Non-targeted metabolomic profiling of Cistus species and association with anticholinesterase efficacy for Alzheimer's disease: In vitro and in silico evaluation

Ethnopharmacological relevance: Alzheimer's disease (AD) is characterized by decreased glucose utilization, and insulin therapy has been associated with improved memory. Therefore, AD is suggested to be classified as "Type 3 diabetes". Cistus L. species are traditionally used to treat diabetes, which is highly associated with AD, and the potential of this genus for treating AD has not been sufficiently investigated. Aim: This study focused on the untargeted metabolomic profiling of methanolic extracts from five Cistus species to investigate the correlation between the metabolites and bioactivity. Materials and methods: Gas chromatography-mass spectrometry and liquid chromatography quadrupole time-offlight mass spectrometry were employed for metabolomics analysis. The inhibitory activity of the extracts on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), as well as their antioxidant capacity, were assessed. Additionally, molecular modeling techniques were utilized to corroborate the correlation between the metabolites and their cholinesterase inhibitory potency. Results: The plant extracts demonstrated inhibitory effects on BChE with IC50 values ranging from 1.80 to 9.83 mu g/mL, which were notably lower than those observed for AChE. Correlation analysis revealed that chlorogenic acid demonstrated strong correlations with AChE inhibitory activity, while sinapyl alcohol was closely associated with BChE inhibitory activity. Additionally, molecular modeling studies supported the inhibitory potential of these metabolites. Conclusion: This study highlights the substantial cholinesterase inhibitory capabilities of Cistus species, with C. creticus demonstrating particularly strong activity against both AChE and BChE. The results indicate that extracts from these species could be valuable natural sources of active metabolites with potent cholinesterase inhibitory effects, presenting promising new options for AD therapy.