Abstract Baccharis dracunculifolia DC. is a Brazilian native plant, presenting wide chemical diversity and numerous pharmaceutical and industrial applications. This research assessed the yield, antioxidant activity and the chemical similarity of essential oils from 10 populations of B. dracunculifolia in the state of Paraná, southern Brazil. The extraction of the volatile compounds was carried out by hydrodistillation, the chemical composition was determined by GC/FID and GC/MS and the antioxidant activity by the DPPH method. The essential oil yield of wild B. dracunculifolia populations ranged from 0.14 to 0.87%. The oils were predominantly composed of oxygenated sesquiterpenes (34.16 - 51.01%), monoterpene hydrocarbons (18.02 - 46.17%) and sesquiterpenes hydrocarbons (9.60 - 17.70%). The major compounds found in all populations were β-pinene (7.65 - 29.8%) and (E)-nerolidol (9.11 - 21.68%). Essential oil solutions (20%) from different populations presented antioxidant capacity ranging from 27.78 to 91.67%. A negative correlation was found between the antioxidant activity and spathulenol (r = -0.696).

Multivariate analyses separated the populations into three groups:

(1) low concentrations of α-pinene (2.02 - 2.06%), (2) high concentrations of α-pinene (4.17 - 4.61%) and β-pinene (22.54 - 29.80%), and (3) intermediate concentrations of α-pinene (2.38 - 3.31%), β-pinene (12.77 - 19.03%) and spathulenol (6.02 - 9.06%).