Integrated experimental and computational study of novel pyrrole derivatives: Microwave-assisted synthesis, enzyme inhibition, antioxidant properties, and neurotoxicity evaluation

Pyrrole derivatives are promising bioactive compounds known for their antioxidant, anti-inflammatory and neuroprotective properties, making them potential candidates for therapeutic development in neurodegenerative diseases. The objective was to synthesize and characterize em_pyr_1 and em_pyr_2, evaluate their radical scavenging activities, enzyme inhibitory effects against MAO-A, MAO-B, AChE, and BChE, assess their neurotoxicity and neuroprotective properties, and examine their molecular interactions through computational studies. The compounds were synthesized via conventional and microwave-assisted Paal–Knorr condensation and characterized by 1 H-NMR, 13 C-NMR, LC–MS, and IR spectroscopy. Antioxidant activities were assessed using DPPH and ABTS assays. Enzyme inhibition was evaluated in vitro . Neurotoxicity was studied in rat brain synaptosomes, mitochondria, and microsomes. Neuroprotection was examined with a 6-hydroxydopamine (6-OHDA) neurotoxicity model and oxidative stress induced by Fe 2+ /ascorbic acid. Molecular docking, molecular dynamics simulations, density functional theory calculations, and in silico toxicity predictions were employed to evaluate binding, stability and safety. Em_pyr_2 showed no DPPH scavenging but significant ABTS scavenging activity (IC 50 = 94.57 ± 1.84 µM) and potent selective MAO-B inhibition (IC 50 = 0.566 ± 0.10 µM). It exhibited low neurotoxicity and preserved glutathione levels (80 % of control) in the 6-OHDA model, reducing malondialdehyde by 38 %. Molecular modeling indicated favorable binding and structural stability, with no toxicity alerts. Em_pyr_2 demonstrates promising antioxidant, selective MAO-B inhibitory, and neuroprotective effects with low neurotoxicity, supporting its potential for further optimization in neurodegenerative disease therapy.