Chemical Composition, Repellent, and Phytotoxic Potentials of the Fractionated Resin Essential Oil from Araucaria heterophylla Growing in Tunisia

Abstract

The resin essential oil (REO) of Araucaria heterophylla trunk bark was investigated for its chemical composition. Then, it was evaluated for its insecticidal and allelopathic activities. The REO was obtained by hydrodistillation for 9 h (yield of 4.2% w/w). Moreover, fractional hydrodistillation was carried out at 3‐hour intervals, resulting in 3 fractions (R1‐R3). GC/MS analysis of the obtained samples allowed the identification of 25 compounds, representing between 91.2 and 96.3% of their total constituents, which consisted predominantly of sesquiterpene hydrocarbons, oxygenated sesquiterpenes and diterpene hydrocarbons. α‐Copaene (1), γ‐muurolene (4), α‐copaen‐11‐ol (7), spathulenol (9), 15‐copaenol (10), ylangenal (21), dehydrosaussurea lactone (22), and sandaracopimaradiene (23) were identified as major compounds. The second part aimed to assess the impact of the A. heterophylla EO and its three fractions for their insecticidal and repellent activity against Tribolium castaneum (Herbst), of which a strong repellent activity was noted. In addition, the studied samples showed high phytotoxic effects against Lactuca sativa. The main compounds of the studied samples were docked into the active pocket of protoporphyrinogen IX oxidase (PDB: 1SEZ), a key enzyme in chlorophyll biosynthesis. Thus, it is recommended to use the REO of A. heterophylla as a natural herbicide.