This study evaluated the antioxidant capacity of the oxidation products of three flavonols using oxygen radical absorbance capacity—fluorescein assay (ORAC-FL), oxygen radical absorbance capacity—pyrogallol red assay (ORAC-PGR), and the cellular antioxidant activity (CAA) assay in human dermal fibroblast (HFF) cells, with 2,2’-azobis(2-amidinopropane) dihydrochloride (AAPH) as a free radical generator under controlled pH and solvent conditions. At pH 2 in a polar aprotic solvent, BZF-OH (benzofuranone-OH) compounds were formed, while methoxylated analogs were obtained at pH 7 in a polar protic solvent. The products generated at pH 2 exhibited significantly higher antioxidant capacities, demonstrating the influence of the reaction environment on modulating antioxidant properties. The antioxidant activity was observed to reflect the combined action of the flavonol precursor and its oxidation products. This led to the proposal of the Gross Antioxidant Capacity (GAC) concept to integrate the contribution of all generated species. Since chemical assays such as ORAC do not fully capture the complexity of biological systems, they should be complemented with cellular approaches for a more accurate evaluation. Additionally, BZF-OH compounds were analyzed as potential cyclooxygenase-2 (COX-2) inhibitors through docking and molecular dynamics simulations, where BZF-Quer-OH showed binding affinities comparable to celecoxib, a selective COX-2 inhibitor. These findings were complemented by an analysis of COX-2 expression in RAW 264.7 cells treated with lipopolysaccharide (LPS), where treatment with the antioxidants significantly inhibited COX-2 expression. In the case of the oxidation products, only the oxidation product of rhamnetin showed a reduction in COX-2 expression compared to the LPS-treated control. Together, these results highlight that flavonol-derived oxidation products not only retain significant antioxidant capacity but may also possess anti-inflammatory properties, opening new perspectives for the development of innovative therapies targeting oxidative stress and chronic inflammation.

Molecular dynamics simulations show that thiol-containing capping agents for silver nanoparticles, such as mercaptohexanol and lipoic acid, spontaneously assemble into dense aggregates at the silver–water interface.

The development of new compounds to treat Chagas disease is imperative due to the adverse effects of current drugs and their low efficacy in the chronic phase. This study aims to investigate nitroisoxazole derivatives that produce oxidative stress while modifying the compounds’ lipophilicity, affecting their ability to fight trypanosomes. The results indicate that these compounds are more effective against the epimastigote form of T. cruzi, with a 52 ± 4% trypanocidal effect for compound 9. However, they are less effective against the trypomastigote form, with a 15 ± 3% trypanocidal effect. Additionally, compound 11 interacts with a higher number of amino acid residues within the active site of the enzyme cruzipain. Furthermore, it was also found that the presence of a nitro group allows for the generation of free radicals; likewise, the large size of the compound enables increased interaction with aminoacidic residues in the active site of cruzipain, contributing to trypanocidal activity. This activity depends on the size and lipophilicity of the compounds. The study recommends exploring new compounds based on the nitroisoxazole skeleton, with larger substituents and lipophilicity to enhance their trypanocidal activity.

Chagas disease is a prevalent health problem in Latin America which has received insufficient attention worldwide. Current treatments for this disease, benznidazole and nifurtimox, have limited efficacy and may cause side effects. A recent study proposed investigating a wide range of nitroindazole and indazolone derivatives as feasible treatments. Therefore, it is proposed that adding a nitro group at the 5-position of the indazole and indazolone structure could enhance trypanocidal activity by inducing oxidative stress through activation of the nitro group by NTRs (nitroreductases). The study results indicate that the nitro group advances free radical production, as confirmed by several analyses. Compound 5a (5-nitro-2-picolyl-indazolin-3-one) shows the most favorable trypanocidal activity (1.1 ± 0.3 µM in epimastigotes and 5.4 ± 1.0 µM in trypomastigotes), with a selectivity index superior to nifurtimox. Analysis of the mechanism of action indicated that the nitro group at the 5-position of the indazole ring induces the generation of reactive oxygen species (ROS), which causes apoptosis in the parasites. Computational docking studies reveal how the compounds interact with critical residues of the NTR and FMNH₂ (flavin mononucleotide reduced) in the binding site, which is also present in active ligands. The lipophilicity of the studied series was shown to influence their activity, and the nitro group was found to play a crucial role in generating free radicals. Further investigations are needed of derivatives with comparable lipophilic characteristics and the location of the nitro group in different positions of the base structure.

Phosphatidylinositol 4,5-bisphosphate (PIP2) is recognized as an essential modulator of transient receptor potential (TRP) channels. Specifically, it influences the vanilloid receptor I (TRPV1), a pain receptor activated by a wide range of stimuli, including the binding of phospholipids, such as PIP2. The primary PIP2-binding site in TRPV1 has been identified through advanced techniques, revealing that the PIP2 binds to a specific pocket composed of positively charged residues located predominantly within the proximal C-terminus region. Additionally, a conserved segment with positively charged amino acids, K431 and R432, situated at the beginning of TRPV1’s S1 transmembrane domain, has attracted considerable attention from the TRP research community. To date, our knowledge of this site’s function and the subsequent effects following PIP2 binding is still emerging. In this work, MD simulations were conducted using coarse-grained models to investigate the binding dynamics of PIP2 on both WT and various mutated forms of TRPV1 channels. Our findings indicate that the K431A and R432A mutations significantly reduce the frequency of PIP2 contacts, suggesting that these mutated residues are part of a “peripheral binding pocket.” This pocket seems to play a crucial role in facilitating the entry of PIP2 to the TRPV1 channel’s primary binding site. Furthermore, our research has shown that these highly conserved residues within the TRPV subfamily are also structurally conserved across other TRP subfamilies, such as TRPM and TRPC, a detail not evident from sequence alignment alone. Consequently, we propose the existence of a structurally conserved peripheral PIP2-binding site shared among the diverse members of the TRP family, which can be categorized into distinct subfamilies.

Nanomaterials, specifically silver nanoparticles (AgNPs), have demonstrated great potential in biomedical applications due to their unique properties, such as antimicrobial activity and conductivity. One promising strategy to improve their biocompatibility and functional specificity is through the functionalization of AgNPs with peptides. By attaching peptides to the surface of AgNPs, their interaction with biological systems can be enhanced and tailored for specific applications. This computational study uses classical molecular dynamics and enhancement sampling techniques to investigate the interaction between AgNPs and RADA16-I peptides, as well as their derivative CLKRADA16-I. It utilizes classical molecular dynamics and enhanced sampling methods to gain insights into the structural information and details of their interaction. Furthermore, this study addresses the need for a better understanding of the interaction between composite materials made of nanoparticles and peptides. Our results demonstrate that the incorporation of the CLK motif significantly augments both structural stability and the binding affinity of peptides to silver nanoparticles. Through computational simulations, we observed that peptides modified with the CLK motif (CLKRADA16-I) exhibit a higher binding affinity toward a silver surface model, with the adsorption energy increasing by up to 4.2 kcal mol⁻¹ relative to unmodified peptides. This calculated interaction energy boosts adsorption and surface coverage, facilitating a packed and more effective peptide coating on the silver nanoparticles. These findings pave the way for the advancement of AgNPs as versatile agents in nanomedicine, particularly necessitating precise molecular recognition and robust bioactive scaffolding. Our study enhances the understanding of nanoparticle–peptide conjugates and their implications for designing next-generation nanomaterials.