Mechanistic insights into the neuroprotective effects of monoterpene-rich Eucalyptus citriodora essential oil: integrated in silico and in vitro analysis in 6-OHDA-treated N2a neuronal cells.
Mechanistic insights into the neuroprotective effects of monoterpene-rich Eucalyptus citriodora essential oil: integrated in silico and in vitro analysis in 6-OHDA-treated N2a neuronal cells.
Where did the research take place?
The study site has not been established. Author addresses may differ from where the research occurred.
Tunis, TN · Author affiliation
Laboratory of Neurophysiology, Cellular Physiopathology, and Biomolecules Valorization LR18ES03, Faculty of Sciences of Tunis, University Tunis El Manar, Tunisia.Location evidence
Siena, IT · Author affiliation
Functional Proteomics Lab, Department of Life Sciences, University of Siena, 53100, Siena, Italy.Location evidence
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Original abstract
Parkinson's disease (PD) is characterized by progressive dopaminergic neuronal loss driven by mitochondrial dysfunction, oxidative stress, and proteostasis collapse, for which current therapies remain symptomatic. This study investigated the neuroprotective effects of Eucalyptus citriodora essential oil (ECEO) on 6-hydroxydopamine (6-OHDA)-induced toxicity in N2a neuroblastoma cells. GC-MS analysis showed that ECEO was dominated by oxygenated monoterpenes, mainly citronellal (60.7%), isopulegol (16%), and citronellol (5.7%). In silico analysis of these constituents showed favorable ADMET profiles, predicted blood-brain barrier permeability, and non-overlapping multitarget engagement across enzymes, GPCRs and nuclear receptors. At the cellular level, ECEO pretreatment significantly restored cell viability (86.7% of control), reduced LDH release, attenuated ROS and NO, and limited mitochondrial depolarization. Quantitative 2D-gel/MALDI-TOF/TOF proteomics identified 94 differentially abundant proteins, of which 20 showed validated PD-related associations (KEGG, Gene4PD, and DisGeNET databases). ECEO pretreatment modulated 12 of these proteins across mechanistically coherent pathways: (i) reversal of 6-OHDA-induced reprogramming of energy metabolism, by normalizing the glycolytic enzymes PKM and PGK1 and restoring the TCA enzyme SUCLG2; (ii) reinforcement of proteostasis through PSMB4 and PSMA3 induction, VCP upregulation and attenuation of ER stress marker HSPA5/BiP; (iii) preservation of mitochondrial and cytoskeletal integrity through PHB1 induction and bilateral TUBB5 restoration. Overall, our results suggest that ECEO exerts significant neuroprotective effects in a cellular PD model by coordinately modulating energy metabolism, proteostasis, antioxidant defense, and structural integrity. Given its predominance in oxygenated monoterpenes the neuroprotective activity of ECEO may result from the combined contribution of the major constituents supporting further investigation in age-related neurodegeneration.