Objective: This study aimed to establish quality standards for the aerial parts of the medicinal plant Iceland poppy (Papaver nudicaule L.). Methods: The anatomical structures of the aerial parts of plants were determined using microscopy. Bioactive compounds were identified and quantified using High-Performance Liquid Chromatography (HPLC). General quality parameters of the aerial parts of the Iceland poppy (Papaver nudicaule L.) were determined using the methods outlined in the European Pharmacopoeia. Results: The plant was collected from gravelly soil along the riverbank near the mouth of the Gorkhi-Terelj Valley in Erdene Soum, Tuv Province. The microstructure of the aerial parts of the Iceland poppy (Papaver nudicaule L.) was determined. The quality parameters of the aerial parts of Iceland poppy (Papaver nudicaule L.) were determined as follows: total ash content 5.54±0.2131%, moisture content 4.11±0.41%, and extractable substances with 70% ethanol were found to be highest at 27.61±0.43%. Additionally, the heavy metal and microbiological purity levels complied with the recommendations of the WHO and the requirements of the European Pharmacopoeia. Conclusion: The standardization criteria for the aerial parts of Papaver nudicaule L. were established. In addition, the pseudoprotopine alkaloid content in the aerial parts of Papaver nudicaule was found to be 0.0288 ± 0.0005%.

Papaver nudicaule L. is a medicinal plant traditionally used in Asian ethnomedicine, yet its phytochemical composition and biological activity remain insufficiently explored. This study bridges phytochemistry and neuroactive potential. It includes metabolite profiling with bioactivity-guided fractionation, performed to evaluate its potential as a source of acetylcholinesterase (AChE) inhibitors. The methanolic extract of the aerial parts was analysed using HPLC–ESI–QTOF-MS/MS, which enabled the tentative identification of 34 compounds, predominantly isoquinoline alkaloids and flavonoid derivatives. The extract was subsequently fractionated by centrifugal partition chromatography (CPC) using an optimised biphasic solvent system, yielding fractions enriched in alkaloid constituents. The obtained fractions were evaluated for AChE inhibitory activity, revealing significantly higher activity than that of the crude extract. The most active fractions exhibited marked inhibition based on the comparison with the reference compound berberine, indicating effective enrichment of bioactive metabolites. Further analysis demonstrated that the activity of the most potent fraction was associated with the presence of amurensinine, which was purified by preparative HPLC and subsequently identified by NMR and LC-MS. The Papaver nudicaule extract showed no significant cytotoxicity toward SH-SY5Y neuronal cells up to 200 µg/mL, whereas the amurensinine-containing fraction reduced cell viability only at higher concentrations (≥100 µg/mL). Notably, when expressed in the micromolar range, this effect corresponds to relatively weak cytotoxicity, suggesting a potential safety margin at lower, biologically relevant concentrations. These findings demonstrate that P. nudicaule possesses a highly diverse alkaloid profile and represents a promising natural source of compounds with potential relevance for the development of agents targeting neurodegenerative disorders.