Essential oil composition and antifungal activity of Heracleum platytaenium Boiss. (Endemic) fruits against soilborne pathogens

The growing resistance of soilborne fungal microorganisms to conventional antifungal compounds has led to increased interest in plant-derived antifungal agents. Heracleum platytaenium, an endemic Apiaceae species, remains underexplored despite its rich essential oil content. This two-year study aimed to characterize the essential oil composition of H. platytaenium fruits, and to evaluate its in vitro antifungal activity against five major soilborne pathogens: Fusarium solani, F. oxysporum, Rhizoctonia solani, Verticillium dahliae, and Pythium spp. Essential oils were extracted via hydrodistillation and characterized by GC-MS analysis. In the fruits of the H. platytaenium species, the essential oil content was determined to be 9.37 ± 0.06% in 2021 and 8.73 ± 0.32% in 2022. The major constituent identified was n-octyl acetate (84.51% in 2021; 90.1% in 2022), with esters dominating the profile. A factorial experiment was established using a completely randomized design, and the antifungal activity of H. platytaenium was tested at 0.025%, 0.05%, and 0.1% (v/v) concentrations against five major soilborne pathogens. The results showed that the strongest inhibition occurred at 0.1% concentration of H. platytaenium against R. solani (9.2 mm mycelial growth), while F. solani and F. oxysporum were the least sensitive. Results confirm the concentration-dependent antifungal efficacy of H. platytaenium essential oil and its potential as a natural biofungicide. The consistent chemical profile of H. platytaenium across the study years further supports its suitability for inclusion in standardized plant protection strategies.