Comparative essential oil profiling and pathway mapping of Juniperus communis and Juniperus sabina

This study provides a comparative characterization of the essential oil profiles and database-supported pathway mapping of Juniperus communis and Juniperus sabina collected from the Salouk region of North Khorasan, Iran. Essential oils were extracted by hydrodistillation, analyzed using GC-MS, statistically compared between species, and interpreted through multivariate analysis and pathway mapping based on KEGG, UniProt, MetaCyc, and supporting literature. Essential oil yield was markedly higher in J. sabina than in J. communis (1.70 and 0.54 g per 100 g dried material, respectively). A total of 63 volatile compounds were identified, with significant interspecific differences for most evaluated metabolites. J. communis was mainly characterized by higher relative abundances of trans-pinene (15.00%), α-phellandrene (14.97%), α-pinene (11.28%), terpinolene (6.66%), and trans-sabinene acetate (5.02%). In contrast, J. sabina showed higher levels of sabinene (12.78%), camphene (10.12%), terpinolene (8.04%), α-terpinene (6.78%), 3-octanol (4.75%), δ-terpinyl acetate (3.83%), and linalool (3.38%). PCA revealed a clear separation between the two species, with the first two dimensions explaining 99.94% of the total variance, indicating that species differentiation was driven by coordinated changes across multiple volatile constituents. Pathway mapping assigned 49 of the 63 detected compounds, approximately 77.78%, to GPP-related routes, highlighting the predominance of monoterpene-derived compounds in both essential oils. Additional metabolites were associated with PEP-, shikimate/phenylalanine-, acetyl-CoA-, valine-, and FPP-related routes, providing a broader biochemical organization of the detected compounds. Overall, the results demonstrate strong chemical differentiation between J. communis and J. sabina and identify dominant and species-associated volatile metabolites that may serve as candidate markers for phytochemical characterization, essential oil quality assessment, chemotaxonomic comparison, and future bioactivity-focused studies.