Mapping and Chemical Diversity of Baccharis dracunculifolia De Candole (1836) Essential Oil Accessed in Rio de Janeiro, Brazil

Brazil is recognized for its rich biodiversity, including aromatic species of economic importance, among which <i>Baccharis dracunculifolia</i> De Candole (1836) stands out. The essential oil distilled from this species exhibits biological and therapeutic activities. Despite its relevance, studies addressing the chemodiversity of this species on a broad scale remain scarce. This study aimed to map and characterize the chemical and physicochemical profiles of <i>B. dracunculifolia</i> essential oils from different regions of the state of Rio de Janeiro, considering the influence of geographic factors and plant sex. Fifty georeferenced accessions of <i>B. dracunculifolia</i> were collected in 2023 and 2025, and dried leaves were subjected to hydrodistillation. The essential oils were characterized through physicochemical analyses and chemically analyzed by GC-FID and GC-MS. Essential oil yields ranged from 0.34 to 2.17%, relative density from 0.89 to 0.96 g/cm³, refractive index from 1.485 to 1.497 n^D, and specific optical rotation from -12.56° to +6.80°. Sixty-two compounds were identified, predominantly oxygenated sesquiterpenes, with <i>E</i>-nerolidol (16.8-51.0%), spathulenol, bicyclogermacrene, and germacrene D as the main compounds. Multivariate analysis revealed five chemical profiles, all containing <i>E</i>-nerolidol as the major compound, indicating moderate to low chemical diversity. No significant differences were observed between the essential oils from female and male plants. However, variation in the chemical profile of the essential oil was observed as a function of year and altitude.