Soybean trypsin inhibitor (STI) is a plant defense protein with established activity against insect digestive proteases. In the present study, a recombinant STI-penetratin fusion protein (rSTIP) was developed to evaluate its insecticidal activity following oral and topical exposure. The codon-optimized rSTIP construct was cloned into pET-28a(+) and expressed in E. coli BL21(DE3). The recombinant protein was predominantly recovered as inclusion bodies and subsequently solubilized, refolded, and purified using Ni-NTA affinity chromatography. Two refolding strategies were evaluated: on-column refolding and glutathione-assisted dialysis. Glutathione-assisted refolding followed by dialysis resulted in the highest recovery of trypsin inhibitory activity (65.5%). LC-MS/MS analysis provided sequence-level confirmation of the STI component. In Drosophila melanogaster larvae, rSTIP exhibited stronger insecticidal activity than the native STI following both oral and topical exposure, with topical application resulting in complete larval mortality within 36 h. Although direct protein penetration or cellular uptake was not evaluated in this investigation, the increased insecticidal activity of STI after conjugation with penetratin suggests improved delivery as a possible mechanism. In the present study, a recombinant STI-penetratin (rSTIP) fusion protein was developed to investigate whether fusion with penetratin could alter the insecticidal activity of STI.

Alzheimer’s disease (AD) is a complex neurodegenerative disorder with limited effective therapies. In this study, a series of 2-(arylamino)thiazol-4(5H)-one derivatives was synthesized using an efficient microwave-assisted protocol, and evaluated for neuroprotective effects against 6-hydroxydopamine (6-OHDA)-induced oxidative stress (OS) in SH-SY5Y neuronal cells and an Aβ42-expressing Drosophila melanogaster model of AD. Among the synthesized compounds, 3n, 3i, and 3b exhibited low cytotoxicity and significant neuroprotection, as evidenced by increased cell viability, reduced reactive oxygen species (ROS) production, and preserved mitochondrial membrane potential. Notably, compound 3n demonstrated the highest activity and effectively ameliorated Aβ42-induced behavioral deficits in vivo. Molecular docking studies predicted favorable binding affinity within the acetylcholinesterase (AChE) active site, with the thiazol scaffold and aryl substituents stabilizing ligand binding through π–π stacking and hydrophobic interactions; compound 3n also formed additional hydrogen bonds enhancing its affinity. Consistent with the docking predictions, in vitro AChE inhibition studies demonstrated that compounds 3n, 3i, and 3b inhibited AChE in a concentration-dependent manner. Network pharmacology predicted seven potential core targets implicated in AD pathogenesis and related pathways, including OS, neuroinflammation, and synaptic dysfunction. Furthermore, in silico pharmacokinetic analysis indicated compliance with Lipinski’s and Veber’s rules, supporting favorable drug-like properties. While further experimental validation is essential, these findings highlight 2-(arylamino)thiazol-4(5H)-one derivatives, particularly compound 3n, as promising multifunctional candidates for further preclinical development against AD.