) demonstrated a highly inhibitory and potent effect against 5-LOX due to the incorporation of the ferrocenyl fragment. Molecular dynamic studies showed a preferential orientation of the ferrocenyl fragment toward the non-heme iron of 5-LOX, which, together with electrochemical and in-vitro studies, allowed us to propose a competitive redox deactivation mechanism mediated by water, where Fe(III)-enzyme can be reduced by the ferrocenyl fragment. An Epa/IC50 relationship was observed, and the stability of the Schiff bases was evaluated by SWV in the biological medium, observing that the hydrolysis does not affect the high potency of the complexes, making them interesting alternatives for pharmacological applications.

Inhibition of Soybean 15-Lipoxygenase and Human 5-Lipoxygenase by Extracts of Leaves, Stem Bark, Phenols and Catechols Isolated From Lithraea caustica (Anacardiaceae)

Lithraea caustica (Molina) Hook. and Arn. (Anacardiaceae), common name Litre, is an evergreen endemic plant used in the Mapuche Chilean folk medicine. The stem juice of L. caustica mixed with Rubus ulmifolius (blackberry) is used to treat cough and the infusion of leaves is used in baths to treat joint inflammations. In this study, the activities of 3-n-alk(en)yl-catechols, obtained from the dichloromethane extract of the epicuticular compounds of fresh leaves (DCME), stem bark petroleum ether extract (PEE), fractions of phenols and phenol-acid compounds obtained from the methanolic extract (methanolic extract) of defatted leaves and aqueous infusion (AE) from fresh leaves, were evaluated as in vitro inhibitors of soybean 15-lipoxygenase (15-sLOX) and human 5-lipoxygenase (5-hLOX), one of the inflammation pathways. The 3-n-alk(en)yl-catechols were characterized by gas chromatography-mass spectrometry and 1D and 2D nuclear magnetic resonance analysis as mixtures of 3-[(10E)-pentadec-10′-en-1-yl]-catechol, 3-[(10Z)-pentadec-10′-en-1-yl]-catechol and 3-n-pentadecylcatechol. In addition, two fractions, obtained from MeOHE, were characterized by liquid chromatography electrospray ionization tandem mass spectrometric as complex mixtures of known acids and phenolic compounds. DCME, MeOHE and ethyl acetate extract (AcOEtE) extracts showed inhibition against 15-sLOX, and the AE of fresh leaves, showed the best inhibition against 5-hLOX. The mixture of 3-n-alk(en)yl-catechols showed inhibition of 15-sLOX and 5-hLOX. The compounds 3-[(10Z)-pentadec-10′-en-1-yl]-catechol (IC₅₀ 2.09 µM) and 3-n-pentadecylcatechol (IC₅₀ 2.74 µM) showed inhibition against 5-hLOX. The inhibition values obtained for the 3-n-alk(en)yl-catechols are in the range of well-known inhibitors of 5-hLOX. Acetylation of the 3-n-alk(en)yl-catechols blocks the inhibitory activity, indicating that the free catechol function is necessary for the enzyme inhibition. In addition, the fractions of phenols and phenol-acid compounds showed inhibitory activity against 15-sLOX and the AE, showed a good inhibition against 5-hLOX. These results would be in agreement with the use of L. caustica, as an anti-inflammatory in Mapuche ethnomedicine.