Multidimensional exploration of essential oils generated via six coniferous tree species: Chemodiversities, antioxidant and antibacterial capacities

Conifer needle essential oils hold promising potential for industrial development; however, their chemical diversity and bioactivity remain largely unexplored. This study evaluated the essential oils from six conifer species — Pinus koraiensis , Pinus tabuliformis , Pinus banksiana , Abies holophylla , Thuja sutchuenensis , and Pinus sylvestris — for their chemical composition, antioxidant activity, antibacterial activity, and potential mechanisms of action. The results indicated that T. sutchuenensis exhibited a significantly higher essential oil yield (2.36 ± 0.06%) compared to the other species. A total of 108 volatile organic compounds were tentatively identified, with their compositions varying considerably among the species. Sesquiterpene hydrocarbons and oxygenated monoterpenes were the two most diverse chemical classes identified in the CNEOs, while β-caryophyllene, bornyl acetate, viridiflorol, elemol, and (-)-α-thujone were the primary differential compounds. PCA and OPLS-DA analyses revealed distinct interspecies differences, identifying β-caryophyllene, viridiflorol, and bornyl acetate as key discriminant compounds. The essential oil from P. banksiana demonstrated the highest antioxidant activity, whereas the oil from T. sutchuenensis displayed the most antibacterial activity. Correlation analysis suggested that β-cadinene and germacrene D were strongly correlated with antioxidant activity, while elemol and (-)-α-thujone were closely associated with antibacterial activity. Network pharmacology and molecular docking analyses provided insights into the potential mechanisms of action at the target and pathway levels. The antioxidant effect may be attributed to interactions with targets such as ESR1, CYP19A1, CYP17A1, and PPARA, while the antibacterial effect appears to involve interference with bacterial DNA replication, transcription, and damage repair. In conclusion, the essential oils of T. sutchuenensis and P. banksiana demonstrated distinct bioactivity profiles, suggesting their respective potential for application in the development of natural antibacterial and antioxidant bio-based materials, respectively. These findings provide a scientific basis for the resource utilization of conifer needle biomass.