Profiling the Variability of Eucalyptus Essential Oils with Activity against the Phylum Nematoda

Abstract

The genus Eucalyptus (Myrtaceae) comprises more than 800 species, mostly native to Australia. Eucalyptus shoots’ essential oils (EOs) are well-known for their extremely high qualitative and quantitative variation in terpenes (mainly mono- and sesquiterpenes). These EOs have a wide range of uses, from the taxonomic characterization of populations based on the chemical profiling of EO chemotypes, to industrial applications, including pharmaceutical and agrochemical and in food and fragrances. In this study, we reviewed the available information concerning the chemical variability of EOs from Eucalyptus spp. assayed against nematodes. Among the most active EOs, those from E. globulus, E. staigeriana, and E. citriodora were most frequently used. EO chemical composition was mainly dominated by 1,8-cineole, limonene, p-cymene, citronellal, and piperitone in varying proportions. Nematicidal activity of Eucalyptus EOs was reported against animal parasitic nematodes, including gastrointestinal nematodes (e.g., Haemonchus contortus), plant parasitic nematodes, such as root-knot nematodes (e.g., Meloidogyne incognita and M. chitwoodi) or the pinewood nematode Bursapelenchus xylophilus, and the free-living nematode Caenorhabditis elegans. Correlation between EO qualitative and quantitative composition with its respective activity may provide valuable information on the nematicidal specificity of EOs. This knowledge can be useful for devising environmentally safer pest management strategies in the conservation of ecosystems biodiversity.