On the vasoprotective mechanisms underlying novel β-phosphorylated nitrones: Focus on free radical characterization, scavenging and NO-donation in a biological model of oxidative stress

Abstract

A series of new hybrid 2-(diethoxyphosphoryl)-N-(benzylidene)propan-2-amine oxide derivatives with different aromatic substitution (PPNs) were synthesized. These molecules were evaluated for their EPR spin trapping potential and NO donation properties in vitro, their cytotoxicity and on precontracted rat aortic rings. A subfamily of the new PPNs featured an antioxidant moiety occurring in natural phenolic acids. From the experimental screening of these hydroxyphenyl-and methoxyphenyl-substituted PPNs, biocompatible nitrones 4d, 4g−i deriving from caffeic, gallic, ferulic and sinapic acids, which combined improved EPR probing of ROS formation, vasorelaxant action and antioxidant potency, might be potential drug candidate alternatives to PBN and its analogues.

New Amino‐Acid‐Based β‐Phosphorylated Nitroxides for Probing Acidic pH in Biological Systems by EPR Spectroscopy

“…Cytotoxicity assays were performed for 10 b and selected α‐aminophosphonates esters to investigate their effects on cell viability and metabolic activity in vitro. IC 50 values against human normal fibroblasts (NHLF) and lung cancer (A549) cell‐lines were determined by measuring the release of intracellular lactate dehydrogenase (LDH) and by a fluorometric microculture cytotoxicity assay (FMCA) and an MTT assay after a 48 h incubation at 37 °C with test compound (0.1–50 m m ). The results are summarized in Table along with that of reference compounds and calculated lipophilicities.…”

“…Cell culture and exposure : Cell cultures were as described earlier . Briefly human alveolar epithelial A549 cells (ATCC CCL‐185; LGC Standards, Molsheim, France) were grown in DMEM containing FCS (10 %), penicillin (100 U mL −1 ), streptomycin (100 μg mL −1 ), and GlutaMax (2 m m ; Gibco) at 37 °C in a CO 2 (5 %) humidified atmosphere.…”

“…Total cellular LDH content was obtained by treating control wells with Triton X‐100 (1 % final) to induce 100 % LDH release. After removal of the incubation medium cells were washed twice with PBS 1X (+/+) (i.e., containing MgCl 2 and CaCl 2 ), and cytotoxicity was determined by using FMCA and MTT assays (Supporting Information).…”

NO and HNO donors, nitrones, and nitroxides: Past, present, and future

“…PBN derivatives 30a–d showed effective in vitro antioxidant properties (IC 50 DPPH = 19–254 μM; peroxyl radical trapping (TRAP) = 1.44–2.22 TE; IC 50 superoxide = 0.2–72.1 μM) and a favorable safety profile, outperforming PBN in in vitro studies of vascular tone control. The cytotoxicity of compounds 30a–d was also evaluated in A549 cells (IC 50 30a = 1.7 mM; 30b = 0.6 mM; 30c = 4.9 mM; 30d = 14.0 mM) and in bovine aortic endothelial cells (BAEC) (IC 10 30a = 0.5 mM; IC 10 30b = 0.2 mM; IC 10 30c = 0.7 mM; IC 10 30d = 2.6 mM), while PBN displayed IC 50 values of 10.6 and 2.4 mM, respectively …”

“…Moreover, derivatives 29a-b led to an increase of reduced GSH levels by 65% 156. Cassien et al developed a new series of 2-(diethoxyphosphoryl)-N-(benzylidene)propan-2-amine oxide PBN derivatives (compounds 30 a-d,Table 2) with different aromatic substitution patterns 157. PBN derivatives 30a-d showed effective in vitro antioxidant properties (IC 50 DPPH = 19-254 M; peroxyl radical trapping (TRAP) = 1.44-2.22 TE; IC 50 superoxide = 0.2-72.1 M) and a favorable safety profile, outperforming PBN in in vitro studies of vascular tone control.…”