Amphotericin B is the most potent antimycotic known to date. However due to its large collateral toxicity, its use, although long standing, had been limited. Many attempts have been made to produce derivatives with reduced collateral damage. The molecular mechanism of polyene has also been closely studied for this purpose and understanding it would contribute to the development of safe derivatives. Our study examined polyene action, including chemical synthesis, electrophysiology, pharmacology, toxicology and molecular dynamics. The results were used to support a novel Amphotericin B derivative with increased selectivity: L-histidine methyl ester of Amphotericin B. We found that this derivative has the same form of action as Amphotericin B, i.e. pore formation in the cell membrane. Its reduced dimerization in solution, when compared to Amphotericin B, is at least partially responsible for its increased selectivity. Here we also present the results of preclinical tests, which show that the derivative is just as potent as Amphotericin B and has increased safety.

We have previously reported the synthesis, in vitro and in silico activities of new GABA analogues as inhibitors of the GABA-AT enzyme from Pseudomonas fluorescens, where the nitrogen atom at the γ-position is embedded in heterocyclic scaffolds. With the goal of finding more potent inhibitors, we now report the synthesis of a new set of GABA analogues with a broader variation of heterocyclic scaffolds at the γ-position such as thiazolidines, methyl-substituted piperidines, morpholine and thiomorpholine and determined their inhibitory potential over the GABA-AT enzyme from Pseudomonas fluorescens. These structural modifications led to compound 9b which showed a 73% inhibition against this enzyme. In vivo studies with PTZ-induced seizures on male CD1 mice show that compound 9b has a neuroprotective effect at a 0.50 mmole/kg dose. A QSAR study was carried out to find the molecular descriptors associated with the structural changes in the GABA scaffold to explain their inhibitory activity against GABA-AT. Employing 3D molecular descriptors allowed us to propose the GABA analogues enantiomeric active form. To evaluate the interaction with Pseudomonas fluorescens and human GABA-AT by molecular docking, the constructions of homology models was carried out. From these calculations, 9b showed a strong interaction with both GABA-AT enzymes in agreement with experimental results and the QSAR model, which indicates that bulky ligands tend to be the better inhibitors especially those with a sulfur atom on their structure.

Paracetamol is a widely used analgesic and antipyretic agent; however, its use is limited by minimal anti‐inflammatory activity and the risk of hepatotoxicity from prolonged oral use or in acute overdose. To address these limitations, four novel phosphorylated paracetamol analogs (2a–2d) were synthesized via a UV‐radical methodology and evaluated through integrated in silico, in vitro, and in vivo for anti‐inflammatory dermal approaches. Molecular docking suggested plausible binding interactions with COX‐1 and COX‐2 for all analogs. In vitro cytotoxicity assays in THP‐1 cells showed that 2a and 2b did not affect cell viability at 100 μM over 24 h. In a TPA‐induced acute ear edema model in CD1 male mice, 2a produced about 50% inhibition of edema at the lowest tested quantity (0.5 mg/ear), representing a fourfold potency advantage over indomethacin at the same amount, while 2b displayed significant anti‐inflammatory and vasoregulatory activity at higher quantities. Computational ADME profiling indicated that all analogs satisfy Lipinski’s drug‐likeness criteria and exhibit low predicted hERG channel risk. These results support N‐phosphorylation of 4‐aminophenol as a viable strategy to improve the topical anti‐inflammatory efficacy of paracetamol analogs.