Comparative Analysis of Essential Oil from the Leaves of Seven Species of the Genus <em>Eugenia</em> L. (Myrtaceae)

The genus Eugenia (Myrtaceae) is widely distributed in Brazil and is known for producing diverse secondary metabolites with various biological activities, although several species remain poorly explored. This study aimed to characterize the chemical composition of essential oils (EOs) from the leaves of seven Eugenia species (E. brasiliensis, E. involucrata, E. longipedunculata, E. myrcianthes, E. neoverrucosa, E. pyriformis, and E. uniflora), compare their chemical profiles using multivariate analysis, and evaluate their insecticidal activity against the flea Ctenocephalides felis felis. EOs were obtained from dried leaves by hydrodistillation using a Clevenger apparatus and analyzed by gas chromatography–mass spectrometry (GC–MS). Principal component analysis (PCA) was applied to compare chemical compositions, and contact bioassays were conducted to assess insecticidal activity against adult fleas. The EOs showed distinct chemical compositions, with major constituents including α-pinene, (E)-caryophyllene, viridiflorene, β-selinene, limonene, and germacrone, depending on the species. PCA revealed clear differences among species, particularly highlighting oils dominated by α-pinene and sesquiterpene-derived compounds. In the bioassays, E. uniflora showed the highest insecticidal activity, reaching 95.1% mortality at 800 µg·cm⁻² and presenting an LC₅₀ of 9.12 µg·cm⁻², whereas E. brasiliensis showed moderate activity (LC₅₀ = 157.82 µg·cm⁻²). These findings expand the chemical knowledge of the genus and indicate the potential of E. uniflora EO as a natural source of compounds with insecticidal activity against C. felis felis.