Phytopathogenic fungi that affect postharvest are a serious problem for agriculture, so this research explores the antifungal potential of three different “rosemary” species growing in Chile through in vitro and in silico assays. The analysis of essential oils (GC/MS) reveals the dominant constituents of Salvia rosmarinus (camphor: 66.96%), Baccharis linearis (lachnophyllum ester: 88.62%) and Fabiana imbricata (an oxygenated sesquiterpene: 43.66%) and shows profiles that differ from chemotypes of the same species from other areas of the world. B. linearis oil was shown to be a versatile antifungal substance, inhibiting Botrytis cinerea and Monilinia fructicola at moderate concentrations; F. imbricata oil stood out as a major inhibitor of mycelial growth of the same isolate of M. fructicola used to test B. linearis oil (EC₅₀ of 15.86 + 0.67 µg/mL) and completely inhibited of its conidial germination. In silico assays confirmed the complexity of interactions of F. imbricata sequiterpenoids with catalytic sites of succinate dehydrogenase and catalase 2, key enzymes in mycelial growth and in maintaining redox homeostasis in the early development of M. fructicola, respectively. The results of this research make F. imbricata a good candidate for the development of a formulation applicable in vivo as an eco-friendly post-harvest antifungal agent.

The aim of this study was to investigate the chemical composition and antifungal activity of the essential oil extracted from leaves of Peumus boldusof the coastal drylands of Chile. The essential oil was characterized by gas chromatography-mass spectrometry. The antifungal activity was evaluated by a microdilution assay against five strains of Candidaof clinical importance. P. boldusessential oil had a yield of 0.32% and nineteen compounds were identified in the analysis, mostly ascaridol (49.95%), o-cymene (13.45%) and eucalyptol (9.71%). All yeast strains tested were sensitive to P. boldusessential oil, with C. guillermondibeing the most sensitive, with a minimum inhibitory concentration (MIC) value of 8 μg/mL, twice lower than the MIC value of 16 μg/mL exhibited by fluconazole and itraconazole. These results suggest that P. boldusessential oil could be used as natural antifungal agents in free form or in a formulation against pathogenic yeasts.